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Our Neil Gehrels Swift Observatory — Swift for short — is celebrating its 20th anniversary! The satellite studies cosmic objects and events using visible, ultraviolet, X-ray, and gamma-ray light. Swift plays a key role in our efforts to observe our ever-changing universe. Here are a few cosmic surprises Swift has caught over the years — plus one scientists hope to see.
Swift was designed to detect and study gamma-ray bursts, the most powerful explosions in the universe. These bursts occur all over the sky without warning, with about one a day detected on average. They also usually last less than a minute – sometimes less than a few seconds – so you need a telescope like Swift that can quickly spot and precisely locate these new events.
In the fall of 2022, for example, Swift helped study a gamma-ray burst nicknamed the BOAT, or brightest of all time. The image above depicts X-rays Swift detected for 12 days after the initial flash. Dust in our galaxy scattered the X-ray light back to us, creating an extraordinary set of expanding rings.
Tidal disruptions happen when an unlucky star strays too close to a black hole. Gravitational forces break the star apart into a stream of gas, as seen above. Some of the gas escapes, but some swings back around the black hole and creates a disk of debris that orbits around it.
These events are rare. They only occur once every 10,000 to 100,000 years in a galaxy the size of our Milky Way. Astronomers can’t predict when or where they’ll pop up, but Swift’s quick reflexes have helped it observe several tidal disruption events in other galaxies over its 20-year career.
Usually, we think of galaxies – and most other things in the universe – as changing so slowly that we can’t see the changes. But about 10% of the universe’s galaxies are active, which means their black hole-powered centers are very bright and have a lot going on. They can produce high-speed particle jets or flares of light. Sometimes scientists can catch and watch these real-time changes.
For example, for several years starting in 2018, Swift and other telescopes observed changes in a galaxy’s X-ray and ultraviolet light that led them to think the galaxy’s magnetic field had flipped 180 degrees.
Magnetars are a type of neutron star, a very dense leftover of a massive star that exploded in a supernova. Magnetars have the strongest magnetic fields we know of — up to 10 trillion times more intense than a refrigerator magnet and a thousand times stronger than a typical neutron star’s.
Occasionally, magnetars experience outbursts related to sudden changes in their magnetic fields that can last for months or even years. Swift detected such an outburst from a magnetar in 2020. The satellite’s X-ray observations helped scientists determine that the city-sized object was rotating once every 10.4 seconds.
Swift has also studied comets in our own solar system. Comets are town-sized snowballs of frozen gases, rock, and dust. When one gets close to our Sun, it heats up and spews dust and gases into a giant glowing halo.
In 2019, Swift watched a comet called 2I/Borisov. Using ultraviolet light, scientists calculated that Borisov lost enough water to fill 92 Olympic-size swimming pools! (Another interesting fact about Borisov: Astronomers think it came from outside our solar system.)
Swift has studied a lot of cool events and objects over its two decades, but there are still a few events scientists are hoping it’ll see.
Swift is an important part of a new era of astrophysics called multimessenger astronomy, which is where scientists use light, particles, and space-time ripples called gravitational waves to study different aspects of cosmic events.
In 2017, Swift and other observatories detected light and gravitational waves from the same event, a gamma-ray burst, for the first time. But what astronomers really want is to detect all three messengers from the same event.
As Swift enters its 20th year, it’ll keep watching the ever-changing sky.
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Love is in the air, and it’s out in space too! The universe is full of amazing chemistry, cosmic couples held together by gravitational attraction, and stars pulsing like beating hearts.
Celestial objects send out messages we can detect if we know how to listen for them. Our upcoming Nancy Grace Roman Space Telescope will help us scour the skies for all kinds of star-crossed signals.
Communication is key for any relationship – including our relationship with space. Different telescopes are tuned to pick up different messages from across the universe, and combining them helps us learn even more. Roman is designed to see some visible light – the type of light our eyes can see, featured in the photo above from a ground-based telescope – in addition to longer wavelengths, called infrared. That will help us peer through clouds of dust and across immense stretches of space.
Other telescopes can see different types of light, and some detectors can even help us study cosmic rays, ghostly neutrinos, and ripples in space called gravitational waves.
This visible and near-infrared image from the Hubble Space Telescope captures two hearts locked in a cosmic embrace. Known as the Antennae Galaxies, this pair’s love burns bright. The two spiral galaxies are merging together, igniting the birth of brand new baby stars.
Stellar nurseries are often very dusty places, which can make it hard to tell what’s going on. But since Roman can peer through dust, it will help us see stars in their infancy. And Roman’s large view of space coupled with its sharp, deep imaging will help us study how galaxy mergers have evolved since the early universe.
Those stars are destined to create new chemistry, forging elements and scattering them into space as they live, die, and merge together. Roman will help us understand the cosmic era when stars first began forming. The mission will help scientists learn more about how elements were created and distributed throughout galaxies.
Did you know that U and I (uranium and iodine) were both made from merging neutron stars? Speaking of which…
When two neutron stars come together in a marriage of sorts, it creates some spectacular fireworks! While they start out as stellar sweethearts, these and some other types of cosmic couples are fated for devastating breakups.
When a white dwarf – the leftover core from a Sun-like star that ran out of fuel – steals material from its companion, it can throw everything off balance and lead to a cataclysmic explosion. Studying these outbursts, called type Ia supernovae, led to the discovery that the expansion of the universe is speeding up. Roman will scan the skies for these exploding stars to help us figure out what’s causing the expansion to accelerate – a mystery known as dark energy.
Plenty of things in our galaxy are single, including hundreds of millions of stellar-mass black holes and trillions of “rogue” planets. These objects are effectively invisible – dark objects lost in the inky void of space – but Roman will see them thanks to wrinkles in space-time.
Anything with mass warps the fabric of space-time. So when an intervening object nearly aligns with a background star from our vantage point, light from the star curves as it travels through the warped space-time around the nearer object. The object acts like a natural lens, focusing and amplifying the background star’s light.
Thanks to this observational effect, which makes stars appear to temporarily pulse brighter, Roman will reveal all kinds of things we’d never be able to see otherwise.
Roman is nearly ready to set its sights on so many celestial spectacles. Follow along with the mission’s build progress in this interactive virtual tour of the observatory, and check out these space-themed Valentine’s Day cards.
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In honor of the completion of our Nancy Grace Roman Space Telescope’s spacecraft — the vehicle that will maneuver the observatory to its place in space and enable it to function once there — we’re bringing you a space craft you can complete at home! Join us for a journey across the cosmos, starting right in your own pantry.
Ingredients:
1 5 oz. bottle clear glue
½ tablespoon baking soda
Food coloring
1 tablespoon contact lens solution
1 tablespoon glitter
Directions:
Pour the glue into a bowl.
Mix in the baking soda.
Add food coloring (we recommend blue, purple, black, or a combination).
Add contact lens solution and use your hands to work it through the slime. It will initially be very sticky! You can add a little extra contact lens solution to make it firmer and less goopy.
Add glitter a teaspoon at a time, using as much or as little as you like!
Did you know that most of your household ingredients are made of stardust? And so are you! Nearly every naturally occurring element was forged by living or dying stars.
Take the baking soda in this slime recipe, for example. It’s made up of sodium, hydrogen, carbon, and oxygen. The hydrogen was made during the big bang, right at the start of the universe. But the other three elements were created by dying stars. So when you show your friends your space-y slime, you can tell them it’s literally made of stardust!
Still feeling crafty? Try your hand at more pantry projects or these 3D and paper spacecraft models. If you’re eager for a more advanced space craft, check out these embroidery creations for inspiration! Or if you’re ready for a break, take a virtual tour of an interactive version of the Roman Space Telescope here.
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We often think of space as “cold,” but its temperature can vary enormously depending on where you visit. If the difference between summer and winter on Earth feels extreme, imagine the range of temperatures between the coldest and hottest places in the universe — it’s trillions of degrees! So let’s take a tour of cosmic temperatures … from the coldest spots to the hottest temperatures yet achieved.
First, a little vocabulary: Astronomers use the Kelvin temperature scale, which is represented by the symbol K. Going up by 1 K is the same as going up 1°C, but the scale begins at 0 K, or -273°C, which is also called absolute zero. This is the temperature where the atoms in stuff stop moving. We’ll measure our temperatures in this tour in kelvins, but also convert them to make them more familiar!
We’ll start on the chilly end of the scale with our CAL (Cold Atom Lab) on the International Space Station, which can chill atoms to within one ten billionth of a degree above 0 K, just a fraction above absolute zero.
Credit: NASA's Goddard Space Flight Center/Scott Wiessinger
Just slightly warmer is the Resolve sensor inside XRISM, pronounced “crism,” short for the X-ray Imaging and Spectroscopy Mission. This is an international collaboration led by JAXA (Japan Aerospace Exploration Agency) with NASA and ESA (European Space Agency). Resolve operates at one twentieth of a degree above 0 K. Why? To measure the heat from individual X-rays striking its 36 pixels!
Credit: NASA's Goddard Space Flight Center/Scott Wiessinger
Resolve and CAL are both colder than the Boomerang Nebula, the coldest known region in the cosmos at just 1 K! This cloud of dust and gas left over from a Sun-like star is about 5,000 light-years from Earth. Scientists are studying why it’s colder than the natural background temperature of deep space.
Credit: NASA's Goddard Space Flight Center/Scott Wiessinger
Let’s talk about some temperatures closer to home. Icy gas giant Neptune is the coldest major planet. It has an average temperature of 72 K at the height in its atmosphere where the pressure is equivalent to sea level on Earth. Explore how that compares to other objects in our solar system!
Credit: NASA's Goddard Space Flight Center/Scott Wiessinger
How about Earth? According to NOAA, Death Valley set the world’s surface air temperature record on July 10, 1913. This record of 330 K has yet to be broken — but recent heat waves have come close. (If you’re curious about the coldest temperature measured on Earth, that’d be 183.95 K (-128.6°F or -89.2°C) at Vostok Station, Antarctica, on July 21, 1983.)
We monitor Earth's global average temperature to understand how our planet is changing due to human activities. Last year, 2023, was the warmest year on our record, which stretches back to 1880.
