Solar System: 5 Things To Know This Week

Galaxies: Cities of Stars

Galaxies are like cities made of oodles of stars, gas, and dust bound together by gravity. These beautiful cosmic structures come in many shapes and sizes. Though there are a slew of galaxies in the universe, there are only a few we can see with the unaided eye or backyard telescope.

How many types are out there, how’d so many of them wind up with weird names, and how many stars live inside them? Hold tight while we explore these cosmic metropolises.

Galaxies come in lots of different shapes, sizes, and colors. But astronomers have noticed that there are mainly three types: spiral, elliptical, and irregular.

Spiral galaxies, like our very own Milky Way, look similar to pinwheels! These galaxies tend to have a bulging center heavily populated by stars, with elongated, sparser arms of dust and stars that wrap around it. Usually, there’s a huge black hole hiding at the center, like the Milky Way’s Sagittarius A* (pronounced A-star). Our galactic neighbor, Andromeda (also known as Messier 31 or M31), is also a spiral galaxy!

Elliptical galaxies tend to be smooth spheres of gas, dust, and stars. Like spiral galaxies, their centers are typically bulges surrounded by a halo of stars (but minus the epic spiral arms). The stars in these galaxies tend to be spread out neatly throughout the galaxies and are some of the oldest stars in the universe! Messier 87 (M87) is one example of an elliptical galaxy. The supermassive black hole at its center was recently imaged by the Event Horizon Telescope.

Irregular galaxies are, well … a bit strange. They have one-of-a-kind shapes, and many just look like messy blobs. Astronomers think that irregular galaxies' uniqueness is a result of interactions with other galaxies, like collisions! Galaxies are so big, with so much distance between their stars, that even when they collide, their stars usually do not. Galaxy collisions have been important to the formation of our Milky Way and others. When two galaxies collide, clouds of gas, dust, and stars are violently thrown around, forming an entirely new, larger one! This could be the cause of some irregular galaxies seen today.

Now that we know the different types of galaxies, what about how many stars they contain? Galaxies can come in lots of different sizes, even among each type. Dwarf galaxies, the smallest version of spiral, elliptical, and irregular galaxies, are usually made up of 1,000 to billions of stars. Compared to our Milky Way’s 200 to 400 billion stars, the dwarf galaxy known as the Small Magellanic Cloud is tiny, with just a few hundred million stars! IC 1101, on the other hand, is one of the largest elliptical galaxies found so far, containing almost 100 trillion stars.

Ever wondered how galaxies get their names? Astronomers have a number of ways to name galaxies, like the constellations we see them in or what we think they resemble. Some even have multiple names!

A more formal way astronomers name galaxies is with two-part designations based on astronomical catalogs, published collections of astronomical objects observed by specific astronomers, observatories, or spacecraft. These give us cryptic names like M51 or Swift J0241.3-0816. Catalog names usually have two parts:

A letter, word, or short acronym that identifies a specific astronomical catalog.

A sequence of numbers and/or letters that uniquely identify the galaxy within that catalog.

For M51, the “M” comes from the Messier catalog, which Charles Messier started compiling in 1771, and the "51" is because it’s the 51st entry in that catalog. Swift J0241.3-0816 is a galaxy observed by the Swift satellite, and the numbers refer to its location in the sky, similar to latitude and longitude on Earth.

There’s your quick intro to galaxies, but there’s much more to learn about them. Keep up with NASA Universe on Facebook and Twitter where we post regularly about galaxies.

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Why Do Some Galactic Unions Lead to Doom?

Three images from our Spitzer Space Telescope show pairs of galaxies on the cusp of cosmic consolidations. Though the galaxies appear separate now, gravity is pulling them together, and soon they will combine to form new, merged galaxies. Some merged galaxies will experience billions of years of growth. For others, however, the merger will kick off processes that eventually halt star formation, dooming the galaxies.

Only a few percent of galaxies in the nearby universe are merging, but galaxy mergers were more common between 6 billion and 10 billion years ago, and these processes profoundly shaped our modern galactic landscape. Scientists study nearby galaxy mergers and use them as local laboratories for that earlier period in the universe's history. The survey has focused on 200 nearby objects, including many galaxies in various stages of merging.

Merging galaxies in the nearby universe appear especially bright to infrared observatories like Spitzer. In these images, different colors correspond to different wavelengths of infrared light, which are not visible to the human eye. Blue corresponds to 3.6 microns, and green corresponds to 4.5 microns - both strongly emitted by stars. Red corresponds to 8.0 microns, a wavelength mostly emitted by dust.

