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, HubbleChandra 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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13 Reasons to Have an Out-of-This-World Friday (the 13th)

1. Not all of humanity is bound to the ground

Since 2000, the International Space Station has been continuously occupied by humans. There, crew members live and work while conducting important research that benefits life on Earth and will even help us eventually travel to deep space destinations, like Mars.

2. We’re working to develop quieter supersonic aircraft that would allow you to travel from New York to Los Angeles in 2 hours

We are working hard to make flight greener, safer and quieter – all while developing aircraft that travel faster, and building an aviation system that operates more efficiently. Seventy years after Chuck Yeager broke the sound barrier in the Bell X-1 aircraft, we’re continuing that supersonic X-plane legacy by working to create a quieter supersonic jet with an aim toward passenger flight.

3. The spacecraft, rockets and systems developed to send astronauts to low-Earth orbit as part of our Commercial Crew Program is also helping us get to Mars

Changes to the human body during long-duration spaceflight are significant challenges to solve ahead of a mission to Mars and back. The space station allows us to perform long duration missions without leaving Earth’s orbit.

Although they are orbiting Earth, space station astronauts spend months at a time in near-zero gravity, which allows scientists to study several physiological changes and test potential solutions. The more time they spend in space, the more helpful the station crew members can be to those on Earth assembling the plans to go to Mars.

4. We’re launching a spacecraft in 2018 that will go “touch the Sun”

In the summer of 2018, we’re launching Parker Solar Probe, a spacecraft that will get closer to the Sun than any other in human history. Parker Solar Probe will fly directly through the Sun’s atmosphere, called the corona. Getting better measurements of this region is key to understanding our Sun. 

For instance, the Sun releases a constant outflow of solar material, called the solar wind. We think the corona is where this solar wind is accelerated out into the solar system, and Parker Solar Probe’s measurements should help us pinpoint how that happens.  

5. You can digitally fly along with spacecraft…that are actually in space…in real-time!

NASA’s Eyes are immersive, 3D simulations of real events, spacecraft locations and trajectories. Through this interactive app, you can experience Earth and our solar system, the universe and the spacecraft exploring them. Want to watch as our Juno spacecraft makes its next orbit around Juno? You can! Or relive all of the Voyager mission highlights in real-time? You can do that too! Download the free app HERE to start exploring.

6. When you feel far away from home, you can think of the New Horizons spacecraft as it heads toward the Kuiper Belt, and the Voyager spacecraft are beyond the influence of our sun…billions of miles away

Our New Horizons spacecraft completed its Pluto flyby in July 2015 and has continued on its way toward the Kuiper Belt. The spacecraft continues to send back important data as it travels toward deeper space at more than 32,000 miles per hour, and is ~3.2 billion miles from Earth.

In addition to New Horizons, our twin Voyager 1 and 2 spacecraft are exploring where nothing from Earth has flown before. Continuing on their more-than-37-year journey since their 1977 launches, they are each much farther away from Earth and the sun than Pluto. In August 2012, Voyager 1 made the historic entry into interstellar space, the region between the stars, filled with material ejected by the death of nearby stars millions of years ago.

7. There are humans brave enough to not only travel in space, but venture outside space station to perform important repairs and updates during spacewalks

Just this month (October 2017) we’ve already had two spacewalks on the International Space Station…with another scheduled on Oct. 20. 

Spacewalks are important events where crew members repair, maintain and upgrade parts of the International Space Station. These activities can also be referred to as EVAs – Extravehicular Activities. Not only do spacewalks require an enormous amount of work to prepare for, but they are physically demanding on the astronauts. They are working in the vacuum of space in only their spacewalking suit. 

8. Smart people are up all night working in control rooms all over NASA to ensure that data keeps flowing from our satellites and spacecraft

Our satellites and spacecraft help scientists study Earth and space. Missions looking toward Earth provide information about clouds, oceans, land and ice. They also measure gases in the atmosphere, such as ozone and carbon dioxide and the amount of energy that Earth absorbs and emits. And satellites monitor wildfires, volcanoes and their smoke.

9. A lot of NASA-developed tech has been transferred for use to the public

Our Technology Transfer Program highlights technologies that were originally designed for our mission needs, but have since been introduced to the public market. HERE are a few spinoff technologies that you might not know about.

10. We have a spacecraft currently traveling  to an asteroid to collect a sample and bring it back to Earth

OSIRIS-REx is our first-ever mission that will travel to an asteroid and bring a sample of it back to Earth. Currently, the spacecraft is on its way to asteroid Bennu where it will survey and map the object before it “high-fives” the asteroid with its robotic arm to collect a sample, which it will send to Earth.

If everything goes according to plan, on Sept. 24, 2023, the capsule containing the asteroid sample will make a soft landing in the Utah desert.

