Black holes are hard to find. Like, really hard to find. They are objects with such strong gravity that light can’t escape them, so we have to rely on clues from their surroundings to find them.
When a star weighing more than 20 times the Sun runs out of fuel, it collapses into a black hole. Scientists estimate that there are tens of millions of these black holes dotted around the Milky Way, but so far we’ve only identified a few dozen. Most of those are found with a star, each circling around the other. Another name for this kind of pair is a binary system.That’s because under the right circumstances material from the star can interact with the black hole, revealing its presence.
The visualization above shows several of these binary systems found in our Milky Way and its neighboring galaxy. with their relative sizes and orbits to scale. The video even shows each system tilted the way we see it here from our vantage point on Earth. Of course, as our scientists gather more data about these black holes, our understanding of them may change.
If the star and black hole orbit close enough, the black hole can pull material off of its stellar companion! As the material swirls toward the black hole, it forms a flat ring called an accretion disk. The disk gets very hot and can flare, causing bright bursts of light.
V404 Cygni, depicted above, is a binary system where a star slightly smaller than the Sun orbits a black hole 10 times its mass in just 6.5 days. The black hole distorts the shape of the star and pulls material from its surface. In 2015, V404 Cygni came out of a 25-year slumber, erupting in X-rays that were initially detected by our Swift satellite. In fact, V404 Cygni erupts every couple of decades, perhaps driven by a build-up of material in the outer parts of the accretion disk that eventually rush in.
In other cases, the black hole’s companion is a giant star with a strong stellar wind. This is like our Sun’s solar wind, but even more powerful. As material rushes out from the companion star, some of it is captured by the black hole’s gravity, forming an accretion disk.
A famous example of a black hole powered by the wind of its companion is Cygnus X-1. In fact, it was the first object to be widely accepted as a black hole! Recent observations estimate that the black hole’s mass could be as much as 20 times that of our Sun. And its stellar companion is no slouch, either. It weighs in at about 40 times the Sun.
We know our galaxy is peppered with black holes of many sizes with an array of stellar partners, but we've only found a small fraction of them so far. Scientists will keep studying the skies to add to our black hole menagerie.
Curious to learn more about black holes? Follow NASA Universe on Twitter and Facebook to keep up with the latest from our scientists and telescopes.
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Prizes, awards and a year’s worth of bragging rights are at stake during our annual Human Exploration Rover Challenge. Year after year, student teams from across the world design, build and race rovers against the clock and each other.
With a space-themed obstacle course, unique rovers, competitive racing, our exhibits and dozens of international teams… it’s everything cool about STEM (science, technology, engineering and mathematics) and space exploration.
1. Bumps, Bruises and Battle Scars
Our space-themed obstacle course often brings racers to their knees, literally. This daunting three-quarter-mile long course is difficult to traverse and isn’t for the faint of heart. It uses both lunar and Mars-themed obstacles to simulate the types of terrain found on distant planets, asteroids or moons.
Plus, teams must race their rovers in, on and around full-scale rockets and space vehicle exhibits on display at the U.S. Space & Rocket Center – the official visitor center for NASA’s Marshall Space Flight Center, both in Huntsville, Alabama. See just how difficult and wild the course can be in our Flickr gallery.
2. Homemade Wheels Only
Rover teams must design and fabricate their own original, or “homemade” wheels. In-Situ Resource Utilization is an important component for our future missions to Mars, asteroids or other planets.
Astronauts can never simply purchase wheels at the store… and neither can our rover teams. Teams must not use any “off-the-shelf” wheels on their rover. By wheels, this means any component used for contact, traction or mobility on the surface of the obstacle course, including, but not limited to wheels, tracks, treads or belts.
And, as in years past, teams are not allowed to incorporate inflated (or un-inflated) pneumatic tires. Inflated tires would be considered an off-the-shelf product, not eligible under the current rules.
