Gravity has been making waves - literally. Earlier this month, the Nobel Prize in Physics was awarded for the first direct detection of gravitational waves two years ago. But astronomers just announced another huge advance in the field of gravitational waves - for the first time, we’ve observed light and gravitational waves from the same source.
There was a pair of orbiting neutron stars in a galaxy (called NGC 4993). Neutron stars are the crushed leftover cores of massive stars (stars more than 8 times the mass of our sun) that long ago exploded as supernovas. There are many such pairs of binaries in this galaxy, and in all the galaxies we can see, but something special was about to happen to this particular pair.
Each time these neutron stars orbited, they would lose a teeny bit of gravitational energy to gravitational waves. Gravitational waves are disturbances in space-time - the very fabric of the universe - that travel at the speed of light. The waves are emitted by any mass that is changing speed or direction, like this pair of orbiting neutron stars. However, the gravitational waves are very faint unless the neutron stars are very close and orbiting around each other very fast.
As luck would have it, the teeny energy loss caused the two neutron stars to get a teeny bit closer to each other and orbit a teeny bit faster. After hundreds of millions of years, all those teeny bits added up, and the neutron stars were *very* close. So close that … BOOM! … they collided. And we witnessed it on Earth on August 17, 2017.
Credit: National Science Foundation/LIGO/Sonoma State University/A. Simonnet
A couple of very cool things happened in that collision - and we expect they happen in all such neutron star collisions. Just before the neutron stars collided, the gravitational waves were strong enough and at just the right frequency that the National Science Foundation (NSF)’s Laser Interferometer Gravitational-Wave Observatory (LIGO) and European Gravitational Observatory’s Virgo could detect them. Just after the collision, those waves quickly faded out because there are no longer two things orbiting around each other!
LIGO is a ground-based detector waiting for gravitational waves to pass through its facilities on Earth. When it is active, it can detect them from almost anywhere in space.
The other thing that happened was what we call a gamma-ray burst. When they get very close, the neutron stars break apart and create a spectacular, but short, explosion. For a couple of seconds, our Fermi Gamma-ray Telescope saw gamma-rays from that explosion. Fermi’s Gamma-ray Burst Monitor is one of our eyes on the sky, looking out for such bursts of gamma-rays that scientists want to catch as soon as they’re happening.
And those gamma-rays came just 1.7 seconds after the gravitational wave signal. The galaxy this occurred in is 130 million light-years away, so the light and gravitational waves were traveling for 130 million years before we detected them.
After that initial burst of gamma-rays, the debris from the explosion continued to glow, fading as it expanded outward. Our Swift, Hubble, Chandra and Spitzer telescopes, along with a number of ground-based observers, were poised to look at this afterglow from the explosion in ultraviolet, optical, X-ray and infrared light. Such coordination between satellites is something that we’ve been doing with our international partners for decades, so we catch events like this one as quickly as possible and in as many wavelengths as possible.
Astronomers have thought that neutron star mergers were the cause of one type of gamma-ray burst - a short gamma-ray burst, like the one they observed on August 17. It wasn’t until we could combine the data from our satellites with the information from LIGO/Virgo that we could confirm this directly.
This event begins a new chapter in astronomy. For centuries, light was the only way we could learn about our universe. Now, we’ve opened up a whole new window into the study of neutron stars and black holes. This means we can see things we could not detect before.
The first LIGO detection was of a pair of merging black holes. Mergers like that may be happening as often as once a month across the universe, but they do not produce much light because there’s little to nothing left around the black hole to emit light. In that case, gravitational waves were the only way to detect the merger.
Image Credit: LIGO/Caltech/MIT/Sonoma State (Aurore Simonnet)
The neutron star merger, though, has plenty of material to emit light. By combining different kinds of light with gravitational waves, we are learning how matter behaves in the most extreme environments. We are learning more about how the gravitational wave information fits with what we already know from light - and in the process we’re solving some long-standing mysteries!
Want to know more? Get more information HERE.
