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Do You Love the Color of the Sun?
Get dazzled by the true spectrum of solar beauty. From fiery reds to cool blues, explore the vibrant hues of the Sun in a mesmerizing color order. The images used to make this gradient come from our Solar Dynamics Observatory. Taken in a variety of wavelengths, they give scientists a wealth of data about the Sun. Don't miss the total solar eclipse crossing North America on April 8, 2024. (It's the last one for 20 years!) Set a reminder to watch with us.
Navigating Deep Space by Starlight
On August 6, 1967, astrophysicist Jocelyn Bell Burnell noticed a blip in her radio telescope data. And then another. Eventually, Bell Burnell figured out that these blips, or pulses, were not from people or machines.
The blips were constant. There was something in space that was pulsing in a regular pattern, and Bell Burnell figured out that it was a pulsar: a rapidly spinning neutron star emitting beams of light. Neutron stars are superdense objects created when a massive star dies. Not only are they dense, but neutron stars can also spin really fast! Every star we observe spins, and due to a property called angular momentum, as a collapsing star gets smaller and denser, it spins faster. It’s like how ice skaters spin faster as they bring their arms closer to their bodies and make the space that they take up smaller.
The pulses of light coming from these whirling stars are like the beacons spinning at the tops of lighthouses that help sailors safely approach the shore. As the pulsar spins, beams of radio waves (and other types of light) are swept out into the universe with each turn. The light appears and disappears from our view each time the star rotates.
After decades of studying pulsars, astronomers wondered—could they serve as cosmic beacons to help future space explorers navigate the universe? To see if it could work, scientists needed to do some testing!
First, it was important to gather more data. NASA’s NICER, or Neutron star Interior Composition Explorer, is a telescope that was installed aboard the International Space Station in 2017. Its goal is to find out things about neutron stars like their sizes and densities, using an array of 56 special X-ray concentrators and sensitive detectors to capture and measure pulsars’ light.
But how can we use these X-ray pulses as navigational tools? Enter SEXTANT, or Station Explorer for X-ray Timing and Navigation Technology. If NICER was your phone, SEXTANT would be like an app on it.
During the first few years of NICER’s observations, SEXTANT created an on-board navigation system using NICER’s pulsar data. It worked by measuring the consistent timing between each pulsar’s pulses to map a set of cosmic beacons.
When calculating position or location, extremely accurate timekeeping is essential. We usually rely on atomic clocks, which use the predictable fluctuations of atoms to tick away the seconds. These atomic clocks can be located on the ground or in space, like the ones on GPS satellites. However, our GPS system only works on or close to Earth, and onboard atomic clocks can be expensive and heavy. Using pulsar observations instead could give us free and reliable “clocks” for navigation. During its experiment, SEXTANT was able to successfully determine the space station’s orbital position!
We can calculate distances using the time taken for a signal to travel between two objects to determine a spacecraft’s approximate location relative to those objects. However, we would need to observe more pulsars to pinpoint a more exact location of a spacecraft. As SEXTANT gathered signals from multiple pulsars, it could more accurately derive its position in space.
So, imagine you are an astronaut on a lengthy journey to the outer solar system. You could use the technology developed by SEXTANT to help plot your course. Since pulsars are reliable and consistent in their spins, you wouldn’t need Wi-Fi or cell service to figure out where you were in relation to your destination. The pulsar-based navigation data could even help you figure out your ETA!
None of these missions or experiments would be possible without Jocelyn Bell Burnell’s keen eye for an odd spot in her radio data decades ago, which set the stage for the idea to use spinning neutron stars as a celestial GPS. Her contribution to the field of astrophysics laid the groundwork for research benefitting the people of the future, who yearn to sail amongst the stars.
Keep up with the latest NICER news by following NASA Universe on X and Facebook and check out the mission’s website. For more on space navigation, follow @NASASCaN on X or visit NASA’s Space Communications and Navigation website.
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Sakura to Supernova
This rare sight is a super-bright, massive Wolf-Rayet star. Calling forth the ephemeral nature of cherry blossoms, the Wolf-Rayet phase is a fleeting stage that only some stars go through soon before they explode.
The star, WR 124, is 15,000 light-years away in the constellation Sagittarius. It is 30 times the mass of the Sun and has shed 10 Suns worth of material – so far. As the ejected gas moves away from the star and cools, cosmic dust forms and glows in the infrared light detectable by NASA's James Webb Space Telescope.
The origin of cosmic dust that can survive a supernova blast is of great interest to astronomers for multiple reasons. Dust shelters forming stars, gathers together to help form planets, and serves as a platform for molecules to form and clump together, including the building blocks of life on Earth.
Stars like WR 124 also help astronomers understand the early history of the universe. Similar dying stars first seeded the young universe with heavy elements forged in their cores – elements that are now common in the current era, including on Earth.
The James Webb Space Telescope opens up new possibilities for studying details in cosmic dust, which is best observed in infrared wavelengths of light. Webb’s Near-Infrared Camera balances the brightness of WR 124’s stellar core and the knotty details in the fainter surrounding gas. The telescope’s Mid-Infrared Instrument reveals the clumpy structure of the gas and dust nebula of the ejected material now surrounding the star.
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Taking Solar Science to New Heights
We're on the verge of launching a new spacecraft to the Sun to take the first-ever images of the Sun's north and south poles!
Credit: ESA/ATG medialab
Solar Orbiter is a collaboration between the European Space Agency (ESA) and NASA. After it launches — as soon as Feb. 9 — it will use Earth's and Venus's gravity to swing itself out of the ecliptic plane — the swath of space, roughly aligned with the Sun’s equator, where all the planets orbit. From there, Solar Orbiter's bird’s eye view will give it the first-ever look at the Sun's poles.
Credit: ESA/ATG medialab
The Sun plays a central role in shaping space around us. Its massive magnetic field stretches far beyond Pluto, paving a superhighway for charged solar particles known as the solar wind. When bursts of solar wind hit Earth, they can spark space weather storms that interfere with our GPS and communications satellites — at their worst, they can even threaten astronauts.
To prepare for potential solar storms, scientists monitor the Sun’s magnetic field. But from our perspective near Earth and from other satellites roughly aligned with Earth's orbit, we can only see a sidelong view of the Sun's poles. It’s a bit like trying to study Mount Everest’s summit from the base of the mountain.
Solar Orbiter will study the Sun's magnetic field at the poles using a combination of in situ instruments — which study the environment right around the spacecraft — and cameras that look at the Sun, its atmosphere and outflowing material in different types of light. Scientists hope this new view will help us understand not only the Sun's day-to-day activity, but also its roughly 11-year activity cycles, thought to be tied to large-scales changes in the Sun's magnetic field.
Solar Orbiter will fly within the orbit of Mercury — closer to our star than any Sun-facing cameras have ever gone — so the spacecraft relies on cutting-edge technology to beat the heat.
Credit: ESA/ATG medialab
Solar Orbiter has a custom-designed titanium heat shield with a calcium phosphate coating that withstands temperatures more than 900 degrees Fahrenheit — 13 times the solar heating that spacecraft face in Earth orbit. Five of the cameras look at the Sun through peepholes in that heat shield; one observes the solar wind out the side.
Over the mission’s seven-year lifetime, Solar Orbiter will reach an inclination of 24 degrees above the Sun’s equator, increasing to 33 degrees with an additional three years of extended mission operations. At closest approach the spacecraft will pass within 26 million miles of the Sun.
Solar Orbiter will be our second major mission to the inner solar system in recent years, following on August 2018’s launch of Parker Solar Probe. Parker has completed four close solar passes and will fly within 4 million miles of the Sun at closest approach.
Solar Orbiter (green) and Parker Solar Probe (blue) will study the Sun in tandem.
The two spacecraft will work together: As Parker samples solar particles up close, Solar Orbiter will capture imagery from farther away, contextualizing the observations. The two spacecraft will also occasionally align to measure the same magnetic field lines or streams of solar wind at different times.
Watch the launch
The booster of a United Launch Alliance Atlas V rocket that will launch the Solar Orbiter spacecraft is lifted into the vertical position at the Vertical Integration Facility near Space Launch Complex 41 at Cape Canaveral Air Force Station in Florida on Jan. 6, 2020. Credit: NASA/Ben Smegelsky
Solar Orbiter is scheduled to launch on Feb. 9, 2020, during a two-hour window that opens at 11:03 p.m. EST. The spacecraft will launch on a United Launch Alliance Atlas V 411 rocket from Space Launch Complex 41 at Cape Canaveral Air Force Station in Florida.
