Comet McNaught Next To The Dome Of The NTT On La Silla. The Picture Was Taken In January 2007.

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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Ask Ethan: Is Spacetime Really A Fabric?

“I’d like somebody to finally acknowledge and admit that showing balls on a bed sheet doesn’t cut it as a picture of reality.”

Okay, I admit it: visualizing General Relativity as balls on a bedsheet doesn’t make a whole lot of sense. For one, if this is what gravity is supposed to be, what pulls the balls “down” onto the bedsheet? For another, if space is three dimensional, why are we talking about a 2D “fabric” of space? And for another, why do these lines curve away from the mass, rather than towards it?

It’s true: this visualization of General Relativity is highly flawed. But, believe it or not, all visualizations of General Relativity inherently have similar flaws. The reason is that space itself is not an observable thing! In Einstein’s theory, General Relativity provides the link between the matter and energy in the Universe, which determines the geometric curvature of spacetime, and how the rest of the matter and energy in the Universe moves in response to that. In this Universe, we can only measure matter and energy, not space itself. We can visualize it how we like, but all visualizations are inherently flawed.

Come get the story of how to make as much sense as possible out of the Universe we actually have.

Make Sure You Observe the Moon on October 20

On Saturday, October 20, NASA will host the ninth annual International Observe the Moon Night. One day each year, everyone on Earth is invited to observe and learn about the Moon together, and to celebrate the cultural and personal connections we all have with our nearest celestial neighbor.

There are a number of ways to celebrate. You can attend an event, host your own, or just look up! Here are 10 of our favorite ways to observe the Moon:

1. Look up

Image credit: NASA’s Scientific Visualization Studio/Ernie Wright

The simplest way to observe the Moon is simply to look up. The Moon is the brightest object in our night sky, the second brightest in our daytime sky and can be seen from all around the world — from the remote and dark Atacama Desert in Chile to the brightly lit streets of Tokyo. On October 20, the near side of the Moon, or the side facing Earth, will be about 80 percent illuminated, rising in the early evening.

See the Moon phase on October 20 or any other day of the year!

2. Peer through a telescope or binoculars

The Moon and Venus are great targets for binoculars. Image Credit: NASA/Bill Dunford

With some magnification help, you will be able to focus in on specific features on the Moon, like the Sea of Tranquility or the bright Copernicus Crater. Download our Moon maps for some guided observing on Saturday.

3. Photograph the Moon

Image credit: NASA/GSFC/ASU

Our Lunar Reconnaissance Orbiter (LRO) has taken more than 20 million images of the Moon, mapping it in stunning detail. You can see featured, captioned images on LRO’s camera website, like the one of Montes Carpatus seen here. And, of course, you can take your own photos from Earth. Check out our tips on photographing the Moon!

4. Take a virtual field trip

Image credit: NASA/JPL-Caltech

Plan a lunar hike with Moontrek. Moontrek is an interactive Moon map made using NASA data from our lunar spacecraft. Fly anywhere you’d like on the Moon, calculate the distance or the elevation of a mountain to plan your lunar hike, or layer attributes of the lunar surface and temperature. If you have a virtual reality headset, you can experience Moontrek in 3D.

5. Touch the topography

Image credit: NASA GSFC/Jacob Richardson

Observe the Moon through touch! If you have access to a 3D printer, you can peruse our library of 3D models and lunar landscapes. This model of the Apollo 11 landing site created by NASA scientist Jacob Richardson, is derived from LRO’s topographic data. Near the center, you can actually feel a tiny dot where astronauts Neil Armstrong and Buzz Aldrin left the Lunar Descent Module.

6. Make Moon art

Image credit: LPI/Andy Shaner

Enjoy artwork of the Moon and create your own! For messy fun, lunar crater paintings demonstrate how the lunar surface changes due to consistent meteorite impacts.