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Welcome to our 6th annual annual Black Hole Friday! Check out these black hole deals from the past year as you prepare to head out for a shopping spree or hunker down at home to avoid the crowds.
First things first, black holes have one basic rule: They are so incredibly dense that to escape their surface you’d have to travel faster than light. But light speed is the cosmic speed limit . . . so nothing can escape a black hole’s surface!
Some black holes form when a very large star dies in a supernova explosion and collapses into a superdense object. This is even more jam-packed than the crowds at your local mall — imagine an object 10 times more massive than the Sun squeezed into a sphere with the diameter of New York City!
Some of these collapsing stars also signal their destruction with a huge burst of gamma rays. Our Fermi Gamma-ray Space Telescope and Neil Gehrels Swift Observatory continuously seek out the signals of these gamma ray bursts — black hole birth announcements that come to us from across the universe.
There are loads of stellar mass black holes, which are just a few 10s of times the Sun’s mass, in our home galaxy alone — maybe even hundreds of millions of them! Our Neutron Star Interior Composition Explorer, or NICER for short, experiment on the International Space Station has been studying some of those relatively nearby black holes.
Near one black hole called GRS 1915+105, NICER found disk winds — fast streams of gas created by heat or pressure. Scientists are still figuring out some puzzles about these types of wind. Where do they come from, for example? And do they change the way material falls into the black hole? Every new example of these disk winds helps astronomers get closer to answering those questions.
But stellar mass black holes aren’t the only ones out there. At the center of nearly every large galaxy lies a supermassive black hole — one with the mass of millions or billions of Suns smooshed into a region no bigger than our solar system.
There’s still some debate about how these monsters form, but astronomers agree that they certainly can collide and combine when their host galaxies collide and combine. Those black holes will have a lot of gas and dust around them. As that material is pulled into the black hole it will heat up due to friction and other forces, causing it to emit light. A group of scientists wondered what light it would produce and created this mesmerizing visualization showing that most of the light produced around these two black holes is UV or X-ray light. We can’t see those wavelengths with our own eyes, but many telescopes can. Models like this could help scientists know what to look for to spot a merger.
It also turns out that these supermassive black holes are the source of some of the brightest objects in the gamma ray sky! In a type of galaxy called active galactic nuclei (also called “AGN” for short) the central black hole is surrounded by a disk of gas and dust that’s constantly falling into the black hole.
But not only that, some of those AGN have jets of energetic particles that are shooting out from near the black hole at nearly the speed of light! Scientists are studying these jets to try to understand how black holes — which pull everything in with their huge amounts of gravity — provide the energy needed to propel the particles in these jets. If that jet is pointed directly at us, it can appear super-bright in gamma rays and we call it a blazar. These blazars make up more than half of the sources our Fermi space telescope sees.
Sometimes scientists get a two-for-one kind of deal when they’re looking for black holes. Our colleagues at the IceCube Neutrino Observatory actually caught a particle from a blazar 4 billion light-years away. IceCube lies a mile under the ice in Antarctica and uses the ice itself to detect neutrinos, tiny speedy particles that weigh almost nothing and rarely interact with anything. When IceCube caught a super-high-energy neutrino and traced its origin to a specific area of the sky, they turned to the astronomical community to pinpoint the source.
Our Fermi spacecraft scans the entire sky about every three hours and for months it had observed a blazar producing more gamma rays than usual. Flaring is a common characteristic in blazars, so this didn’t attract special attention. But when the alert from IceCube came through, scientists realized the neutrino and the gamma rays came from the same patch of sky! This method of using two or more kinds of signals to learn about one event or object is called multimessenger astronomy, and it’s helping us learn a lot about the universe.
Get more fun facts and information about black holes HERE and follow us on social media today for other cool facts and findings about black holes!
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The James Webb Space Telescope is launching on December 22, 2021. Webb’s revolutionary technology will explore every phase of cosmic history—from within our solar system to the most distant observable galaxies in the early universe, to everything in between. Postdoctoral Research Associate Naomi Rowe-Gurney will be taking your questions about Webb and Webb science in an Answer Time session on Tuesday, December 14 from noon to 1 p.m EST here on our Tumblr!