Read more: https://go.nasa.gov/2VioFB0.

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25 Years of Exploring the Universe with NASA's Chandra Xray Observatory

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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What’s Up for May 2016?

What's Up for May? Two huge solar system highlights: Mercury transits the sun and Mars is closer to Earth than it has been in 11 years.

On May 9, wake up early on the west coast or step out for coffee on the east coast to see our smallest planet cross the face of the sun. The transit will also be visible from most of South America, western Africa and western Europe.

A transit occurs when one astronomical body appears to move across the face of another as seen from Earth or from a spacecraft. But be safe! You'll need to view the sun and Mercury through a solar filter when looking through a telescope or when projecting the image of the solar disk onto a safe surface. Look a little south of the sun's Equator. It will take about 7 1/2 hours for the tiny planet's disk to cross the sun completely. Since Mercury is so tiny it will appear as a very small round speck, whether it's seen through a telescope or projected through a solar filter. The next Mercury transit will be Nov. 11, 2019.

Two other May highlights involve Mars. On May 22 Mars opposition occurs. That's when Mars, Earth and the sun all line up, with Earth directly in the middle.

Eight days later on May 30, Mars and Earth are nearest to each other in their orbits around the sun. Mars is over half a million miles closer to Earth at closest approach than at opposition. But you won't see much change in the diameter and brightness between these two dates. As Mars comes closer to Earth in its orbit, it appears larger and larger and brighter and brighter. 

During this time Mars rises after the sun sets. The best time to see Mars at its brightest is when it is highest in the sky, around midnight in May and a little earlier in June. 

Through a telescope you can make out some of the dark features on the planet, some of the lighter features and sometimes polar ice and dust storm-obscured areas showing very little detail.

After close approach, Earth sweeps past Mars quickly. So the planet appears large and bright for only a couple weeks. 

But don't worry if you miss 2016's close approach. 2018's will be even better, as Mars' close approach will be, well, even closer.

You can find out about our #JourneytoMars missions at mars.nasa.gov, and you can learn about all of our missions at http://www.nasa.gov.

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Tune in, Starliner! How NASA’s Near Space Network Powers Communications

On May 19, 2022, our partners at Boeing launched their Starliner CST-100 spacecraft to the International Space Station as a part of our Commercial Crew Program. This latest test puts the company one step closer to joining the SpaceX Crew Dragon in ferrying astronauts to and from the orbiting laboratory. We livestreamed the launch and docking at the International Space Station, but how? Let’s look at the communications and navigation infrastructure that makes these missions possible.

Primary voice and data communications are handled by our constellation of Tracking and Data Relay Satellites (TDRS), part of our Near Space Network. These spacecraft relay communications between the crewed vehicles and mission controllers across the country via terrestrial connections with TDRS ground stations in Las Cruces, New Mexico, and Guam, a U.S. territory in the Pacific Ocean.

TDRS, as the primary communications provider for the space station, is central to the services provided to Commercial Crew vehicles. All spacecraft visiting the orbiting laboratory need TDRS services to successfully complete their missions.

During launches, human spaceflight mission managers ensure that Commercial Crew missions receive all the TDRS services they need from the Near Space Operations Control Center at our Goddard Space Flight Center in Greenbelt, Maryland. There, communications engineers synthesize network components into comprehensive and seamless services for spacecraft as they launch, dock, undock, and deorbit from the space station.

Nearby, at our Flight Dynamics Facility, navigation engineers track the spacecraft on their ascent, leveraging years of experience supporting the navigation needs of crewed missions. Using tracking data sent to our Johnson Space Center in Houston and relayed to Goddard, these engineers ensure astronaut safety throughout the vehicles’ journey to the space station.

Additionally, our Search and Rescue office monitors emergency beacons on Commercial Crew vehicles from their lab at Goddard. In the unlikely event of a launch abort, the international satellite-aided search and rescue network will be able to track and locate these beacons, helping rescue professionals to return the astronauts safely. For this specific uncrewed mission, the search and rescue system onboard the Boeing Starliner will not be activated until after landing for ground testing.

To learn more about NASA’s Space Communications and Navigation (SCaN) services and technologies, visit  https://www.nasa.gov/directorates/heo/scan/index.html. To learn more about NASA’s Near Space Network, visit https://esc.gsfc.nasa.gov/projects/NSN.

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Crazyspacesuit: Were you aware of the Overview Effect before experiencing it?

Why We Celebrate Search and Rescue Technologies on 4/06

Today (4/06), we celebrate the special radio frequency transmitted by emergency beacons to the international search and rescue network. 