11. There are Earth-sized planets outside our solar system that may be habitable

To date, we have confirmed 3,000+ exoplanets, which are planets outside our solar system that orbit a Sun-like star. Of these 3,000, some are in the habitable zone – where the temperature is just right for liquid water to exist on the surface.  

Recently, our Spitzer Space Telescope revealed the first known system of SEVEN Earth-size planets around a single star. Three of these plants are firmly in the habitable zone, and could have liquid water on the surface, which is key to life as we know it.

12. Earth looks like art from space

In 1960, the United States put its first Earth-observing environmental satellite into orbit around the planet. Over the decades, these satellites have provided invaluable information, and the vantage point of space has provided new perspectives on Earth.

The beauty of Earth is clear, and the artistry ranges from the surreal to the sublime.

13. We’re building a telescope that will be able to see the first stars ever formed in the universe

Wouldn’t it be neat to see a period of the universe’s history that we’ve never seen before? That’s exactly what the James Webb Space Telescope (JWST) will be able to do…plus more!

Specifically, Webb will see the first objects that formed as the universe cooled down after the Big Bang. We don’t know exactly when the universe made the first stars and galaxies – or how for that matter. That is what we are building Webb to help answer.

Happy Friday the 13th! We hope it’s out-of-this-world!

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Solar System: 10 Things to Know This Week

Need some space? 

Here are 10 perspective-building images for your computer desktop and mobile device wallpaper. 

These are all real images, sent very recently by our planetary missions throughout the solar system. 

1. Our Sun

Warm up with this view from our Solar Dynamics Observatory showing active regions on the Sun in October 2017. They were observed in a wavelength of extreme ultraviolet light that reveals plasma heated to over a million degrees. 

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2. Jupiter Up-Close

This series of enhanced-color images shows Jupiter up close and personal, as our Juno spacecraft performed its eighth flyby of the gas giant planet on Sept. 1, 2017. 

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3. Saturn’s and Its Rings

With this mosaic from Oct. 28, 2016, our Cassini spacecraft captured one of its last looks at Saturn and its main rings from a distance. 

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4. Gale Crater on Mars

This look from our Curiosity Mars rover includes several geological layers in Gale crater to be examined by the mission, as well as the higher reaches of Mount Sharp beyond. The redder rocks of the foreground are part of the Murray formation. Pale gray rocks in the middle distance of the right half of the image are in the Clay Unit. A band between those terrains is “Vera Rubin Ridge,” where the rover is working currently. The view combines six images taken with the rover’s Mast Camera (Mastcam) on Jan. 24, 2017. 

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5. Sliver of Saturn

Cassini peers toward a sliver of Saturn’s sunlit atmosphere while the icy rings stretch across the foreground as a dark band on March 31, 2017. This view looks toward the unilluminated side of the rings from about 7 degrees below the ring plane. 

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6. Dwarf Planet Ceres 

This image of the limb of dwarf planet Ceres shows a section of the northern hemisphere, as seen by our Dawn mission. Prominently featured is Occator Crater, home of Ceres’ intriguing “bright spots.” The latest research suggests that the bright material in this crater is comprised of salts left behind after a briny liquid emerged from below. 

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7. Martian Crater

This image from our Mars Reconnaissance Orbiter (MRO) shows a crater in the region with the most impressive known gully activity in Mars’ northern hemisphere. Gullies are active in the winter due to carbon dioxide frost, but northern winters are shorter and warmer than southern winters, so there is less frost and less gully activity. 

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8. Dynamic Storm on Jupiter

A dynamic storm at the southern edge of Jupiter’s northern polar region dominates this Jovian cloudscape, courtesy of Juno. This storm is a long-lived anticyclonic oval named North North Temperate Little Red Spot 1. Citizen scientists Gerald Eichstädt and Seán Doran processed this image using data from the JunoCam imager. 

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9. Rings Beyond Saturn’s Sunlit Horizon 

This false-color view from the Cassini spacecraft gazes toward the rings beyond Saturn’s sunlit horizon. Along the limb (the planet’s edge) at left can be seen a thin, detached haze. 

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10. Saturn’s Ocean-Bearing Moon Enceladus

Saturn’s active, ocean-bearing moon Enceladus sinks behind the giant planet in a farewell portrait from Cassini. This view of Enceladus was taken by NASA’s Cassini spacecraft on Sept. 13, 2017. It is among the last images Cassini sent back before its mission came to an end on Sept. 15, after nearly 20 years in space. 

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Applying Wallpaper:
1. Click on the screen resolution you would like to use.
2. Right-click on the image (control-click on a Mac) and select the option ‘Set the Background’ or 'Set as Wallpaper’ (or similar).

Places to look for more of our pictures include solarsystem.nasa.gov/galleries, images.nasa.gov and www.jpl.nasa.gov/spaceimages.

Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com