3. New “Sample Retrieval” Component Added
Teams may choose to compete in this optional challenge, collecting four samples (liquid, small pebbles, large rocks and soil) using a mechanical arm or a grabber they design and build. Teams must collect a soil sample and liquid sample while driving their rover, as well as collect rock samples (both large and small) while off the rover, all within a 25-minute time limit. The “Sample Retrieval” challenge highlights our deep-space exploration goals. Teams competing are eligible for the $250 prize awarded to the winner of each high school and college/university division.
4. Caution: Real STEM @work
The sights and sounds of welding, grinding and computer programming are prevalent in this hands-on, experiential activity where students solve similar problems faced by our workforce. Rover Challenge provides a unique test-bed to get students involved in real-world research and development. Their progress and success may glean potential technologies for future exploration of Mars and beyond.
5. Draws Inspiration from Apollo and Journey to Mars
Rover Challenge was inspired by the historic success of the lunar rovers from the Apollo missions, each one built by engineers and scientists at NASA Marshall. While we continue to honor our past achievements, we now highlight future accomplishments on deep-space exploration missions to Mars, asteroids or other planets. The addition of the “Sample Return” component and the Martian obstacles emphasize our commitment toward space exploration.
6. Our International Spirit is Alive and Well
Just like the International Space Station; we bring the best of several nations together to promote and celebrate space exploration. Nearly 80 teams are coming from as far away as Italy, Germany, India, Mexico, Columbia and Russia, as well as more “local” talent from the United States and Puerto Rico. View this year’s registered teams HERE.
7. Real-time Racing on Social Media
From start to finish, each racing rover team will be broadcast, live, on the Marshall Center’s Ustream channel. Plus, enjoy real-time race updates, results and awards by following Rover Challenge Twitter: @RoverChallenge
NASA’s Human Exploration Rover Challenge will take place at the U.S. Space & Rocket Center in Huntsville, Alabama, April 8-9. For event details, rules, course information and more, please visit: http://www.nasa.gov/roverchallenge
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Black holes, cosmic rays, neutron stars and even new kinds of physics — for 10 years, data from our Fermi Gamma-ray Space Telescope have helped unravel some of the biggest mysteries of the cosmos. And Fermi is far from finished!
On June 11, 2008, at Cape Canaveral in Florida, the countdown started for Fermi, which was called the Gamma-ray Large Area Space Telescope (GLAST) at the time.
The telescope was renamed after launch to honor Enrico Fermi, an Italian-American pioneer in high-energy physics who also helped develop the first nuclear reactor.
Fermi has had many other things named after him, like Fermi’s Paradox, the Fermi National Accelerator Laboratory, the Enrico Fermi Nuclear Generating Station, the Enrico Fermi Institute, and the synthetic element fermium.
Photo courtesy of Argonne National Laboratory
The Fermi telescope measures some of the highest energy bursts of light in the universe; watching the sky to help scientists answer all sorts of questions about some of the most powerful objects in the universe.
Its main instrument is the Large Area Telescope (LAT), which can view 20% of the sky at a time and makes a new image of the whole gamma-ray sky every three hours. Fermi’s other instrument is the Gamma-ray Burst Monitor. It sees even more of the sky at lower energies and is designed to detect brief flashes of gamma-rays from the cosmos and Earth.
This sky map below is from 2013 and shows all of the high energy gamma rays observed by the LAT during Fermi’s first five years in space. The bright glowing band along the map’s center is our own Milky Way galaxy!
Well, they’re a form of light. But light with so much energy and with such short wavelengths that we can’t see them with the naked eye. Gamma rays require a ton of energy to produce — from things like subatomic particles (such as protons) smashing into each other.
Here on Earth, you can get them in nuclear reactors and lightning strikes. Here’s a glimpse of the Seattle skyline if you could pop on a pair of gamma-ray goggles. That purple streak? That’s still the Milky Way, which is consistently the brightest source of gamma rays in our sky.
