Tess - Blog Posts

ref sheet time

Tess: I’m not really a hugging person.

Ben: I’m not sure you get a vote.

Sunset Ocean || Eine Alea Aquarius FF

Der Sonnenuntergang war das erste, die Umrisse des Bootes, der Crusis, waren das zweite und Tess, die an der Reling saß war das letzte. Das war was Kit sah, als sie die kleine Treppe, die unter Deck führte, her hoch lief. Sie lächelte. Ihre Freundin schaute auf das Meer, das vor ihr Lag, ihre Beine baumelten zwischen den Stäben des Gitters der Reling. Kit schaute kurz zu Alea, die gerade das Boot steuerte. Alea winkte ihr zu. Ben und Sammy hatten den Tag über viel erledigen müssen und Alea war sich extra früh schlafen gegangen, um Sammy von der Nachmittagsschicht abzulösen und die Nacht durchzumachen. Ben war damit einverstanden gewesen, weil das Meer am Abend ruhig ausgesehen hatte. Die Wetterausichten schienen das zu bestätigen. Lennox hatte darauf bestanden, auch früher schlafen zu gehen, weil er müde war. Später würde er Alea sicher Gesellschaft leisten.

Leise schlich sich Kit an Tess heran. Das funktionierte nur mäßig gut, die Planken knarzten zu sehr. Tess Kopf schwang herum. Kit lächelte. Tess lächelte zurück. Kit bog sich vor. "Kann ich mich setzten?" Erst jetzt bemerkte sie, dass sich Tess auf ihr Akkordeon stützte. Sie musste vorher geübt haben. Ihre Freundin lachte kurz auf, zog ein Kissen von der Sitzbank und klopfte dann neben sich auf die Planken auf das Kissen. "Klar" Kit setzte sich langsam. Einige Minuten angenehmer Stille folgten in denen sie einfach nebeneinander saßen. Tess brach die Stille leise, "Das Meer ist bei Sonnenuntergängen immer so anders. Es fühlt sich irgendwie wärmer an, obwohl die Nacht eigentlich kalt ist." Kit nickte. "Sonnenuntergänge fühlen sich an wie ein Portal in eine andere Welt. Vom Warmen Tag in die kühle Nacht." Sie legte ihren Kopf aus Tess Schulter. "Fühlt sich aber seltsam gut dafür an, nicht?" Kit fühlte Tess Stimme an ihrem Kopf perfekt im Einklang mit den leisen Wellen, die gegen das Boot klatschten.

"Spielst du ein bisschen?" Kit zeigte auf das Akkordeon, das Tess immer noch auf dem Schoss hatte. Akkordeons waren nicht unbedingt was man unter "konventionell Romantisch", "passt gut zu Meeresrauschen" oder "entspannend" beschreiben würde. Aber Tess schien einen Weg gefunden zu haben, dass es genau das war. Tess nickte. Kit lag zwar noch etwas zu sehr auf ihr, um ihre Arme richtig bewegen zu können, aber Kit merkte das schnell genug, um den Moment nicht zu ruinieren. Und Tess spielte. Und Kit hörte ihr zu. Sie fand sich in Tag, oder ehr Abendträumen, wieder. Als Tess langsame aufhörte, legte Kit ihren Kopf wieder auf Tess Schulter.

"Denkst du wirklich, wir können das Meer retten?" Tess schien es schon eine Weile zu beschäftigen. "Wir müssen es zumindest versuchen. Wenn nicht für das überleben von der Meerwelt und dem Planeten, wenigstens für uns. Wenn der Planet stirbt ist es wenigstens nicht unsere Schuld." Tess lachte auf. "Das ist aber sehr selbstlos", meinte sie sarkastisch. "Aber es stimmt doch. Das meiste ist doch gar nicht unter unserer Kontrolle. Du kannst Protestieren gehen, deine Lebensweise ändern und andere darauf Aufmerksam machen was für Probleme es gibt, aber es liegt am ende doch an einflussreicheren Menschen. Wir sind Jugendliche, Kinder. Wir müssen tun was wir können, aber letzten Endes hängt es doch von Regierungen ab, Erwachsenen. Aber wenn wir etwas tun , aber die die etwas ändern können, nicht, dann können wir am ende sagen, das wir es wenigstens versucht haben." Tess schwieg. Dann nickte sie. "Wir müssen es schaffen, nicht versuchen." Kit nickte.

Sie saßen wieder einige Minuten einfach da. Die leisen Meeresgeräusche machten Kit etwas schläfrig. Tess schien das zu merken und nahm sanft Kits Kopf von ihrer Schulter und legte ihn auf ihre Beine. Tess fing an ihr durch die Haare zu streichen Kit rückte sich in eine gemütliche Position zurecht und sickerte in einen angenehm Traumlosen schlaf, während die letzten Sonnenstrahlen am Horizont verschwanden.

The Stellar Buddy System

Our Sun has an entourage of planets, moons, and smaller objects to keep it company as it traverses the galaxy. But it’s still lonely compared to many of the other stars out there, which often come in pairs. These cosmic couples, called binary stars, are very important in astronomy because they can easily reveal things that are much harder to learn from stars that are on their own. And some of them could even host habitable planets!

The birth of a stellar duo

New stars emerge from swirling clouds of gas and dust that are peppered throughout the galaxy. Scientists still aren’t sure about all the details, but turbulence deep within these clouds may give rise to knots that are denser than their surroundings. The knots have stronger gravity, so they can pull in more material and the cloud may begin to collapse.

The material at the center heats up. Known as a protostar, it is this hot core that will one day become a star. Sometimes these spinning clouds of collapsing gas and dust may break up into two, three, or even more blobs that eventually become stars. That would explain why the majority of the stars in the Milky Way are born with at least one sibling.

Seeing stars

We can’t always tell if we’re looking at binary stars using just our eyes. They’re often so close together in the sky that we see them as a single star. For example, Sirius, the brightest star we can see at night, is actually a binary system (see if you can spot both stars in the photo above). But no one knew that until the 1800s.