Credit: NASA's Goddard Space Flight Center/Scott Wiessinger
The inside of our planet is even hotter. Earth’s inner core is a solid sphere made of iron and nickel that’s about 759 miles (1,221 kilometers) in radius. It reaches temperatures up to 5,600 K.
Credit: NASA's Goddard Space Flight Center/Scott Wiessinger
We might assume stars would be much hotter than our planet, but the surface of Rigel is only about twice the temperature of Earth’s core at 11,000 K. Rigel is a young, blue star in the constellation Orion, and one of the brightest stars in our night sky.
Credit: NASA's Goddard Space Flight Center/Scott Wiessinger
We study temperatures on large and small scales. The electrons in hydrogen, the most abundant element in the universe, can be stripped away from their atoms in a process called ionization at a temperature around 158,000 K. When these electrons join back up with ionized atoms, light is produced. Ionization is what makes some clouds of gas and dust, like the Orion Nebula, glow.
Credit: NASA's Goddard Space Flight Center/Scott Wiessinger
We already talked about the temperature on a star’s surface, but the material surrounding a star gets much, much hotter! Our Sun’s surface is about 5,800 K (10,000°F or 5,500°C), but the outermost layer of the solar atmosphere, called the corona, can reach millions of kelvins.
Our Parker Solar Probe became the first spacecraft to fly through the corona in 2021, helping us answer questions like why it is so much hotter than the Sun's surface. This is one of the mysteries of the Sun that solar scientists have been trying to figure out for years.
Credit: NASA's Goddard Space Flight Center/Scott Wiessinger
Looking for a hotter spot? Located about 240 million light-years away, the Perseus galaxy cluster contains thousands of galaxies. It’s surrounded by a vast cloud of gas heated up to tens of millions of kelvins that glows in X-ray light. Our telescopes found a giant wave rolling through this cluster’s hot gas, likely due to a smaller cluster grazing it billions of years ago.
Credit: NASA's Goddard Space Flight Center/Scott Wiessinger
Now things are really starting to heat up! When massive stars — ones with eight times the mass of our Sun or more — run out of fuel, they put on a show. On their way to becoming black holes or neutron stars, these stars will shed their outer layers in a supernova explosion. These layers can reach temperatures of 300 million K!
Credit: NASA's Goddard Space Flight Center/Jeremy Schnittman
We couldn’t explore cosmic temperatures without talking about black holes. When stuff gets too close to a black hole, it can become part of a hot, orbiting debris disk with a conical corona swirling above it. As the material churns, it heats up and emits light, making it glow. This hot environment, which can reach temperatures of a billion kelvins, helps us find and study black holes even though they don’t emit light themselves.
JAXA’s XRISM telescope, which we mentioned at the start of our tour, uses its supercool Resolve detector to explore the scorching conditions around these intriguing, extreme objects.
Credit: NASA's Goddard Space Flight Center/CI Lab
Our universe’s origins are even hotter. Just one second after the big bang, our tiny, baby universe consisted of an extremely hot — around 10 billion K — “soup” of light and particles. It had to cool for a few minutes before the first elements could form. The oldest light we can see, the cosmic microwave background, is from about 380,000 years after the big bang, and shows us the heat left over from these earlier moments.
Credit: NASA's Goddard Space Flight Center/Scott Wiessinger
We’ve ventured far in distance and time … but the final spot on our temperature adventure is back on Earth! Scientists use the Large Hadron Collider at CERN to smash teensy particles together at superspeeds to simulate the conditions of the early universe. In 2012, they generated a plasma that was over 5 trillion K, setting a world record for the highest human-made temperature.
Want this tour as a poster? You can download it here in a vertical or horizontal version!
Credit: NASA's Goddard Space Flight Center/Scott Wiessinger
Explore the wonderful and weird cosmos with NASA Universe on X, Facebook, and Instagram. And make sure to follow us on Tumblr for your regular dose of space!
Illustration of the Chandra telescope in orbit around Earth. Credit: NASA/CXC & J. Vaughan
On July 23, 1999, the space shuttle Columbia launched into orbit carrying NASA’s Chandra X-ray Observatory. August 26 marked 25 years since Chandra released its first images.
These were the first of more than 25,000 observations Chandra has taken. This year, as NASA celebrates the 25th anniversary of this telescope and the incredible data it has provided, we’re taking a peek at some of its most memorable moments.
About the Spacecraft
The Chandra telescope system uses four specialized mirrors to observe X-ray emissions across the universe. X-rays that strike a “regular” mirror head on will be absorbed, so Chandra’s mirrors are shaped like barrels and precisely constructed. The rest of the spacecraft system provides the support structure and environment necessary for the telescope and the science instruments to work as an observatory. To provide motion to the observatory, Chandra has two different sets of thrusters. To control the temperatures of critical components, Chandra's thermal control system consists of a cooling radiator, insulators, heaters, and thermostats. Chandra's electrical power comes from its solar arrays.
Learn more about the spacecraft's components that were developed and tested at NASA’s Marshall Space Flight Center in Huntsville, Alabama. Fun fact: If the state of Colorado were as smooth as the surface of the Chandra X-ray Observatory mirrors, Pike's Peak would be less than an inch tall.
Engineers in the X-ray Calibration Facility at NASA’s Marshall Space Flight Center in Huntsville, Alabama, integrating the Chandra X-ray Observatory’s High-Resolution Camera with the mirror assembly, in this photo taken March 16, 1997. Credit: NASA
Launch
When space shuttle Columbia launched on July 23, 1999, Chandra was the heaviest and largest payload ever launched by the shuttle. Under the command of Col. Eileen Collins, Columbia lifted off the launch pad at NASA’s Kennedy Space Center in Florida. Chandra was deployed on the mission’s first day.
Reflected in the waters, space shuttle Columbia rockets into the night sky from Launch Pad 39-B on mission STS-93 from Kennedy Space Center. Credit: NASA
First Light Images
Just 34 days after launch, extraordinary first images from our Chandra X-ray Observatory were released. The image of supernova remnant Cassiopeia A traces the aftermath of a gigantic stellar explosion in such captivating detail that scientists can see evidence of what is likely the neutron star.
“We see the collision of the debris from the exploded star with the matter around it, we see shock waves rushing into interstellar space at millions of miles per hour,” said Harvey Tananbaum, founding Director of the Chandra X-ray Center at the Smithsonian Astrophysical Observatory.
Cassiopeia A is the remnant of a star that exploded about 300 years ago. The X-ray image shows an expanding shell of hot gas produced by the explosion colored in bright orange and yellows. Credit: NASA/CXC/SAO
A New Look at the Universe
NASA released 25 never-before-seen views to celebrate the telescopes 25th anniversary. This collection contains different types of objects in space and includes a new look at Cassiopeia A. Here the supernova remnant is seen with a quarter-century worth of Chandra observations (blue) plus recent views from NASA’s James Webb Space Telescope (grey and gold).
This image features deep data of the Cassiopeia A supernova, an expanding ball of matter and energy ejected from an exploding star in blues, greys and golds. The Cassiopeia A supernova remnant has been observed for over 2 million seconds since the start of Chandra’s mission in 1999 and has also recently been viewed by the James Webb Space Telescope. Credit: NASA/CXC/SAO
Can You Hear Me Now?
In 2020, experts at the Chandra X-ray Center/Smithsonian Astrophysical Observatory (SAO) and SYSTEM Sounds began the first ongoing, sustained effort at NASA to “sonify” (turn into sound) astronomical data. Data from NASA observatories such as Chandra, the Hubble Space Telescope, and the James Webb Space Telescope, has been translated into frequencies that can be heard by the human ear.
SAO Research shows that sonifications help many types of learners – especially those who are low-vision or blind -- engage with and enjoy astronomical data more.
Click to watch the “Listen to the Universe” documentary on NASA+ that explores our sonification work: Listen to the Universe | NASA+
An image of the striking croissant-shaped planetary nebula called the Cat’s Eye, with data from the Chandra X-ray Observatory and Hubble Space Telescope. NASA’s Data sonification from Chandra, Hubble and/or Webb telecopes allows us to hear data of cosmic objects. Credit: NASA/CXO/SAO
Celebrate With Us!
Dedicated teams of engineers, designers, test technicians, and analysts at Marshall Space Flight Center in Huntsville, Alabama, are celebrating with partners at the Chandra X-ray Center and elsewhere outside and across the agency for the 25th anniversary of the Chandra X-ray Observatory. Their hard work keeps the spacecraft flying, enabling Chandra’s ongoing studies of black holes, supernovae, dark matter, and more.
Chandra will continue its mission to deepen our understanding of the origin and evolution of the cosmos, helping all of us explore the Universe.
The Chandra Xray Observatory, the longest cargo ever carried to space aboard the space shuttle, is shown in Columbia’s payload bay. This photo of the payload bay with its doors open was taken just before Chandra was tilted upward for release and deployed on July 23, 1999. Credit: NASA
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This photo contains both flight (flat in the foreground) and qualification assembly (upright in the background) versions of the Solar Array Sun Shield for NASA’s Nancy Grace Roman Space Telescope. These panels will both shade the mission’s instruments and power the observatory.
Seeing double? You’re looking at our Nancy Grace Roman Space Telescope’s Solar Array Sun Shield laying flat in pieces in the foreground, and its test version connected and standing upright in the back. The Sun shield will do exactly what it sounds like –– shade the observatory –– and also collect sunlight for energy to power Roman.
These solar panels are twins, just like several of Roman’s other major components. Only one set will actually fly in space as part of the Roman spacecraft…so why do we need two?
Sometimes engineers do major tests to simulate launch and space conditions on a spare. That way, they don’t risk damaging the one that will go on the observatory. It also saves time because the team can do all the testing on the spare while building up the flight version. In the Sun shield’s case, that means fitting the flight version with solar cells and eventually getting the panels integrated onto the spacecraft.
Our Nancy Grace Roman Space Telescope's primary structure (also called the spacecraft bus) moves into the big clean room at our Goddard Space Flight Center (top). While engineers integrate other components onto the spacecraft bus in the clean room, the engineering test unit (also called the structural verification unit) undergoes testing in the centrifuge at Goddard. The centrifuge spins space hardware to ensure it will hold up against the forces of launch.