In space, you find that kind of energy in places like black holes and neutron stars. The raindrop-looking animation below shows a big flare of gamma rays that Fermi spotted coming from something called a blazar, which is a kind of quasar, which is different from a pulsar... actually, let’s back this up a little bit.
One of the sources of gamma rays that Fermi spots are pulsars. Pulsars are a kind of neutron star, which is a kind of star that used to be a lot bigger, but collapsed into something that’s smaller and a lot denser. Pulsars send out beams of gamma rays. But the thing about pulsars is that they rotate.
So Fermi only sees a beam of gamma rays from a pulsar when it’s pointed towards Earth. Kind of like how you only periodically see the beam from a lighthouse. These flashes of light are very regular. You could almost set your watch by them!
Quasars are supermassive black holes surrounded by disks of gas. As the gas falls into the black hole, it releases massive amount of energy, including — you guessed it — gamma rays. Blazars are quasars that send out beams of gamma rays and other forms of light — right in our direction.
When Fermi sees them, it’s basically looking straight down this tunnel of light, almost all the way back to the black hole. This means we can learn about the kinds of conditions in that environment when the rays were emitted. Fermi has found about 5,500 individual sources of gamma rays, and the bulk of them have been blazars, which is pretty nifty.
But gamma rays also have many other sources. We’ve seen them coming from supernovas where stars die and from star factories where stars are born. They’re created in lightning storms here on Earth, and our own Sun can toss them out in solar flares.
Gamma rays were in the news last year because of something Fermi spotted at almost the same time as the National Science Foundation (NSF)’s Laser Interferometer Gravitational-Wave Observatory (LIGO) and European Gravitational Observatory’s Virgo on August 17, 2017. Fermi, LIGO, Virgo, and numerous other observatories spotted the merger of two neutron stars. It was the first time that gravitational waves and light were confirmed to come from the same source.
Fermi has been looking at the sky for almost 10 years now, and it’s helped scientists advance our understanding of the universe in many ways. And the longer it looks, the more we’ll learn. Discover more about how we’ll be celebrating Fermi’s achievements all year.
Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com.
While even the most “normal” black hole seems exotic compared to the tranquil objects in our solar system, there are some record-breaking oddballs. Tag along as we look at the biggest, closest, farthest, and even “spinniest” black holes discovered in the universe … that we know of right now!
Located 700 million light-years away in the galaxy Holmberg 15A, astronomers found a black hole that is a whopping 40 billion times the mass of the Sun — setting the record for the biggest black hole found so far. On the other hand, the smallest known black hole isn’t quite so easy to pinpoint. There are several black holes with masses around five times that of our Sun. There’s even one candidate with just two and a half times the Sun’s mass, but scientists aren’t sure whether it’s the smallest known black hole or actually the heaviest known neutron star!
You may need to take a seat for this one. The black hole GRS 1915+105 will make you dizzier than an afternoon at an amusement park, as it spins over 1,000 times per second! Maybe even more bizarre than how fast this black hole is spinning is what it means for a black hole to spin at all! What we're actually measuring is how strongly the black hole drags the space-time right outside its event horizon — the point where nothing can escape. Yikes!
If you’re from Earth, the closest black hole that we know of right now, Mon X-1 in the constellation Monoceros, is about 3,000 light-years away. But never fear — that’s still really far away! The farthest known black hole is J0313-1806. The light from its surroundings took a whopping 13 billion years to get to us! And with the universe constantly expanding, that distance continues to grow.
So, we know about large (supermassive, hundreds of thousands to billions of times the Sun's mass) and small (stellar-mass, five to dozens of times the Sun's mass) black holes, but what about other sizes? Though rare, astronomers have found a couple that seem to fit in between and call them intermediate-mass black holes. As for tiny ones, primordial black holes, there is a possibility that they were around when the universe got its start — but there’s not enough evidence so far to prove that they exist!
One thing that’s on astronomers’ wishlist is to see two supermassive black holes crashing into one another. Unfortunately, that event hasn’t been detected — yet! It could be only a matter of time before one reveals itself.