Precise observations showed that Sirius was swaying back and forth like it was at a middle school dance. In 1862, astronomer Alvan Graham Clark used a telescope to see that Sirius is actually two stars that orbit each other.

But even through our most powerful telescopes, some binary systems still masquerade as a single star. Fortunately there are a couple of tricks we can use to spot these pairs too.

Since binary stars orbit each other, there’s a chance that we’ll see some stars moving toward and away from us as they go around each other. We just need to have an edge-on view of their orbits. Astronomers can detect this movement because it changes the color of the star’s light – a phenomenon known as the Doppler effect.

Stars we can find this way are called spectroscopic binaries because we have to look at their spectra, which are basically charts or graphs that show the intensity of light being emitted over a range of energies. We can spot these star pairs because light travels in waves. When a star moves toward us, the waves of its light arrive closer together, which makes its light bluer. When a star moves away, the waves are lengthened, reddening its light.

Sometimes we can see binary stars when one of the stars moves in front of the other. Astronomers find these systems, called eclipsing binaries, by measuring the amount of light coming from stars over time. We receive less light than usual when the stars pass in front of each other, because the one in front will block some of the farther star’s light.

Sibling rivalry

Twin stars don’t always get along with each other – their relationship may be explosive! Type Ia supernovae happen in some binary systems in which a white dwarf – the small, hot core left over when a Sun-like star runs out of fuel and ejects its outer layers – is stealing material away from its companion star. This results in a runaway reaction that ultimately detonates the thieving star. The same type of explosion may also happen when two white dwarfs spiral toward each other and collide. Yikes!

Scientists know how to determine how bright these explosions should truly be at their peak, making Type Ia supernovae so-called standard candles. That means astronomers can determine how far away they are by seeing how bright they look from Earth. The farther they are, the dimmer they appear. Astronomers can also look at the wavelengths of light coming from the supernovae to find out how fast the dying stars are moving away from us.

Studying these supernovae led to the discovery that the expansion of the universe is speeding up. Our Nancy Grace Roman Space Telescope will scan the skies for these exploding stars when it launches in the mid-2020s to help us figure out what’s causing the expansion to accelerate – a mystery known as dark energy.

Spilling stellar secrets

Astronomers like finding binary systems because it’s a lot easier to learn more about stars that are in pairs than ones that are on their own. That’s because the stars affect each other in ways we can measure. For example, by paying attention to how the stars orbit each other, we can determine how massive they are. Since heavier stars burn hotter and use up their fuel more quickly than lighter ones, knowing a star’s mass reveals other interesting things too.

By studying how the light changes in eclipsing binaries when the stars cross in front of each other, we can learn even more! We can figure out their sizes, masses, how fast they’re each spinning, how hot they are, and even how far away they are. All of that helps us understand more about the universe.

Tatooine worlds

Thanks to observatories such as our Kepler Space Telescope, we know that worlds like Luke Skywalker’s home planet Tatooine in “Star Wars” exist in real life. And if a planet orbits at the right distance from the two stars, it could even be habitable (and stay that way for a long time).

In 2019, our Transiting Exoplanet Survey Satellite (TESS) found a planet, known as TOI-1338 b, orbiting a pair of stars. These worlds are tricker to find than planets with only one host star, but TESS is expected to find several more!

Want to learn more about the relationships between stellar couples? Check out this Tumblr post: https://nasa.tumblr.com/post/190824389279/cosmic-couples-and-devastating-breakups

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Three NASA Telescopes Look at an Angry Young Star Together

Science is a shared endeavor. We learn more when we work together. Today, July 18, we’re using three different space telescopes to observe the same star/planet system!

As our Transiting Exoplanet Survey Satellite (TESS) enters its third year of observations, it's taking a new look at a familiar system this month. And today it won't be alone. Astronomers are looking at AU Microscopii, a young fiery nearby star – about 22 million years old – with the TESS, NICER and Swift observatories.

TESS will be looking for more transits – the passage of a planet across a star – of a recently-discovered exoplanet lurking in the dust of AU Microscopii (called AU Mic for short). Astronomers think there may be other worlds in this active system, as well!

Our Neutron star Interior Composition Explorer (NICER) telescope on the International Space Station will also focus on AU Mic today. While NICER is designed to study neutron stars, the collapsed remains of massive stars that exploded as supernovae, it can study other X-ray sources, too. Scientists hope to observe stellar flares by looking at the star with its high-precision X-ray instrument.

Scientists aren't sure where the X-rays are coming from on AU Mic — it could be from a stellar corona or magnetic hot spots. If it's from hot spots, NICER might not see the planet transit, unless it happens to pass over one of those spots, then it could see a big dip!

A different team of astronomers will use our Neil Gehrels Swift Observatory to peer at AU Mic in X-ray and UV to monitor for high-energy flares while TESS simultaneously observes the transiting planet in the visible spectrum. Stellar flares like those of AU Mic can bathe planets in radiation.

Studying high-energy flares from AU Mic with Swift will help us understand the flare-rate over time, which will help with models of the planet’s atmosphere and the system’s space weather. There's even a (very) small chance for Swift to see a hint of the planet's transit!

The flares that a star produces can have a direct impact on orbiting planets' atmospheres. The high-energy photons and particles associated with flares can alter the chemical makeup of a planet's atmosphere and erode it away over time.

Another time TESS teamed up with a different spacecraft, it discovered a hidden exoplanet, a planet beyond our solar system called AU Mic b, with the now-retired Spitzer Space Telescope. That notable discovery inspired our latest poster! It’s free to download in English and Spanish.

Spitzer’s infrared instrument was ideal for peering at dusty systems! Astronomers are still using data from Spitzer to make discoveries. In fact, the James Webb Space Telescope will carry on similar study and observe AU Mic after it launches next year.

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Cosmic Piece of Pi!

Did you know that pi is involved nearly anywhere you look? We’re not talking about your favorite pastry! Pi (also written as the Greek letter 𝞹, or the number 3.14159...) is an irrational number, which means it can’t be written as a simple fraction like ½. It is the ratio of a circle’s circumference (the distance around its edge) to its diameter (the distance across it) and will always be the same number, regardless of the circle’s size. Here are some places you can find pi in the universe around us!

