Our Spitzer Space Telescope has revealed the first known system of seven Earth-size planets around a single star. Three of these planets are firmly located in an area called the habitable zone, where liquid water is most likely to exist on a rocky planet.
This exoplanet system is called TRAPPIST-1, named for The Transiting Planets and Planetesimals Small Telescope (TRAPPIST) in Chile. In May 2016, researchers using TRAPPIST announced they had discovered three planets in the system.
Assisted by several ground-based telescopes, Spitzer confirmed the existence of two of these planets and discovered five additional ones, increasing the number of known planets in the system to seven.
This is the FIRST time three terrestrial planets have been found in the habitable zone of a star, and this is the FIRST time we have been able to measure both the masses and the radius for habitable zone Earth-sized planets.
All of these seven planets could have liquid water, key to life as we know it, under the right atmospheric conditions, but the chances are highest with the three in the habitable zone.
At about 40 light-years (235 trillion miles) from Earth, the system of planets is relatively close to us, in the constellation Aquarius. Because they are located outside of our solar system, these planets are scientifically known as exoplanets. To clarify, exoplanets are planets outside our solar system that orbit a sun-like star.
In this animation, you can see the planets orbiting the star, with the green area representing the famous habitable zone, defined as the range of distance to the star for which an Earth-like planet is the most likely to harbor abundant liquid water on its surface. Planets e, f and g fall in the habitable zone of the star.
Using Spitzer data, the team precisely measured the sizes of the seven planets and developed first estimates of the masses of six of them. The mass of the seventh and farthest exoplanet has not yet been estimated.
For comparison…if our sun was the size of a basketball, the TRAPPIST-1 star would be the size of a golf ball.
Based on their densities, all of the TRAPPIST-1 planets are likely to be rocky. Further observations will not only help determine whether they are rich in water, but also possibly reveal whether any could have liquid water on their surfaces.
The sun at the center of this system is classified as an ultra-cool dwarf and is so cool that liquid water could survive on planets orbiting very close to it, closer than is possible on planets in our solar system. All seven of the TRAPPIST-1 planetary orbits are closer to their host star than Mercury is to our sun.
The planets also are very close to each other. How close? Well, if a person was standing on one of the planet’s surface, they could gaze up and potentially see geological features or clouds of neighboring worlds, which would sometimes appear larger than the moon in Earth’s sky.
The planets may also be tidally-locked to their star, which means the same side of the planet is always facing the star, therefore each side is either perpetual day or night. This could mean they have weather patterns totally unlike those on Earth, such as strong wind blowing from the day side to the night side, and extreme temperature changes.
Because most TRAPPIST-1 planets are likely to be rocky, and they are very close to one another, scientists view the Galilean moons of Jupiter – lo, Europa, Callisto, Ganymede – as good comparisons in our solar system. All of these moons are also tidally locked to Jupiter. The TRAPPIST-1 star is only slightly wider than Jupiter, yet much warmer.
How Did the Spitzer Space Telescope Detect this System?
Spitzer, an infrared telescope that trails Earth as it orbits the sun, was well-suited for studying TRAPPIST-1 because the star glows brightest in infrared light, whose wavelengths are longer than the eye can see. Spitzer is uniquely positioned in its orbit to observe enough crossing (aka transits) of the planets in front of the host star to reveal the complex architecture of the system.
Every time a planet passes by, or transits, a star, it blocks out some light. Spitzer measured the dips in light and based on how big the dip, you can determine the size of the planet. The timing of the transits tells you how long it takes for the planet to orbit the star.
The TRAPPIST-1 system provides one of the best opportunities in the next decade to study the atmospheres around Earth-size planets. Spitzer, Hubble and Kepler will help astronomers plan for follow-up studies using our upcoming James Webb Space Telescope, launching in 2018. With much greater sensitivity, Webb will be able to detect the chemical fingerprints of water, methane, oxygen, ozone and other components of a planet’s atmosphere.
At 40 light-years away, humans won’t be visiting this system in person anytime soon...that said...this poster can help us imagine what it would be like:
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This Sunday, Sept. 27 a Super Blood Moon will be visible in the U.S. and much of the world. This is the first time in more than 30 years that you’ll be able to witness a supermoon in combination with a lunar eclipse!