Engineers at our Goddard Space Flight Center recently tested the Solar Array Sun Shield qualification assembly in a thermal vacuum chamber, which simulates the hot and cold temperatures and low-pressure environment that the panels will experience in space. And since the panels will be stowed for launch, the team practiced deploying them in space-like conditions. They passed all the tests with flying colors!
The qualification panels will soon pass the testing baton to the flight version. After the flight Solar Array Sun Shield is installed on the Roman spacecraft, the whole spacecraft will go through lots of testing to ensure it will hold up during launch and perform as expected in space.
For more information about the Roman Space Telescope, visit: www.nasa.gov/roman. You can also virtually tour an interactive version of the telescope here.
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Observations from both NASA’s James Webb and Hubble space telescopes created this colorful image of galaxy cluster MACS0416. The colors of different galaxies indicate distances, with bluer galaxies being closer and redder galaxies being more distant or dusty. Some galaxies appear as streaks due to gravitational lensing — a warping effect caused by large masses gravitationally bending the space that light travels through.
While Taylor's Eras Tour explores decades of music, our universe’s eras set the stage for life to exist today. By unraveling cosmic history, scientists can investigate how it happened, from the universe’s origin and evolution to its possible fate.
This infographic outlines the history of the universe.
Scientists aren’t sure what exactly existed at the very beginning of the universe, but they think there wasn’t any normal matter or physics. Things probably didn’t behave like we expect them to today.
Artist's interpretation of the beginning of the universe, with representations of the early cosmos and its expansion.
When the universe debuted, it almost immediately became unstable. Space expanded faster than the speed of light during a very brief period known as inflation. Scientists are still exploring what drove this exponential expansion.
When inflation ended, the universe continued to expand, but much slower. All the energy that previously drove the rapid expansion went into light and matter — normal stuff! Small subatomic particles — protons, neutrons, and electrons — now floated around, though the universe was too hot for them to combine and form atoms.
The particles gravitated together, especially in clumpy spots. The push and pull between gravity and the particles’ inability to stick together created oscillations, or sound waves.
Artist's interpretation of protons and neutrons colliding to form ionized deuterium — a hydrogen isotope with one proton and one neutron — and ionized helium — two protons and two neutrons.
After about three minutes, the universe had expanded and cooled enough for protons and neutrons to stick together. This created the very first elements: hydrogen, helium, and very small amounts of lithium and beryllium.
But it was still too hot for electrons to combine with the protons and neutrons. These free electrons floated around in a hot foggy soup that scattered light and made the universe appear dark.
This animated artist’s concept begins by showing ionized atoms (red blobs), free electrons (green blobs), and photons of light (blue flashes). The ionized atoms scattered light until neutral atoms (shown as brown blobs) formed, clearing the way for light to travel farther through space.
As the universe expanded and cooled further, electrons joined atoms and made them neutral. With the electron plasma out of the way, some light could travel much farther.
An image of the cosmic microwave background (CMB) across the entire sky, taken by ESA's (European Space Agency) Planck space telescope. The CMB is the oldest light we can observe in the universe. Frozen sound waves are visible as miniscule fluctuations in temperature, shown through blue (colder) and red (warmer) coloring.
As neutral atoms formed, the sound waves created by the push and pull between subatomic particles stopped. The waves froze, leaving ripples that were slightly denser than their surroundings. The excess matter attracted even more matter, both normal and “dark.” Dark matter has gravitational influence on its surroundings but is invisible and does not interact with light.
This animation illustrates the absorption of photons — light particles — by neutral hydrogen atoms.
Other than the cosmic microwave background, there wasn't much light during this era since stars hadn’t formed yet. And what light there was usually didn't make it very far since neutral hydrogen atoms are really good at absorbing light. This kicked off an era known as the cosmic dark ages.
This animation illustrates the beginning of star formation as gas begins to clump due to gravity. These protostars heat up as material compresses inside them and throw off material at high speeds, creating shockwaves shown here as expanding rings of light.
Over time, denser areas pulled in more and more matter, in some places becoming so heavy it triggered a collapse. When the matter fell inward, it became hot enough for nuclear fusion to start, marking the birth of the first stars!
A simulation of dark matter forming structure due to gravity.
As the universe expanded, the frozen sound waves created earlier — which now included stars, gas, dust, and more elements produced by stars — stretched and continued attracting more mass. Pulling material together eventually formed the first galaxies, galaxy clusters, and wide-scale, web-like structure.
In this animation, ultraviolet light from stars ionizes hydrogen atoms by breaking off their electrons. Regions already ionized are blue and translucent, areas undergoing ionization are red and white, and regions of neutral gas are dark and opaque.
The first stars were massive and hot, meaning they burned their fuel supplies quickly and lived short lives. However, they gave off energetic ultraviolet light that helped break apart the neutral hydrogen around the stars and allowed light to travel farther.
Animation showing a graph of the universe’s expansion over time. While cosmic expansion slowed following the end of inflation, it began picking up the pace around 5 billion years ago. Scientists still aren't sure why.
By studying the universe’s expansion rate over time, scientists made the shocking discovery that it’s speeding up. They had thought eventually gravity should cause the matter to attract itself and slow down expansion. Some mysterious pressure, dubbed dark energy, seems to be accelerating cosmic expansion. About 10 billion years into the universe’s story, dark energy – whatever it may be – became dominant over matter.
An image of Earth rising in the Moon’s sky. Nicknamed “Earthrise,” Apollo 8 astronauts saw this sight during the first crewed mission to the Moon.
We owe our universe today to each of its unique stages. However, scientists still have many questions about these eras.
Our upcoming Nancy Grace Roman Space Telescope will look back in time to explore cosmic mysteries like dark energy and dark matter – two poorly understood aspects of the universe that govern its evolution and ultimate fate.
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Meet BurstCube! This shoebox-sized satellite is designed to study the most powerful explosions in the cosmos, called gamma-ray bursts. It detects gamma rays, the highest-energy form of light.
BurstCube may be small, but it had a huge journey to get to space.
First, BurstCube was designed and built at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. Here you can see Julie Cox, an early career engineer, working on BurstCube’s gamma-ray detecting instrument in the Small Satellite Lab at Goddard.
BurstCube is a type of spacecraft called a CubeSat. These tiny missions give early career engineers and scientists the chance to learn about mission development — as well as do cool science!
Then, after assembling the spacecraft, the BurstCube team took it on the road to conduct a bunch of tests to determine how it will operate in space. Here you can see another early career engineer, Kate Gasaway, working on BurstCube at NASA’s Wallops Flight Facility in Virginia.
She and other members of the team used a special facility there to map BurstCube’s magnetic field. This will help them know where the instrument is pointing when it’s in space.
The next stop was back at Goddard, where the team put BurstCube in a vacuum chamber. You can see engineers Franklin Robinson, Elliot Schwartz, and Colton Cohill lowering the lid here. They changed the temperature inside so it was very hot and then very cold. This mimics the conditions BurstCube will experience in space as it orbits in and out of sunlight.
Then, up on a Goddard rooftop, the team — including early career engineer Justin Clavette — tested BurstCube’s GPS. This so-called open-sky test helps ensure the team can locate the satellite once it’s in orbit.
The next big step in BurstCube’s journey was a flight to Houston! The team packed it up in a special case and took it to the airport. Of course, BurstCube got the window seat!
Once in Texas, the BurstCube team joined their partners at Nanoracks (part of Voyager Space) to get their tiny spacecraft ready for launch. They loaded the satellite into a rectangular frame called a deployer, along with another small satellite called SNoOPI (Signals of Opportunity P-band Investigation). The deployer is used to push spacecraft into orbit from the International Space Station.
From Houston, BurstCube traveled to Cape Canaveral Space Force Station in Florida, where it launched on SpaceX’s 30th commercial resupply servicing mission on March 21, 2024. BurstCube traveled to the station along with some other small satellites, science experiments, as well as a supply of fresh fruit and coffee for the astronauts.
A few days later, the mission docked at the space station, and the astronauts aboard began unloading all the supplies, including BurstCube!
And finally, on April 18, 2024, BurstCube was released into orbit. The team will spend a month getting the satellite ready to search the skies for gamma-ray bursts. Then finally, after a long journey, this tiny satellite can embark on its big mission!
BurstCube wouldn’t be the spacecraft it is today without the input of many early career engineers and scientists. Are you interested in learning more about how you can participate in a mission like this one? There are opportunities for students in middle and high school as well as college!
Keep up on BurstCube’s journey with NASA Universe on X and Facebook. And make sure to follow us on Tumblr for your regular dose of space!
Follow, follow the Sun / And which way the wind blows / When this day is done 🎶 Today, April 8, 2024, the last total solar eclipse until 2045 crossed North America.
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On Monday, April 8, 2024, there’ll be a total solar eclipse – and it’ll be the last one to cross North America for 20 years. Make sure you’re tuned in to our live broadcast for this exciting event: there’ll be views from along the path of totality, special guests, and plenty of science.
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The Nancy Grace Roman Space Telescope is NASA’s next flagship astrophysics mission, set to launch by May 2027. We’re currently integrating parts of the spacecraft in the NASA Goddard Space Flight Center clean room.
Once Roman launches, it will allow astronomers to observe the universe like never before. In celebration of Black History Month, let’s get to know some Black scientists and engineers, past and present, whose contributions will allow Roman to make history.
The late Dr. Beth Brown worked at NASA Goddard as an astrophysicist. in 1998, Dr. Brown became the first Black American woman to earn a Ph.D. in astronomy at the University of Michigan. While at Goddard, Dr. Brown used data from two NASA X-ray missions – ROSAT (the ROentgen SATellite) and the Chandra X-ray Observatory – to study elliptical galaxies that she believed contained supermassive black holes.
With Roman’s wide field of view and fast survey speeds, astronomers will be able to expand the search for black holes that wander the galaxy without anything nearby to clue us into their presence.
In 1961, Dr. Harvey Washington Banks was the first Black American to graduate with a doctorate in astronomy. His research was on spectroscopy, the study of how light and matter interact, and his research helped advance our knowledge of the field. Roman will use spectroscopy to explore how dark energy is speeding up the universe's expansion.
NOTE - Sensitive technical details have been digitally obscured in this photograph.