Our Transiting Exoplanet Survey Satellite, TESS, watches slices of the sky in its hunt for worlds outside our solar system — how many exoplanets are in its night-sky pie? Last July, TESS scientists created a mosaic of 208 images of the southern sky. At that time, it contained 29 confirmed and 1,000 possible exoplanets, and we’re still studying the data to find more. Since this awe-inspiring image is of the southern hemisphere (or half of a 3D circle), there will always be pi! Every slice contains something delicious for scientists to study.

Pi recently played a crucial role in new discoveries about Alpha Draconis, a well-studied pair of stars. After discovering these stars regularly eclipse each other, pi helped scientists learn more about them. Scientists detected the eclipses while monitoring the brightness of Alpha Draconis for periodic dips that could’ve been caused by planets passing between the star and us. Instead of a planet, though, researchers found that its smaller partner in crime was passing in between us and the larger star for about six hours at a time! 💫

Pi comes in handy as we learn more about these two stars. Knowing the percentage of the decrease in Alpha Draconis’ light and the formula for the area of a circle (A=𝞹r2 — or area equals pi times the square of the circle's radius), scientists can predict the sizes of both stars.  Because stars typically orbit in an elliptical (or oval) shape, pi also helps scientists use the detection of these eclipses to figure out the orbits of the two stars!

So far we’ve seen pi in many places! But it's also interesting to look at where pi can't be found! We mentioned earlier that many orbit calculations involve pi … but not every one does! Pi does not factor into calculations of hyperbolic orbits — orbits that aren't complete, or don't return to where they started — the same way that it does with elliptical orbits! This is most commonly seen with comets. While many comets orbit normally in our solar system, some oddballs just pass through, like the interstellar ‘Oumuamua that zipped passed us in 2017. ☄️

Perhaps the most popular place you may find pi is in the shape of a typical pie! While NASA’s Fermi Gamma-ray Space Telescope studies gamma-rays, and not blueberries, we think this cool Fermi pie is worth sharing for Pi Day!

Find more ways scientists look up at the night sky and use pi here. And now, don’t be irrational, and go have some pi(e)! 🥧

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TESS’s first-year of planet-hunting was out of this world

Have you ever looked up at the night sky and wondered ... what other kinds of planets are out there? Our Transiting Exoplanet Survey Satellite (TESS) just spent its first year bringing us a step closer to exploring the planets around the nearest and brightest stars in the southern sky and is now doing the same in the north.

TESS has been looking for dips in the brightness of stars that could be a sign of something we call “transits.” A transit happens when a planet passes between its star and us. It’s like when a bug flies in front of a light bulb. You may not notice the tiny drop in brightness when the bug blocks some of the light from reaching your eyes, but a sensitive camera could. The cameras on TESS are designed to detect those tiny drops in starlight caused by a transiting planet many light-years away.

In the last year TESS has found 24 planets and more than 900 new candidate planets. And TESS is only halfway through its goal of mapping over three-fourths of our skies, which means there’s plenty more to discover!

TESS has been looking for planets around the closest, brightest stars because they will be the best planets to explore more thoroughly with future missions. We can even see a few of these stars with our own eyes, which means we’ve been looking at these planets for millions of years and didn’t even know it.

We spent thousands of years staring at our closest neighbor, the Moon, and asking questions: What is it like? Could we live there? What is it made of (perhaps cheese?). Of course, now we can travel to the Moon and explore it ourselves (turns out, not made of cheese).

But for the worlds TESS is discovering, the commute to answer those questions would be killer. It took 35 years for Voyager 1 to cross into interstellar space (the region between stars), and it’s zipping along at over 38,000 mph! At that rate it would take more than a half-a-million years to reach the nearest stars and planets that TESS is discovering.

While exploring these distant worlds in person isn’t an option, we have other ways of learning what they are like. TESS can tell us where a planet is, its size and its overall temperature, but observatories on the ground and in space like our upcoming James Webb Space Telescope will be able to learn even more — like whether or not a planet has an atmosphere and what it’s made of.

Here are a few of the worlds that our planet hunter discovered in the last year.

Earth-Sized Planet

The first Earth-sized planet discovered by TESS is about 90% the size of our home planet and orbits a star 53 light-years away. The planet is called HD 21749 c (what a mouthful!) and is actually the second planet TESS has discovered orbiting that star, which you can see in the southern constellation Reticulum.

The planet may be Earth-sized, but it would not be a pleasant place to live. It’s very close to its star and could have a surface temperature of 800 degrees Fahrenheit, which would be like sitting inside a commercial pizza oven.

Water World?

The other planet discovered in that star system, HD 21749 b, is about three times Earth’s size and orbits the star every 36 days. It has the longest orbit of any planet within 100 light-years of our solar system detected with TESS so far.

The planet is denser than Neptune, but isn’t made of rock. Scientists think it might be a water planet or have a totally new type of atmosphere. But because the planet isn’t ideal for follow-up study, for now we can only theorize what the planet is actually like. Could it be made of pudding? Maybe … but probably not.

Magma World

One of the first planets TESS discovered, called LHS 3844 b, is roughly Earth’s size, but is so close to its star that it orbits in just 11 hours. For reference, Mercury, which is more than two and a half times closer to the Sun than we are, completes an orbit in just under three months.

Because the planet is so close to its star, the day side of the planet might get so hot that pools and oceans of magma form on its rocky surface, which would make for a rather unpleasant day at the beach.    

TESS’s Smallest Planet

The smallest planet TESS has discovered, called L 98-59 b, is between the size of Earth and Mars and orbits its star in a little over two days. Its star also hosts two other TESS-discovered worlds.

Because the planet lies so close to its star, it gets 22 times the radiation we get here on Earth. Yikes! It is also not located in its star’s habitable zone, which means there probably isn’t any liquid water on the surface. Those two factors make it an unlikely place to find life, but scientists believe it will be a good candidate for follow-up studies by other telescopes.

