00:00A new super-Earth has been spotted by astronomers, and it's quite intriguing.
00:05This planet, called TOI-715b, is about 1.5 the size of Earth, which is why it's called
00:12the super-Earth.
00:13It's also relatively close to us in space terms – only 137 light-years away.
00:20For comparison, most exoplanets are hundreds of light-years away.
00:24And all the interesting stuff, like black holes and nebulas, are usually more than thousands
00:29of light-years away from us.
00:31So could it be habitable?
00:35The habitable zone is an estimate of where a planet might have the right conditions for
00:39liquid water.
00:41This is what we call some distance from the star where the temperatures on the planet
00:45should be okay-ish, and water should stay liquid on its surface.
00:49It's not super-precise, because it depends on a bunch of factors like the type of star,
00:55how reflective the planet is, its size, and so on.
00:59Also, just being in this zone isn't enough for water to actually be there.
01:03The planet also needs the right kind of atmosphere and a few other things.
01:08So we invented a stricter definition in 2014 – the conservative habitable zone.
01:14It's a more precise term defining the best candidates that have liquid water.
01:19Otherwise, we get too many potentially habitable planets that are not actually habitable at
01:24all.
01:25The CHZ is based on how much energy a planet gets from its star compared to Earth.
01:31If a rocky planet gets between 40-85%, it's considered to be in the CHZ no matter how
01:38far away it is from its star.
01:41These planets have a higher chance of being habitable.
01:44And yes, TOI-715b is located there.
01:51This super-Earth orbits the M-type star, also called Red Dwarf.
01:55It's a star that's much smaller and cooler than our Sun – about a quarter of the Sun's
02:01size and mass.
02:02But if the planet is located in the habitable zone, it's actually a better option for
02:07life.
02:08Red Dwarfs live much longer than our Sun, a yellow dwarf.
02:12This also means that they have more time to form little creatures on their planets.
02:16And this Red Dwarf really is older than our star.
02:19Our Sun is 4.6 billion years old, and this star is 6.6 billion years old, give or take
02:26a few hundred million.
02:28It doesn't have much magnetic activity, so it's not dangerous.
02:32It doesn't flare up like younger Red Dwarfs.
02:35These flares can be super strong and might even hurt planets by taking away their atmospheres.
02:40Although some planets around it do have thinner atmospheres, it seems like this Red Dwarf
02:46has already gone all out.
02:48These Red Dwarfs are where we're looking for planets that could support life right
02:53now.
02:54Our Super Earth is really close to its star, zooming around it in just 19 days.
02:59Since the star is small and the planet is so close, the planet passing in front of its
03:04star happens a lot and looks really clear.
03:07This makes it easy for telescopes like the James Webb to study its atmosphere without
03:12needing too much time.
03:15Speaking of the James Webb Space Telescope, it's bringing us into a new era of understanding
03:20distant planets beyond our Solar System.
03:23Imagine being able to see what gases make up the air on a planet millions of light-years
03:28away.
03:29James Webb will help us to find worlds that could support life.
03:34Right now, it's trying to figure out whether TOI-715b has an atmosphere.
03:39If it does, its atmosphere might be easier to spot compared to a planet that's drier
03:44and denser.
03:46And then we might get even more height because it would look like a good place for life.
03:51On top of all that, there might be another planet in this system, also in the habitable
03:56zone.
03:57We're not sure whether it's really there, it's just a candidate with a crazy name.
04:02But if it turns out to be real, it would be about the size of Earth.
04:06Also, it would be the smallest planet in the habitable zone ever spotted by the TESS telescope.
04:14Another cool thing about TOI-715b is that it cannot just have water on it, but be an
04:21entire water world.
04:22An ocean planet is a type of planet that has an ocean covering its surface or has subsurface
04:28oceans.
04:29They might not have much dry land because the water can cover everything.
04:33Sometimes the entire planet can be covered in other liquids, like lava or ammonia.
04:39When it comes to planets outside our Solar System, we can't see surface water directly
04:43with our current technology.
04:45Instead, scientists look for water vapor in the atmosphere as a hint there might be liquid
04:51water below.
04:52And, of course, we wonder if these planets can have life, hopefully not in the form of
04:57Leviathan-like monsters.
04:59Our models show that planets with oceans might be pretty common in our galaxy.
05:04This means there could be lots of ocean worlds out there waiting to be discovered.
05:11But the most important part about TOI-715b is that it's in the so-called small planet
05:18radius gap.
05:20If we give the planets a lineup, there will be those that are bigger and smaller than
05:24Earth.
05:25But there's a sudden gap in planets that are about from 1.5 to 2 times bigger than
05:30Earth.
05:31Where are they?
05:33This gap is interesting to scientists because it tells us something about how planets form
05:37and change over time.
05:39It's not that planets don't form in this size range.
05:42They actually start off larger, and then lose some of their mass, like a balloon gradually
05:47deflating.
05:48Perhaps it happens because of how they orbit their stars, with stars blowing away some
05:53of their mass as they dance around it, as our Sun does with gas from comet tails.
05:59This gap holds a lot of mystery, and planets, like our new super-Earth, are clues that could
06:04help us unravel it.
06:06We aren't sure whether it exists around red dwarfs.
06:10Maybe it's a gap in how dense these planets are rather than in their actual size.
06:14So studying our discovered planet is even more interesting.
06:18It'll help us learn more about distant stars and their planets.
06:23Now I mentioned tests a while back.
06:25NASA's TESS, Transiting Exoplanet Survey Satellite, has been in space for 6 years now
06:31and has been incredibly successful.
06:34NASA launched TESS because we already found over 5,000 planets orbiting other stars, mainly
06:40thanks to the Kepler telescope.
06:43But Kepler mostly found large planets, not necessarily like Earth.
06:47We decided to focus TESS on finding smaller Earth-like planets around nearby bright stars,
06:53making them easier to study with future telescopes.
06:57Here's how it works.
07:00The camera observes stars and looks for changes in their brightness.
07:04If the brightness suddenly drops for a while and then gets back, it could mean there is
07:08a planet passing in front of it.
07:11But stars can dim for other reasons too.
07:14For example, flaring up or having dark spots on their surface, which is why we need to
07:19be careful with this data.
07:21TESS shows us the size and orbit of these planets.
07:25Then ground telescopes help determine their mass.
07:28With these three parameters, we can figure out what the planets are made of and if they're
07:32rocky like Earth or gassy like Jupiter.
07:35Yeah, you want to avoid Jupiter after taco night!
07:41One example of TESS's discoveries was the TOI-700 system.
07:46There it discovered its first-ever Earth-like planet, TOI-700d.
07:52This exoplanet also orbited a red dwarf, and it's even closer to us, about 100 light-years
07:57away.
07:58Unfortunately, it's unlikely to be habitable because the temperatures there are crazy.
08:04Another big discovery was made in the AU Microscopy System.
08:09TESS discovered a planet about 4 times the size of Earth, and another nearly 3 times
08:13Earth's size.
08:15This system has become a key area for studying how stars and planets form and change over
08:20time.
08:21TESS has also spotted a variety of other exciting finds, including supernova, hot worlds, and
08:27so on.
08:28And as it enters its 6th year, we can only expect more exciting findings to come!
08:36That's it for today!
08:37So hey, if you pacified your curiosity, then give the video a like and share it with your
08:41friends!
08:42Or if you want more, just click on these videos and stay on the Bright Side!
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