Launch coverage begins at 10:30 p.m. EST on Feb. 9 at nasa.gov/live. Stay up to date with mission at nasa.gov/solarorbiter!
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New Science from our Mission to Touch the Sun
In August 2018, our Parker Solar Probe mission launched to space, soon becoming the closest-ever spacecraft from the Sun. Now, scientists have announced their first discoveries from this exploration of our star!
The Sun may look calm to us here on Earth, but it's an active star, unleashing powerful bursts of light, deluges of particles moving near the speed of light and billion-ton clouds of magnetized material. All of this activity can affect our technology here on Earth and in space.
Parker Solar Probe's main science goals are to understand the physics that drive this activity — and its up-close look has given us a brand-new perspective. Here are a few highlights from what we've learned so far.
1. Surprising events in the solar wind
The Sun releases a continual outflow of magnetized material called the solar wind, which shapes space weather near Earth. Observed near Earth, the solar wind is a relatively uniform flow of plasma, with occasional turbulent tumbles. Closer to the solar wind's source, Parker Solar Probe saw a much different picture: a complicated, active system.
One type of event in particular drew the eye of the science teams: flips in the direction of the magnetic field, which flows out from the Sun, embedded in the solar wind. These reversals — dubbed "switchbacks" — last anywhere from a few seconds to several minutes as they flow over Parker Solar Probe. During a switchback, the magnetic field whips back on itself until it is pointed almost directly back at the Sun.
The exact source of the switchbacks isn't yet understood, but Parker Solar Probe's measurements have allowed scientists to narrow down the possibilities — and observations from the mission's 21 remaining solar flybys should help scientists better understand these events.
2. Seeing tiny particle events
The Sun can accelerate tiny electrons and ions into storms of energetic particles that rocket through the solar system at nearly the speed of light. These particles carry a lot of energy, so they can damage spacecraft electronics and even endanger astronauts, especially those in deep space, outside the protection of Earth's magnetic field — and the short warning time for such particles makes them difficult to avoid.
Energetic particles from the Sun impact a detector on ESA & NASA's SOHO satellite.
Parker Solar Probe's energetic particle instruments have measured several never-before-seen events so small that all trace of them is lost before they reach Earth. These instruments have also measured a rare type of particle burst with a particularly high number of heavier elements — suggesting that both types of events may be more common than scientists previously thought.
3. Rotation of the solar wind
Near Earth, we see the solar wind flowing almost straight out from the Sun in all directions. But the Sun rotates as it releases the solar wind, and before it breaks free, the wind spins along in sync with the Sun's surface. For the first time, Parker was able to observe the solar wind while it was still rotating – starting more than 20 million miles from the Sun.
The strength of the circulation was stronger than many scientists had predicted, but it also transitioned more quickly than predicted to an outward flow, which helps mask the effects of that fast rotation from the vantage point where we usually see them from, near Earth, about 93 million miles away. Understanding this transition point in the solar wind is key to helping us understand how the Sun sheds energy, with implications for the lifecycles of stars and the formation of protoplanetary disks.
4. Hints of a dust-free zone
Parker also saw the first direct evidence of dust starting to thin out near the Sun – an effect that has been theorized for nearly a century, but has been impossible to measure until now. Space is awash in dust, the cosmic crumbs of collisions that formed planets, asteroids, comets and other celestial bodies billions of years ago. Scientists have long suspected that, close to the Sun, this dust would be heated to high temperatures by powerful sunlight, turning it into a gas and creating a dust-free region around the Sun.
For the first time, Parker's imagers saw the cosmic dust begin to thin out a little over 7 million miles from the Sun. This decrease in dust continues steadily to the current limits of Parker Solar Probe's instruments, measurements at a little over 4 million miles from the Sun. At that rate of thinning, scientists expect to see a truly dust-free zone starting a little more than 2-3 million miles from the Sun — meaning the spacecraft could observe the dust-free zone as early as 2020, when its sixth flyby of the Sun will carry it closer to our star than ever before.
These are just a few of Parker Solar Probe's first discoveries, and there's plenty more science to come throughout the mission! For the latest on our Sun, follow @NASASun on Twitter and NASA Sun Science on Facebook.
Celebrate #BlackHoleFriday with Nurturing Baby Stars
Are you throwing all your money into a black hole today?
Forget Black Friday — celebrate #BlackHoleFriday with us and get sucked into this recent discovery of a black hole that may have sparked star births across multiple galaxies.
If confirmed, this discovery would represent the widest reach ever seen for a black hole acting as a stellar kick-starter — enhancing star formation more than one million light-years away. (One light year is equal to 6 trillion miles.)
A black hole is an extremely dense object from which no light can escape. The black hole's immense gravity pulls in surrounding gas and dust. Sometimes, black holes hinder star birth. Sometimes — like perhaps in this case — they increase star birth.
Telescopes like our Chandra X-ray Observatory help us detect the X-rays produced by hot gas swirling around the black hole. Have more questions about black holes? Click here to learn more.
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Say hello to the Saturn Nebula 👋
Garden-variety stars like the Sun live fairly placid lives in their galactic neighborhoods, casually churning out heat and light for billions of years. When these stars reach retirement age, however, they transform into unique and often psychedelic works of art. This Hubble Space Telescope image of the Saturn Nebula shows the result, called a planetary nebula. While it looks like a piece of wrapped cosmic candy, what we see is actually the outer layers of a dying star.
Stars are powered by nuclear fusion, but each one comes with a limited supply of fuel. When a medium-mass star exhausts its nuclear fuel, it will swell up and shrug off its outer layers until only a small, hot core remains. The leftover core, called a white dwarf, is a lot like a hot coal that glows after a barbecue — eventually it will fade out. Until then, the gaseous debris fluoresces as it expands out into the cosmos, possibly destined to be recycled into later generations of stars and planets.
Using Hubble’s observations, scientists have characterized the nebula’s composition, structure, temperature and the way it interacts with surrounding material. Studying planetary nebulas is particularly interesting since our Sun will experience a similar fate around five billion years down the road.
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Five Record-Setting Gamma-ray Bursts!
For 10 years, our Fermi Gamma-ray Space Telescope has scanned the sky for gamma-ray bursts (GRBs), the universe’s most luminous explosions!
Most GRBs occur when some types of massive stars run out of fuel and collapse to create new black holes. Others happen when two neutron stars, superdense remnants of stellar explosions, merge. Both kinds of cataclysmic events create jets of particles that move near the speed of light.
A new catalog of the highest-energy blasts provides scientists with fresh insights into how they work. Below are five record-setting events from the catalog that have helped scientists learn more about GRBs:
1. Super-short burst in Boötes!
The short burst 081102B, which occurred in the constellation Boötes on Nov. 2, 2008, is the briefest LAT-detected GRB, lasting just one-tenth of a second!
2. Long-lived burst!
Long-lived burst 160623A, spotted on June 23, 2016, in the constellation Cygnus, kept shining for almost 10 hours at LAT energies — the longest burst in the catalog.
For both long and short bursts, the high-energy gamma-ray emission lasts longer than the low-energy emission and happens later.
3. Highest energy gamma-rays!
The highest-energy individual gamma ray detected by Fermi’s LAT reached 94 billion electron volts (GeV) and traveled 3.8 billion light-years from the constellation Leo. It was emitted by 130427A, which also holds the record for the most gamma rays — 17 — with energies above 10 GeV.
4. In a constellation far, far away!
The farthest known GRB occurred 12.2 billion light-years away in the constellation Carina. Called 080916C, researchers calculate the explosion contained the power of 9,000 supernovae.
5. Probing the physics of our cosmos!
The known distance to 090510 helped test Einstein’s theory that the fabric of space-time is smooth and continuous. Fermi detected both a high-energy and a low-energy gamma ray at nearly the same instant. Having traveled the same distance in the same amount of time, they showed that all light, no matter its energy, moves at the same speed through the vacuum of space.
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5 of Your Fermi Gamma-ray Space Telescope Questions Answered
The Fermi Gamma-ray Space Telescope is a satellite in low-Earth orbit that detects gamma rays from exotic objects like black holes, neutron stars and fast-moving jets of hot gas. For 11 years Fermi has seen some of the highest-energy bursts of light in the universe and is helping scientists understand where gamma rays come from.
Confused? Don’t be! We get a ton of questions about Fermi and figured we'd take a moment to answer a few of them here.