Aerospace engineer Sheri Thorn is ensuring Roman’s primary mirror will be protected from the Sun so we can capture the best images of deep space. Thorn works on the Deployable Aperture Cover, a large, soft shade known as a space blanket. It will be mounted to the top of the telescope in the stowed position and then deployed after launch. Thorn helped in the design phase and is now working on building the flight hardware before it goes to environmental testing and is integrated to the spacecraft.
Roman will be orbiting a million miles away at the second Lagrange point, or L2. Staying updated on the telescope's status and health will be an integral part of keeping the mission running. Electronics engineer Sanetra Bailey is the person who is making sure that will happen. Bailey works on circuits that will act like the brains of the spacecraft, telling it how and where to move and relaying information about its status back down to Earth.
Learn more about Sanetra Bailey and her journey to NASA.
Roman’s field of view will be at least 100 times larger than the Hubble Space Telescope's, even though the primary mirrors are the same size. What gives Roman the larger field of view are its 18 detectors. Dr. Gregory Mosby is one of the detector scientists on the Roman mission who helped select the flight detectors that will be our “eyes” to the universe.
Dr. Beth Brown, Dr. Harvey Washington Banks, Sheri Thorn, Sanetra Bailey, and Dr. Greg Mosby are just some of the many Black scientists and engineers in astrophysics who have and continue to pave the way for others in the field. The Roman Space Telescope team promises to continue to highlight those who came before us and those who are here now to truly appreciate the amazing science to come.
To stay up to date on the mission, check out our website and follow Roman on X and Facebook.
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A simulated image of NASA’s Nancy Grace Roman Space Telescope’s future observations toward the center of our galaxy, spanning less than 1 percent of the total area of Roman’s Galactic Bulge Time-Domain Survey. The simulated stars were drawn from the Besançon Galactic Model.
The view from your backyard might paint the universe as an unchanging realm, where only twinkling stars and nearby objects, like satellites and meteors, stray from the apparent constancy. But stargazing through NASA’s upcoming Nancy Grace Roman Space Telescope will offer a front row seat to a dazzling display of cosmic fireworks sparkling across the sky.
Roman will view extremely faint infrared light, which has longer wavelengths than our eyes can see. Two of the mission’s core observing programs will monitor specific patches of the sky. Stitching the results together like stop-motion animation will create movies that reveal changing objects and fleeting events that would otherwise be hidden from our view.
Watch this video to learn about time-domain astronomy and how time will be a key element in NASA’s Nancy Grace Roman Space Telescope’s galactic bulge survey. Credit: NASA’s Goddard Space Flight Center
This type of science, called time-domain astronomy, is difficult for telescopes that have smaller views of space. Roman’s large field of view will help us see huge swaths of the universe. Instead of always looking at specific things and events astronomers have already identified, Roman will be able to repeatedly observe large areas of the sky to catch phenomena scientists can't predict. Then astronomers can find things no one knew were there!
One of Roman’s main surveys, the Galactic Bulge Time-Domain Survey, will monitor hundreds of millions of stars toward the center of our Milky Way galaxy. Astronomers will see many of the stars appear to flash or flicker over time.
This animation illustrates the concept of gravitational microlensing. When one star in the sky appears to pass nearly in front of another, the light rays of the background source star are bent due to the warped space-time around the foreground star. The closer star is then a virtual magnifying glass, amplifying the brightness of the background source star, so we refer to the foreground star as the lens star. If the lens star harbors a planetary system, then those planets can also act as lenses, each one producing a short change in the brightness of the source. Thus, we discover the presence of each exoplanet, and measure its mass and how far it is from its star. Credit: NASA's Goddard Space Flight Center Conceptual Image Lab
That can happen when something like a star or planet moves in front of a background star from our point of view. Because anything with mass warps the fabric of space-time, light from the distant star bends around the nearer object as it passes by. That makes the nearer object act as a natural magnifying glass, creating a temporary spike in the brightness of the background star’s light. That signal lets astronomers know there’s an intervening object, even if they can’t see it directly.
This artist’s concept shows the region of the Milky Way NASA’s Nancy Grace Roman Space Telescope’s Galactic Bulge Time-Domain Survey will cover – relatively uncharted territory when it comes to planet-finding. That’s important because the way planets form and evolve may be different depending on where in the galaxy they’re located. Our solar system is situated near the outskirts of the Milky Way, about halfway out on one of the galaxy’s spiral arms. A recent Kepler Space Telescope study showed that stars on the fringes of the Milky Way possess fewer of the most common planet types that have been detected so far. Roman will search in the opposite direction, toward the center of the galaxy, and could find differences in that galactic neighborhood, too.
Using this method, called microlensing, Roman will likely set a new record for the farthest-known exoplanet. That would offer a glimpse of a different galactic neighborhood that could be home to worlds quite unlike the more than 5,500 that are currently known. Roman’s microlensing observations will also find starless planets, black holes, neutron stars, and more!
This animation shows a planet crossing in front of, or transiting, its host star and the corresponding light curve astronomers would see. Using this technique, scientists anticipate NASA’s Nancy Grace Roman Space Telescope could find 100,000 new worlds. Credit: NASA’s Goddard Space Flight Center/Chris Smith (USRA/GESTAR)
Stars Roman sees may also appear to flicker when a planet crosses in front of, or transits, its host star as it orbits. Roman could find 100,000 planets this way! Small icy objects that haunt the outskirts of our own solar system, known as Kuiper belt objects, may occasionally pass in front of faraway stars Roman sees, too. Astronomers will be able to see how much water the Kuiper belt objects have because the ice absorbs specific wavelengths of infrared light, providing a “fingerprint” of its presence. This will give us a window into our solar system’s early days.
This animation visualizes a type Ia supernova.
Roman’s High Latitude Time-Domain Survey will look beyond our galaxy to hunt for type Ia supernovas. These exploding stars originate from some binary star systems that contain at least one white dwarf – the small, hot core remnant of a Sun-like star. In some cases, the dwarf may siphon material from its companion. This triggers a runaway reaction that ultimately detonates the thief once it reaches a specific point where it has gained so much mass that it becomes unstable.
NASA’s upcoming Nancy Grace Roman Space Telescope will see thousands of exploding stars called supernovae across vast stretches of time and space. Using these observations, astronomers aim to shine a light on several cosmic mysteries, providing a window onto the universe’s distant past. Credit: NASA’s Goddard Space Flight Center
Since these rare explosions each peak at a similar, known intrinsic brightness, astronomers can use them to determine how far away they are by simply measuring how bright they appear. Astronomers will use Roman to study the light of these supernovas to find out how quickly they appear to be moving away from us.
By comparing how fast they’re receding at different distances, scientists can trace cosmic expansion over time. This will help us understand whether and how dark energy – the unexplained pressure thought to speed up the universe’s expansion – has changed throughout the history of the universe.
NASA’s Nancy Grace Roman Space Telescope will survey the same areas of the sky every few days. Researchers will mine this data to identify kilonovas – explosions that happen when two neutron stars or a neutron star and a black hole collide and merge. When these collisions happen, a fraction of the resulting debris is ejected as jets, which move near the speed of light. The remaining debris produces hot, glowing, neutron-rich clouds that forge heavy elements, like gold and platinum. Roman’s extensive data will help astronomers better identify how often these events occur, how much energy they give off, and how near or far they are.
And since this survey will repeatedly observe the same large vista of space, scientists will also see sporadic events like neutron stars colliding and stars being swept into black holes. Roman could even find new types of objects and events that astronomers have never seen before!
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A Geminid meteor streaks across the sky as the Soyuz TMA-19M spacecraft is rolled out by train to the launch pad at the Baikonur Cosmodrome on Sunday, Dec. 13, 2015, in Kazakhstan. Credit: NASA/Joel Kowsky
Every December, we have a chance to see one of our favorite meteor showers – the Geminids. To help you prepare, we’ve answered some of your most commonly asked questions. Happy viewing, stargazers!
These radar images of near-Earth object 3200 Phaethon were generated by astronomers at the National Science Foundation's Arecibo Observatory on Dec. 17, 2017. Observations of Phaethon were conducted at Arecibo from Dec. 15 through 19, 2017. At time of closest approach on Dec. 16 at 3 p.m. PST (6 p.m. EST, 2300 UTC), the asteroid was about 6.4 million miles (10.3 million kilometers) away, or about 27 times the distance from Earth to the Moon. Credit: Arecibo Observatory/NASA/NSF
The Geminids are caused by debris from a celestial object known as 3200 Phaethon striking Earth’s atmosphere. Phaethon’s origin is the subject of some debate. Some astronomers consider it to be an extinct comet, based on observations showing some small amount of material leaving its surface. Others argue that it has to be an asteroid because of its orbit and its similarity to the main-belt asteroid Pallas.
All meteors appear to come from the same place in the sky, which is called the radiant. The Geminids appear to radiate from a point in the constellation Gemini, hence the name “Geminids.” The graphic shows the radiants of 388 meteors with speeds of 35 km/s observed by the NASA Fireball Network in December 2020. All the radiants are in Gemini, which means they belong to the Geminid shower. Credit: NASA
All meteors associated with a shower have similar orbits, and they all appear to come from the same place in the sky, which is called the radiant. The Geminids appear to radiate from a point in the constellation Gemini, hence the name “Geminids.”
A Geminid streaks across the sky in this photo from December 2019. Credit: NASA
The Geminid meteor shower is active for much of December, but the peak will occur during the night of Dec. 13 into the morning of Dec. 14, 2023. Meteor rates in rural areas can be upwards of one per minute this year with minimal moonlight to interfere.
As with all meteor showers, all you need is a clear sky, darkness, a bit of patience, and perhaps warm outerwear and blankets for this one. You don’t need to look in any particular direction, as meteors can generally be seen all over the sky. If you want to take photographs, check out these helpful tips.
An infographic based on 2019’s meteor camera data for the Geminids. Credit: NASA
Find the darkest place you can and give your eyes about 30 minutes to adapt to the dark. Avoid looking at your cell phone, as it will disrupt your night vision. Lie flat on your back and look straight up, taking in as much sky as possible.