7. Relax on your couch

Image credit: NASA’s Scientific Visualization Studio/Ernie Wright

There are many movies that feature our nearest neighbor, from A Voyage to the Moon by George Melies, to Apollo 13, to the newly released First Man. You can also spend your evening with our lunar playlist on YouTube or this video gallery, learning about the Moon’s role in eclipses, looking at the Moon phases from the far side, and seeing the latest science portrayed in super high resolution. You’ll impress all of your friends with your knowledge of supermoons.

8. Listen to the Moon

Video credit: NASA’s Scientific Visualization Studio/Ernie Wright

Make a playlist of Moon songs. For inspiration, check out this list of lunar tunes. We also recommend LRO’s official music video, The Moon and More, featuring Javier Colon, season 1 winner of NBC’s “The Voice.” Or you can just watch this video featuring “Clair de Lune,” by French composer Claude Debussy, over and over.

9. See the Moon through the eyes of a spacecraft

Image credit: NASA/GSFC/MIT

Visible light is just one tool that we use to explore our universe. Our spacecraft contain many different types of instruments to analyze the Moon’s composition and environment. Review the Moon’s gravity field with data from the GRAIL spacecraft or decipher the maze of this slope map from the laser altimeter onboard LRO. This collection from LRO features images of the Moon’s temperature and topography. You can learn more about our different missions to explore the Moon here.

10. Continue your observations throughout the year

Image credit: NASA’s Scientific Visualization Studio/Ernie Wright

An important part of observing the Moon is to see how it changes over time. International Observe the Moon Night is the perfect time to start a Moon journal. See how the shape of the Moon changes over the course of a month, and keep track of where and what time it rises and sets. Observe the Moon all year long with these tools and techniques!

However you choose to celebrate International Observe the Moon Night, we want to hear about it! Register your participation and share your experiences on social media with #ObserveTheMoon or on our Facebook page. Happy observing!

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

All Cats Are Beautiful

Loving Vincent (2017) dir. Dorota Kobiela, Hugh Welchman

Far from Westeros, a Three-Eyed Raven Helps NASA Find Its Way

Perched on the outside of the International Space Station is Raven—a technology-filled module that helps NASA develop a relative navigation capability, which is essentially autopilot for spacecraft. Raven has been testing technologies to enable autonomous rendezvous in space, which means the ability to approach things in space without human involvement, even from the ground.

Developed by the Satellite Servicing Projects Division (SSPD), our three-eyed Raven has visible, infrared, and Lidar sensors and uses those “eyes” to image and track visiting spacecraft as they come and go from the space station. Although Raven is all-seeing, it only sees all in black and white. Color images do not offer an advantage in the case of Raven and Restore-L, which also utilize infrared and Lidar sensors.

The data from Raven’s sensors is sent to its processor, which autonomously sends commands that swivel Raven on its gimbal, or pointing system. When Raven turns using this system, it is able to track a vehicle. While these maneuvers take place, NASA operators evaluate the movements and make adjustments to perfect the relative navigation system technologies. 

A few days ago, Raven completed its 21st observation of a spacecraft when it captured images of Northrop Grumman’s Cygnus vehicle delivering science investigations and supplies as part of its 11th commercial resupply services mission, including another SSPD payload called the Robotic External Leak Locator.

And just last month, Raven celebrated its two-year anniversary in space, marking the occasion with an observation of SpaceX’s Crew Dragon during the Demo-1 mission.

What is this—a spacecraft for ants??

While this shot of Dragon isn’t terribly impressive because of where the spacecraft docked on station, Raven has captured some truly great images when given the right viewing conditions. 

From SpaceX Dragon resupply mission observations…

…to Cygnus supply vehicles.

Raven has observed six unique types of spacecraft. 

It has also conducted a few observations not involving spacecraft, including the time it captured Hurricane Irma…

…or the time it captured station’s Dextre arm removing the Robotic Refueling Mission 3 payload, another mission developed by SSPD, from the Dragon spacecraft that delivered it to the orbiting laboratory.