What is a supermoon? It’s a new or full moon that occurs when it is at, or near its closest approach to Earth. This event, combined with Earth’s shadow slowly swallowing the moon during the lunar eclipse, will provide for a spectacular night.
To make this lunar event even more exciting (not that it really needed it), we will be hosting a photo contest! During the event, we invite you to send us your best image of the Super Blood Moon on our Facebook page. Enter HERE.
After the entry window is closed, six finalists will be selected. These finalists will have their image voted on by the public. The winning image will be featured on our official social media platforms and on NASA.gov.
Are you interested? Here are the details:
Contest Entry Opens: Sept. 27 at 10:00 p.m. EDT
Contest Entry Closes: Sept. 28 at 10:00 a.m. EDT
Voting on Finalists Opens: Sept. 28 3:00 p.m. EDT
Voting on Finalists Closes: Sept. 29 11:59 p.m. EDT
For more information and specifics about the lunar event, visit our page on NASA.gov, and make sure that this Sunday, Sept. 27, you get outside, look up and take some awesome pictures!
ENTER HERE: http://go.nasa.gov/superbloodmoon-contest
Full Terms and Conditions can be found HERE.
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Today – Thursday, June 21 – is the summer solstice in the northern hemisphere. But what causes this change in seasons? And what exactly is a solstice? It’s all about Earth’s tilt!
Many people believe that Earth is closer to the Sun in the summer and that is why it is hotter. And, likewise, they think Earth is farthest from the Sun in the winter.
Although this idea makes sense, it is incorrect. There is a different reason for Earth's seasons.
Earth's axis is an imaginary pole going right through the center of Earth from "top" to "bottom." Earth spins around this pole, making one complete turn each day. That is why we have day and night, and why every part of Earth's surface gets some of each.
Earth has seasons because its axis doesn't stand up straight. Today, the north pole is tipped toward the Sun, and the south pole is tipped away from the Sun. The northern summer solstice is an instant in time when the north pole of the Earth points more directly toward the Sun than at any other time of the year. It marks the beginning of summer in the northern hemisphere and winter in the southern hemisphere.
To mark the beginning of summer, here are four ways to enjoy the many wonders of space throughout the season:
1. Spot the International Space Station
As the third brightest object in the sky, the International Space Station is easy to see if you know when to look up. Sign up to get alerts when the station is overhead: https://spotthestation.nasa.gov/. Visible to the naked eye, it looks like a fast-moving plane only much higher and traveling thousands of miles an hour faster!
2. Treat your ears to space-related podcasts
From our “Gravity Assist” podcast that takes you on a journey through the solar system (including the Sun!) to our “NASA in Silicon Valley” podcast that provides an in-depth look at people who push the boundaries of innovation, we have podcast offerings that will suit everyone’s taste. For a full list of our podcasts, visit https://www.nasa.gov/podcasts.
3. Explore space by downloading NASA apps
Our apps for smartphones, tablets and digital media players showcase a huge collection of space-related content, including images, videos on-demand, NASA Television, mission information, feature stories, satellite tracking and much more. For a full list of our apps available for download, visit https://www.nasa.gov/connect/apps.html
4. Watch launches to space
This summer, we have multiple opportunities for you to take in the sights of spacecraft launches that will deliver supplies and equipment to astronauts living aboard the International Space Station, explore our solar system and much more. Be sure to mark your calendar for upcoming launches and landings!
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Hi! The Sun is so bright I need shades... that are ISO 12312-2 compliant! So glad that you are all here and excited about the eclipse. I’m Alexa Halford and ready to answer your questions.
When you think of NASA, you probably think of space. Which makes sense, because space is a huge part of what we do. That being said, here at NASA we are also involved in many other research areas, and even play a role in hurricane weather forecasting.
Our satellites, computer modeling, instruments, aircraft and field missions all contribute to a mix of information used by scientists to get a better understanding of these storms. Aspects of storms from rainfall rates to surface wind speed are all analyzed to help identify the potential for storm formation or intensification.
Currently, our satellites are passing overhead as Hurricane Joaquin (above) travels through the Atlantic Ocean. Our Global Precipitation Measurement, or GPM Core satellite captured images and rainfall rates of the storm. GPM showed a large area of very intense rain, which indicates that large amounts of heat are being released into the storm’s center. This fuels the circulation and provides the means for its intensification.