A Geminid streaks across the sky in this photo from December 2011. Credit: NASA
According to Bill Cooke, lead for the Meteoroid Environment Office at NASA’s Marshall Space Flight Center in Huntsville, Alabama, “Most meteors appear to be colorless or white, however the Geminids appear with a greenish hue. They’re pretty meteors!” Depending on the meteor’s chemical composition, the meteor will emit different colors when burned in the Earth’s atmosphere. Oxygen, magnesium, and nickel usually produce green.
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Get these deals before they are sucked into a black hole and gone forever! This “Black Hole Friday,” we have some cosmic savings that are sure to be out of this world.
Your classic black holes — the ultimate storage solution.
Galactic 5-for-1 special! Learn more about Stephan’s Quintet.
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Standard candles: Exploding stars that are reliably bright. Multi-functional — can be used to measure distances in space!
Feed the black hole in your stomach. Spaghettification’s on the menu.
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Add some planets to your solar system! Grab our Exoplanet Bundle.
Get ready to ride this (gravitational) wave before this Black Hole Merger ends!
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Should you ever travel to a black hole? No. But if you do, here’s a free guide to make your trip as safe* as possible. *Note: black holes are never safe.
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Astronomers used three of NASA's Great Observatories to capture this multiwavelength image showing galaxy cluster IDCS J1426.5+3508. It includes X-rays recorded by the Chandra X-ray Observatory in blue, visible light observed by the Hubble Space Telescope in green, and infrared light from the Spitzer Space Telescope in red. This rare galaxy cluster has important implications for understanding how these megastructures formed and evolved early in the universe.
Let’s add another item to your travel bucket list: the early universe! You don’t need the type of time machine you see in sci-fi movies, and you don’t have to worry about getting trapped in the past. You don’t even need to leave the comfort of your home! All you need is a powerful space-based telescope.
But let’s start small and work our way up to the farthest reaches of space. We’ll explain how it all works along the way.
This animation illustrates how fast light travels between Earth and the Moon. The farther light has to travel, the more noticeable its speed limit becomes.
The speed of light is superfast, but it isn’t infinite. It travels at about 186,000 miles (300 million meters) per second. That means that it takes time for the light from any object to reach our eyes. The farther it is, the more time it takes.
You can see nearby things basically in real time because the light travel time isn’t long enough to make a difference. Even if an object is 100 miles (161 kilometers) away, it takes just 0.0005 seconds for light to travel that far. But on astronomical scales, the effects become noticeable.
This infographic shows how long it takes light to travel to different planets in our solar system.
Within our solar system, light’s speed limit means it can take a while to communicate back and forth between spacecraft and ground stations on Earth. We see the Moon, Sun, and planets as they were slightly in the past, but it's not usually far enough back to be scientifically interesting.
As we peer farther out into our galaxy, we use light-years to talk about distances. Smaller units like miles or kilometers would be too overwhelming and we’d lose a sense of their meaning. One light-year – the distance light travels in a year – is nearly 6 trillion miles (9.5 trillion kilometers). And that’s just a tiny baby step into the cosmos.
The Sun’s closest neighboring star, Proxima Centauri, is 4.2 light-years away. That means we see it as it was about four years ago. Betelgeuse, a more distant (and more volatile) stellar neighbor, is around 700 light-years away. Because of light’s lag time, astronomers don’t know for sure whether this supergiant star is still there! It may have already blasted itself apart in a supernova explosion – but it probably has another 10,000 years or more to go.
What looks much like craggy mountains on a moonlit evening is actually the edge of a nearby, young, star-forming region NGC 3324 in the Carina Nebula. Captured in infrared light by the Near-Infrared Camera (NIRCam) on NASA’s James Webb Space Telescope, this image reveals previously obscured areas of star birth.
The Carina Nebula clocks in at 7,500 light-years away, which means the light we receive from it today began its journey about 3,000 years before the pyramids of Giza in Egypt were built! Many new stars there have undoubtedly been born by now, but their light may not reach Earth for thousands of years.
An artist’s concept of our Milky Way galaxy, with rough locations for the Sun and Carina nebula marked.
If we zoom way out, you can see that 7,500 light-years away is still pretty much within our neighborhood. Let’s look further back in time…
This stunning image by the NASA/ESA Hubble Space Telescope features the spiral galaxy NGC 5643. Looking this good isn’t easy; 30 different exposures, for a total of nine hours of observation time, together with Hubble’s high resolution and clarity, were needed to produce an image of such exquisite detail and beauty.
Peering outside our Milky Way galaxy transports us much further into the past. The Andromeda galaxy, our nearest large galactic neighbor, is about 2.5 million light-years away. And that’s still pretty close, as far as the universe goes. The image above shows the spiral galaxy NGC 5643, which is about 60 million light-years away! That means we see it as it was about 60 million years ago.
As telescopes look deeper into the universe, they capture snapshots in time from different cosmic eras. Astronomers can stitch those snapshots together to unravel things like galaxy evolution. The closest ones are more mature; we see them nearly as they truly are in the present day because their light doesn’t have to travel as far to reach us. We can’t rewind those galaxies (or our own), but we can get clues about how they likely developed. Looking at galaxies that are farther and farther away means seeing these star cities in ever earlier stages of development.
The farthest galaxies we can see are both old and young. They’re billions of years old now, and the light we receive from them is ancient since it took so long to traverse the cosmos. But since their light was emitted when the galaxies were young, it gives us a view of their infancy.
This animation is an artist’s concept of the big bang, with representations of the early universe and its expansion.
Comparing how fast objects at different distances are moving away opened up the biggest mystery in modern astronomy: cosmic acceleration. The universe was already expanding as a result of the big bang, but astronomers expected it to slow down over time. Instead, it’s speeding up!
The universe’s expansion makes it tricky to talk about the distances of the farthest objects. We often use lookback time, which is the amount of time it took for an object’s light to reach us. That’s simpler than using a literal distance, because an object that was 10 billion light-years away when it emitted the light we received from it would actually be more than 16 billion light-years away right now, due to the expansion of space. We can even see objects that are presently over 30 billion light-years from Earth, even though the universe is only about 14 billion years old.
This James Webb Space Telescope image shines with the light from galaxies that are more than 13.4 billion years old, dating back to less than 400 million years after the big bang.
Our James Webb Space Telescope has helped us time travel back more than 13.4 billion years, to when the universe was less than 400 million years old. When our Nancy Grace Roman Space Telescope launches in a few years, astronomers will pair its vast view of space with Webb’s zooming capabilities to study the early universe in better ways than ever before. And don’t worry – these telescopes will make plenty of pit stops along the way at other exciting cosmic destinations across space and time.
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The Nancy Grace Roman Space Telescope’s flight harness is transferred from the mock-up structure to the spacecraft flight structure.
If our Nancy Grace Roman Space Telescope were alive, its nervous system would be the intricate wiring, or “harness,” that helps different parts of the observatory communicate with one another. Just like the human body sends information through nerves to function, Roman will send commands through this special harness to help achieve its mission: answering longstanding questions about dark energy, dark matter, and exoplanets, among other mind-bending cosmic queries.
Roman’s harness weighs around 1,000 pounds and is made of about 32,000 wires and 900 connectors. If those parts were laid out end-to-end, they would be 45 miles long from start to finish. Coincidentally, the human body’s nerves would span the same distance if lined up. That’s far enough to reach nearly three-fourths of the way to space, twice as far as a marathon, or eight times taller than Mount Everest!
An aerial view of the harness technicians working to secure Roman’s harness to the spacecraft flight structure.
Over a span of two years, 11 technicians spent time at the workbench and perched on ladders, cutting wire to length, carefully cleaning each component, and repeatedly connecting everything together.
Space is usually freezing cold, but spacecraft that are in direct sunlight can get incredibly hot. Roman’s harness went through the Space Environment Simulator – a massive thermal vacuum chamber – to expose the components to the temperatures they’ll experience in space. Technicians “baked” vapors out of the harness to make sure they won’t cause problems later in orbit.
Technicians work to secure Roman’s harness to the interior of the spacecraft flight structure. They are standing in the portion of the spacecraft bus where the propellant tanks will be mounted.
The next step is for engineers to weave the harness through the flight structure in Goddard’s big clean room, a space almost perfectly free of dust and other particles. This process will be ongoing until most of the spacecraft components are assembled. The Roman Space Telescope is set to launch by May 2027.
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On August 6, 1967, astrophysicist Jocelyn Bell Burnell noticed a blip in her radio telescope data. And then another. Eventually, Bell Burnell figured out that these blips, or pulses, were not from people or machines.
The blips were constant. There was something in space that was pulsing in a regular pattern, and Bell Burnell figured out that it was a pulsar: a rapidly spinning neutron star emitting beams of light. Neutron stars are superdense objects created when a massive star dies. Not only are they dense, but neutron stars can also spin really fast! Every star we observe spins, and due to a property called angular momentum, as a collapsing star gets smaller and denser, it spins faster. It’s like how ice skaters spin faster as they bring their arms closer to their bodies and make the space that they take up smaller.
The pulses of light coming from these whirling stars are like the beacons spinning at the tops of lighthouses that help sailors safely approach the shore. As the pulsar spins, beams of radio waves (and other types of light) are swept out into the universe with each turn. The light appears and disappears from our view each time the star rotates.
After decades of studying pulsars, astronomers wondered—could they serve as cosmic beacons to help future space explorers navigate the universe? To see if it could work, scientists needed to do some testing!
First, it was important to gather more data. NASA’s NICER, or Neutron star Interior Composition Explorer, is a telescope that was installed aboard the International Space Station in 2017. Its goal is to find out things about neutron stars like their sizes and densities, using an array of 56 special X-ray concentrators and sensitive detectors to capture and measure pulsars’ light.
But how can we use these X-ray pulses as navigational tools? Enter SEXTANT, or Station Explorer for X-ray Timing and Navigation Technology. If NICER was your phone, SEXTANT would be like an app on it.
During the first few years of NICER’s observations, SEXTANT created an on-board navigation system using NICER’s pulsar data. It worked by measuring the consistent timing between each pulsar’s pulses to map a set of cosmic beacons.