Other Data

While TESS’s team is hunting for planets around close, bright stars, it’s also collecting information on all sorts of other things. From transits around dimmer, farther stars to other objects in our solar system and events outside our galaxy, data from TESS can help astronomers learn a lot more about the universe. Comets and black holes and supernovae, oh my!

Interested in joining the hunt? TESS’s data are released online, so citizen scientists around the world can help us discover new worlds and better understand our universe.

Stay tuned for TESS’s next year of science as it monitors the stars that more than 6.5 billion of us in the northern hemisphere see every night.

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One Year Into Our Planet-Hunting TESS Mission

Our Transiting Exoplanet Survey Satellite (TESS), launched last year on April 18, is completing a year in space, surveying the skies to find the closest, most exciting planets outside our solar system for further study. Worlds that TESS is hunting for include super-Earths, rocky planets, gas giants, and maybe even some Earth-sized planets — and much, much more! TESS is scanning the whole sky one section at a time, monitoring the brightness of stars for periodic dips caused by planets transiting (that is, passing in front of) those stars. So far, TESS has found 548 candidates and 10 confirmed exoplanets.

Since its launch, TESS has orbited Earth a total of 28 times. TESS has a unique elliptical orbit that circuits around Earth twice every time the Moon orbits. This allows TESS’s cameras to monitor each patch of sky continuously for nearly a month at a time. To get into this special orbit, TESS made a series of loops culminating in a lunar gravitational assist, which gave it the final push it needed.

Did you know that TESS has some serious mileage? The spacecraft has traveled about 20 million miles so far, which works out to an average of about 2,200 miles per hour. That’s faster than any roadrunner we’ve ever seen! This would be four times faster than an average jet. You’d get to your destination in no time!

TESS downloads data during its closest approach to Earth about every two weeks. So far, it has returned 12,000 gigabytes of data. That’s as if you streamed about 3,000 movies on Netflix. Get the popcorn ready! If you total all the pixels from every image taken using all four of the TESS cameras — which is about 600 full-frame images per orbit, you’d get about 805 billion pixels. This is like half a million iPhone screens put together!

When the Kepler Space Telescope reached the end of its mission, it passed the planet-finding torch to TESS. Where Kepler's view was deep — looking for planets as far away as 3,000 light-years — TESS's view is wide, surveying nearly the entire sky over two years. Each sector TESS views is 20 times larger than Kepler's field of view.

TESS will continue to survey the sky and is expected to find about 20,000 exoplanets in the two years it'll take to complete a scan of nearly the entire sky. Before TESS, several thousand candidate exoplanets were found, and more than 3,000 of these were confirmed. Some of these exoplanets are expected to range from small, rocky worlds to giant planets, showcasing the diversity of planets in the galaxy.

The TESS mission is led by MIT and came together with the help of many different partners. You can keep up with the latest from the TESS mission by following mission updates and keep track of the number of candidates and confirmed exoplanets.

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Space Telescope Gets to Work

Our latest space telescope, Transiting Exoplanet Survey Satellite (TESS), launched in April. This week, planet hunters worldwide received all the data from the first two months of its planet search. This view, from four cameras on TESS, shows just one region of Earth’s southern sky.

The Transiting Exoplanet Survey Satellite (TESS) captured this strip of stars and galaxies in the southern sky during one 30-minute period in August. Created by combining the view from all four of its cameras, TESS images will be used to discover new exoplanets. Notable features in this swath include the Large and Small Magellanic Clouds and a globular cluster called NGC 104. The brightest stars, Beta Gruis and R Doradus, saturated an entire column of camera detector pixels on the satellite’s second and fourth cameras.

Credit: NASA/MIT/TESS

The data in the images from TESS will soon lead to discoveries of planets beyond our solar system – exoplanets. (We’re at 3,848 so far!)

But first, all that data (about 27 gigabytes a day) needs to be processed. And where do space telescopes like TESS get their data cleaned up? At the Star Wash, of course!

TESS sends about 10 billion pixels of data to Earth at a time. A supercomputer at NASA Ames in Silicon Valley processes the raw data, turning those pixels into measures of a star’s brightness.

And that brightness? THAT’S HOW WE FIND PLANETS! A dip in a star’s brightness can reveal an orbiting exoplanet in transit.

TESS will spend a year studying our southern sky, then will turn and survey our northern sky for another year. Eventually, the space telescope will observe 85 percent of Earth’s sky, including 200,000 of the brightest and closest stars to Earth.

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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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NASA’s New Planet Hunter Reveals a Sky Full of Stars

NASA’s newest planet-hunting satellite — the Transiting Exoplanet Survey Satellite, or TESS for short — has just released its first science image using all of its cameras to capture a huge swath of the sky! TESS is NASA’s next step in the search for planets outside our solar system, called exoplanets.

This spectacular image, the first released using all four of TESS’ cameras, shows the satellite’s full field of view. It captures parts of a dozen constellations, from Capricornus (the Sea Goat) to Pictor (the Painter’s Easel) — though it might be hard to find familiar constellations among all these stars! The image even includes the Large and Small Magellanic Clouds, our galaxy’s two largest companion galaxies.

The science community calls this image “first light,” but don’t let that fool you — TESS has been seeing light since it launched in April. A first light image like this is released to show off the first science-quality image taken after a mission starts collecting science data, highlighting a spacecraft’s capabilities.

TESS has been busy since it launched from NASA’s Kennedy Space Center in Cape Canaveral, Florida. First TESS needed to get into position, which required a push from the Moon. After nearly a month in space, the satellite passed about 5,000 miles from the Moon, whose gravity gave it the boost it needed to get into a special orbit that will keep it stable and maximize its view of the sky.

During those first few weeks, we also got a sneak peek of the sky through one of TESS’s four cameras. This test image captured over 200,000 stars in just two seconds! The spacecraft was pointed toward the constellation Centaurus when it snapped this picture. The bright star Beta Centauri is visible at the lower left edge, and the edge of the Coalsack Nebula is in the right upper corner.