Maximum sustained winds have increased to near 80 mph and additional strengthening is expected. Joaquin could become a major hurricane during the next few days.
In 2016, we’re launching the Cyclone Global Navigation Satellite System (CYGNSS), which is a constellation of eight small satellites. With this launch, we will be able to better understand the rapid intensification of hurricanes, and improve hurricane intensity forecasts.
In addition to our satellite technology, we also conduct field missions to study hurricanes. In our most recent field mission, we investigated the process that underlie hurricane formation and intensity change in the Atlantic Ocean basin.
Hi Kate! What did you learn from your Heart Cells experiment? Sounds so interesting!
It is so small that you cannot see it on Google maps. It measures 25 by 45 meters (27 by 49 yards), about half the size of a football field. This barren bit of rock off the coast of Canada also has an unusual namesake: the Landsat 1 satellite. The small size is actually what made the island notable in 1973, when it was initially discovered. Well, that, and the polar bear trying to eat one of the surveyors.
Betty Fleming, a researcher with the Topographic Survey of Canada, was hunting for uncharted islands and rocks amidst data from the new Landsat 1 satellite. She was particularly interested in the new satellite's ability to find small features. Working with the Canadian Hydrographic Service, Fleming scanned images of the Labrador coast, an area that was poorly charted. About 20 kilometers (12 miles) offshore, the satellite detected a tiny, rocky island. Surveyors were sent to verify the existence of the island and encountered a hungry polar bear on the island. The surveyor quickly retreated. Eventually, the island became known as “Landsat Island,” after the satellite that discovered it. Watch the video to learn more about Betty Fleming and how Landsat Island was discovered by satellite and ground surveyors.
For more details about Landsat Island, read the full stories here:
The Island Named After a Satellite
The Unsung Woman Who Discovered an Unknown Island
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Black holes are some of the most bizarre and fascinating objects in the cosmos. Astronomers want to study lots of them, but there’s one big problem – black holes are invisible! Since they don’t emit any light, it’s pretty tough to find them lurking in the inky void of space. Fortunately there are a few different ways we can “see” black holes indirectly by watching how they affect their surroundings.
If you’ve spent some time stargazing, you know what a calm, peaceful place our universe can be. But did you know that a monster is hiding right in the heart of our Milky Way galaxy? Astronomers noticed stars zipping superfast around something we can’t see at the center of the galaxy, about 10 million miles per hour! The stars must be circling a supermassive black hole. No other object would have strong enough gravity to keep them from flying off into space.
Two astrophysicists won half of the Nobel Prize in Physics last year for revealing this dark secret. The black hole is truly monstrous, weighing about four million times as much as our Sun! And it seems our home galaxy is no exception – our Hubble Space Telescope has revealed that the hubs of most galaxies contain supermassive black holes.
Technology has advanced enough that we’ve been able to spot one of these supermassive black holes in a nearby galaxy. In 2019, astronomers took the first-ever picture of a black hole in a galaxy called M87, which is about 55 million light-years away. They used an international network of radio telescopes called the Event Horizon Telescope.
In the image, we can see some light from hot gas surrounding a dark shape. While we still can’t see the black hole itself, we can see the “shadow” it casts on the bright backdrop.
Black holes can come in a smaller variety, too. When a massive star runs out of the fuel it uses to shine, it collapses in on itself. These lightweight or “stellar-mass” black holes are only about 5-20 times as massive as the Sun. They’re scattered throughout the galaxy in the same places where we find stars, since that’s how they began their lives. Some of them started out with a companion star, and so far that’s been our best clue to find them.
Some black holes steal material from their companion star. As the material falls onto the black hole, it gets superhot and lights up in X-rays. The first confirmed black hole astronomers discovered, called Cygnus X-1, was found this way.
If a star comes too close to a supermassive black hole, the effect is even more dramatic! Instead of just siphoning material from the star like a smaller black hole would do, a supermassive black hole will completely tear the star apart into a stream of gas. This is called a tidal disruption event.
But what if two companion stars both turn into black holes? They may eventually collide with each other to form a larger black hole, sending ripples through space-time – the fabric of the cosmos!
These ripples, called gravitational waves, travel across space at the speed of light. The waves that reach us are extremely weak because space-time is really stiff.
