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Discovering the Universe Through the Constellation Orion

Do you ever look up at the night sky and get lost in the stars? Maybe while you’re stargazing, you spot some of your favorite constellations. But did you know there’s more to constellations than meets the eye? They’re not just a bunch of imaginary shapes made up of stars — constellations tell us stories about the universe from our perspective on Earth.

What is a constellation?

A constellation is a named pattern of stars that looks like a particular shape. Think of it like connecting the dots. If you join the dots — stars, in this case — and use your imagination, the picture would look like an object, animal, or person. For example, the ancient Greeks believed an arrangement of stars in the sky looked like a giant hunter with a sword attached to his belt, so they named it after a famous hunter in their mythology, Orion. It’s one of the most recognizable constellations in the night sky and can be seen around the world. The easiest way to find Orion is to go outside on a clear night and look for three bright stars close together in an almost-straight line. These three stars represent Orion's belt. Two brighter stars to the north mark his shoulders, and two more to the south represent his feet.

Credit: NASA/STScI

Over time, cultures around the world have had different names and numbers of constellations depending on what people thought they saw. Today, there are 88 officially recognized constellations. Though these constellations are generally based on what we can see with our unaided eyes, scientists have also invented unofficial constellations for objects that can only be seen in gamma rays, the highest-energy form of light.

Perspective is everything

The stars in constellations may look close to each other from our point of view here on Earth, but in space they might be really far apart. For example, Alnitak, the star at the left side of Orion's belt, is about 800 light-years away. Alnilam, the star in the middle of the belt, is about 1,300 light-years away. And Mintaka, the star at the right side of the belt, is about 900 light-years away. Yet they all appear from Earth to have the same brightness. Space is three-dimensional, so if you were looking at the stars that make up the constellation Orion from another part of our galaxy, you might see an entirely different pattern!

The superstars of Orion

Now that we know a little bit more about constellations, let’s talk about the supercool cosmic objects that form them – stars! Though over a dozen stars make up Orion, two take center stage. The red supergiant Betelgeuse (Orion's right shoulder) and blue supergiant Rigel (Orion's left foot) stand out as the brightest members in the constellation.

Credit: Derrick Lim

Betelgeuse is a young star by stellar standards, about 10 million years old, compared to our nearly 5 billion-year-old Sun. The star is so huge that if it replaced the Sun at the center of our solar system, it would extend past the main asteroid belt between Mars and Jupiter! But due to its giant mass, it leads a fast and furious life.

Betelgeuse is destined to end in a supernova blast. Scientists discovered a mysterious dimming of Betelgeuse in late 2019 caused by a traumatic outburst that some believed was a precursor to this cosmic event. Though we don’t know if this incident is directly related to an imminent supernova, there’s a tiny chance it might happen in your lifetime. But don't worry, Betelgeuse is about 550 light-years away, so this event wouldn't be dangerous to us – but it would be a spectacular sight.

Rigel is also a young star, estimated to be 8 million years old. Like Betelgeuse, Rigel is much larger and heavier than our Sun. Its surface is thousands of degrees hotter than Betelgeuse, though, making it shine blue-white rather than red. These colors are even noticeable from Earth. Although Rigel is farther from Earth than Betelgeuse (about 860 light-years away), it is intrinsically brighter than its companion, making it the brightest star in Orion and one of the brightest stars in the night sky.

Credit: Rogelio Bernal Andreo

Buckle up for Orion’s belt

Some dots that make up constellations are actually more than one star, but from a great distance they look like a single object. Remember Mintaka, the star at the far right side of Orion's belt? It is not just a single star, but actually five stars in a complex star system.

Credit: X-ray: NASA/CXC/GSFC/M. Corcoran et al.; Optical: Eckhard Slawik

Sword or a stellar nursery?

Below the three bright stars of Orion’s belt lies his sword, where you can find the famous Orion Nebula. The nebula is only 1,300 light-years away, making it the closest large star-forming region to Earth. Because of its brightness and prominent location just below Orion’s belt, you can actually spot the Orion Nebula from Earth! But with a pair of binoculars, you can get a much more detailed view of the stellar nursery. It’s best visible in January and looks like a fuzzy “star” in the middle of Orion’s sword.

More to discover in constellations

In addition to newborn stars, Orion also has some other awesome cosmic objects hanging around. Scientists have discovered exoplanets, or planets outside of our solar system, orbiting stars there. One of those planets is a giant gas world three times more massive than Jupiter. It’s estimated that on average there is at least one planet for every star in our galaxy. Just think of all the worlds you may be seeing when you look up at the night sky!

It’s also possible that the Orion Nebula might be home to a black hole, making it the closest known black hole to Earth. Though we may never detect it, because no light can escape black holes, making them invisible. However, space telescopes with special instruments can help find black holes. They can observe the behavior of material and stars that are very close to black holes, helping scientists find clues that can lead them closer to discovering some of these most bizarre and fascinating objects in the cosmos.

Next time you go stargazing, remember that there’s more to the constellations than meets the eye. Let them guide you to some of the most incredible and mysterious objects of the cosmos — young stars, brilliant nebulae, new worlds, star systems, and even galaxies!

To keep up with the most recent stellar news, follow NASA Universe on Twitter and Facebook.

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Meet the Artemis Team Returning Humans to the Moon

We. Are. Going 🌙

Today, we introduced the eighteen NASA Astronauts forming the Artemis team. Together, they’ll use their diverse range of backgrounds, expertise, and experience to pave the way for humans to return to the Moon, to stay. 

Meet the heroes of the future who’ll carry us back to the Moon and beyond - the Artemis generation. 

Joe Acaba 

Fun fact: Joe is a veteran of the U.S. Peace Corps! Get to know Joe personally with this video –> Watch HERE. 