Though these are the records now, in early 2021 … records are meant to be broken, so who knows what we’ll find next!
Add some of these records and rare finds to your black hole-watch list, grab your handy-dandy black hole field guide to learn even more about them — and get to searching!
Keep up with NASA Universe on Facebook and Twitter where we post regularly about black holes.
Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com.
Headaches can be a common complaint during spaceflight. The Space Headaches experiment improves our understanding of such conditions, which helps in the development of methods to alleviate associated symptoms, and improve the well-being and performance of crew members in orbit. This can also improve our knowledge of similar conditions on Earth.
Holiday lights don’t come in one shape or size, just like they don’t only appear on Earth. Take a look at a few of these celestial light shows:
1. Galactic Wreath of Lights
This festive image captured by our Hubble Space Telescope resembles a holiday wreath made of sparkling lights. This galactic wreath is located around 6,500 light-years away.
2. Red and Green Aurora
This beautiful aurora was captured by Astronaut Scott Kelly while aboard the International Space Station. He shared it with his Twitter followers on June, 22 during his Year in Space mission. This image of Earth’s aurora is festive with its red and green lights.
3. Holiday Snow Angel
Our Hubble Space Telescope captured this stunning image of what looks like a soaring, celestial snow angel. This picture shows a bipolar star-forming region, called Sharpless 2-106.
4. Cosmic Holiday Ornament
This festive-looking nearby planetary nebula resembles a glass-blown holiday ornament with a glowing ribbon entwined. This cosmic decoration was spotted by our Hubble Space Telescope.
5. Holiday Lights on the Sun
Even the sun gets festive with it’s festive looking solar flares. This significant flare was seen by our Solar Dynamics Observatory (SOHO) on Dec. 19, 2014. Even though solar flares are powerful bursts of radiation, it cannot pas through Earth’s atmosphere to physically affect humans on the ground. That said, when intense enough, the radiation can disturb the atmosphere in the layer where GPS and communications signals travel.
Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com
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.
Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com
Asteroids are the storytellers of our solar system’s youth. They are the closest we can get to the original material that makes up the sun, planets, and moons.
This week, our OSIRIS-REx spacecraft made history when it touched a pristine, ancient asteroid named Bennu to collect a sample from the surface. The intrepid spacecraft will now bring the asteroid sample – and its stories – back home to Earth.
Why is it that asteroid Bennu holds the history of our origins? Let’s go back to the beginning...
About 4.5 billion years ago, our solar system began as a spinning, swirling cloud made up of tiny bits of gaseous and rocky material. Most of that material – more than 99% of it – gathered in the center and went on to become the Sun.
The leftovers began to spin around the Sun, colliding into one another and forming larger and larger objects, eventually becoming planets, dwarf planets, and moons.
But asteroids didn't become part of planets or moons. So, while the material in planets and moons were superheated and altered during the formation of the solar system and weathered by geologic processes over time, asteroids remained pristine.
Each asteroid holds knowledge from that special time in our solar system’s history. Each one contains information about the chemicals, minerals, and molecules that were present when the solar system was just starting to form.
With missions like OSIRIS-REx, we are going on a journey to these ancient worlds, seeking to learn what they remember, seeking to expand our knowledge, and deepen our understanding of our origins.
Learn more about the OSIRIS-REx mission HERE, or follow the mission on Facebook, Twitter and Instagram.
Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com
It takes thousands of people and years of hard work to get a spacecraft from Earth to Mars. So when our Perseverance (Percy) rover touches down on the Martian surface, it will be because of the talented minds that helped to make it happen.
The team is on track to launch Perseverance on July 20 and land in Mars’ Jezero Crater in February 2021. Each week leading up to launch, learn not only what it’s like to work on this mission but also about the diverse background and career trajectories of the team members at our Jet Propulsion Laboratory.
Want to stay up to date on Percy’s mission? Follow her on Twitter and Facebook. For more information, visit the official mission site, HERE.
Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com
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