has identified over 850 candidate exoplanets, or planets outside our solar system, some

of which have the potential to support life. TESS, that hardworking gal, has been on this

exoplanet-hunting mission for over a year. And not only has this satellite exceeded the wildest

dreams of the many scientists who use it to find exoplanets, but it has also gathered

unprecedented data on other astrophysical phenomena, like exocomets and supernovae.

TESS uses four large, specially designed cameras that are able to scan the sky for stars outside

our solar system. The cameras view overlapping sectors of the sky for 27 days at a time,

waiting to see the brightness from a star blip in a certain way, an event called a transit.

This indicates that something has passed in front of the star, likely something that’s

orbiting it...like a planet. This method is called transit photometry, giving TESS the

first part of its name. And TESS double checks her work, too.

That same object must pass by the same star, causing the same blip, at least three times

before being considered a candidate exoplanet.  Once potential exoplanets are identified, TESS then

notifies astronomers on the ground to take a closer look with their telescopes to confirm.

TESS has already helped identify at least 28 confirmed new exoplanets, with more being confirmed

every day.

Scientists are looking at these planets to see if any of them could potentially host

alien life, but that’s not even the only reason we’re interested in exoplanets.

Some of them are what scientists are calling ‘missing link’ planets.

These are somewhere in between smaller, rocky planets, like our Earth and larger, gaseous

planets like Neptune.  We don’t have any of these in-betweener

planets in our solar system, so these ‘missing links’ will be really exciting to study,

since they’ll help us understand how these kinds of planets form along-side rockier,

more Earth-like worlds, and how these solar systems evolve in the first place.

TESS has pointed us to several solar systems that look really promising, including three

planets of particular interest that orbit a relatively quiet star that’s relatively

close to us.  When I say ‘quiet’, I don’t mean that

it’s not blasting heavy death metal, I mean that this star doesn't flare very often, which

makes it and the planets that move around it easier to study.  And when I say ‘close’,

it is 73 light-years away, which sounds like quite a ways, but is actually considered a

close neighbor of ours!  The star in question is a red dwarf star called

‘TESS object of interest 270’, or TOI 270 for short. It’s got at least three planets

orbiting it, and those are the ones we’re looking at closely: TOI 270 B, C, and D.

They’re all varying distances from the star, with estimated temperatures ranging from a

toasty 254 degrees Celsius to a nice and cool 66 degrees.

One of the larger, gassier planets is identified as a mini-Neptune—one of these missing link

planets.  It was initially thought to be in the ‘habitable

zone’ of its star, meaning it could have liquid oceans and host life.

But as scientists looked at it more closely, they now think that TOI-270 D’s atmosphere

is too thick, making the planet a greenhouse that’s probably far too hot to host life.

So that’s a bummer, but researchers still want to probe the compositions and characteristics

of the planets orbiting TOI-270.  Plus they think there may be other planets

in this system, so we’re not giving up. TOI-270 is just one of many systems that TESS

has pointed us toward.  And while looking for star-planet systems

like these, TESS was also able to observe other exciting things outside our solar system,

like exocomets And because TESS looks at one particular patch

of sky for so long, it can also observe stellar events, like the beginnings of supernovae.

Again, this means TESS can then tell ground telescopes to take a closer look, which researchers

hope will help us better understand the origins of astronomical explosions of all different

kinds. And get this—scientists can use those observations to calculate how fast the

universe is expanding. Hopefully we’ll be able to get even closer

looks at all the stuff that TESS has scouted out for us when the James Webb Space Telescope

eventually launches.  The JWST could even take measurements of the

compositions of these exciting planets and their atmospheres, telling us even more about

whether these exoplanets could support life. Thanks for the recon mission, TESS. We can’t

wait to see what else you point out for us. If you want to see just how close we are to

launching the JWST, check out this video here, and make sure you subscribe to Seeker for

all your planetary discovery news. If you have other planet questions for us, leave

them down in the comments below and as always, thanks for watching.