The Closest Alien Planets

about a year ago I made a video where I crossed the Earth similarity index with the conservative list of habitable planets to come up with the 16 most promising exoplanets we've discovered so far and well I really liked that video I thought it was a fun idea and I'm really proud of how everything in it turned out but I did have one small issue with it you see while our ability to detect exoplanets May reach thousands of light years away our ability to make actual observations on such planets is far more limited meaning that despite having found nearly 5 000 of these alien worlds we know next to nothing about any of them besides maybe their mass and orbit however that's all going to change very soon thanks to the launch of the James Webb Space Telescope earlier this year in the very near future we'll be capable of teasing out even more details like the exact sizes of certain exoplanets as well as the presence of an atmosphere heck maybe even the composition of their atmospheres that altogether provide us with a far better understanding of these planets than we have now though of course just like anything else the James Webb Space Telescope does have its limitations and it's likely we'll only be able to collect good solid data on the exoplanets closest to us but when I took a look at a list of the nearest known exoplanets I found myself largely unfamiliar with even the nearest of our neighbors and unless you work for NASA I expected the same is true for all you watching too and well how are we supposed to know what planets to spend our time looking at with our big new toy if we don't know at least a little about them all first so now I have a new Mission not to find habitable exoplanets but rather simply to familiarize ourselves with those closest to us so we can figure out which ones we should be paying more attention to and see if we can come to any conclusions about our Cosmic neighborhood foreign before we get started I just want to make two things clear first everything I talk about in this video is subject to change and likely will change as we continue to gather information and make more educated inferences right now we live in an age of Rapid Discovery and advancement and because of that I'm sure in almost no time at all this video will become drastically outdated both because of what I say about individual planets but also for all the really interesting ones that I'll likely skip over because they're yet to be discovered and so the selection of planets we look at today should be considered more of a random sample than an all-inclusive list and two if it wasn't already clear at this point we know very little about all of these places and so any depiction of them can't be considered anything more than an artistic interpretation I mean I think I did a reasonably good job at using the information at hand to portray these planets but of course I also had to fill in a few gaps so just keep that in mind got it okay cool then let's get started because our two main methods for discovering worlds beyond our own both involve how they'd interact with their parent star the search for the nearest exoplanets actually starts with the search for the nearest stars for simplicity's sake we're going to imagine these all sitting in one straight line away from us and after traveling only a little over four light years will arrive at our closest neighbor Alpha Centauri from Earth Alpha Centauri appears as a single point of light but a closer look will actually reveal a three star system two of these Alpha Centauri A and B are very similar to our sun in both size and temperature explaining why their combined Delight forms the third brightest star in our Sky while the third Alpha Centauri C is a much smaller and dimmer Red Dwarf that can't even be seen from Earth but Alpha Centauri C has another name Proxima centaur alluding to the fact that this is the closest star in our proximity it's here around this faint ball of burning gas that will find the nearest alien worlds remarkably a total of three planets have been found in orbit around Proxima Centauri aptly named Proxima b c and d and perhaps even luckier than that one of them Proxima B sits within its star's habitable zone where liquid water is theoretically possible now technically I already talked about Proxima B in the first exoplanets video I made but I'd like to take a moment just to appreciate how miraculous it is that the very closest star to us just so happens to also host a potentially habitable world with a mass almost identical to the Earth so this suggests Proxima B is a rocky planet while it's relatively larger estimated radius appears to suggest its density is far lower than the Earth's meaning the planet's composition likely features more lightweight compounds like water rather than heavier elements like iron indicating this may in fact be an oceanic World it only helps to improve its chances of harboring life however surviving around Proxima Centauri wouldn't exactly be easy thanks to its nature as a flare star every so often releasing huge bursts of radiation many times greater than its typical output bombarding any and all nearby planets with enough energy to strip even a thick atmosphere and deep ocean from its surface right now it's uncertain whether a planet like Proxima B would be able to resist such damaging degrees of radiation but models show that with a thick enough atmosphere and a strong enough magnetosphere it is at the very least possible if so the planet's magnetism would redirect the Stellar winds to its poles producing spectacular auroras many times greater in size and Luminosity than those experienced by the Earth this has all been to say that while Proxima B certainly has some of the basic necessities to support life so many other factors go into this that without more information or image of the planet could range anywhere from a dry and Barren Rock to a lush wet world but okay I know what you guys are thinking what about the other two planets discovered around Proxima Centauri well despite what their names may lead you to think Proxima D actually orbits closest to its star with a mass of only around a quarter of the Earth's not only is Proxima d one of the smallest exoplanets ever discovered but also qualifies it as another Rocky or terrestrial planet that being said at this short of a distance to its star this will be a thoroughly scorched world with a surface exposed to space and a poor candidate for finding life Proxima C on the other hand orbits the furthest away and with a mass of around seven Earths crosses the line from Super Earth into mini Neptune plunging its surface beneath a dense icy atmosphere similar to the gas giants of our solar system this is likely another unremarkable World cold dim and lifeless but we shouldn't forget that even planets like