🚨 Ask your questions now by visiting http://nasa.tumblr.com/ask.
Dr. Naomi Rowe-Gurney recently completed her PhD at the University of Leicester and is now working at NASA Goddard Space Flight Center as a postdoc through Howard University. As a planetary scientist for the James Webb Space Telescope, she’s an expert on the atmospheres of the ice giants in our solar system — Uranus and Neptune — and how the Webb telescope will be able to learn more about them.
Webb is so big it has to fold origami-style to fit into its rocket and will unfold like a “Transformer” in space.
Webb is about 100 times more powerful than the Hubble Space Telescope and designed to see the infrared, a region Hubble can only peek at.
With unprecedented sensitivity, it will peer back in time over 13.5 billion years to see the first galaxies born after the Big Bang––a part of space we’ve never seen.
It will study galaxies near and far, young and old, to understand how they evolve.
Webb will explore distant worlds and study the atmospheres of planets orbiting other stars, known as exoplanets, searching for chemical fingerprints of possible habitability.
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Scotland is part of the bedrock of geology, so to speak.
In the late 18th century, Scottish farmer and scientist James Hutton helped found the science of geology. Observing how wind and water weathered rocks and deposited layers of soil at his farm in Berwickshire, Hutton made a conceptual leap into a deeper and expansive view of time. After spending decades observing the processes of erosion and sedimentation, and traveling the Scottish countryside in search of fossils, stream cuts and interesting rock formations, Hutton became convinced that Earth had to be much older than 6,000 years, the common belief in Western civilization at the time.
In 1788, a boat trip to Siccar Point, a rocky promontory in Berwickshire, helped crystallize Hutton’s view. The Operational Land Imager (OLI) on Landsat 8 acquired this image of the area on June 4, 2018, top. A closer view of Siccar Point is below.
At Siccar Point, Hutton was confronted with the juxtaposition of two starkly different types of rock—a gently sloping bed of young red sandstone that was over a near vertical slab of older graywacke that had clearly undergone intensive heating, uplift, buckling, and folding. Hutton argued to his two companions on the boat that the only way to get the two rock formations jammed up against one another at such an odd angle was that an enormous amount of time must have elapsed between when they had been deposited at the bottom of the ocean.
He was right.
Read more: https://go.nasa.gov/2OBnyJ8
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Got basic questions about the James Webb Space Telescope and what amazing things we’ll learn from it? We’ve got your answers right here!
The James Webb Space Telescope, or Webb, is our upcoming infrared space observatory, which will launch in 2021. It will spy the first luminous objects that formed in the universe and shed light on how galaxies evolve, how stars and planetary systems are born, and how life could form on other planets.
Our James Webb Space Telescope is a giant space telescope that observes infrared light. Rather than a replacement for the Hubble Space Telescope, it’s a scientific successor that will complement and extend its discoveries.
Being able to see longer wavelengths of light than Hubble and having greatly improved sensitivity will let Webb look further back in time to see the first galaxies that formed in the early universe, and to peer inside dust clouds where stars and planetary systems are forming today.
We have yet to observe the era of our universe’s history when galaxies began to form.
We have a lot to learn about how galaxies got supermassive black holes in their centers, and we don't really know whether the black holes caused the galaxies to form or vice versa.
We can't see inside dust clouds with high resolution, where stars and planets are being born nearby, but Webb will be able to do just that.
We don't know how many planetary systems might be hospitable to life, but Webb could tell whether some Earth-like planets have enough water to have oceans.
We don't know much about dark matter or dark energy, but we expect to learn more about where the dark matter is now, and we hope to learn the history of the acceleration of the universe that we attribute to dark energy.
And then, there are the surprises we can't imagine!
By viewing the universe at infrared wavelengths with such sensitivity, Webb will show us things never before seen by any other telescope. For example, it is only at infrared wavelengths that we can see the first stars and galaxies forming after the Big Bang.