This 406 MHz frequency, used only for search and rescue, can be "heard" by satellites hundreds of miles above the ground! The satellites then "forward" the location of the beacon back to Earth, helping first responders locate people in distress worldwide, whether from a plane crash, a boating accident or other emergencies.

Our Search and Rescue office, based out of our Goddard Space Flight Center, researches and develops emergency beacon technology, passing the technology to companies who manufacture the beacons, making them available to the public at retail stores. The beacons are designed for personal, maritime and aviation use.

The search and rescue network, Cospas-Sarsat, is an international program that ensures the compatibility of distress alert services with the needs of users. Its current space segment relies on instruments onboard low-Earth and geosynchronous orbiting satellites, hundreds to thousands of miles above us. 

Space instruments forward distress signals to the search and rescue ground segment, which is operated by partner organizations around the world! They manage specific regions of the ground network. For example, the National Oceanic and Atmospheric Administration (NOAA) operates the region containing the United States, which reaches across the Atlantic and Pacific Oceans as well as parts of Central and South America.

NOAA notifies organizations that coordinate search and rescue efforts of a 406 MHz distress beacon's activation and location. Within the U.S., the U.S. Air Force responds to land-based emergencies and the U.S. Coast Guard responds to water-based emergencies. Local public service organizations like police and fire departments, as well as civilian volunteers, serve as first responders.

Here at NASA, we research, design and test search and rescue instruments and beacons to refine the existing network. Aeronautical beacon tests took place at our Langley Research Center in 2015. Using a 240-foot-high structure originally used to test Apollo spacecraft, our Search and Rescue team crashed three planes to test the survivability of these beacons, developing guidelines for manufacturers and installation into aircraft.

In the future, first responders will rely on a new constellation of search and rescue instruments on GPS systems on satellites in medium-Earth orbit, not hundreds, but THOUSANDS of miles overhead. These new instruments will enable the search and rescue network to locate a distress signal more quickly than the current system and achieve accuracy an order of magnitude better, from a half mile to approximately 300 feet. Our Search and Rescue office is developing second-generation 406 MHz beacons that make full use of this new system.

We will also incorporate these second-generation beacons into the Orion Crew Survival System. The Advanced Next-Generation Emergency Locator (ANGEL) beacons will be attached to astronaut life preservers. After splashdown, if the Orion crew exits the capsule due to an emergency, these beacons will make sure we know the exact location of floating astronauts! Our Johnson Space Center is testing this technology for used in future human spaceflight and exploration missions.

If you're the owner of an emergency beacon, remember that beacon registration is free, easy and required by law. 

To register your beacon, visit: beaconregistration.noaa.gov

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Science, Technology, Engineering and Math: STEM

Today is College Signing Day and we’re working with the White House to celebrate all graduating seniors and inspire more young people to Reach Higher and enroll in higher education.

Additionally, choosing a degree within a STEM (Science, Math, Engineering and Technology) field enables the United States to remain the global economic and technological leader. We feel that it’s our duty to help inspire the next generation of scientists, technologists, engineers and astronauts.

It’s important that each and every student feels empowered and equipped with the knowledge to solve tough problems, evaluate evidence and analyze information. These are all skills students can learn through studying a subjects in STEM.

College is one of the stepping stones to many careers, including becoming an astronaut! Here are a few of our astronauts on their college graduation day, along with their astronaut portrait. 

Astronaut Victor Glover

Undergraduate: California Polytechnic State University Graduate: Air University and Naval Postgraduate School Astronaut Class: 2013

Astronaut Reid Wiseman

Undergraduate: Rensselaer Polytechnic Institute Graduate: Johns hopkins University Astronaut Class: 2009

Astronaut Thomas Marshburn

Undergraduate: Davidson College Graduate: University of Virginia, Wake Forest University and University of Texas medical Branch Astronaut Class: 2004

Astronaut Karen Nyberg

Undergraduate: University of North Dakota Graduate: University of Texas at Austin Astronaut Class: 2000

Astronaut Bob Behnken

Undergraduate: Washington University Graduate: California Institute of Technology Astronaut Class: 2000

Astronaut Peggy Whitson

Undergraduate: Iowa Wesleyan College Graduate: Rice University Astronaut Class: 1996

Astronaut Joseph Acaba

Undergraduate: University of California Graduate: University of Arizona Astronaut Class: 2004

Astronaut Rex Walheim

Undergraduate: University of California, Berkeley Graduate: University of Houston Astronaut Class: 1996

Whether you want to be an astronaut, an engineer or the administrator of NASA, a college education opens a universe of possibilities:

Administrator Charles Bolden

Here, Administrator Bolden wears the jersey of Keenan Reynolds, a scholar athlete who graduates from the Naval Academy this year. His jersey is on its way to the college football hall of fame. Bolden holds a drawing of himself as a midshipman in the Navy. 