these could still become unexpected homes for biology not in their clouds or on their surfaces but rather among their many potential moons and okay while we technically haven't found even a single EXO Moon yet that doesn't mean there aren't any and if the mini moons of our Solar System's gas giants are any indication chances are planets like these will host several large satellites moons like Jupiter's IO Saturn's Titan and Neptune's Triton show us that even far beyond the reaches of a star's supposed habitable zone their interplay with their host planet's gravity can generate heat of its own enough to support substantial volcanism build atmospheres maintain liquid bodies and even Harbor entire subsurface oceans this endless possibility for EXO moons in turn means that even planets like Proxima C that would otherwise be written off as too big or too cold should not be so quickly dismissed as potential alien habitats overall the Proxima system represents an almost perfect exam sample of a typical or standard planetary system a dim star parent to one small rocky planet one medium-sized potentially Wet Planet and then one big gaseous one appearing almost like a simplified version of our solar system as for the other two stars in Alpha Centauri well we don't know I mean we know it's possible for there to be planets orbiting either one or even both of these stars but so far none have been confirmed continuing our Trek through space the next closest star to have confirmed exoplanets orbiting it would be wolf 359 at just eight light years away another red dwarf too dim to be seen from Earth which is sort of weird when you think about it how most stars closest to us are literally invisible While others can actually turn out to be more than one star and serves as a good lesson on just how much remains to be discovered across the vastness that is space following in the same Trend as the proximas the wolf 359 system features one close orbiting rocky planet creatively named wolf 359c and another more distant gaseous Planet wolf 359 B Wolf 359c the smaller terrestrial planet orbits far too close to ever be considered habitable receiving over three times more radiation from its star than the earth receives likely stripping its surface of any atmosphere leaving it as a Barren Rock comparable to Mercury in contrast at over 40 Earth masses wolf 359b is definitely another gas giant sitting between Neptune and Saturn in terms of size with an even greater mass than Proxima c not only does Wolf's likelihood of Hosting moons increase but so does the number of moons it's capable of Hosting if we think of each EXO Moon as a roll of a dice then the more you have the more likely it is that at least one has favorable conditions and so as we continue to explore space I wouldn't be surprised if we found an interesting correlation between a gas Giant's size and its probability of harboring life the next closest exoplanets can be found around the star laland21185 yet another red dwarf two faint to be seen from the Earth where we'll find a very similar situation as wolf 359 two confirmed exoplanets one small rock and one big ball of gas while the land B is only twice as massive as the Earth suggesting a similar size in composition it again orbits far too close to a flare star to be considered a prospect for light and the land C is another mini Neptune equally uninviting to biology and it's by this point that I hope you're picking up on a pattern as it turns out habitable planets are a little hard to come by and so if you want to see some more promising outlooks we're gonna have to speed through a few of these next up is Epsilon eridani a k-type star that falls between the size of m-type red dwarfs and g-type stars like our sun these are also known as orange dwarfs and this one is known to host only a single planet at a mass of approximately 1.2 Jupiters this is definitely another gas giant and the biggest one we've looked at so far besides its many possible moons the only notable quality of this jofian world is that it's the first and only only one we'll look at today that's been given a proper name a gear this name comes from contests held by the international astronomical Union in 2014 and again in 2019 though to be honest I couldn't find any Rhyme or Reason behind the planets they chose to receive names some were big some were small some were nearby others were incredibly far away some could maybe host a life many more like a gear definitely could not and all around as it stands now it's a pretty mixed bag when it comes to named exoplanets but I expect that as the first images of the nearest alien worlds start coming in through the James Webb Space Telescope and intense scientific analysis begins it'll be these planets that are prioritized for proper titles meaning even the names you're hearing in this video will probably sound incredibly outdated sooner rather than later continuing on next we'll come across lasale 9352 but okay to avoid things getting repetitive it should suffice to say that neither of us sales two planets appear to orbit within the habitable zone so we can probably just skip them for now and okay finally this brings us to the star Ross one two eight found at a distance of 11 light years away while only one planet has been confirmed here this is nonetheless where we'll find perhaps the most promising Prospect for life so far though much of this isn't due to the planet itself but rather the star it orbits while sure it's another red dwarf the major difference here is that ross128 is a relatively quiet star producing far less damaging radiation than the others we've looked at today giving Ross one to a b more than a good chance of supporting an atmosphere with a mass of 1.8 Earths this is likely another terrestrial world one that orbits on the inner side of its habitable zone making this surely a hot environment this closeness also means the planet has a high likelihood of being tidally locked permanently exposing one side of its surface towards its star and the other towards the black void of space this however appears to be the norm among planets orbiting red dwarfs including all the others mentioned so far while not necessarily a death sentence it sure would make life in a place like this more complicated though current models do show that with an Earth-like atmosphere the temperature extremes between the hot and cold sides wouldn't be so drastic as to make the whole planet uninhabitable of course that still doesn't mean life here would be easy being a hot world its possible temperatures under the focus could reach high enough to spontaneously boil water leaving a vast desert Wasteland at its Center surrounded by a ring of warm Lakes where the sunlight isn't so intense Beyond this Twilight region if the planet contained enough water it's possible that oceans could cover its