And it is with infrared light that we can see stars and planetary systems forming inside clouds of dust that are opaque to visible light, such as in the above visible and infrared light comparison image of the Carina Nebula.
YES, Webb will take amazing pictures! We are going to be looking at things we've never seen before and looking at things we have seen before in completely new ways.
The beauty and quality of an astronomical image depends on two things: the sharpness and the number of pixels in the camera. On both of these counts, Webb is very similar to, and in many ways better than, Hubble.
Additionally Webb can see orange and red visible light. Webb images will be different, but just as beautiful as Hubble's. Above, there is another comparison of infrared and visible light Hubble images, this time of the Monkey Head Nebula.
The first targets for Webb will be determined through a process similar to that used for the Hubble Space Telescope and will involve our experts, the European Space Agency (ESA), the Canadian Space Agency (CSA), and scientific community participants.
The first engineering target will come before the first science target and will be used to align the mirror segments and focus the telescope. That will probably be a relatively bright star or possibly a star field.
Webb is designed to look deeper into space to see the earliest stars and galaxies that formed in the universe and to look deep into nearby dust clouds to study the formation of stars and planets.
In order to do this, Webb has a much larger primary mirror than Hubble (2.5 times larger in diameter, or about 6 times larger in area), giving it more light-gathering power. It also will have infrared instruments with longer wavelength coverage and greatly improved sensitivity than Hubble.
Finally, Webb will operate much farther from Earth, maintaining its extremely cold operating temperature, stable pointing and higher observing efficiency than with the Earth-orbiting Hubble.
Webb will be able to tell us the composition of the atmospheres of planets outside our solar system, aka exoplanets. It will observe planetary atmospheres through the transit technique. A transit is when a planet moves across the disc of its parent star.
Webb will also carry coronographs to enable photography of exoplanets (planets outside our solar system) near bright stars (if they are big and bright and far from the star), but they will be only "dots," not grand panoramas. Coronographs block the bright light of stars, which could hide nearby objects like exoplanets.
Consider how far away exoplanets are from us, and how small they are by comparison to this distance! We didn’t even know what Pluto really looked like until we were able to send an observatory to fly right near it in 2015, and Pluto is in our own solar system!
Yes! Webb will be able to observe the planets at or beyond the orbit of Mars, satellites, comets, asteroids and objects in the distant, icy Kuiper Belt.
Many important molecules, ices and minerals have strong characteristic signatures at the wavelengths Webb can observe.
Webb will also monitor the weather of planets and their moons.
Because the telescope and instruments have to be kept cold, Webb’s protective sunshield will block the inner solar system from view. This means that the Sun, Earth, Moon, Mercury, and Venus, and of course Sun-grazing comets and many known near-Earth objects cannot be observed.
Webb will be able to see what the universe looked like around a quarter of a billion years (possibly back to 100 million years) after the Big Bang, when the first stars and galaxies started to form.
Webb will launch in 2021 from French Guiana on a European Space Agency Ariane 5 rocket.
Webb’s mission lifetime after launch is designed to be at least 5-1/2 years, and could last longer than 10 years. The lifetime is limited by the amount of fuel used for maintaining the orbit, and by the possibility that Webb’s components will degrade over time in the harsh environment of space.
Looking for some more in-depth FAQs? You can find them HERE.
Learn more about the James Webb Space Telescope HERE, or follow the mission on Facebook, Twitter and Instagram.
IMAGE CREDITS Carina Nebula: ESO/T. Preibisch Monkey Head Nebula: NASA, ESA, the Hubble Heritage Team (STScI/AURA), and J. Hester
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At that unimaginable distance, it takes the radio signal almost 16 hours to arrive. The spacecraft is Voyager 2, which launched 40 years ago this month. It's still operating, sending back dispatches from the dark reaches well beyond the orbit of Pluto. Even now, scientists are still actively exploring the outer boundaries of the solar system using Voyager 2, decades after its "Grand Tour" of the giant planets Jupiter, Saturn, Uranus and Neptune revealed their splendors like never before. This week, we recall 10 highlights from one of the most epic voyages in human history.