1. Who was this Fermi guy?
The Fermi telescope was named after Enrico Fermi in recognition of his work on how the tiny particles in space become accelerated by cosmic objects, which is crucial to understanding many of the objects that his namesake satellite studies.
Enrico Fermi was an Italian physicist and Nobel Prize winner (in 1938) who immigrated to the United States to be a professor of physics at Columbia University, later moving to the University of Chicago.
Original image courtesy Argonne National Laboratory
Over the course of his career, Fermi was involved in many scientific endeavors, including the Manhattan Project, quantum theory and nuclear and particle physics. He even engineered the first-ever atomic reactor in an abandoned squash court (squash is the older, English kind of racquetball) at the University of Chicago.
There are a number of other things named after Fermi, too: Fermilab, the Enrico Fermi Nuclear Generating Station, the Enrico Fermi Institute and more. (He’s kind of a big deal in the physics world.)
Fermi even had something to say about aliens! One day at lunch with his buddies, he wondered if extraterrestrial life existed outside our solar system, and if it did, why haven't we seen it yet? His short conversation with friends sparked decades of research into this idea and has become known as the Fermi Paradox — given the vastness of the universe, there is a high probability that alien civilizations exist out there, so they should have visited us by now.
2. So, does the Fermi telescope look for extraterrestrial life?
No. Although both are named after Enrico Fermi, the Fermi telescope and the Fermi Paradox have nothing to do with one another.
Fermi does not look for aliens, extraterrestrial life or anything of the sort! If aliens were to come our way, Fermi would be no help in identifying them, and they might just slip right under Fermi’s nose. Unless, of course, those alien spacecraft were powered by processes that left behind traces of gamma rays.
Fermi detects gamma rays, the highest-energy form of light, which are often produced by events so far away the light can take billions of years to reach Earth. The satellite sees pulsars, active galaxies powered by supermassive black holes and the remnants of exploding stars. These are not your everyday stars, but the heavyweights of the universe.
3. Does the telescope shoot gamma rays?
No. Fermi DETECTS gamma rays using its two instruments, the Large Area Telescope (LAT) and the Gamma-ray Burst Monitor (GBM).
The LAT sees about one-fifth of the sky at a time and records gamma rays that are millions of times more energetic than visible light. The GBM detects lower-energy emissions, which has helped it identify more than 2,000 gamma-ray bursts – energetic explosions in galaxies extremely far away.
The highest-energy gamma ray from a gamma-ray burst was detected by Fermi’s LAT, and traveled 3.8 billion light-years to reach us from the constellation Leo.
4. Will gamma rays turn me into a superhero?
Nope. In movies and comic books, the hero has a tragic backstory and a brush with death, only to rise out of some radioactive accident stronger and more powerful than before. In reality, that much radiation would be lethal.
In fact, as a form of radiation, gamma rays are dangerous for living cells. If you were hit with a huge amount of gamma radiation, it could be deadly — it certainly wouldn’t be the beginning of your superhero career.
5. That sounds bad…does that mean if a gamma-ray burst hit Earth, it would wipe out the planet and destroy us all?
Thankfully, our lovely planet has an amazing protector from gamma radiation: an atmosphere. That is why the Fermi telescope is in orbit; it’s easier to detect gamma rays in space!
Gamma-ray bursts are so far away that they pose no threat to Earth. Fermi sees gamma-ray bursts because the flash of gamma rays they release briefly outshines their entire home galaxies, and can sometimes outshine everything in the gamma-ray sky.
If a habitable planet were too close to one of these explosions, it is possible that the jet emerging from the explosion could wipe out all life on that planet. However, the probability is extremely low that a gamma-ray burst would happen close enough to Earth to cause harm. These events tend to occur in very distant galaxies, so we’re well out of reach.
We hope that this has helped to clear up a few misconceptions about the Fermi Gamma-ray Space Telescope. It’s a fantastic satellite, studying the craziest extragalactic events and looking for clues to unravel the mysteries of our universe!
Now that you know the basics, you probably want to learn more! Follow the Fermi Gamma-ray Space Telescope on Twitter (@NASAFermi) or Facebook (@nasafermi), and check out more awesome stuff on our Fermi webpage.
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Say hello to the Jewel Box Cluster 👋
This Hubble Space Telescope image shows a young, open star cluster known as NGC 4755 or the Jewel Box. Just like old school friends that drift apart after graduation, the stars in open clusters only remain together for a limited time. They disperse into space over the course of a few hundred million years, pulled away by the gravitational tugs of other passing clusters and clouds of gas.
The Jewel Box is a spartan collection of just over 100 stars. The cluster is about 6,500 light-years away from Earth, which means that the light we see from it today was emitted before the Great Pyramids in Egypt were built.
Head outside and you can see it for yourself! The Jewel Box is visible to the naked eye, but will masquerade as a single star. Grab a pair of binoculars if you want to see more of the cluster’s sparkling stellar population. It is located in the southern constellation of the cross (Crux).
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DYK the bright clusters and nebulae of planet Earth's night sky are often named for flowers or insects?
Though its wingspan covers over 3 light-years, NGC 6302: The Butterfly Nebula is no exception! With an estimated surface temperature of about 250,000 degrees C, the dying central star of this particular planetary nebula has become exceptionally hot, shining brightly in ultraviolet light but hidden from direct view by a dense torus of dust. This sharp close-up was recorded by the Hubble Space Telescope in 2009. The Hubble image data is reprocessed here, showing off the remarkable details of the complex planetary nebula.
Image Credit: NASA, ESA, Hubble, HLA; Reprocessing & Copyright: Robert Eder
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The Lagoon Nebula
This colorful image, taken by our Hubble Space Telescope between Feb. 12 and Feb. 18, 2018 , celebrated the Earth-orbiting observatory’s 28th anniversary of viewing the heavens, giving us a window seat to the universe’s extraordinary tapestry of stellar birth and destruction.
At the center of the photo, a monster young star 200,000 times brighter than our Sun is blasting powerful ultraviolet radiation and hurricane-like stellar winds, carving out a fantasy landscape of ridges, cavities, and mountains of gas and dust.
This region epitomizes a typical, raucous stellar nursery full of birth and destruction. The clouds may look majestic and peaceful, but they are in a constant state of flux from the star’s torrent of searing radiation and high-speed particles from stellar winds. As the monster star throws off its natal cocoon of material with its powerful energy, it is suppressing star formation around it.
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Five Facts About the Kepler Space Telescope That Will Blow You Away!
Ten years ago, on March 6, 2009, a rocket lifted off a launch pad at Cape Canaveral Air Force Station in Florida. It carried a passenger that would revolutionize our understanding of our place in the cosmos--NASA’s first planet hunter, the Kepler space telescope. The spacecraft spent more than nine years in orbit around the Sun, collecting an unprecedented dataset for science that revealed our galaxy is teeming with planets. It found planets that are in some ways similar to Earth, raising the prospects for life elsewhere in the cosmos, and stunned the world with many other first-of-a-kind discoveries. Here are five facts about the Kepler space telescope that will blow you away:
Kepler observed more than a half million stars looking for planets beyond our solar system.
It discovered more than 2,600 new worlds…
…many of which could be promising places for life.
Kepler’s survey revealed there are more planets than stars in our galaxy.
The spacecraft is now drifting around the Sun more than 94 million miles away from Earth in a safe orbit.
NASA retired the Kepler spacecraft in 2018. But to this day, researchers continue to mine its archive of data, uncovering new worlds.
*All images are artist illustrations. Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com
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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Gobble Up These Black (Hole) Friday Deals!
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!
Black hole birth announcements
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.
NICER black holes
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.
Merging monster black holes
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.
Black holes power bright gamma ray lights
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.
Catching particles from near a black hole
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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Things That Go Bump in the Gamma Rays
Some people watch scary movies because they like being startled. A bad guy jumps out from around a corner! A monster emerges from the shadows! Scientists experience surprises all the time, but they’re usually more excited than scared. Sometimes theories foreshadow new findings — like when there’s a dramatic swell in the movie soundtrack — but often, discoveries are truly unexpected.
Scientists working with the Fermi Gamma-Ray Space Telescope have been jumping to study mysterious bumps in the gamma rays for a decade now. Gamma rays are the highest-energy form of light. Invisible to human eyes, they’re created by some of the most powerful and unusual events and objects in the universe. In celebration of Halloween, here are a few creepy gamma-ray findings from Fermi’s catalog.