Thus far, Raven has had a great, productive life aboard the station, but its work isn’t done yet! Whether it’s for Restore-L, which will robotically refuel a satellite, or getting humans to the Moon or Mars, the technologies Raven is demonstrating for a relative navigation system will support future NASA missions for decades to come.

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

Throwback Thursday: Apollo 11 FAQ Edition

With the help of the NASA History Office, we’ve identified some of the most frequently asked questions surrounding the first time humans walked on the surface of another world. Read on and click here to check out our previous Apollo FAQs. 

How many moon rocks did the Apollo crews bring back? What did we learn?

The six crews that landed on the Moon brought back 842 pounds (382 kilograms) of rocks, sand and dust from the lunar surface. Each time, they were transferred to Johnson Space Center’s Lunar Receiving Laboratory, a building that also housed the astronauts during their three weeks of quarantine. Today the building now houses other science divisions, but the lunar samples are preserved in the Lunar Sample Receiving Laboratory.

Built in 1979, the laboratory is the chief repository of the Apollo samples.

From these pieces of the Moon we learned that its chemical makeup is similar to that of Earth’s, with some differences. Studying the samples has yielded clues to the origins of the solar system. In March of 2019, we announced that three cases of pristine Moon samples will be unsealed for the first time in 50 years so that we can take advantage of the improved technology that exists today! 

Did you know you might not have to travel far to see a piece of the Moon up close? Visit our Find a Moon Rock page to find out where you can visit a piece of the Moon.

What did Apollo astronauts eat on their way to the Moon?

Astronaut food has come a long way since the days of Project Mercury, our first human spaceflight program that ran from 1958-1963. Back then, astronauts “enjoyed” food in cube form or squeezed out of tubes. Early astronaut food menus were designed less for flavor and more for nutritional value, but that eventually shifted as technology evolved. Astronauts today can enjoy whole foods like apples, pizza and even tacos. 

Apollo crews were the first to have hot water, making it easier to rehydrate their foods and improve its taste. They were also the first to use a “spoon bowl,” a plastic container that was somewhat like eating out of a Ziploc bag with a spoon. Here’s an example of a day’s menu for a voyage to the Moon:

Breakfast: bacon squares, strawberry cubes and an orange drink.

Lunch: beef and potatoes, applesauce and a brownie.

Dinner: salmon salad, chicken and rice, sugar cookie cubes and a pineapple grapefruit drink.

What did Michael Collins do while he orbited the Moon, alone in the Command Module?

As Neil Armstrong and Buzz Aldrin worked on the lunar surface, Command Module pilot Michael Collins orbited the Moon, alone, for the next 21.5 hours. On board he ran systems checks, made surface observations and communicated with Mission Control when there wasn’t a communications blackout. Blackouts happened every time Collins went behind the Moon. In 2009, Collins wrote this in response to a flurry of media questions about the 40th anniversary of the mission:

Q. Circling the lonely Moon by yourself, the loneliest person in the universe, weren’t you lonely? A. No. Far from feeling lonely or abandoned, I feel very much a part of what is taking place on the lunar surface. I know that I would be a liar or a fool if I said that I have the best of the three Apollo 11 seats, but I can say with truth and equanimity that I am perfectly satisfied with the one I have. This venture has been structured for three men, and I consider my third to be as necessary as either of the other two.”

What will Artemis astronauts bring back when they land on the Moon?

Artemis missions to the Moon will mark humanity’s first permanent presence on another world. The first woman and the next man to explore the lunar surface will land where nobody has ever attempted to land before – on the Moon’s south pole where there are billions of tons of water ice that can be used for oxygen and fuel. We don’t know yet what astronauts will bring back from this unexplored territory, but we do know that they will return with hope and inspiration for the next generation of explorers: the Artemis generation. Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com.

Pulsar planets are planets that are found orbiting pulsars, or rapidly rotating neutron stars. The first such planet to be discovered was around a millisecond pulsar and was the first extrasolar planet to be confirmed as discovered.

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