When calculating position or location, extremely accurate timekeeping is essential. We usually rely on atomic clocks, which use the predictable fluctuations of atoms to tick away the seconds. These atomic clocks can be located on the ground or in space, like the ones on GPS satellites. However, our GPS system only works on or close to Earth, and onboard atomic clocks can be expensive and heavy. Using pulsar observations instead could give us free and reliable “clocks” for navigation. During its experiment, SEXTANT was able to successfully determine the space station’s orbital position!
We can calculate distances using the time taken for a signal to travel between two objects to determine a spacecraft’s approximate location relative to those objects. However, we would need to observe more pulsars to pinpoint a more exact location of a spacecraft. As SEXTANT gathered signals from multiple pulsars, it could more accurately derive its position in space.
So, imagine you are an astronaut on a lengthy journey to the outer solar system. You could use the technology developed by SEXTANT to help plot your course. Since pulsars are reliable and consistent in their spins, you wouldn’t need Wi-Fi or cell service to figure out where you were in relation to your destination. The pulsar-based navigation data could even help you figure out your ETA!
None of these missions or experiments would be possible without Jocelyn Bell Burnell’s keen eye for an odd spot in her radio data decades ago, which set the stage for the idea to use spinning neutron stars as a celestial GPS. Her contribution to the field of astrophysics laid the groundwork for research benefitting the people of the future, who yearn to sail amongst the stars.
Keep up with the latest NICER news by following NASA Universe on X and Facebook and check out the mission’s website. For more on space navigation, follow @NASASCaN on X or visit NASA’s Space Communications and Navigation website.
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The James Webb Space Telescope has just completed a successful first year of science. Let’s celebrate by seeing the birth of Sun-like stars in this brand-new image from the Webb telescope!
This is a small star-forming region in the Rho Ophiuchi cloud complex. At 390 light-years away, it's the closest star-forming region to Earth. There are around 50 young stars here, all of them similar in mass to the Sun, or smaller. The darkest areas are the densest, where thick dust cocoons still-forming protostars. Huge red bipolar jets of molecular hydrogen dominate the image, appearing horizontally across the upper third and vertically on the right. These occur when a star first bursts through its natal envelope of cosmic dust, shooting out a pair of opposing jets into space like a newborn first stretching her arms out into the world. In contrast, the star S1 has carved out a glowing cave of dust in the lower half of the image. It is the only star in the image that is significantly more massive than the Sun.
Thanks to Webb’s sensitive instruments, we get to witness moments like this at the beginning of a star’s life. One year in, Webb’s science mission is only just getting started. The second year of observations has already been selected, with plans to build on an exciting first year that exceeded expectations. Here’s to many more years of scientific discovery with Webb.
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Credits: NASA, ESA, CSA, STScI, Klaus Pontoppidan (STScI)
We only have one universe. That’s usually plenty – it’s pretty big after all! But there are some things scientists can’t do with our real universe that they can do if they build new ones using computers.
The universes they create aren’t real, but they’re important tools to help us understand the cosmos. Two teams of scientists recently created a couple of these simulations to help us learn how our Nancy Grace Roman Space Telescope sets out to unveil the universe’s distant past and give us a glimpse of possible futures.
Caution: you are now entering a cosmic construction zone (no hard hat required)!
This simulated Roman deep field image, containing hundreds of thousands of galaxies, represents just 1.3 percent of the synthetic survey, which is itself just one percent of Roman's planned survey. The full simulation is available here. The galaxies are color coded – redder ones are farther away, and whiter ones are nearer. The simulation showcases Roman’s power to conduct large, deep surveys and study the universe statistically in ways that aren’t possible with current telescopes.
One Roman simulation is helping scientists plan how to study cosmic evolution by teaming up with other telescopes, like the Vera C. Rubin Observatory. It’s based on galaxy and dark matter models combined with real data from other telescopes. It envisions a big patch of the sky Roman will survey when it launches by 2027. Scientists are exploring the simulation to make observation plans so Roman will help us learn as much as possible. It’s a sneak peek at what we could figure out about how and why our universe has changed dramatically across cosmic epochs.
This video begins by showing the most distant galaxies in the simulated deep field image in red. As it zooms out, layers of nearer (yellow and white) galaxies are added to the frame. By studying different cosmic epochs, Roman will be able to trace the universe's expansion history, study how galaxies developed over time, and much more.
As part of the real future survey, Roman will study the structure and evolution of the universe, map dark matter – an invisible substance detectable only by seeing its gravitational effects on visible matter – and discern between the leading theories that attempt to explain why the expansion of the universe is speeding up. It will do it by traveling back in time…well, sort of.
Looking way out into space is kind of like using a time machine. That’s because the light emitted by distant galaxies takes longer to reach us than light from ones that are nearby. When we look at farther galaxies, we see the universe as it was when their light was emitted. That can help us see billions of years into the past. Comparing what the universe was like at different ages will help astronomers piece together the way it has transformed over time.
This animation shows the type of science that astronomers will be able to do with future Roman deep field observations. The gravity of intervening galaxy clusters and dark matter can lens the light from farther objects, warping their appearance as shown in the animation. By studying the distorted light, astronomers can study elusive dark matter, which can only be measured indirectly through its gravitational effects on visible matter. As a bonus, this lensing also makes it easier to see the most distant galaxies whose light they magnify.
The simulation demonstrates how Roman will see even farther back in time thanks to natural magnifying glasses in space. Huge clusters of galaxies are so massive that they warp the fabric of space-time, kind of like how a bowling ball creates a well when placed on a trampoline. When light from more distant galaxies passes close to a galaxy cluster, it follows the curved space-time and bends around the cluster. That lenses the light, producing brighter, distorted images of the farther galaxies.
Roman will be sensitive enough to use this phenomenon to see how even small masses, like clumps of dark matter, warp the appearance of distant galaxies. That will help narrow down the candidates for what dark matter could be made of.
In this simulated view of the deep cosmos, each dot represents a galaxy. The three small squares show Hubble's field of view, and each reveals a different region of the synthetic universe. Roman will be able to quickly survey an area as large as the whole zoomed-out image, which will give us a glimpse of the universe’s largest structures.
A separate simulation shows what Roman might expect to see across more than 10 billion years of cosmic history. It’s based on a galaxy formation model that represents our current understanding of how the universe works. That means that Roman can put that model to the test when it delivers real observations, since astronomers can compare what they expected to see with what’s really out there.
In this side view of the simulated universe, each dot represents a galaxy whose size and brightness corresponds to its mass. Slices from different epochs illustrate how Roman will be able to view the universe across cosmic history. Astronomers will use such observations to piece together how cosmic evolution led to the web-like structure we see today.
This simulation also shows how Roman will help us learn how extremely large structures in the cosmos were constructed over time. For hundreds of millions of years after the universe was born, it was filled with a sea of charged particles that was almost completely uniform. Today, billions of years later, there are galaxies and galaxy clusters glowing in clumps along invisible threads of dark matter that extend hundreds of millions of light-years. Vast “cosmic voids” are found in between all the shining strands.
Astronomers have connected some of the dots between the universe’s early days and today, but it’s been difficult to see the big picture. Roman’s broad view of space will help us quickly see the universe’s web-like structure for the first time. That’s something that would take Hubble or Webb decades to do! Scientists will also use Roman to view different slices of the universe and piece together all the snapshots in time. We’re looking forward to learning how the cosmos grew and developed to its present state and finding clues about its ultimate fate.
This image, containing millions of simulated galaxies strewn across space and time, shows the areas Hubble (white) and Roman (yellow) can capture in a single snapshot. It would take Hubble about 85 years to map the entire region shown in the image at the same depth, but Roman could do it in just 63 days. Roman’s larger view and fast survey speeds will unveil the evolving universe in ways that have never been possible before.
Roman will explore the cosmos as no telescope ever has before, combining a panoramic view of the universe with a vantage point in space. Each picture it sends back will let us see areas that are at least a hundred times larger than our Hubble or James Webb space telescopes can see at one time. Astronomers will study them to learn more about how galaxies were constructed, dark matter, and much more.
The simulations are much more than just pretty pictures – they’re important stepping stones that forecast what we can expect to see with Roman. We’ve never had a view like Roman’s before, so having a preview helps make sure we can make the most of this incredible mission when it launches.
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This all-sky mosaic was constructed from 912 Transiting Exoplanet Survey Satellite (TESS) images. Prominent features include the Milky Way, a glowing arc that represents the bright central plane of our galaxy, and the Large and Small Magellanic Clouds – satellite galaxies of our own located, respectively, 160,000 and 200,000 light-years away. In the northern sky, look for the small, oblong shape of the Andromeda galaxy (M 31), the closest big spiral galaxy, located 2.5 million light-years away. The black regions are areas of sky that TESS didn’t image. Credit: NASA/MIT/TESS and Ethan Kruse (University of Maryland College Park)
On April 18, 2018, we launched the Transiting Exoplanet Survey Satellite, better known as TESS. It was designed to search for planets beyond our solar system – exoplanets – and to discover worlds for our James Webb Space Telescope, which launched three years later, to further explore. TESS images sections of sky, one hemisphere at a time. When we put all the images together, we get a great look at Earth’s sky!
In its five years in space, TESS has discovered 326 planets and more than 4,300 planet candidates. Along the way, the spacecraft has observed a plethora of other objects in space, including watching as a black hole devoured a star and seeing six stars dancing in space. Here are some notable results from TESS so far:
During its first five years in space, our Transiting Exoplanet Survey Satellite has discovered exoplanets and identified worlds that can be further explored by the James Webb Space Telescope. Credit: NASA/JPL-Caltech
1. TESS’ first discovery was a world called Pi Mensae c. It orbits the star Pi Mensae, about 60 light-years away from Earth and visible to the unaided eye in the Southern Hemisphere. This discovery kicked off NASA's new era of planet hunting.
2. Studying planets often helps us learn about stars too! Data from TESS & Spitzer helped scientists detect a planet around the young, flaring star AU Mic, providing a unique way to study how planets form, evolve, and interact with active stars.