Kayla Barron

Fun fact: Kayla got her start in public service through serving in the U.S. Navy. Get to know Kayla personally with this video –> Watch HERE.

Raja Chari

Fun fact: Raja’s nickname is “Grinder,” and he comes from a test pilot background. Get to know Raja personally with this video –> Watch HERE. 

Jessica Watkins

Fun fact: Jessica is a rugby national champion winner and geologist. Get to know Jessica personally with this video –> Watch HERE. 

Matthew Dominick

Fun fact: Matthew sums himself up as a father, a husband and an explorer. Get to know Matthew personally with this video –> Watch HERE. 

Jasmin Moghbeli

Fun fact: Jasmin says she still wakes up every morning and it feels like a “pinch me moment” to think she’s actually an astronaut right now. Get to know Jasmin personally with this video –> Watch HERE. 

Victor Glover

Fun fact: Victor’s dream is to work on the surface of the Moon. Get to know Victor personally with this video –> Watch HERE. 

Jessica Meir

Fun fact: Jessica was five years old when she knew she wanted to be an astronaut. Get to know Jessica personally with this video –> Watch HERE. 

Woody Hoburg

Fun fact: Woody used to spend summers away from graduate school working search and rescue in Yosemite National Park. Get to know Woody personally with this video –> Watch HERE. 

Anne McClain

Fun fact: Anne is a West Point alumni who describes herself as an impractical dreamer. Get to know Anne personally with this video –> Watch HERE. 

Jonny Kim

Fun fact: Jonny is also a U.S. Navy SEAL with a medical degree from Harvard. Get to know Jonny personally with this video –> Watch HERE. 

Nicole Mann

Fun fact: Nicole is a U.S. Lieutenant Colonel in the Marine Corps! Get to know Nicole personally with this video –> Watch HERE. 

Kjell Lindgren

Fun fact: Kjell was a flight surgeon, a physician who takes care of astronauts, before applying to be an astronaut himself! Get to know Kjell personally with this video –> Watch HERE.

Christina Koch

Fun fact: Christina set a record for the longest single spaceflight by a woman with a total of 328 days in space. Get to know Christina personally with this video –> Watch HERE.

Frank Rubio

Fun fact: Frank was a Black Hawk helicopter pilot in the U.S. Army and family medical physician. Get to know Frank personally with this video –> Watch HERE.

Stephanie Wilson

Fun fact: Stephanie was the voice in Mission Control leading our NASA Astronauts for the all-woman spacewalk last year. Get to know Stephanie personally with this video –> Watch HERE.

Scott Tingle

Fun fact: Scott said he wanted to be an astronaut in a high school class and the students laughed – look at him now. Get to know Scott personally with this video –> Watch HERE.

Kate Rubins

Fun fact: Kate is actually IN space right now, so she will have to get her official portrait when she comes home! She is also the first person to sequence DNA in space. Get to know Kate personally with this video –> Watch HERE.  Stay up to date with our Artemis program and return to the Moon by following NASA Artemis on Twitter, Facebook and Instagram. 

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We Found the Perfect Spot to Land our Moon Rover

After an extensive selection process, we chose the mountainous area west of Nobile Crater at the Moon’s South Pole as the landing site for our first-ever robotic Moon rover. The Volatiles Investigating Polar Exploration Rover, or VIPER, will explore the Moon’s surface and subsurface in search of water and other resources beginning in late 2023. Thanks to past missions, such as satellites orbiting the Moon or impacting its surface, we know there is ice at the Moon’s poles. But how much? And where did it come from? VIPER aims to answer these questions and more by venturing into shadowed craters and visiting other areas of scientific interest over its 100-day mission. The findings will inform future landing sites under the Artemis program and help pave the way toward establishing a long-term human presence on the Moon. Here are five things to know:

The landing site is located just outside the western rim of Nobile Crater at the Moon’s South Pole.

The region has suitable lighting and terrain for our solar-powered rover to navigate.

VIPER will travel up to 15 miles in search of water and other resources.

Its traverse will change depending on what it finds, but it could look like this.

Drivers on Earth will tell the rover where to explore during its 100-day mission.

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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"Equipped with his five senses, man explores the universe around him and calls the adventure science."

-Edwin P. Hubble

That's a wrap! Thank you all for the wonderful questions.

NASA Mars Perseverance Rover Mission Engineer Chloe Sackier answered questions about how we prepared for the mission, Perseverance’s entry, descent, and landing, and what Perseverance will do once on Mars.

Check out her full Answer Time for more: Career | Preparation | Entry, Descent, & Landing | Operation

We hope you had fun today and learned a little bit about our robotic astrobiologist landing on Mars on February 18th. You won't want to miss this! Tune in to NASA TV HERE starting at 2:15 p.m. EST.

If today’s Answer Time got you excited, team up with us to #CoutdownToMars! We created a virtual Mars photo booth, have sounds of Mars to listen to and more for all you Earthlings to channel your inner Martian. Check out ways to participate HERE.

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why are cheetahs not technically big cats? is it just because they're weird as hell or do they not meet some big cat criteria?

so the thing about Big Cats is that they’re all closely related members of the genus Panthera! 

because they’re all part of the same lineage, they share a lot of traits like the ability to roar.

and cheetahs are actually members of a completely different cat lineage altogether, the genus Acinonyx!

they’re not very closely related to the big cats at all and are actually most closely related to Pumas, which you can totally see if you stack them up next to each other and squint really hard. 

it’s okay though, the cheetah can still be the biggest cat in our hearts :’)

Bill Nye for most of his career: Imma do science for kids. Science without politics. Nice, tame science for the kiddos.

Bill Nye now:

When Dead Stars Collide!

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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How will the audio feed from Perseverance make its way back to Earth?