After settling into orbit, scientists ran a number of checks on TESS, including testing its ability to collect a set of stable images over a prolonged period of time. TESS not only proved its ability to perform this task, it also got a surprise! A comet named C/2018 N1 passed through TESS’s cameras for about 17 hours in July.

The images show a treasure trove of cosmic curiosities. There are some stars whose brightness changes over time and asteroids visible as small moving white dots. You can even see an arc of stray light from Mars, which is located outside the image, moving across the screen.

Now that TESS has settled into orbit and has been thoroughly tested, it’s digging into its main mission of finding planets around other stars. How will it spot something as tiny and faint as a planet trillions of miles away? The trick is to look at the star!

So far, most of the exoplanets we’ve found were detected by looking for tiny dips in the brightness of their host stars. These dips are caused by the planet passing between us and its star – an event called a transit. Over its first two years, TESS will stare at 200,000 of the nearest and brightest stars in the sky to look for transits to identify stars with planets.

TESS will be building on the legacy of NASA’s Kepler spacecraft, which also used transits to find exoplanets. TESS’s target stars are about 10 times closer than Kepler’s, so they’ll tend to be brighter. Because they're closer and brighter, TESS’s target stars will be ideal candidates for follow-up studies with current and future observatories.

TESS is challenging over 200,000 of our stellar neighbors to a staring contest! Who knows what new amazing planets we’ll find?

The TESS mission is led by MIT and came together with the help of many different partners. You can keep up with the latest from the TESS mission by following mission updates.

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The Hunt for New Worlds Continues with TESS

We're getting ready to start our next mission to find new worlds! The Transiting Exoplanet Survey Satellite (TESS) will find thousands of planets beyond our solar system for us to study in more detail. It's preparing to launch from our Kennedy Space Center at Cape Canaveral in Florida.

Once it launches, TESS will look for new planets that orbit bright stars relatively close to Earth. We're expecting to find giant planets, like Jupiter, but we're also predicting we'll find Earth-sized planets. Most of those planets will be within 300 light-years of Earth, which will make follow-up studies easier for other observatories.

TESS will find these new exoplanets by looking for their transits. A transit is a temporary dip in a star's brightness that happens with predictable timing when a planet crosses between us and the star. The information we get from transits can tell us about the size of the planet relative to the size of its star. We've found nearly 3,000 planets using the transit method, many with our Kepler space telescope. That's over 75% of all the exoplanets we've found so far!

TESS will look at nearly the entire sky (about 85%) over two years. The mission divides the sky into 26 sectors. TESS will look at 13 of them in the southern sky during its first year before scanning the northern sky the year after.

What makes TESS different from the other planet-hunting missions that have come before it? The Kepler mission (yellow) looked continually at one small patch of sky, spotting dim stars and their planets that are between 300 and 3,000 light-years away. TESS (blue) will look at almost the whole sky in sections, finding bright stars and their planets that are between 30 and 300 light-years away.

TESS will also have a brand new kind of orbit (visualized below). Once it reaches its final trajectory, TESS will finish one pass around Earth every 13.7 days (blue), which is half the time it takes for the Moon (gray) to orbit. This position maximizes the amount of time TESS can stare at each sector, and the satellite will transmit its data back to us each time its orbit takes it closest to Earth (orange).

Kepler's goal was to figure out how common Earth-size planets might be. TESS's mission is to find exoplanets around bright, nearby stars so future missions, like our James Webb Space Telescope, and ground-based observatories can learn what they're made of and potentially even study their atmospheres. TESS will provide a catalog of thousands of new subjects for us to learn about and explore.

The TESS mission is led by MIT and came together with the help of many different partners. Learn more about TESS and how it will further our knowledge of exoplanets, or check out some more awesome images and videos of the spacecraft. And stay tuned for more exciting TESS news as the spacecraft launches!

Watch the Launch!

*April 16 Update*

Launch teams are standing down today to conduct additional Guidance Navigation and Control analysis, and teams are now working towards a targeted launch of the Transiting Exoplanet Survey Satellite (TESS) on Wednesday, April 18. The TESS spacecraft is in excellent health, and remains ready for launch. TESS will launch on a Falcon 9 rocket from Space Launch Complex 40 at Cape Canaveral Air Force Station in Florida.

For more information and updates, visit: https://blogs.nasa.gov/tess/

Live Launch Coverage!

TESS is now slated to launch on Wednesday, April 18 on a SpaceX Falcon 9 rocket from our Kennedy Space Center in Florida.

Watch HERE.

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Solar System: 10 Things to Know This Week

Planets Outside Our Solar System

Let the planet-hunting begin!

Our Transiting Exoplanet Survey Satellite (TESS), which will scan the skies to look for planets beyond our solar system—known as exoplanets—is now in Florida to begin preparations for launch in April. Below, 10 Things to know about the many, many unknown planets out there awaiting our discovery.

1—Exo-what?

We call planets in our solar system, well, planets, but the many planets we’re starting to discover outside of our solar system are called exoplanets. Basically, they’re planets that orbit another star.

2—All eyes on TRAPPIST-1.

Remember the major 2016 announcement that we had discovered seven planets 40 light-years away, orbiting a star called TRAPPIST-1? Those are all exoplanets. (Here’s a refresher.)

3—Add 95 new ones to that.

Just last month, our Kepler telescope discovered 95 new exoplanets beyond our solar system (on top of the thousands of exoplanets Kepler has discovered so far). The total known planet count beyond our solar system is now more than 3,700. The planets range in size from mostly rocky super-Earths and fluffy mini-Neptunes, to Jupiter-like giants. They include a new planet orbiting a very bright star—the brightest star ever discovered by Kepler to have a transiting planet.

4—Here comes TESS.

How many more exoplanets are out there waiting to be discovered? TESS will monitor more than 200,000 of the nearest and brightest stars in search of transit events—periodic dips in a star’s brightness caused by planets passing in front—and is expected to find thousands of exoplanets.

5—With a sidekick, too.