Voyager 2 set out from Earth on Aug. 20, 1977. Even though it launched before its twin spacecraft, Voyager 1, it carried the '2' moniker because mission planners knew its trajectory would bring it to Jupiter after Voyager 1's arrival there.
Voyager 2's trajectory was special because it took advantage of a rare orbital alignment to fly by all four gas giant planets: Jupiter, Saturn, Uranus and Neptune. It was the first, and so far the only, spacecraft to carry out a close-up reconnaissance of Uranus and Neptune.
Voyager 2 flew by Jupiter in April 1979, capturing striking images of the planet's volcanic moon Io and its violent storms larger than the entire Earth.
Jupiter has its own ring system, and Voyager 2 provided the first pictures.
During its Jupiter encounter, Voyager 2 obtained close-up looks at Jupiter's moon Europa, including linear cracks and other features which first led scientists to realize Europa probably hides a vast sea of liquid water beneath an icy shell, the first known world outside Earth that could have an ocean.
Voyager 2 zoomed through the Saturn system in August 1981. It saw hints of mysterious features that the Cassini mission would later reveal in stunning detail, including Enceladus, with its bright surface that suggested geologic activity, and Saturn's intriguing hexagonal jet stream.
In January 1984, Voyager offered humanity its first detailed look at the seventh planet, Uranus, the only one tilted on its side relative to the Sun. Voyager images revealed 11 new moons, including Juliet, Puck, Cressida, Rosalind and Ophelia. The moon Miranda presented a bizarre landscape that left scientists debating its origins for years. Voyager also captured views of the planet's lacy rings, and found that it is the coldest in the solar system, at minus 353 degrees Fahrenheit (59 Kelvin).
After picking up a gravitational speed boost at each previous planetary encounter, by the time Voyager reached Neptune it shot through the entire system of Neptunian rings and moons in a matter of hours. Voyager saw a titanic storm in Neptune's windy atmosphere, discovered new moons, and revealed active geysers erupting on Triton's frigid surface.
Although their cameras are no longer functioning, other key scientific instruments on board both Voyager spacecraft are still collecting data. Voyager 1 is exploring the boundary between the Sun's realm and interstellar space. Voyager 2 hasn't traveled quite as far. In September 2007, it crossed the termination shock (where the speed of the solar wind of charged particles drops below the speed of sound) at a point about 84 Astronomical Units from the Sun (more than twice the distance to Pluto). See https://go.nasa.gov/2uwrndb
Voyager's mission is far from over. Engineers estimate the spacecraft will have enough power to operate into the mid-2020s. You can ride along at www.jpl.nasa.gov/voyager, or by following @NASAVoyager on Twitter and by downloading our free 3-D space simulation software, Eyes on the Solar System at eyes.nasa.gov.
One more thing: Inspired by the messages of goodwill carried on Voyager's Golden Record, you're invited to send a short, uplifting message to Voyager and all that lies beyond it via social media. With input from the Voyager team and a public vote, one of these messages will be selected for us to beam into interstellar space on Sept. 5, 2017—the 40th anniversary of Voyager 1's launch. Post your message on social media with the tag #MessageToVoyager by Aug 15. Details: www.jpl.nasa.gov/voyager/message/
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Each month, we highlight a different research topic on the International Space Station. In May, our focus is physical science.
The space station is a laboratory unlike any on Earth; on-board, we can control gravity as a variable and even remove it entirely from the equation. Removing gravity reveals fundamental aspects of physics hidden by force-dependent phenomena such as buoyancy-driven convection and sedimentation.
Gravity often masks or distorts subtle forces such as surface tension and diffusion; on space station, these forces have been harnessed for a wide variety of physical science applications (combustion, fluids, colloids, surface wetting, boiling, convection, materials processing, etc).
Other examples of observations in space include boiling in which bubbles do not rise, colloidal systems containing crystalline structures unlike any seen on Earth and spherical flames burning around fuel droplets. Also observed was a uniform dispersion of tin particles in a liquid melt, instead of rising to the top as would happen in Earth’s gravity.