Deputy Administrator Dava Newman

Deputy Administrator Dava Newman sports her college shirt, along with Lisa Guerra, Technical Assistant to the Associate Administrator. Both women studied aerospace engineering at Notre Dame. 

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Bend Your Mind With Special Relativity

Ever dreamed of traveling nearly as fast as light? Zipping across the universe to check out the sights seems like it could be fun. But, not so fast. There are a few things you should know before you jump into your rocket. At near the speed of light, the day-to-day physics we know on Earth need a few modifications. And if you’re thinking Albert Einstein will be entering this equation, you’re right!

We live our daily lives using what scientists call Newtonian physics, as in Isaac Newton, the guy who had the proverbial apple fall on his head. Imagine that you are on a sidewalk, watching your friend walk toward the front of a bus as it drives away. The bus is moving at 30 mph. Your friend walks at 3 mph. To you, your friend is moving at 33 mph — you simply add the two speeds together. (The 30 mph the bus is moving plus 3 mph that your friend is moving inside the bus.) This is a simple example of Newtonian physics.

However, imagine that your friend on the bus turns on a flashlight, and you both measure the speed of its light. You would both measure it to be moving at 670 million mph (or 1 billion kilometers per hour) — this is the speed of light. Even though the flashlight is with your friend on the moving bus, you still both measure the speed of light to be exactly the same. Suddenly you see how Einstein’s physics is different from Newton’s.

This prediction was a key part of Einstein’s special theory of relativity: The speed of light is the same for any observer, no matter their relative speed. This leads to many seemingly weird effects.  

Before talking about those surprising effects, it’s good to take a moment to talk about point of view. For the rest of this discussion, we’ll assume that you’re at rest — sitting in one spot in space, not moving. And your friend is on a rocket ship that you measure to be traveling at 90% the speed of light. Neither of you is changing speed or direction. Scientists give this a fancy name — an “inertial frame of reference.”

With the stage set, now we can talk about a couple of super-weird effects of traveling near the speed of light. Relativity messes with simple things like distance and time, doing stuff that might blow your mind!

Let’s say you have a stick that is 36 inches long (91 centimeters). Your friend on the rocket doesn’t know the stick’s length, so they measure it by comparing it to a ruler they have as they zoom past you. They find your stick is just 16 inches (40 centimeters) long — less than half the length you measured! This effect is called length contraction. And if they were moving even faster, your friend would measure your stick to be even shorter. The cool thing about relativity is that both of those measurements are right! We see these effects in particle physics with fast-moving particles.

If your friend was traveling to our nearest neighbor star, Proxima Centauri, how far would they think it was? From Earth, we measure Proxima Centauri to be 4.2 light-years away (where one light-year is the distance light travels in a year, or about 5.8 trillion miles). However, your friend, who is traveling at 90% the speed of light in the rocket, would measure the distance between Earth and Proxima Centauri to be just over 1.8 light-years.

That’s just length … let’s talk about time!

Now let’s say you and your friend on the rocket have identical synchronized clocks. When your friend reaches Proxima Centauri, they send you a signal, telling you how long their trip took them. Their clock says the trip took just over two years. Remember, they measure the distance to be 1.8 light-years. However, you would see that your clock, which stayed at rest with you, says the trip took 4.7 years — more than twice as long!

This effect is called time dilation — time on moving clocks appears to tick slower.

None of this accounts for your friend accelerating their rocket or stopping at Proxima Centauri. All of this math gets more complicated if you and your friend were speeding up, slowing down, or changing directions. For instance, if your friend slowed down to stop at Proxima Centauri, they would have aged less than you on their trip!

Now you’re ready for a few tips on near-light-speed travel! Watch the video below for more.

Now, if you need to relax a bit after this whirlwind, near-light-speed trip, you can grab our coloring pages of scenes from the video. And if you enjoyed the trip, download a postcard to send to a friend. Finally, if you want to explore more of the wonders of the universe, follow NASA Universe on Facebook and Twitter.

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Mohammad AlMulla

Mohammad AlMulla, born in Dubai, received his commercial pilot's license from Australia at the age of 19. AlMulla was a training lead with the Dubai Police before becoming an astronaut candidate for the United Arab Emirates. https://mbrsc.ae/team/mohammed_mulla/

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