Our upcoming James Webb Space Telescope, will provide important follow-up observations of some of the most promising TESS-discovered exoplanets. It will also allow scientists to study their atmospheres and, in some special cases, search for signs that these planets could support life.

6—Prepped for launch.

TESS is scheduled to launch on a SpaceX Falcon 9 rocket from Cape Canaveral Air Force Station nearby our Kennedy Space Center in Florida, no earlier than April 16, pending range approval.

7—A groundbreaking find.

In 1995, 51 Pegasi b (also called "Dimidium") was the first exoplanet discovered orbiting a star like our Sun. This find confirmed that planets like the ones in our solar system could exist elsewhere in the universe.

8—Trillions await.

A recent statistical estimate places, on average, at least one planet around every star in the galaxy. That means there could be a trillion planets in our galaxy alone, many of them in the range of Earth’s size.

9—Signs of life.

Of course, our ultimate science goal is to find unmistakable signs of current life. How soon can that happen? It depends on two unknowns: the prevalence of life in the galaxy and a bit of luck. Read more about the search for life.

10—Want to explore the galaxy?

No need to be an astronaut. Take a trip outside our solar system with help from our Exoplanet Travel Bureau.

Read the full version of this week’s ‘10 Things to Know’ article HERE. 

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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.

Solar System: Things to Know This Week

What's next for NASA? A quick look at some of the big things coming up:

1. We will add to our existing robotic fleet at the Red Planet with the InSight Mars lander set to study the planet's interior.

This terrestrial planet explorer will address one of the most fundamental issues of planetary and solar system science - understanding the processes that shaped the rocky planets of the inner solar system (including Earth) more than four billion years ago.

2. The Mars 2020 rover will look for signs of past microbial life, gather samples for potential future return to Earth.

The Mars 2020 mission takes the next step by not only seeking signs of habitable conditions on the Red Planet in the ancient past, but also searching for signs of past microbial life itself. The Mars 2020 rover introduces a drill that can collect core samples of the most promising rocks and soils and set them aside in a "cache" on the surface of Mars.

3. The James Webb Space Telescope will be the premier observatory of the next decade, studying the history of our Universe in infrared.

Webb will study every phase in the history of our Universe, ranging from the first luminous glows after the Big Bang, to the formation of solar systems capable of supporting life on planets like Earth, to the evolution of our own solar system.

4. The Parker Solar Probe will "touch the Sun," traveling closer to the surface than any spacecraft before.

This spacecraft, about the size of a small car, will travel directly into the sun's atmosphere about 4 million miles from our star's surface. Parker Solar Probe and its four suites of instruments – studying magnetic and electric fields, energetic particles, and the solar wind – will be protected from the Sun’s enormous heat by a 4.5-inch-thick carbon-composite heat shield.

5. Our OSIRIS-REx spacecraft arrives at the near-Earth asteroid Bennu in August 2018, and will return a sample for study in 2023.

This mission will help scientists investigate how planets formed and how life began, as well as improve our understanding of asteroids that could impact Earth.

6. Launching in 2018, the Transiting Exoplanet Survey Satellite (TESS) will search for planets around 200,000 bright, nearby stars.

The Transiting Exoplanet Survey Satellite (TESS) is the next step in the search for planets outside of our solar system (exoplanets), including those that could support life. The mission will find exoplanets that periodically block part of the light from their host stars, events called transits.

7. A mission to Jupiter's ocean-bearing moon Europa is being planned for launch in the 2020s.

The mission will place a spacecraft in orbit around Jupiter in order to perform a detailed investigation of Europa -- a world that shows strong evidence for an ocean of liquid water beneath its icy crust and which could host conditions favorable for life.

8. We will launch our first integrated test flight of the Space Launch System rocket and Orion spacecraft, known as Exploration Mission-1.

The Space Launch System rocket will launch with Orion atop it. During Exploration Mission-1, Orion will venture thousands of miles beyond the moon during an approximately three week mission.

9. We are looking at what a flexible deep space gateway near the Moon could be.

We’ve issued a draft announcement seeking U.S. industry-led studies for an advanced solar electric propulsion (SEP) vehicle capability. The studies will help define required capabilities and reduce risk for the 50 kilowatt-class SEP needed for the agency’s near-term exploration goals.

10. Want to know more? Read the full story.

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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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It’s May the 4th: Are Star Wars Planets Real?

Look at what we’ve found so far.

Is your favorite Star Wars planet a desert world or an ice planet or a jungle moon?

It’s possible that your favorite planet exists right here in our galaxy. Astronomers have found over 3,700 planets around other stars, called “exoplanets.”

Some of these alien worlds could be very similar to arid Tatooine, watery Scarif and even frozen Hoth, according to our scientists.

Find out if your planet exists in a galaxy far, far away or all around you. And May the Fourth be with you!

Planets With Two Suns

From Luke Skywalker’s home world Tatooine, you can stand in the orange glow of a double sunset. The same could said for Kepler-16b, a cold gas giant roughly the size of Saturn, that orbits two stars. Kepler-16b was the Kepler telescope’s first discovery of a planet in a “circumbinary” orbit (that is, circling both stars, as opposed to just one, in a double star system). 

The best part is that Tatooine aka Kepler-16b was just the first. It has family. A LOT of family. Half the stars in our galaxy are pairs, rather than single stars like our sun. If every star has at least one planet, that’s billions of worlds with two suns. Billions! Maybe waiting for life to be found on them.

Desert Worlds

Mars is a cold desert planet in our solar system, and we have plenty of examples of scorching hot planets in our galaxy (like Kepler-10b), which orbits its star in less than a day)! Scientists think that if there are other habitable planets in the galaxy, they’re more likely to be desert planets than ocean worlds. That’s because ocean worlds freeze when they’re too far from their star, or boil off their water if they’re too close, potentially making them unlivable. Perhaps, it’s not so weird that both Luke Skywalker and Rey grew up on planets that look a lot alike.