So what? By understanding the fundamentals of combustion and surface tension, we may make more efficient combustion engines; better portable medical diagnostics; stronger, lighter alloys; medicines with longer shelf-life, and buildings that are more resistant to earthquakes.
Findings from physical science research on station may improve the understanding of material properties. This information could potentially revolutionize development of new and improved products for use in everything from automobiles to airplanes to spacecraft.
For more information on space station research, follow @ISS_Research on Twitter!
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1. A Ceres of Fortunate Events
Our Dawn mission continues its exploration at Ceres, and the team is working with the data coming back to Earth, looking for explanations for the tiny world’s strange features. Follow Dawn’s expedition HERE.
2. Icy Moon Rendezvous
One of the most interesting places in the entire solar system is Saturn’s moon Enceladus, with its underground ocean and spectacular geyser plume. This month, the Cassini spacecraft will be buzzing close by Enceladus several times, the last such encounters of the mission. On October 14, Cassini will perform a targeted flyby at a distance of just 1,142 miles (1,838 kilometers) over the moon’s northern latitudes. Ride along with Cassini HERE.
3. Make Your Own Mars Walkabout
You can retrace Opportunity’s journey, see where the Curiosity rover is now, or even follow along with fictional astronaut Mark Watney from The Martian movie using the free online app MarsTrek. The app lets you zoom in on almost any part of the planet and see images obtained by our spacecraft, so you can plan your on Red Planet excursion. Take a hike HERE.
4. Elusive Features on Jupiter
New imagery from our Hubble Space Telescope is capturing details never before seen on Jupiter. High-resolution maps and spinning globes, rendered in the 4K Ultra HD format, reveal an elusive wave and changes to Jupiter’s Great Red Spot. Explore Jupiter HERE.
5. Mr. Blue Sky
Another week, another amazing picture from Pluto. The first color images of Pluto’s atmospheric hazes, returned by our New Horizons spacecraft last week, reveal that the hazes are blue. Who would have expected a blue sky in the Kuiper Belt? Most of the data collected during July’s Pluto flyby remains aboard the spacecraft, but the team publishes new batches of pictures and other findings on a weekly basis. Keep up with the latest HERE.
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The stunning Veil Nebula was created after a star about 20 times the mass of the Sun lived fast and died young – exploding in a cataclysmic release of energy known as a supernova.
In a violent stellar explosion roughly 10,000 years ago, shockwaves and debris created this staggeringly beautiful trail through space. The picture above shows a mosaic of six Hubble Space Telescope pictures, a small area roughly two light-years across, and only a tiny fraction of the nebula's vast 110 light-year structure.
To learn more about Hubble’s celebration of Nebula November and see new nebula images, visit our space telescope's nebula page.
You can also keep up with Hubble on Twitter, Instagram, Facebook, and Flickr!
Image credits: NASA, ESA, and the Hubble Heritage Team (STScI/AURA)
Our latest space telescope, Transiting Exoplanet Survey Satellite (TESS), launched in April. This week, planet hunters worldwide received all the data from the first two months of its planet search. This view, from four cameras on TESS, shows just one region of Earth’s southern sky.
The Transiting Exoplanet Survey Satellite (TESS) captured this strip of stars and galaxies in the southern sky during one 30-minute period in August. Created by combining the view from all four of its cameras, TESS images will be used to discover new exoplanets. Notable features in this swath include the Large and Small Magellanic Clouds and a globular cluster called NGC 104. The brightest stars, Beta Gruis and R Doradus, saturated an entire column of camera detector pixels on the satellite’s second and fourth cameras.
Credit: NASA/MIT/TESS
The data in the images from TESS will soon lead to discoveries of planets beyond our solar system – exoplanets. (We’re at 3,848 so far!)
But first, all that data (about 27 gigabytes a day) needs to be processed. And where do space telescopes like TESS get their data cleaned up? At the Star Wash, of course!