Stellar Graveyards
If you were to walk through a cemetery at night, you’d expect to trip over headstones or grave markers. Maybe you’d worry about running into a ghost. If you could explore the stellar gravesite created when a star explodes as a supernova, you’d find a cloud of debris expanding into interstellar space. Some of the chemical elements in that debris, like gold and platinum, go on to create new stars and planets! Fermi found that supernova remnants IC 443 and W44 also accelerate mysterious cosmic rays, high-energy particles moving at nearly the speed of light. As the shockwave of the supernova expands, particles escape its magnetic field and interact with non-cosmic-ray particles to produce gamma rays.
Ghost Particles
But the sources of cosmic rays aren’t the only particle mysteries Fermi studies. Just this July, Fermi teamed up with the IceCube Neutrino Observatory in Antarctica to discover the first source of neutrinos outside our galactic neighborhood. Neutrinos are particles that weigh almost nothing and rarely interact with anything. Around a trillion of them pass through you every second, ghost-like, without you noticing and then continue on their way. (But don’t worry, like a friendly ghost, they don’t harm you!) Fermi traced the neutrino IceCube detected back to a supermassive black hole in a distant galaxy. By the time it reached Earth, it had traveled for 3.7 billion years at almost the speed of light!
Black Widow Pulsars
Black widows and redbacks are species of spiders with a reputation for devouring their partners. Astronomers have discovered two types of star systems that behave in a similar way. Sometimes when a star explodes as a supernova, it collapses back into a rapidly spinning, incredibly dense star called a pulsar. If there’s a lighter star nearby, it can get stuck in a close orbit with the pulsar, which blasts it with gamma rays, magnetic fields and intense winds of energetic particles. All these combine to blow clouds of material off the low-mass star. Eventually, the pulsar can eat away at its companion entirely.
Dark Matter
What’s scarier than a good unsolved mystery? Dark matter is a little-understood substance that makes up most of the matter in the universe. The stuff that we can see — stars, people, haunted houses, candy — is made up of normal matter. But our surveys of the cosmos tell us there’s not enough normal matter to keep things working the way they do. There must be another type of matter out there holding everything together. One of Fermi’s jobs is to help scientists narrow down the search for dark matter. Last year, researchers noticed that most of the gamma rays coming from the Andromeda galaxy are confined to its center instead of being spread throughout. One possible explanation is that accumulated dark matter at the center of the galaxy is emitting gamma rays!
Fermi has helped us learn a lot about the gamma-ray universe over the last 10 years. Learn more about its accomplishments and the other mysteries it’s working to solve. What other surprises are waiting out among the stars?
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The Kepler space telescope has shown us our galaxy is teeming with planets — and other surprises
The Kepler space telescope has taught us there are so many planets out there, they outnumber even the stars. Here is a sample of these wondrous, weird and unexpected worlds (and other spectacular objects in space) that Kepler has spotted with its “eye” opened to the heavens.
Kepler has found that double sunsets really do exist.
Yes, Star Wars fans, the double sunset on Tatooine could really exist. Kepler discovered the first known planet around a double-star system, though Kepler-16b is probably a gas giant without a solid surface.
Kepler has gotten us closer to finding planets like Earth.
Nope. Kepler hasn’t found Earth 2.0, and that wasn’t the job it set out to do. But in its survey of hundreds of thousands of stars, Kepler found planets near in size to Earth orbiting at a distance where liquid water could pool on the surface. One of them, Kepler-62f, is about 40 percent bigger than Earth and is likely rocky. Is there life on any of them? We still have a lot more to learn.
This sizzling world is so hot iron would melt!
One of Kepler’s early discoveries was the small, scorched world of Kepler-10b. With a year that lasts less than an Earth day and density high enough to imply it’s probably made of iron and rock, this “lava world” gave us the first solid evidence of a rocky planet outside our solar system.
If it’s not an alien megastructure, what is this oddly fluctuating star?
When Kepler detected the oddly fluctuating light from “Tabby’s Star,” the internet lit up with speculation of an alien megastructure. Astronomers have concluded it’s probably an orbiting dust cloud.
Kepler caught this dead star cannibalizing its planet.
What happens when a solar system dies? Kepler discovered a white dwarf, the compact corpse of a star in the process of vaporizing a planet.
These Kepler planets are more than twice the age of our Sun!
The five small planets in Kepler-444 were born 11 billion years ago when our galaxy was in its youth. Imagine what these ancient planets look like after all that time?
Kepler found a supernova exploding at breakneck speed.
This premier planet hunter has also been watching stars explode. Kepler recorded a sped-up version of a supernova called a “fast-evolving luminescent transit” that reached its peak brightness at breakneck speed. It was caused by a star spewing out a dense shell of gas that lit up when hit with the shockwave from the blast.
* All images are artist illustrations.
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10 Steps to Confirm a Planet Around Another Star
So you think you found an exoplanet -- a planet around another star? It’s not as simple as pointing a telescope to the sky and looking for a planet that waves back. Scientists gather many observations and carefully analyze their data before they can be even somewhat sure that they’ve discovered new worlds.
Here are 10 things to know about finding and confirming exoplanets.
This is an illustration of the different elements in our exoplanet program, including ground-based observatories, like the W. M. Keck Observatory, and space-based observatories like Hubble, Spitzer, Kepler, TESS, James Webb Space Telescope, WFIRST and future missions.
1. Pick your tool to take a look.
The vast majority of planets around other stars have been found through the transit method so far. This technique involves monitoring the amount of light that a star gives off over time, and looking for dips in brightness that may indicate an orbiting planet passing in front of the star.
We have two specialized exoplanet-hunting telescopes scanning the sky for new planets right now -- Kepler and the Transiting Exoplanet Survey Satellite (TESS) -- and they both work this way. Other methods of finding exoplanets include radial velocity (looking for a “wobble” in a star's position caused by a planet’s gravity), direct imaging (blocking the light of the star to see the planet) and microlensing (watching for events where a star passes in front of another star, and the gravity of the first star acts as a lens).
Here’s more about finding exoplanets.
2. Get the data.
To find a planet, scientists need to get data from telescopes, whether those telescopes are in space or on the ground. But telescopes don’t capture photos of planets with nametags. Instead, telescopes designed for the transit method show us how brightly thousands of stars are shining over time. TESS, which launched in April and just began collecting science data, beams its stellar observations back to Earth through our Deep Space Network, and then scientists get to work.
3. Scan the data for planets.
Researchers combing through TESS data are looking for those transit events that could indicate planets around other stars. If the star’s light lessens by the same amount on a regular basis -- for example, every 10 days -- this may indicate a planet with an orbital period (or “year”) of 10 days. The standard requirement for planet candidates from TESS is at least two transits -- that is, two equal dips in brightness from the same star.
4. Make sure the planet signature couldn’t be something else.
Not all dips in a star's brightness are caused by transiting planets. There may be another object -- such as a companion star, a group of asteroids, a cloud of dust or a failed star called a brown dwarf, that makes a regular trip around the target star. There could also be something funky going on with the telescope’s behavior, how it delivered the data, or other “artifacts” in data that just aren’t planets. Scientists must rule out all non-planet options to the best of their ability before moving forward.
5. Follow up with a second detection method.
Finding the same planet candidate using two different techniques is a strong sign that the planet exists, and is the standard for “confirming” a planet. That’s why a vast network of ground-based telescopes will be looking for the same planet candidates that TESS discovers. It is also possible that TESS will spot a planet candidate already detected by another telescope in the past. With these combined observations, the planet could then be confirmed. The first planet TESS discovered, Pi Mensae c, orbits a star previously observed with the radial-velocity method on the ground. Scientists compared the TESS data and the radial-velocity data from that star to confirm the presence of planet “c.”
Scientists using the radial-velocity detection method see a star’s wobble caused by a planet’s gravity, and can rule out other kinds of objects such as companion stars. Radial-velocity detection also allows scientists to calculate the mass of the planet.
6. …or at least another telescope.
Other space telescopes may also be used to help confirm exoplanets, characterize them and even discover additional planets around the same stars. If the planet is detected by the same method, but by two different telescopes, and has received enough scrutiny that the scientists are more than 99 percent sure it’s a planet, it is said to be “validated” instead of “confirmed.”
7. Write a paper.
After thoroughly analyzing the data, and running tests to make sure that their result still looks like the signature of a planet, scientists write a formal paper describing their findings. Using the transit method, they can also report the size of the planet. The planet’s radius is related to how much light it blocks from the star, as well as the size of the star itself. The scientists then submit the study to a journal.