Located less than 32 light-years from Earth, AU Microscopii is among the youngest planetary systems ever observed by astronomers, and its star throws vicious temper tantrums. This devilish young system holds planet AU Mic b captive inside a looming disk of ghostly dust and ceaselessly torments it with deadly blasts of X-rays and other radiation, thwarting any chance of life… as we know it! Beware! There is no escaping the stellar fury of this system. The monstrous flares of AU Mic will have you begging for eternal darkness. Credit: NASA/JPL-Caltech
3. In addition to finding exoplanets on its own, TESS serves as a pathfinder for the James Webb Space Telescope. TESS discovered the rocky world LHS 3844 b, but Webb will tell us more about its composition. Our telescopes, much like our scientists, work together.
4. Though TESS may be a planet-hunter, it also helps us study black holes! In 2019, TESS saw a ‘‘tidal disruption event,’’ otherwise known as a black hole shredding a star.
When a star strays too close to a black hole, intense tides break it apart into a stream of gas. The tail of the stream escapes the system, while the rest of it swings back around, surrounding the black hole with a disk of debris. Credit: NASA's Goddard Space Flight Center
5. In 2020, TESS discovered its first Earth-size world in the habitable zone of its star – the distance from a star at which liquid water could exist on a planet’s surface. Earlier this year, a second rocky planet was discovered in the system.
You can see the exoplanets that orbit the star TOI 700 moving within two marked habitable zones, a conservative habitable zone, and an optimistic habitable zone. Planet d orbits within the conservative habitable zone, while planet e moves within an optimistic habitable zone, the range of distances from a star where liquid surface water could be present at some point in a planet’s history. Credit: NASA Goddard Space Flight Center
6. Astronomers used TESS to find a six-star system where all stars undergo eclipses. Three binary pairs orbit each other, and, in turn, the pairs are engaged in an elaborate gravitational dance in a cosmic ballroom 1,900 light-years away in the constellation Eridanus.
7. Thanks to TESS, we learned that Delta Scuti stars pulse to the beat of their own drummer. Most seem to oscillate randomly, but we now know HD 31901 taps out a beat that merges 55 pulsation patterns.
Sound waves bouncing around inside a star cause it to expand and contract, which results in detectable brightness changes. This animation depicts one type of Delta Scuti pulsation — called a radial mode — that is driven by waves (blue arrows) traveling between the star's core and surface. In reality, a star may pulsate in many different modes, creating complicated patterns that enable scientists to learn about its interior. Credit: NASA’s Goddard Space Flight Center
8. Last is a galaxy that flares like clockwork! With TESS and Swift, astronomers identified the most predictably and frequently flaring active galaxy yet. ASASSN-14ko, which is 570 million light-years away, brightens every 114 days!
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This rare sight is a super-bright, massive Wolf-Rayet star. Calling forth the ephemeral nature of cherry blossoms, the Wolf-Rayet phase is a fleeting stage that only some stars go through soon before they explode.
The star, WR 124, is 15,000 light-years away in the constellation Sagittarius. It is 30 times the mass of the Sun and has shed 10 Suns worth of material – so far. As the ejected gas moves away from the star and cools, cosmic dust forms and glows in the infrared light detectable by NASA's James Webb Space Telescope.
The origin of cosmic dust that can survive a supernova blast is of great interest to astronomers for multiple reasons. Dust shelters forming stars, gathers together to help form planets, and serves as a platform for molecules to form and clump together, including the building blocks of life on Earth.
Stars like WR 124 also help astronomers understand the early history of the universe. Similar dying stars first seeded the young universe with heavy elements forged in their cores – elements that are now common in the current era, including on Earth.
The James Webb Space Telescope opens up new possibilities for studying details in cosmic dust, which is best observed in infrared wavelengths of light. Webb’s Near-Infrared Camera balances the brightness of WR 124’s stellar core and the knotty details in the fainter surrounding gas. The telescope’s Mid-Infrared Instrument reveals the clumpy structure of the gas and dust nebula of the ejected material now surrounding the star.
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NASA engineers recently completed tests of the high-gain antenna for our Nancy Grace Roman Space Telescope. This observatory has some truly stellar plans once it launches by May 2027. Roman will help unravel the secrets of dark energy and dark matter – two invisible components that helped shape our universe and may determine its ultimate fate. The mission will also search for and image planets outside our solar system and explore all kinds of other cosmic topics.
However, it wouldn’t be able to send any of the data it will gather back to Earth without its antenna. Pictured above in a test chamber, this dish will provide the primary communication link between the Roman spacecraft and the ground. It will downlink the highest data volume of any NASA astrophysics mission so far.
The antenna reflector is made of a carbon composite material that weighs very little but will still withstand wide temperature fluctuations. It’s very hot and cold in space – Roman will experience a temperature range of minus 26 to 284 degrees Fahrenheit (minus 32 to 140 degrees Celsius)!
The dish spans 5.6 feet (1.7 meters) in diameter, standing about as tall as a refrigerator, yet only weighs 24 pounds (10.9 kilograms) – about as much as a dachshund. Its large size will help Roman send radio signals across a million miles of intervening space to Earth.
At one frequency, the dual-band antenna will receive commands and send back information about the spacecraft’s health and location. It will use another frequency to transmit a flood of data at up to 500 megabits per second to ground stations on Earth. The dish is designed to point extremely accurately at Earth, all while both Earth and the spacecraft are moving through space.
Engineers tested the antenna to make sure it will withstand the spacecraft’s launch and operate as expected in the extreme environment of space. The team also measured the antenna’s performance in a radio-frequency anechoic test chamber. Every surface in the test chamber is covered in pyramidal foam pieces that minimize interfering reflections during testing. Next, the team will attach the antenna to the articulating boom assembly, and then electrically integrate it with Roman’s Radio Frequency Communications System.
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Award-winning NASA mathematician and computer programmer Melba Mouton is being honored with the naming of a mountain at the Moon’s South Pole. Mouton joined NASA in 1959, just a year after the space agency was established. She was the leader of a team that coded computer programs to calculate spacecraft trajectories and locations. Her contributions were instrumental to landing the first humans on the Moon.
She also led the group of "human computers," who tracked the Echo satellites. Roy and her team's computations helped produce the orbital element timetables by which millions could view the satellite from Earth as it passed overhead.
The towering lunar landmark now known as “Mons Mouton” stands at a height greater than 19,000 feet. The mountain was created over billions of years by lunar impacts. Huge craters lie around its base—some with cliff-like edges that descend into areas of permanent darkness. Mons Mouton is the future landing site of VIPER, our first robotic Moon rover. The rover will explore the Moon’s surface to help gain a better understanding of the origin of lunar water. Here are things to know:
The VIPER mission is managed by our Ames Research Center in California’s Silicon Valley. The approximately 1,000-pound rover will be delivered to the Moon by a commercial vendor as part of our Commercial Lunar Payload Services initiative, delivering science and technology payloads to and near the Moon.
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This is a season where our thoughts turn to others and many exchange gifts with friends and family. For astronomers, our universe is the gift that keeps on giving. We’ve learned so much about it, but every question we answer leads to new things we want to know. Stars, galaxies, planets, black holes … there are endless wonders to study.
In honor of this time of year, let’s count our way through some of our favorite gifts from astronomy.
So far, there is only one planet that we’ve found that has everything needed to support life as we know it — Earth. Even though we’ve discovered over 5,200 planets outside our solar system, none are quite like home. But the search continues with the help of missions like our Transiting Exoplanet Survey Satellite (TESS). And even you (yes, you!) can help in the search with citizen science programs like Planet Hunters TESS and Backyard Worlds.
Astronomers found out that our Milky Way galaxy is blowing bubbles — two of them! Each bubble is about 25,000 light-years tall and glows in gamma rays. Scientists using data from our Fermi Gamma-ray Space Telescope discovered these structures in 2010, and we're still learning about them.
Most black holes fit into two size categories: stellar-mass goes up to hundreds of Suns, and supermassive starts at hundreds of thousands of Suns. But what happens between those two? Where are the midsize ones? With the help of NASA’s Hubble Space Telescope, scientists found the best evidence yet for that third, in between type that we call intermediate-mass black holes. The masses of these black holes should range from around a hundred to hundreds of thousands of times the Sun’s mass. The hunt continues for these elusive black holes.
When looking at this stunning image of Stephan’s Quintet from our James Webb Space Telescope, it seems like five galaxies are hanging around one another — but did you know that one of the galaxies is much closer than the others? Four of the five galaxies are hanging out together about 290 million light-years away, but the fifth and leftmost galaxy in the image below — called NGC 7320 — is actually closer to Earth at just 40 million light-years away.
Astronomers found a six-star system where all of the stars undergo eclipses, using data from our TESS mission, a supercomputer, and automated eclipse-identifying software. The system, called TYC 7037-89-1, is located 1,900 light-years away in the constellation Eridanus and the first of its kind we’ve found.
In 2017, our now-retired Spitzer Space Telescope helped find seven Earth-size planets around TRAPPIST-1. It remains the largest batch of Earth-size worlds found around a single star and the most rocky planets found in one star’s habitable zone, the range of distances where conditions may be just right to allow the presence of liquid water on a planet’s surface.
Further research has helped us understand the planets’ densities, atmospheres, and more!
The primary mirror on our Nancy Grace Roman Space Telescope is approximately eight feet in diameter, similar to our Hubble Space Telescope. But Roman can survey large regions of the sky over 1,000 times faster, allowing it to hunt for thousands of exoplanets and measure light from a billion galaxies.
In 2017, the National Science Foundation (NSF)’s Laser Interferometer Gravitational-Wave Observatory (LIGO) and European Gravitational Observatory’s Virgo detected gravitational waves from a pair of colliding neutron stars. Less than two seconds later, our telescopes detected a burst of gamma rays from the same event. It was the first time light and gravitational waves were seen from the same cosmic source. But then nine days later, astronomers saw X-ray light produced in jets in the collision’s aftermath. This later emission is called a kilonova, and it helped astronomers understand what the slower-moving material is made of.
Our NuSTAR X-ray observatory is the first space telescope able to focus on high-energy X-rays. Its ten-meter-long (33 foot) mast, which deployed shortly after launch, puts NuSTAR’s detectors at the perfect distance from its reflective optics to focus X-rays. NuSTAR recently celebrated 10 years since its launch in 2012.
How long did our Hubble Space Telescope stare at a seemingly empty patch of sky to discover it was full of thousands of faint galaxies? More than 11 days of observations came together to capture this amazing image — that’s about 1 million seconds spread over 400 orbits around Earth!