Ice Planets

An icy super-Earth named OGLE-2005-BLG-390Lb reminded scientists so much of the frozen Rebel base they nicknamed it “Hoth,” after its frozen temperature of minus 364 degrees Fahrenheit. Another Hoth-like planet was discovered in April 2017; an Earth-mass icy world orbiting its star at the same distance as Earth orbits the sun. But its star is so faint, the surface of OGLE-2016-BLG-1195Lb is probably colder than Pluto.

Forest worlds

Both the forest moon of Endor and Takodana, the home of Han Solo’s favorite cantina in “Force Awakens,” are green like our home planet. But astrobiologists think that plant life on other worlds could be red, black, or even rainbow-colored!

In February 2017, the Spitzer Space Telescope discovered seven Earth-sized planets in the same system, orbiting the tiny red star TRAPPIST-1.

The light from a red star, also known as an M dwarf, is dim and mostly in the infrared spectrum (as opposed to the visible spectrum we see with our sun). And that could mean plants with wildly different colors than what we’re used to seeing on Earth. Or, it could mean animals that see in the near-infrared.

What About Moons?

In Star Wars, Endor, the planet with the cute Ewoks, is actually a habitable moon of a gas giant. Now, we’re looking for life on the moons of our own gas giants. Saturn’s moon Enceladus or Jupiter’s moon Europa are ocean worlds that may well support life. Our Cassini spacecraft explored the Saturn system and its moons, before the mission ended in 2017. Watch the video and learn more about the missions’s findings.

And Beyond

The next few years will see the launch of a new generation of spacecraft to search for planets around other stars. Our TESS spacecraft launched in April 2018, and will discover new exoplanets by the end of the year. The James Webb Space Telescope is slated to launch in 2020. That’s one step closer to finding life.

You might want to take our ‘Star Wars: Fact or Fiction?’ quiz. Try it! Based on your score you may obtain the title of Padawan, Jedi Knight, or even Jedi Master! 

You don’t need to visit a galaxy far, far away to find wondrous worlds. Just visit this one ... there’s plenty to see.

Discover more about exoplanets here: https://exoplanets.nasa.gov/

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A Space Odyssey: 21 Years of Searching for Another Earth

There are infinite worlds both like and unlike this world of ours. We must believe that in all worlds there are living creatures and plants and other things we see in this world. – Epicurus, c. 300 B.C.

Are we alone? Are there other planets like ours? Does life exist elsewhere in the universe?

These are questions mankind has been asking for years—since the time of Greek philosophers. But for years, those answers have been elusive, if not impossible to find.

The month of October marks the 21st anniversary of the discovery of the first planet orbiting another sun-like star (aka. an exoplanet), 51 Pegasi b or “Dimidium.” Its existence proved that there were other planets in the galaxy outside our solar system.*

Even more exciting is the fact that astronomers are in hot pursuit of the first discovery of an Earth-like exoplanet orbiting a star other than the sun. The discovery of the so-called "blue dot" could redefine our understanding of the universe and our place in it, especially if astronomers can also find signs that life exists on that planet's surface.

Astronomy is entering a fascinating era where we're beginning to answer tantalizing questions that people have pondered for thousands of years.

Are we alone?

In 1584, when the Catholic monk Giordano Bruno asserted that there were "countless suns and countless earths all rotating around their suns," he was accused of heresy.

But even in Bruno's time, the idea of a plurality of worlds wasn't entirely new. As far back as ancient Greece, humankind has speculated that other solar systems might exist and that some would harbor other forms of life.

Still, centuries passed without convincing proof of planets around even the nearest stars.

Are there other planets like ours?

The first discovery of a planet orbiting a star similar to the sun came in 1995. The Swiss team of Michel Mayor and Didier Queloz of Geneva announced that they had found a rapidly orbiting gas world located blisteringly close to the star 51 Pegasi.

This announcement marked the beginning of a flood of discoveries. Exotic discoveries transformed science fiction into science fact:

a pink planet

worlds with two or even three suns

a gas giant as light as Styrofoam

a world in the shape of an egg

a lava planet

But what about another Earth?

Our first exoplanet mission**, Kepler, launched in 2009 and revolutionized how astronomers understand the universe and our place in it. Kepler was built to answer the question—how many habitable planets exist in our galaxy?

And it delivered: Thousands of planet discoveries poured in, providing statistical proof that one in five sun-like stars (yellow, main-sequence G type) harbor Earth-sized planets orbiting in their habitable zones– where it’s possible liquid water could exist on their surface.

Now, our other missions like the Hubble and Spitzer space telescopes point at promising planetary systems (TRAPPIST-1) to figure out whether they are suitable for life as we know it.

Does life exist elsewhere in the universe?

Now that exoplanet-hunting is a mainstream part of astronomy, the race is on to build instruments that can find more and more planets, especially worlds that could be like our own.

Our Transiting Exoplanet Survey Satellite (TESS), set for launch in 2017-2018, will look for super-Earth and Earth-sized planets around stars much closer to home. TESS will find new planets the same way Kepler does—via the transit method—but will cover 400 times the sky area.

The James Webb Space Telescope, to launch in 2018, wil be our most powerful space telescope to date. Webb will use its spectrograph to look at exoplanet atmospheres, searching for signs of life.

We still don’t know where or which planets are in the habitable zones of the nearest stars­ to Earth. Searching out our nearest potentially habitable neighbors will be the next chapter in this unfolding story.

*The first true discovery of extrasolar planets was actually a triplet of dead worlds orbiting the remains of an exploded star, called a pulsar star. Two of three were found by Dr. Alexander Wolszczan in 1992– a full three years before Dimidium’s discovery. But because they are so strange, and can’t support life as we know it, most scientists would reserve the “first” designation for a planet orbiting a normal star.

** The French CoRoT mission, launched in 2006, was the first dedicated exoplanet space mission. It has contributed dozens of confirmed exoplanets to the ranks and boasts a roster of some of the most well-studied planets outside our solar system.

To stay up-to-date on our latest exoplanet discoveries, visit: https://exoplanets.nasa.gov

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TESS: The Planet Hunter

So you’re thinking...who’s TESS? But, it’s more like: WHAT is TESS? 