8. Wait for peer review.
Scientific journals have a rigorous peer review process. This means scientific experts not involved in the study review it and make sure the findings look sound. The peer-reviewers may have questions or suggestions for the scientists. When everyone agrees on a version of the study, it gets published.
9. Publish the study.
When the study is published, scientists can officially say they have found a new planet. This may still not be the end of the story, however. For example, the TRAPPIST telescope in Chile first thought they had discovered three Earth-size planets in the TRAPPIST-1 system. When our Spitzer Space Telescope and other ground-based telescopes followed up, they found that one of the original reported planets (the original TRAPPIST-1d) did not exist, but they discovered five others --bringing the total up to seven wondrous rocky worlds.
10. Catalog and celebrate -- and look closer if you can!
Confirmed planets get added to our official catalog. So far, Kepler has sent back the biggest bounty of confirmed exoplanets of any telescope -- more than 2,600 to date. TESS, which just began its planet search, is expected to discover many thousands more. Ground-based follow-up will help determine if these planets are gaseous or rocky, and possibly more about their atmospheres. The forthcoming James Webb Space Telescope will be able to take a deeper look at the atmospheres of the most interesting TESS discoveries.
Scientists sometimes even uncover planets with the help of people like you: exoplanet K2-138 was discovered through citizen scientists in Kepler’s K2 mission data. Based on surveys so far, scientists calculate that almost every star in the Milky Way should have at least one planet. That makes billions more, waiting to be found! Stay up to date with our latest discoveries using this exoplanet counter.
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10 Things: How to Photograph a Meteor Shower
Taking photographs of a meteor shower can be an exercise in patience as meteors streak across the sky quickly and unannounced, but with these tips – and some good fortune – you might be rewarded with a great photo.
These tips are meant for a DSLR or mirrorless camera, but some point-and-shoot cameras with manual controls could be used as well.
1. The Photo Op: Perseids Meteors
The Perseids are dusty remnants of comet 109P/Swift-Tuttle.
Earth passes through the comet’s invisible, multi-billion mile trail of tiny debris each year around August, creating a meteor shower of so-called “shooting stars” as the particles are vaporized in our atmosphere.
Perseid meteors already are streaking across the sky. This year's shower peaks on a moonless summer night -from 4 pm on the 12th until 4 am on the 13th Eastern Daylight Time.
Read more on the Perseids ›
2. Get away from city lights and find a place with dark skies.
In this 30 second exposure, a meteor streaks across the sky in Spruce Knob, West Virginia, during the 2016 Perseids meteor shower. Credit: NASA/Bill Ingalls
Too much light and it will be hard for your eyes to see fainter meteors, plus your image will get flooded with the glow of light. Turning down the brightness of the camera’s LCD screen will help keep your eyes adjusted to the dark. The peak of the 2018 Perseid meteor shower occurs just after the new moon, meaning a thin crescent will set long before the best viewing hours, leaving hopeful sky watchers with a moonlight-free sky!
3. Use a tripod.
In this ten-second exposure, a meteor streaks across the sky above Washington, DC during the 2015 Perseids meteor shower, Credit: NASA/Joel Kowsky
Meteor photography requires long exposures, and even the steadiest of hands can’t hold a camera still enough for a clear shot. Heavier tripods help reduce shaking caused by wind and footsteps, but even a lightweight tripod will do. You can always place sandbags against the feet of the tripod to add weight and stability. If you don’t have a tripod, you might be able to prop your camera on or up against something around you, but be sure to secure your camera.
4. Use a wide-angle lens.
In this 30 second exposure taken with a circular fish-eye lens, a meteor streaks across the sky during the 2016 Perseids meteor shower as a photographer wipes moisture from the camera lens Friday, August 12, 2016 in Spruce Knob, West Virginia. Credit: NASA/Bill Ingalls
A wide-angle lens will capture more of the sky and give you a greater chance of capturing a meteor in your shot, while a zoom lens captures a smaller area of the sky. The odds of a meteor streaking past that small patch are lower.
5. Use a shutter release cable or the camera’s built-in timer.
Long exposures are not just for meteors. In this shot taken at Joshua Tree National Park, a hiker's headlamp leaves a trail of light along a twilight path. Credit: National Park Service / Hannah Schwalbe
A tripod does a great job of reducing most of the shaking your camera experiences, but even the act of pressing the shutter button can blur your extended exposure. Using the self-timer gives you several seconds for any shaking from pressing the shutter button to stop before the shutter is released. A shutter release cable (without a self-timer) eliminates the need to touch the camera at all. And if your camera has wifi capabilities, you might be able to activate the shutter from a mobile device.
6. Manually focus your lens.
In this 30 second exposure, a meteor streaks across the sky during the annual Perseids meteor shower Friday, August 12, 2016 in Spruce Knob, West Virginia. Credit: NASA/Bill Ingalls
At night, autofocus will struggle to find something on which to focus. Setting your focus to infinity will get you close, but chances are you’ll have to take some test images and do some fine tuning. With your camera on a tripod, take a test image lasting a few seconds, then use the camera’s screen to review the image. Zoom in to a star to see how sharp your focus is. If the stars look like fuzzy blobs, make tiny adjustments to the focus and take another test image.
Repeat until you are happy with the result.
If your camera has a zoomable electronic viewfinder or live view option, you might be able to zoom to a star and focus without having to take a test image.
7. Aim your camera.
The Perseids appear to radiate from the constellation Perseus, visible in the northern sky soon after sunset this time of year.
Even though we don’t know when or where a single meteor will appear, we do know the general area from which they’ll originate.
Meteor showers get their name based on the point in the sky from which they appear to radiate. In the case of the Perseids, during their peak, they appear to come from the direction of the constellation Perseus in the northern sky.
8. Calculate your exposure time.
In this 20-second exposure, a meteor lights up the sky over the top of a mountain ridge near Park City, Utah. Even though this image was captured during the annual Perseid meteor shower, this "shooting star" is probably not one of the Perseid meteors, which originate from material left behind by Comet Swift-Tuttle. Instead, it's likely one of the many bits of rock and dust that randomly fall into the atmosphere on any given night. Credit: NASA/Bill Dunford
As Earth rotates, the stars in the sky appear to move, and if your shutter is open long enough, you might capture some of that movement. If you want to avoid apparent star movement, you can follow the 500 Rule. Take 500 and divide it by the length in millimeters of your lens. The resulting number is the length of time in seconds that you can keep your shutter open before seeing star trails. For example, if you’re using a 20 mm lens, 25 seconds (500 divided by 20) is the longest you can set your exposure time before star trails start to show up in your images.
9. Experiment!
In this 30 second exposure photo, hikers find their way to the top of Spruce Knob in West Virginia to view the annual Perseids meteor shower, Friday, August 12, 2016. Credit: NASA/Bill Ingalls
Once you know the maximum exposure time, you can set your shutter priority to that length and let the camera calculate other settings for your first image. Depending on how the image turns out, you can manually adjust aperture (set it to a lower number if the image is too dark) and ISO (set it to a higher number if the image is too dark) to improve your next images. Changing only one setting at a time will give you a better understanding of how those changes affect your image.
10. Enjoy the show.
The crew of the International Space Station captured this Perseid meteor falling to Earth over China in 2011. Credit: NASA
With your camera settings adjusted, capturing that perfect photo is just a matter of time and luck. The highest rate of meteors visible per hour is in the hours after midnight and before dawn. Set up your camera next to a lounge chair or a blanket to witness the wonder of a meteor shower for yourself – and, with any luck, you’ll take home some envy-inducing shots, too!
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Gamma-ray Bursts: Black Hole Birth Announcements
Gamma-ray bursts are the brightest, most violent explosions in the universe, but they can be surprisingly tricky to detect. Our eyes can't see them because they are tuned to just a limited portion of the types of light that exist, but thanks to technology, we can even see the highest-energy form of light in the cosmos — gamma rays.
So how did we discover gamma-ray bursts?
Accidentally!
We didn’t actually develop gamma-ray detectors to peer at the universe — we were keeping an eye on our neighbors! During the Cold War, the United States and the former Soviet Union both signed the Nuclear Test Ban Treaty of 1963 that stated neither nation would test nuclear weapons in space. Just one week later, the US launched the first Vela satellite to ensure the treaty wasn’t being violated. What they saw instead were gamma-ray events happening out in the cosmos!