Pulsars are collapsed stellar cores that pack the mass of our Sun into a whirling city-sized ball, compressing matter to its limits. Our NICER telescope aboard the International Space Station helped us precisely measure one called J0030 and found it had a radius of about twelve kilometers — roughly the size of Chicago! This discovery has expanded our understanding of pulsars with the most precise and reliable size measurements of any to date.
Stay tuned to NASA Universe on Twitter and Facebook to keep up with what’s going on in the cosmos every day. You can learn more about the universe here.
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Location: In the Scorpius constellation
Distance from Earth: About 44,000 light-years
Object type: Globular star cluster
Discovered by: James Dunlop in 1826
Each tiny point of light in this image is its own star - and there are more than a million of them! This stunning image captured by the Hubble Telescope depicts NGC 6441, a globular cluster that weighs about 1.6 million times the mass of our Sun. Globular clusters like NGC 6441 are groups of old stars held together by their mutual gravitational attraction, appearing nearly spherical in shape due to the density of stars that comprises them. This particular cluster is one of the most massive and luminous in our Milky Way Galaxy. It is also home to a planetary nebula and four pulsars (rotating neutron stars that emit beams of radiation at steady intervals, detected when the beams are aimed at Earth).
Read more information about NGC 6441 here.
Right now, the Hubble Space Telescope is delving into its #StarrySights campaign! Find more star cluster content and spectacular new images by following along on Hubble’s Twitter, Facebook, and Instagram.
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Location: In the Carina spiral arm of our Milky Way Galaxy
Distance from Earth: About 20,000 light-years
Object type: Nebula and open star cluster
Discovered by: Sir John Herschel in 1834
Imaged here by the Hubble Space Telescope, NGC 3603 is a collection of thousands of large, hot stars, including some of the most massive stars known to us. Scientists categorize it as an “open cluster” because of its spread-out shape and low density of stars. Surrounding the bright star cluster are plumes of interstellar gas and dust, which comprise the nebula part of this cosmic object. New stars are formed from the gaseous material within these clouds! NGC 3603 holds stars at a variety of life stages, making it a laboratory for scientists to study star evolution and formation. Astronomers estimate that star formation in and around the cluster has been occurring for 10 to 20 million years.
Read more information about NGC 3603 here.
Right now, the Hubble Space Telescope is delving into its #StarrySights campaign! Find more star cluster content and breathtaking new images by following along on Hubble’s Twitter, Facebook, and Instagram.
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Boo! Did we get you? 🎃
This solar jack-o-lantern, captured by our Solar Dynamics Observatory (SDO) in October 2014, gets its ghoulish grin from active regions on the Sun, which emit more light and energy than the surrounding dark areas. Active regions are markers of an intense and complex set of magnetic fields hovering in the sun’s atmosphere.
The SDO has kept an unblinking eye on the Sun since 2010, recording phenomena like solar flares and coronal loops. It measures the Sun’s interior, atmosphere, magnetic field, and energy output, helping us understand our nearest star.
Grab the high-resolution version here.
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The universe is full of dazzling sights, but there’s an eerie side of space, too. Nestled between the stars, shadowy figures lurk unseen. The entire galaxy could even be considered a graveyard, full of long-dead stars. And it’s not just the Milky Way – the whole universe is a bit like one giant haunted house! Our Nancy Grace Roman Space Telescope will illuminate all kinds of spine-chilling cosmic mysteries when it launches in 2027, but for now settle in for some true, scary space stories.
One of the first signs that things are about to get creepy in a scary movie is when the lights start to flicker. That happens all the time in space, too! But instead of being a sinister omen, it can help us find planets circling other stars.
Roman will stare toward the heart of our galaxy and watch to see when pairs of stars appear to align in the sky. When that happens, the nearer star – and orbiting planets – can lens light from the farther star, creating a brief brightening. That’s because every massive object warps the fabric of space-time, changing the path light takes when it passes close by. Roman could find around 1,000 planets using this technique, which is called microlensing.
The mission will also see little flickers when planets cross in front of their host star as they orbit and temporarily dim the light we receive from the star. Roman could find an additional 100,000 planets this way!
Roman is going to be one of the best ghost hunters in the galaxy! Since microlensing relies on an object’s gravity, not its light, it can find all kinds of invisible specters drifting through the Milky Way. That includes rogue planets, which roam the galaxy alone instead of orbiting a star…
…and solo stellar-mass black holes, which we can usually only find when they have a visible companion, like a star. Astronomers think there should be 100 million of these black holes in our galaxy.
Black holes aren’t the only dead stars hiding in the sky. When stars that aren’t quite massive enough to form black holes run out of fuel, they blast away their outer layers and become neutron stars. These stellar cores are the densest material we can directly observe. One sugar cube of neutron star material would weigh about 1 billion tons (or 1 trillion kilograms) on Earth! Roman will be able to detect when these extreme objects collide.
Smaller stars like our Sun have less dramatic fates. After they run out of fuel, they swell up and shrug off their outer layers until only a small, hot core called a white dwarf remains. Those outer layers may be recycled into later generations of stars and planets. Roman will explore regions where new stars are bursting to life, possibly containing the remnants of such dead stars.
If we zoom out far enough, the structure of space looks like a giant cobweb! The cosmic web is the large-scale backbone of the universe, made up mainly of a mysterious substance known as dark matter and laced with gas, upon which galaxies are built. Roman will find precise distances for more than 10 million galaxies to map the structure of the cosmos, helping astronomers figure out why the expansion of the universe is speeding up.
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A new image from NASA's James Webb Space Telescope reveals a remarkable cosmic sight: at least 17 concentric dust rings emanating from a pair of stars. Just 5,300 light-years from Earth, the star duo are collectively known as Wolf-Rayet 140. Each ring was created when the two stars came close together and their stellar winds (streams of gas they blow into space) collided so forcefully that some of the gas was compressed into dust. The stars' orbits bring them together about once every eight years, and forms a half-shell of dust that looks like a ring from our perspective. Like a cosmic fingerprint, the 17 rings reveal more than a century of stellar interactions—and the "fingerprint" belonging to Wolf-Rayet 140 may be equally unique. Other Wolf-Rayet stars produce dust, but no other pair are known to produce rings quite like Wolf-Rayet 140.
Learn more about Wolf-Rayet 140.
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Does the object in this image look like a mirror? Maybe not, but that’s exactly what it is! To be more precise, it’s a set of mirrors that will be used on an X-ray telescope. But why does it look nothing like the mirrors you’re familiar with? To answer that, let’s first take a step back. Let’s talk telescopes.
The basic function of a telescope is to gather and focus light to amplify the light’s source. Astronomers have used telescopes for centuries, and there are a few different designs. Today, most telescopes use curved mirrors that magnify and focus light from distant objects onto your eye, a camera, or some other instrument. The mirrors can be made from a variety of materials, including glass or metal.
Space telescopes like the James Webb and Hubble Space Telescopes use large mirrors to focus light from some of the most distant objects in the sky. However, the mirrors must be tailored for the type and range of light the telescope is going to capture—and X-rays are especially hard to catch.
X-rays tend to zip through most things. This is because X-rays have much smaller wavelengths than most other types of light. In fact, X-rays can be smaller than a single atom of almost every element. When an X-ray encounters some surfaces, it can pass right between the atoms!
Doctors use this property of X-rays to take pictures of what’s inside you. They use a beam of X-rays that mostly passes through skin and muscle but is largely blocked by denser materials, like bone. The shadow of what was blocked shows up on the film.
This tendency to pass through things includes most mirrors. If you shoot a beam of X-rays into a standard telescope, most of the light would go right through or be absorbed. The X-rays wouldn’t be focused by the mirror, and we wouldn’t be able to study them.
X-rays can bounce off a specially designed mirror, one turned on its side so that the incoming X-rays arrive almost parallel to the surface and glance off it. At this shallow angle, the space between atoms in the mirror's surface shrinks so much that X-rays can't sneak through. The light bounces off the mirror like a stone skipping on water. This type of mirror is called a grazing incidence mirror.
Telescope mirrors curve so that all of the incoming light comes to the same place. Mirrors for most telescopes are based on the same 3D shape — a paraboloid. You might remember the parabola from your math classes as the cup-shaped curve. A paraboloid is a 3D version of that, spinning it around the axis, a little like the nose cone of a rocket. This turns out to be a great shape for focusing light at a point.
Mirrors for visible and infrared light and dishes for radio light use the “cup” portion of that paraboloid. For X-ray astronomy, we cut it a little differently to use the wall. Same shape, different piece. The mirrors for visible, infrared, ultraviolet, and radio telescopes look like a gently-curving cup. The X-ray mirror looks like a cylinder with very slightly angled walls.
The image below shows how different the mirrors look. On the left is one of the Chandra X-ray Observatory’s cylindrical mirrors. On the right you can see the gently curved round primary mirror for the Stratospheric Observatory for Infrared Astronomy telescope.
If we use just one grazing incidence mirror in an X-ray telescope, there would be a big hole, as shown above (left). We’d miss a lot of X-rays! Instead, our mirror makers fill in that cylinder with layers and layers of mirrors, like an onion. Then we can collect more of the X-rays that enter the telescope, giving us more light to study.
Nested mirrors like this have been used in many X-ray telescopes. Above is a close-up of the mirrors for an upcoming observatory called the X-ray Imaging and Spectroscopy Mission (XRISM, pronounced “crism”), which is a Japan Aerospace Exploration Agency (JAXA)-led international collaboration between JAXA, NASA, and the European Space Agency (ESA).
The XRISM mirror assembly uses thin, gold-coated mirrors to make them super reflective to X-rays. Each of the two assemblies has 1,624 of these layers packed in them. And each layer is so smooth that the roughest spots rise no more than one millionth of a millimeter.
Why go to all this trouble to collect this elusive light? X-rays are a great way to study the hottest and most energetic areas of the universe! For example, at the centers of certain galaxies, there are black holes that heat up gas, producing all kinds of light. The X-rays can show us light emitted by material just before it falls in.
Stay tuned to NASA Universe on Twitter and Facebook to keep up with the latest on XRISM and other X-ray observatories.
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