The Transiting Exoplanet Survey Satellite (TESS) is an explorer-class planet finder that is scheduled to launch in April 2018. This mission will search the entire sky for exoplanets — planets outside our solar system that orbit sun-like stars.

In the first-ever space borne all-sky transit survey, TESS will identify planets ranging from Earth-sized to gas giants, orbiting a wide range of stellar types and orbital distances.

The main goal of this mission is to detect small planets with bright host stars in the solar neighborhood, so that we can better understand these planets and their atmospheres.

TESS will have a full time job monitoring the brightness of more than 200,000 stars during a two year mission. It will search for temporary drops in brightness caused by planetary transits. These transits occur when a planet’s orbit carries it directly in front of its parent star as viewed from Earth (cool GIF below).

TESS will provide prime targets for further, more detailed studies with the James Webb Space Telescope (JWST), as well as other large ground-based and space-based telescopes of the future.

What is the difference between TESS and our Kepler spacecraft?

TESS and Kepler address different questions: Kepler answers "how common are Earth-like planets?" while TESS answers “where are the nearest transiting rocky planets?”

What do we hope will come out of the TESS mission?

The main goal is to find rocky exoplanets with solid surfaces at the right distance from their stars for liquid water to be present on the surface. These could be the best candidates for follow-up observations, as they fall within the “habitable zone” and be at the right temperatures for liquid water on their surface.

TESS will use four cameras to study sections of the sky’s north and south hemispheres, looking for exoplanets. The cameras would cover about 90 percent of the sky by the end of the mission. This makes TESS an ideal follow-up to the Kepler mission, which searches for exoplanets in a fixed area of the sky. Because the TESS mission surveys the entire sky, TESS is expected to find exoplanets much closer to Earth, making them easier for further study.

Stay updated on this planet-hunting mission HERE.

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NASA’s Fleet of Planet-hunters and World-explorers

Around every star there could be at least one planet, so we’re bound to find one that is rocky, like Earth, and possibly suitable for life. While we’re not quite to the point where we can zoom up and take clear snapshots of the thousands of distant worlds we’ve found outside our solar system, there are ways we can figure out what exoplanets light years away are made of, and if they have signs of basic building blocks for life. Here are a few current and upcoming missions helping us explore new worlds:

Kepler

Launched in 2009, the Kepler space telescope searched for planets by looking for telltale dips in a star’s brightness caused by crossing, or transiting, planets. It has confirmed more than 1,000 planets; of these, fewer than 20 are Earth-size (therefore possibly rocky) and in the habitable zone -- the area around a star where liquid water could pool on the surface of an orbiting planet. Astronomers using Kepler data found the first Earth-sized planet orbiting in the habitable zone of its star and one in the habitable zone of a sun-like star.

In May 2013, a second pointing wheel on the spacecraft broke, making it not stable enough to continue its original mission. But clever engineers and scientists got to work, and in May 2014, Kepler took on a new job as the K2 mission. K2 continues the search for other worlds but has introduced new opportunities to observe star clusters, young and old stars, active galaxies and supernovae.

Transiting Exoplanet Survey Satellite (TESS)

Revving up for launch around 2017-2018, NASA’s Transiting Exoplanet Survey Satellite (TESS) will find new planets the same way Kepler does, but right in the stellar backyard of our solar system while covering 400 times the sky area. It plans to monitor 200,000 bright, nearby stars for planets, with a focus on finding Earth and Super-Earth-sized planets. 

Once we’ve narrowed down the best targets for follow-up, astronomers can figure out what these planets are made of, and what’s in the atmosphere. One of the ways to look into the atmosphere is through spectroscopy.  

As a planet passes between us and its star, a small amount of starlight is absorbed by the gas in the planet’s atmosphere. This leaves telltale chemical “fingerprints” in the star’s light that astronomers can use to discover the chemical composition of the atmosphere, such as methane, carbon dioxide, or water vapor. 

James Webb Space Telescope

Launching in 2018, NASA’s most powerful telescope to date, the James Webb Space Telescope (JWST), will not only be able to search for planets orbiting distant stars, its near-infrared multi-object spectrograph will split infrared light into its different colors- spectrum- providing scientists with information about an physical properties about an exoplanet’s atmosphere, including temperature, mass, and chemical composition. 

Hubble Space Telescope

Hubble Space Telescope is better than ever after 25 years of science, and has found evidence for atmospheres bleeding off exoplanets very close to their stars, and even provided thermal maps of exoplanet atmospheres. Hubble holds the record for finding the farthest exoplanets discovered to date, located 26,000 light-years away in the hub of our Milky Way galaxy.

Chandra X-ray Observatory

Chandra X-ray Observatory can detect exoplanets passing in front of their parent stars. X-ray observations can also help give clues on an exoplanet’s atmosphere and magnetic fields. It has observed an exoplanet that made its star act much older than it actually is. 

Spitzer Space Telescope

Spitzer Space Telescope has been unveiling hidden cosmic objects with its dust-piercing infrared vision for more than 12 years. It helped pioneer the study of atmospheres and weather on large, gaseous exoplanets. Spitzer can help narrow down the sizes of exoplanets, and recently confirmed the closest known rocky planet to Earth.

SOFIA

The Stratospheric Observatory for Infrared Astronomy (SOFIA) is an airplane mounted with an infrared telescope that can fly above more than 99 percent of Earth's atmospheric water vapor. Unlike most space observatories, SOFIA can be routinely upgraded and repaired. It can look at planetary-forming systems and has recently observed its first exoplanet transit. 

What’s Coming Next?

Analyzing the chemical makeup of Earth-sized, rocky planets with thin atmospheres is a big challenge, since smaller planets are incredibly faint compared to their stars. One solution is to block the light of the planets' glaring stars so that we can directly see the reflected light of the planets. Telescope instruments called coronagraphs use masks to block the starlight while letting the planet's light pass through. Another possible tool is a large, flower-shaped structure known as the starshade. This structure would fly in tandem with a space telescope to block the light of a star before it enters the telescope. 

All images (except SOFIA) are artist illustrations.

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