Things Going Bump in the Cosmos
Each of these gamma-ray events, dubbed “gamma-ray bursts” or GRBs, lasted such a short time that information was very difficult to gather. For decades their origins, locations and causes remained a cosmic mystery, but in recent years we’ve been able to figure out a lot about GRBs. They come in two flavors: short-duration (less than two seconds) and long-duration (two seconds or more). Short and long bursts seem to be caused by different cosmic events, but the end result is thought to be the birth of a black hole.
Short GRBs are created by binary neutron star mergers. Neutron stars are the superdense leftover cores of really massive stars that have gone supernova. When two of them crash together (long after they’ve gone supernova) the collision releases a spectacular amount of energy before producing a black hole. Astronomers suspect something similar may occur in a merger between a neutron star and an already-existing black hole.
Long GRBs account for most of the bursts we see and can be created when an extremely massive star goes supernova and launches jets of material at nearly the speed of light (though not every supernova will produce a GRB). They can last just a few seconds or several minutes, though some extremely long GRBs have been known to last for hours!
A Gamma-Ray Burst a Day Sends Waves of Light Our Way!
Our Fermi Gamma-ray Space Telescope detects a GRB nearly every day, but there are actually many more happening — we just can’t see them! In a GRB, the gamma rays are shot out in a narrow beam. We have to be lined up just right in order to detect them, because not all bursts are beamed toward us — when we see one it's because we're looking right down the barrel of the gamma-ray gun. Scientists estimate that there are at least 50 times more GRBs happening each day than we detect!
So what’s left after a GRB — just a solitary black hole? Since GRBs usually last only a matter of seconds, it’s very difficult to study them in-depth. Fortunately, each one leaves an afterglow that can last for hours or even years in extreme cases. Afterglows are created when the GRB jets run into material surrounding the star. Because that material slows the jets down, we see lower-energy light, like X-rays and radio waves, that can take a while to fade. Afterglows are so important in helping us understand more about GRBs that our Neil Gehrels Swift Observatory was specifically designed to study them!
Last fall, we had the opportunity to learn even more from a gamma-ray burst than usual! From 130 million light-years away, Fermi witnessed a pair of neutron stars collide, creating a spectacular short GRB. What made this burst extra special was the fact that ground-based gravitational wave detectors LIGO and Virgo caught the same event, linking light and gravitational waves to the same source for the first time ever!
For over 10 years now, Fermi has been exploring the gamma-ray universe. Thanks to Fermi, scientists are learning more about the fundamental physics of the cosmos, from dark matter to the nature of space-time and beyond. Discover more about how we’ll be celebrating Fermi’s achievements all year!
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The Sun is not silent. The low, pulsing hum of our star's heartbeat allows scientists to peer inside, revealing huge rivers of solar material flowing around before their eyes — er, ears.
Data from ESA (European Space Agency) and NASA’s Solar and Heliospheric Observatory (SOHO), sonified by the Stanford Experimental Physics Lab, captures the Sun’s natural vibrations and reveals what can’t be seen with the naked eye.
In this audiogram, our heliophysicist Alex Young explains how this simple sound connects us with the Sun and all the other stars in the universe.
This piece features low frequency sounds of the Sun. For the best listening experience, listen to this story with headphones. 🎧
Read more: https://go.nasa.gov/2LMW42o
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Pick Your Favorite Findings From Fermi’s First Decade
The Fermi Gamma-ray Space Telescope has been observing some of the most extreme objects and events in the universe — from supermassive black holes to merging neutron stars and thunderstorms — for 10 years. Fermi studies the cosmos using gamma rays, the highest-energy form of light, and has discovered thousands of new phenomena for scientists.
Here are a few of our favorite Fermi discoveries, pick your favorite in the first round of our “Fermi Science Playoff.”
Colliding Neutron Stars
In 2017, Fermi detected a gamma ray burst at nearly the same moment ground observatories detected gravitational waves from two merging neutron stars. This was the first time light and ripples in space-time were detected from the same source.
The Sun and Moon in Gamma Rays
In 2016, Fermi showed the Moon is brighter in gamma rays than the Sun. Because the Moon doesn’t have a magnetic field, the surface is constantly pelted from all directions by cosmic rays. These produce gamma rays when they run into other particles, causing a full-Moon gamma-ray glow.
Record Rare from a Blazar
The supermassive black hole at the center of the galaxy 3C 279 weighs a billion times the mass of our Sun. In June 2015, this blazar became the brightest gamma-ray source in the sky due to a record-setting flare.
The First Gamma-Ray Pulsar in Another Galaxy
In 2015, for the first time, Fermi discovered a gamma-ray pulsar, a kind of rapidly spinning superdense star, in a galaxy outside our own. The object, located on the outskirts of the Tarantula Nebula, also set the record for the most luminous gamma-ray pulsar we’ve seen so far.
A Gamma-Ray Cycle in Another Galaxy
Many galaxies, including our own, have black holes at their centers. In active galaxies, dust and gas fall into and “feed” the black hole, releasing light and heat. In 2015 for the first time, scientists using Fermi data found hints that a galaxy called PG 1553+113 has a years-long gamma-ray emission cycle. They’re not sure what causes this cycle, but one exciting possibility is that the galaxy has a second supermassive black hole that causes periodic changes in what the first is eating.
Gamma Rays from Novae
A nova is a fairly common, short-lived kind of explosion on the surface of a white dwarf, a type of compact star not much larger than Earth. In 2014, Fermi observed several novae and found that they almost always produce gamma-rays, giving scientists a new type of source to explore further with the telescope.
A Record-Setting Cosmic Blast
Gamma-ray bursts are the most luminous explosions in the universe. In 2013, Fermi spotted the brightest burst it’s seen so far in the constellation Leo. In the first three seconds alone, the burst, called GRB 130427A, was brighter than any other burst seen before it. This record has yet to be shattered.
Cosmic Rays from Supernova Leftovers
Cosmic rays are particles that travel across the cosmos at nearly the speed of light. They are hard to track back to their source because they veer off course every time they encounter a magnetic field. In 2013, Fermi showed that these particles reach their incredible speed in the shockwaves of supernova remains — a theory proposed in 1949 by the satellite’s namesake, the Italian-American physicist Enrico Fermi.
Discovery of a Transformer Pulsar
In 2013, the pulsar in a binary star system called AY Sextanis switched from radio emissions to high-energy gamma rays. Scientists think the change reflects erratic interaction between the two stars in the binary.
Gamma-Ray Measurement of a Gravitational Lens
A gravitational lens is a kind of natural cosmic telescope that occurs when a massive object in space bends and amplifies light from another, more distant object. In 2012, Fermi used gamma rays to observe a spiral galaxy 4.03 billion light-years away bending light coming from a source 4.35 billion light-years away.
New Limits on Dark Matter
We can directly observe only 20 percent of the matter in the universe. The rest is invisible to telescopes and is called dark matter — and we’re not quite sure what it is. In 2012, Fermi helped place new limits on the properties of dark matter, essentially narrowing the field of possible particles that can describe what dark matter is.
‘Superflares’ in the Crab Nebula
The Crab Nebula supernova remnant is one of the most-studied targets in the sky — we’ve been looking at it for almost a thousand years! In 2011, Fermi saw it erupt in a flare five times more powerful than any previously seen from the object. Scientists calculate the electrons in this eruption are 100 times more energetic than what we can achieve with particle accelerators on Earth.
Thunderstorms Hurling Antimatter into Space
Terrestrial gamma-ray flashes are created by thunderstorms. In 2011, Fermi scientists announced the satellite had detected beams of antimatter above thunderstorms, which they think are a byproduct of gamma-ray flashes.
Giant Gamma-Ray Bubbles in the Milky Way
Using data from Fermi in 2010, scientists discovered a pair of “bubbles” emerging from above and below the Milky Way. These enormous bubbles are half the length of the Milky Way and were probably created by our galaxy’s supermassive black hole only a few million years ago.
Hint of Starquakes in a Magnetar
Neutron stars have magnetic fields trillions of times stronger than Earth’s. Magnetars are neutron stars with magnetic fields 1,000 times stronger still. In 2009, Fermi saw a storm of gamma-ray bursts from a magnetar called SGR J1550-5418, which scientists think were related to seismic waves rippling across its surface.
A Dark Pulsar
We observe many pulsars using radio waves, visible light or X-rays. In 2008, Fermi found the first gamma-ray only pulsar in a supernova remnant called CTA 1. We think that the “beam” of gamma rays we see from CTA 1 is much wider than the beam of other types of light from that pulsar. Those other beams never sweep across our vision — only the gamma-rays.