TESS sends about 10 billion pixels of data to Earth at a time. A supercomputer at NASA Ames in Silicon Valley processes the raw data, turning those pixels into measures of a star’s brightness.
And that brightness? THAT’S HOW WE FIND PLANETS! A dip in a star’s brightness can reveal an orbiting exoplanet in transit.
TESS will spend a year studying our southern sky, then will turn and survey our northern sky for another year. Eventually, the space telescope will observe 85 percent of Earth’s sky, including 200,000 of the brightest and closest stars to Earth.
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A quarter-century ago, the Solar and Heliospheric Observatory (SOHO) launched to space. Its 25 years of data have changed the way we think about the Sun — illuminating everything from the Sun’s inner workings to the constant changes in its outermost atmosphere.
SOHO — a joint mission of the European Space Agency and NASA — carries 12 instruments to study different aspects of the Sun. One of the gamechangers was SOHO’s coronagraph, a type of instrument that uses a solid disk to block out the bright face of the Sun and reveal the relatively faint outer atmosphere, the corona. With SOHO’s coronagraph, scientists could image giant eruptions of solar material and magnetic fields, called coronal mass ejections, or CMEs. SOHO’s images revealed shape and structure of CMEs in breathtaking detail.
These solar storms can impact robotic spacecraft in their path, or — when intense and aimed at Earth — threaten astronauts on spacewalks and even disrupt power grids on the ground. SOHO is particularly useful in viewing Earth-bound storms, called halo CMEs — so called because when a CME barrels toward us on Earth, it appears circular, surrounding the Sun, much like watching a balloon inflate by looking down on it.
Before SOHO, the scientific community debated whether or not it was even possible to witness a CME coming straight toward us. Today, SOHO images are the backbone of space weather prediction models, regularly used in forecasting the impacts of space weather events traveling toward Earth.
Beyond the day-to-day monitoring of space weather, SOHO has been able to provide insight about our dynamic Sun on longer timescales as well. With 25 years under its belt, SOHO has observed a full magnetic cycle — when the Sun’s magnetic poles switch places and then flip back again, a process that takes about 22 years in total. This trove of data has led to revolutions in solar science: from revelations about the behavior of the solar core to new insight into space weather events that explode from the Sun and travel throughout the solar system.
Data from SOHO, sonified by the Stanford Experimental Physics Lab, captures the Sun’s natural vibrations and provides scientists with a concrete representation of its dynamic movements.
The legacy of SOHO’s instruments — such as the extreme ultraviolet imager, the first of its kind to fly in orbit — also paved the way for the next generation of NASA solar satellites, like the Solar Dynamics Observatory and STEREO. Even with these newer instruments now in orbit, SOHO’s data remains an invaluable part of solar science, producing nearly 200 scientific papers every year.
Relatively early in its mission, SOHO had a brush with catastrophe. During a routine calibration procedure in June 1998, the operations team lost contact with the spacecraft. With the help of a radio telescope in Arecibo, the team eventually located SOHO and brought it back online by November of that year. But luck only held out so long: Complications from the near loss emerged just weeks later, when all three gyroscopes — which help the spacecraft point in the right direction — failed. The spacecraft was no longer stabilized. Undaunted, the team’s software engineers developed a new program that would stabilize the spacecraft without the gyroscopes. SOHO resumed normal operations in February 1999, becoming the first spacecraft of its kind to function without gyroscopes.
SOHO’s coronagraph have also helped the Sun-studying mission become the greatest comet finder of all time. The mission’s data has revealed more than 4,000 comets to date, many of which were found by citizen scientists. SOHO’s online data during the early days of the mission made it possible for anyone to carefully scrutinize a image and potentially spot a comet heading toward the Sun. Amateur astronomers from across the globe joined the hunt and began sending their findings to the SOHO team. To ease the burden on their inboxes, the team created the SOHO Sungrazer Project, where citizen scientists could share their findings.
Keep up with the latest SOHO findings at nasa.gov/soho, and follow along with @NASASun on Twitter and facebook.com/NASASunScience.
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