Three scientists received the 2017 Nobel Prize in Physics for using LIGO to observe gravitational waves that were sent out from colliding stellar-mass black holes. Though gravitational waves are hard to detect, they offer a way to find black holes without having to see any light.
We’re teaming up with the European Space Agency for a mission called LISA, which stands for Laser Interferometer Space Antenna. When it launches in the 2030s, it will detect gravitational waves from merging supermassive black holes – a likely sign of colliding galaxies!
So we have a few ways to find black holes by seeing stuff that’s close to them. But astronomers think there could be 100 million black holes roaming the galaxy solo. Fortunately, our Nancy Grace Roman Space Telescope will provide a way to “see” these isolated black holes, too.
Roman will find solitary black holes when they pass in front of more distant stars from our vantage point. The black hole’s gravity will warp the starlight in ways that reveal its presence. In some cases we can figure out a black hole’s mass and distance this way, and even estimate how fast it’s moving through the galaxy.
For more about black holes, check out these Tumblr posts!
⚫ Gobble Up These Black (Hole) Friday Deals!
⚫ Hubble’s 5 Weirdest Black Hole Discoveries
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Every second, every square meter of Earth’s atmosphere is pelted by thousands of high-energy particles traveling at nearly the speed of light. These zippy little assailants are called cosmic rays, and they’ve been puzzling scientists since they were first discovered in the early 1900s. One of the Fermi Gamma-ray Space Telescope’s top priority missions has been to figure out where they come from.
“Cosmic ray” is a bit of a misnomer. Makes you think they’re light, right? But they aren’t light at all! They’re particles that mostly come from outside our solar system — which means they're some of the only interstellar matter we can study — although the Sun also produces some. Cosmic rays hit our atmosphere and break down into secondary cosmic rays, most of which disperse quickly in the atmosphere, although a few do make it to Earth’s surface.
Cosmic rays aren't dangerous to those of us who spend our lives within Earth's atmosphere. But if you spend a lot of time in orbit or are thinking about traveling to Mars, you need to plan how to protect yourself from the radiation caused by cosmic rays.
Cosmic rays are subatomic particles — smaller particles that make up atoms. Most of them (99%) are nuclei of atoms like hydrogen and helium stripped of their electrons. The other 1% are lone electrons. When cosmic rays run into molecules in our atmosphere, they produce secondary cosmic rays, which include even lighter subatomic particles.
Most cosmic rays reach the same amount of energy a small particle accelerator could produce. But some zoom through the cosmos at energies 40 million times higher than particles created by the world’s most powerful man-made accelerator, the Large Hadron Collider. (Lightning is also a pretty good particle accelerator).
So where do cosmic rays come from? We should just be able to track them back to their source, right? Not exactly. Any time they run into a strong magnetic field on their way to Earth, they get deflected and bounce around like a game of cosmic pinball. So there’s no straight line to follow back to the source. Most of the cosmic rays from a single source don’t even make it to Earth for us to measure. They shoot off in a different direction while they’re pin balling.
Photo courtesy of Argonne National Laboratory
In 1949 Enrico Fermi — an Italian-American physicist, pioneer of high-energy physics and Fermi satellite namesake — suggested that cosmic rays might accelerate to their incredible speeds by ricocheting around inside the magnetic fields of interstellar gas clouds. And in 2013, the Fermi satellite showed that the expanding clouds of dust and gas produced by supernovas are a source of cosmic rays.
When a star explodes in a supernova, it produces a shock wave and rapidly expanding debris. Particles trapped by the supernova remnant magnetic field bounce around wildly.
Every now and then, they cross the shock wave and their energy ratchets up another notch. Eventually they become energetic enough to break free of the magnetic field and zip across space at nearly the speed of light — some of the fastest-traveling matter in the universe.
How can we track them back to supernovas when they don’t travel in a straight line, you ask? Very good question! We use something that does travel in a straight line — gamma rays (actual rays of light this time, on the more energetic end of the electromagnetic spectrum).
When the particles get across the shock wave, they interact with non-cosmic-ray particles in clouds of interstellar gas. Cosmic ray electrons produce gamma rays when they pass close to an atomic nucleus. Cosmic ray protons, on the other hand, produce gamma rays when they run into normal protons and produce another particle called a pion (Just hold on! We’re almost there!) which breaks down into two gamma rays.