Have a favorite Fermi discovery or want to learn more? Cast your vote in the first of four rounds of the Fermi Science Playoff to help rank Fermi’s findings. Or follow along as we celebrate the mission all year.
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When galaxies collide — a common event in the universe — a fresh burst of star formation typically takes place as gas clouds mash together. At this point, the galaxy has a blue hue, but the color does not mean it is cold: it is a result of the intense heat of newly formed blue–white stars. Those stars do not last long, and after a few billion years the reddish hues of aging, smaller stars dominate an elliptical galaxy's spectrum.
Our Hubble Space Telescope (@NASAHubble) caught sight of a soft, diffuse-looking galaxy, perhaps the aftermath of a long-ago galactic collision when two spiral galaxies, each perhaps much like the Milky Way, swirled together for millions of years.
In such mergers, the original galaxies are often stretched and pulled apart as they wrap around a common center of gravity. After a few back-and-forths, this starry tempest settles down into a new, round object. The now subdued celestial body is technically known as an elliptical galaxy.
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Credit: ESA/Hubble & NASA
Researchers Just Found (For The First Time) An 8th Planet Orbiting A Star Far, Far Away
Our Milky Way galaxy is full of hundreds of billions of worlds just waiting to be found. In 2014, scientists using data from our planet-hunting Kepler space telescope discovered seven planets orbiting Kepler-90, a Sun-like star located 2,500 light-years away. Now, an eighth planet has been identified in this planetary system, making it tied with our own solar system in having the highest number of known planets. Here’s what you need to know:
The new planet is called Kepler-90i.
Kepler-90i is a sizzling hot, rocky planet. It’s the smallest of eight planets in the Kepler-90 system. It orbits so close to its star that a “year” passes in just 14 days.
Average surface temperatures on Kepler-90i are estimated to hover around 800 degrees Fahrenheit, making it an unlikely place for life as we know it.
Its planetary system is like a scrunched up version of our solar system.
The Kepler-90 system is set up like our solar system, with the small planets located close to their star and the big planets farther away. This pattern is evidence that the system’s outer gas planets—which are about the size of Saturn and Jupiter—formed in a way similar to our own.
But the orbits are much more compact. The orbits of all eight planets could fit within the distance of Earth’s orbit around our Sun! Sounds crowded, but think of it this way: It would make for some great planet-hopping.
Kepler-90i was discovered using machine learning.
Most planets beyond our solar system are too far away to be imaged directly. The Kepler space telescope searches for these exoplanets—those planets orbiting stars beyond our solar system—by measuring how the brightness of a star changes when a planet transits, or crosses in front of its disk. Generally speaking, for a given star, the greater the dip in brightness, the bigger the planet!
Researchers trained a computer to learn how to identify the faint signal of transiting exoplanets in Kepler’s vast archive of deep-space data. A search for new worlds around 670 known multiple-planet systems using this machine-learning technique yielded not one, but two discoveries: Kepler-90i and Kepler-80g. The latter is part of a six-planet star system located 1,000 light-years away.
This is just the beginning of a new way of planet hunting.
Kepler-90 is the first known star system besides our own that has eight planets, but scientists say it won’t be the last. Other planets may lurk around stars surveyed by Kepler. Next, researchers are using machine learning with sophisticated computer algorithms to search for more planets around 150,000 stars in the Kepler database.
In the meantime, we’ll be doing more searching with telescopes.
Kepler is the most successful planet-hunting spacecraft to date, with more than 2,500 confirmed exoplanets and many more awaiting verification. Future space missions, like the Transiting Exoplanet Survey Satellite (TESS), the James Webb Space Telescope and Wide-Field Infrared Survey Telescope (WFIRST) will continue the search for new worlds and even tell us which ones might offer promising homes for extraterrestrial life.
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*All images of exoplanets are artist illustrations.
September 2017 Was 🔥 on the Sun
The Sun started September 2017 with flair, emitting 31 sizable solar flares and releasing several powerful coronal mass ejections, or CMEs, between Sept. 6-10.
Solar flares are powerful bursts of radiation. Harmful radiation from a flare cannot pass through Earth’s atmosphere to physically affect humans on the ground, however — when intense enough — they can disturb the atmosphere in the layer where GPS and communications signals travel.
CMEs are massive clouds of solar material and magnetic fields that erupt from the Sun at incredible speeds. Depending on the direction they’re traveling in, CMEs can spark powerful geomagnetic storms in Earth’s magnetic field.
As always, we and our partners had many missions observing the Sun from both Earth and space, enabling scientists to study these events from multiple perspectives. With this integrated picture of solar activity, scientists can better track the evolution of solar eruptions and work toward improving our understanding of space weather.
The National Oceanic and Atmospheric Administration (NOAA)’s Geostationary Operational Environmental Satellite-16, or GOES-16, watches the Sun’s upper atmosphere — called the corona — at six different wavelengths, allowing it to observe a wide range of solar phenomena. GOES-16 caught this footage of an X9.3 flare on Sept. 6, 2017.
This was the most intense flare recorded during the current 11-year solar cycle. X-class denotes the most intense flares, while the number provides more information about its strength. An X2 is twice as intense as an X1, an X3 is three times as intense, and so on. GOES also detected solar energetic particles associated with this activity.
Our Solar Dynamics Observatory captured these images of X2.2 and X9.3 flares on Sept. 6, 2017, in a wavelength of extreme ultraviolet light that shows solar material heated to over one million degrees Fahrenheit.
JAXA/NASA’s Hinode caught this video of an X8.2 flare on Sept. 10, 2017, the second largest flare of this solar cycle, with its X-ray Telescope. The instrument captures X-ray images of the corona to help scientists link changes in the Sun’s magnetic field to explosive solar events like this flare.
Key instruments aboard our Solar and Terrestrial Relations Observatory, or STEREO, include a pair of coronagraphs — instruments that use a metal disk called an occulting disk to study the corona. The occulting disk blocks the Sun’s bright light, making it possible to discern the detailed features of the Sun’s outer atmosphere and track coronal mass ejections as they erupt from the Sun.
On Sept. 9, 2017, STEREO watched a CME erupt from the Sun. The next day, STEREO observed an even bigger CME. The Sept. 10 CME traveled away from the Sun at calculated speeds as high as 7 million mph, and was one of the fastest CMEs ever recorded. The CME was not Earth-directed: It side-swiped Earth’s magnetic field, and therefore did not cause significant geomagnetic activity. Mercury is in view as the bright white dot moving leftwards in the frame.
Like STEREO, ESA/NASA’s Solar and Heliospheric Observatory, or SOHO, uses a coronagraph to track solar storms. SOHO also observed the CMEs that occurred during Sept. 9-10, 2017; multiple views provide more information for space weather models. As the CME expands beyond SOHO’s field of view, a flurry of what looks like snow floods the frame. These are high-energy particles flung out ahead of the CME at near-light speeds that struck SOHO’s imager.
Our Interface Region Imaging Spectrometer, or IRIS, captured this video on Sept. 10, 2017, showing jets of solar material swimming down toward the Sun’s surface. These structures are sometimes observed in the corona during solar flares, and this particular set was associated with the X8.2 flare of the same day.
Our Solar Radiation and Climate Experiment, or SORCE, collected the above data on total solar irradiance, the total amount of the Sun’s radiant energy, throughout Sept. 2017. While the Sun produced high levels of extreme ultraviolet light, SORCE actually detected a dip in total irradiance during the month’s intense solar activity.
A possible explanation for this observation is that over the active regions — where solar flares originate — the darkening effect of sunspots is greater than the brightening effect of the flare’s extreme ultraviolet emissions. As a result, the total solar irradiance suddenly dropped during the flare events.
Scientists gather long-term solar irradiance data in order to understand not only our dynamic star, but also its relationship to Earth’s environment and climate. We are ready to launch the Total Spectral solar Irradiance Sensor-1, or TSIS-1, this December to continue making total solar irradiance measurements.
The intense solar activity also sparked global aurora on Mars more than 25 times brighter than any previously seen by NASA’s Mars Atmosphere and Volatile Evolution, or MAVEN, mission. MAVEN studies the Martian atmosphere’s interaction with the solar wind, the constant flow of charged particles from the Sun. These images from MAVEN’s Imaging Ultraviolet Spectrograph show the appearance of bright aurora on Mars during the September solar storm. The purple-white colors show the intensity of ultraviolet light on Mars’ night side before (left) and during (right) the event.