The proton- and electron-produced gamma rays are slightly different. Fermi data taken over four years showed that most of the gamma rays coming from some supernova remnants have the energy signatures of cosmic ray protons knocking into normal protons. That means supernova remnants really are powerful particle accelerators, creating a lot of the cosmic rays that we see!
There are still other cosmic ray sources on the table — like active galactic nuclei — and Fermi continues to look for them. Learn more about what Fermi’s discovered over the last 10 years and how we’re celebrating its accomplishments.
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On Aug. 21, all of North America will experience a solar eclipse.
If skies are clear, eclipse-watchers will be able to see a partial solar eclipse over several hours, and some people – within the narrow path of totality – will see a total solar eclipse for a few moments.
It’s never safe to look at the Sun, and an eclipse is no exception. During a partial eclipse (or on any regular day) you must use special solar filters or an indirect viewing method to watch the Sun.
If you have solar viewing glasses, check to make sure they’re safe and undamaged before using them to look at the Sun. Make sure you put them on before looking up at the Sun, and look away before removing them. Eclipse glasses can be used over your regular eyeglasses, but they should never be used when looking through telescopes, binoculars, camera viewfinders, or any other optical device.
If you don’t have eclipse glasses, you can still watch the eclipse indirectly! You can make a pinhole projector out of a box, or use any other object with tiny holes – like a piece of cardstock with a hole, or your outstretched, interlaced fingers – to project an image of the partially eclipsed Sun onto the ground.
Of course, if it’s cloudy (or you’d just rather stay inside), you can watch the whole thing online with us at nasa.gov/eclipselive. Tune in starting at noon ET.
If you’re in the path of totality, there will be a few brief moments when it is safe to look directly at the eclipse. Only once the Moon has completely covered the Sun and there is no light shining through is it safe to look at the eclipse. Make sure you put your eclipse glasses back on or return to indirect viewing before the first flash of sunlight appears around the Moon’s edge.
A solar eclipse happens when the Moon passes directly between the Sun and Earth, casting its shadow down on Earth’s surface. The path of totality – where the Moon completely covers the Sun – is traced out by the Moon’s inner shadow, the umbra. People within the Moon’s outer shadow, the penumbra, can see a partial eclipse.
The Moon’s orbit around Earth is tilted by about five degrees, meaning that its shadow usually doesn’t fall on Earth. Only when the Moon lines up exactly between the Sun and Earth do we see an eclipse.
Though the Sun is about 400 times wider than the Moon, it is also about 400 times farther away, making their apparent sizes match up almost exactly. This is what allows the Moon to block out the Sun’s bright face, while revealing the comparatively faint, pearly-white corona.
Eclipses are a beautiful sight to see, and they’re also helpful for our scientists, so we’re funding eleven ground-based science investigations to learn more about the Sun and Earth.
Total solar eclipses reveal the innermost regions of the Sun’s atmosphere, the corona. Though it’s thought to house the processes that kick-start much of the space weather that can influence Earth, as well as heating the whole corona to extraordinarily high temperatures, we can’t study this region at any other time. This is because coronagraphs – the instruments we use to study the Sun’s atmosphere by creating artificial eclipses – must cover up much of the corona, as well as the Sun’s face in order to produce clear images.
Eclipses also give us the chance to study Earth’s atmosphere under uncommon conditions: the sudden loss of solar radiation from within the Moon’s shadow. We’ll be studying the responses of both Earth’s ionosphere – the region of charged particles in the upper atmosphere – and the lower atmosphere.
Learn all about the Aug. 21 eclipse at eclipse2017.nasa.gov, and follow @NASASun on Twitter and NASA Sun Science on Facebook for more. Watch the eclipse through the eyes of NASA at nasa.gov/eclipselive starting at 12 PM ET on Aug. 21.
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Is there any other way to actually look at the eclipse (besides television/streams) without using the special eclipse glasses?
Unfortunately, you can not directly look at the eclipse without the proper eye protection https://eclipse2017.nasa.gov/safety. But there are lots of fun indirect methods that you can use. The GIF shows how you can make a pin hole projector with your hands. We also have patterns for 3D printers to make your own pin hole projector in the shape of the US or your state https://eclipse2017.nasa.gov/2d3d-printable-pinhole-projectors
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