For all the latest on solar and space weather research, follow us on Twitter @NASASun or Facebook.
GOES images are courtesy of NOAA. Hinode images are courtesy of JAXA and NASA. SOHO images are courtesy of ESA and NASA.
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The Sun Just Released the Most Powerful Flare of this Solar Cycle
The Sun released two significant solar flares on Sept. 6, including one that clocked in as the most powerful flare of the current solar cycle.
The solar cycle is the approximately 11-year-cycle during which the Sun’s activity waxes and wanes. The current solar cycle began in December 2008 and is now decreasing in intensity and heading toward solar minimum, expected in 2019-2020. Solar minimum is a phase when solar eruptions are increasingly rare, but history has shown that they can nonetheless be intense.
Footage of the Sept. 6 X2.2 and X9.3 solar flares captured by the Solar Dynamics Observatory in extreme ultraviolet light (131 angstrom wavelength)
Our Solar Dynamics Observatory satellite, which watches the Sun constantly, captured images of both X-class flares on Sept. 6.
Solar flares are classified according to their strength. X-class denotes the most intense flares, followed by M-class, while the smallest flares are labeled as A-class (near background levels) with two more levels in between. Similar to the Richter scale for earthquakes, each of the five levels of letters represents a 10-fold increase in energy output.
The first flare peaked at 5:10 a.m. EDT, while the second, larger flare, peaked at 8:02 a.m. EDT.
Footage of the Sept. 6 X2.2 and X9.3 solar flares captured by the Solar Dynamics Observatory in extreme ultraviolet light (171 angstrom wavelength) with Earth for scale
Solar flares are powerful bursts of radiation. Harmful radiation from a flare cannot pass through Earth's atmosphere to physically affect humans on the ground, however — when intense enough — they can disturb Earth’s atmosphere in the layer where GPS and communications signals travel.
Both Sept. 6 flares erupted from an active region labeled AR 2673. This area also produced a mid-level solar flare on Sept. 4, 2017. This flare peaked at 4:33 p.m. EDT, and was about a tenth the strength of X-class flares like those measured on Sept. 6.
Footage of the Sept. 4 M5.5 solar flare captured by the Solar Dynamics Observatory in extreme ultraviolet light (131 angstrom wavelength)
This active region continues to produce significant solar flares. There were two flares on the morning of Sept. 7 as well.
For the latest updates and to see how these events may affect Earth, please visit NOAA’s Space Weather Prediction Center at http://spaceweather.gov, the U.S. government’s official source for space weather forecasts, alerts, watches and warnings.
Follow @NASASun on Twitter and NASA Sun Science on Facebook to keep up with all the latest in space weather research.
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Five Famous Pulsars from the Past 50 Years
Early astronomers faced an obstacle: their technology. These great minds only had access to telescopes that revealed celestial bodies shining in visible light. Later, with the development of new detectors, scientists opened their eyes to other types of light like radio waves and X-rays. They realized cosmic objects look very different when viewed in these additional wavelengths. Pulsars — rapidly spinning stellar corpses that appear to pulse at us — are a perfect example.
The first pulsar was observed 50 years ago on August 6, 1967, using radio waves, but since then we have studied them in nearly all wavelengths of light, including X-rays and gamma rays.
Typical Pulsar
Most pulsars form when a star — between 8 and 20 times the mass of our sun — runs out of fuel and its core collapses into a super dense and compact object: a neutron star.
These neutron stars are about the size of a city and can rotate slowly or quite quickly, spinning anywhere from once every few hours to hundreds of times per second. As they whirl, they emit beams of light that appear to blink at us from space.
First Pulsar
One day five decades ago, a graduate student at the University of Cambridge, England, named Jocelyn Bell was poring over the data from her radio telescope - 120 meters of paper recordings.
Image Credit: Sumit Sijher
She noticed some unusual markings, which she called “scruff,” indicating a mysterious object (simulated above) that flashed without fail every 1.33730 seconds. This was the very first pulsar discovered, known today as PSR B1919+21.
Best Known Pulsar
Before long, we realized pulsars were far more complicated than first meets the eye — they produce many kinds of light, not only radio waves. Take our galaxy’s Crab Nebula, just 6,500 light years away and somewhat of a local celebrity. It formed after a supernova explosion, which crushed the parent star's core into a neutron star.
The resulting pulsar, nestled inside the nebula that resulted from the supernova explosion, is among the most well-studied objects in our cosmos. It’s pictured above in X-ray light, but it shines across almost the entire electromagnetic spectrum, from radio waves to gamma rays.
Brightest Gamma-ray Pulsar
Speaking of gamma rays, in 2015 our Fermi Gamma-ray Space Telescope discovered the first pulsar beyond our own galaxy capable of producing such high-energy emissions.
Located in the Tarantula Nebula 163,000 light-years away, PSR J0540-6919 gleams nearly 20 times brighter in gamma-rays than the pulsar embedded in the Crab Nebula.
Dual Personality Pulsar
No two pulsars are exactly alike, and in 2013 an especially fast-spinning one had an identity crisis. A fleet of orbiting X-ray telescopes, including our Swift and Chandra observatories, caught IGR J18245-2452 as it alternated between generating X-rays and radio waves.
Scientists suspect these radical changes could be due to the rise and fall of gas streaming onto the pulsar from its companion star.
Transformer Pulsar
This just goes to show that pulsars are easily influenced by their surroundings. That same year, our Fermi Gamma Ray Space Telescope uncovered another pulsar, PSR J1023+0038, in the act of a major transformation — also under the influence of its nearby companion star.
The radio beacon disappeared and the pulsar brightened fivefold in gamma rays, as if someone had flipped a switch to increase the energy of the system.
NICER Mission
Our Neutron star Interior Composition Explorer (NICER) mission, launched this past June, will study pulsars like those above using X-ray measurements.
With NICER’s help, scientists will be able to gaze even deeper into the cores of these dense and mysterious entities.
For more information about NICER, visit https://www.nasa.gov/nicer
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Our Kepler Space Telescope team has identified 219 new planet candidates, 10 of which are near-Earth size and in the habitable zone of their respective stars. The habitable zone is the range of distance from a star where liquid water could pool on the surface of a rocky planet to possibly sustain life. This artist rendering is of one of the thousands of planets detected by Kepler beyond our solar system. These exoplanets, as they’re called, vary widely in size and orbital distances, showing us that most stars are home to at least one planet. Learn more.
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Image credit: NASA/JPL-Caltech
We Just Identified More Than 200 New (Potential) Planets
The Kepler space telescope is our first mission capable of identifying Earth-size planets around other stars. On Monday, June 19, 2017, scientists from many countries gathered at our Ames Research Center to talk about the latest results from the spacecraft, which include the identification of more than 200 potential new worlds! Here’s what you need to know:
We found 219 new planet candidates.
All of these worlds were found in a patch of sky near the Cygnus constellation in our Milky Way galaxy. Between 2009 and 2013, Kepler searched more than 200,000 stars in the region for orbiting planets. The 219 new planet candidates are part of the more than 4,000 planet candidates and 2,300 confirmed planets Kepler has identified to date.
Ten of these worlds are like our own.
Out of the 219 new planet candidates, 10 are possibly rocky, terrestrial worlds and orbit their star in the habitable zone – the range of distances from a star where liquid water could pool on the surface of a rocky planet.
Small planets come in two sizes.
Kepler has opened up our eyes to the existence of many small worlds. It turns out a lot of these planets are either approximately 1.5 times the size of Earth or just smaller than Neptune. The cool names given to planets of these sizes? Super Earths and mini-Neptunes.
Some of the new planets could be habitable.
Water is a key ingredient to life as we know it. Many of the new planet candidates are likely to have small rocky cores enveloped by a thick atmosphere of hydrogen and helium, and some are thought to be ocean worlds. That doesn’t necessarily mean the oceans of these planets are full of water, but we can dream, can’t we?
Other Earths are out there.
Kepler’s survey has made it possible for us to measure the number of Earth-size habitable zone planets in our galaxy. Determining how many planets like our own that exist is the big question we’ll explore next.
The hunt for new planets continues.
Kepler continues to search for planets in different regions of space. With the launch of our Transiting Exoplanet Survey Satellite (TESS) and the James Webb Space Telescope (JWST) in 2018, we’re going to search for planets nearest the sun and measure the composition of their atmospheres. In the mid-2020s, we have our sights on taking a picture of small planets like Earth with our Wide-Field Infrared Survey Telescope (WFIRST).
*All images of planets are artist illustrations.
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