backside these would be night oceans places that never see daylight where the stars serve as the only illumination but if exploration efforts of our own Ocean's depths have taught us anything it's that life doesn't always need light and places such as this could easily be rich with all sorts of Fantastical species to better control the amount of light they've received from their star any plants that do manage to photosynthesize in the narrow Twilight Zone would also likely be red rather than green though actually I already spent a whole other video explaining how this all works so if you're curious go check out that video next leaving Ross one two eight will reach another patch of mostly uninteresting sights strove 2398's two planets come in at 13 Earth masses and 15 Earth masses making them both likely Neptune ice giants groom bridge 34's two planets are a familiar Rock and gas pair where both lie outside the habitable zone and Epsilon Indy's single planet is three times more massive than Jupiter qualifying it as definitely uninhabitable though again perhaps harboring hundreds of prospective moons but once we've venture to 12 light years away we'll arrive at our next point of Interest Tau City for a nice change of pace Tau study is not another red dwarf but rather a g-type star like our sun with a similar size Luminosity temperature even color meaning any plants here would most likely be some shade of green though not necessarily the same exact green as we're familiar with the similarities continue in counting the planets found in the system where one two three four confirmed and four additional unconfirmed planets add up to a potential eight Planet system for now though I'm only going to look at the four planets that have actually been proven Tau City g h e and f two of these Tau City E and F Orbit on either side of their habitable zone the difficult thing about these two planets however is that only their minimum masses are known both being at least four Earth masses this is important to know because anywhere over five Earth masses and a planet runs the risk of becoming a mini Neptune where their gravity can hold on to such a dense atmosphere that its surface plunges Into Obscurity beneath heavy clouds of ice four Earth masses puts these planets in the gray zone between terrestrial and neptunian meaning if either of their masses turn out to be any greater than this lowest possible estimate then they're likely not worth talking about but if we put on our Optimist hats for a minute and just believe that these planets aren't too far gone then we'd find two super Earths future entering thick atmospheres strong magnetospheres and lots of volcanic activity for Tau City e however the closer of the two this bigger size would likely be a death sentence its atmosphere trapping far too much of the sun's energy to be habitable generating a runaway greenhouse effect that leaded to resemble Venus more than Earth on the other hand being on the far side of the habitable zone Tau City F's great size would be a blessing as its thicker atmosphere would allow it to more effectively trap what little heat energy reaches its surface helping it fight against the cold of space and increasing its potential habitability of course this doesn't mean life is definitely here only that one of the many necessary factors is satisfied a good sign but far from a sure thing while as of now a lot remains uncertain about this system the sheer number of planets expected to be found here paired with the star's similarity to ours has driven continued interest around these alien worlds the two other more earth-sized planets Tau City G and H both sit far too close to their star and are likely little more than rocky worlds stripped of any atmosphere to the point where I don't really feel bad about skipping over them but okay it was at this point in writing my script that I realized I didn't actually know how to end a video like this I mean there are nearly 5 000 planets for us to explore but there are only so many ways of saying I don't know we need more information and plus I'm kinda aiming to keep this video under 30 minutes so let's look at one more example and then see if there are any bigger Trends we can parse out the next star with confirmed exoplanets is gliese 1061 and yes it's another red dwarf here three planets have been confirmed all of which are Rocky and two of which gleesy 1061c and iglesi 1061d orbit within their habitable zone and this is where things get real interesting as it opens up the possibility of exchange you see lately I've been talking a lot about a field of study called Island biogeography and we've been learning how isolation in Island environments can have some pretty wild evolutionary effects and what are planets if not inherently isolated environments yep that's right planets are islands specifically in my last video I described an evolutionary process called adaptive radiation that here on Earth occurs when an organism finds a new environment with unfilled niches like an island over time the advantages of filling these niches leads to speciation producing a variety of different organisms or species all with one common ancestor but now I want to apply this evolutionary model to extraterrestrial life a field of study I think is only fitting to call astrobio geography in the simplest of scenario areas like what we'll find around gliese 1061 will have two planets both capable of supporting some form of life but hang on to save myself the trouble of saying gliese 1061c and D over and over and over again how about we call them something like I don't know something like Chip and Dale with so many factors at Play It's really anyone's guess as to which planet life would develop on first but considering everything else even it's my guess that life would more readily develop in a warmer environment than a colder one though that's just a hunch either way it's almost a sure thing that life would start on one planet before the other for our purposes let's just say Chip's position closer to its star allows it to develop the first biology in the system like this chip essentially serves as this system's mainland from here the only conceivable way for life from Chip to migrate to Dale would be some sort of random impact event an asteroid Collision that kicks up a bunch of material from Chip's surface into space this mechanism for planetary colonization limits migration to only the most simple most resilient of microbes as these would have the best and really the only chances of surviving their potentially decades-long Voyage on an asteroid nevertheless if some of this material Finds Its way too Dale and survives re-entry into the atmosphere it will have successfully seeded the planet with a chipian life except here on Dale the environment isn't quite the same it's colder the gravity is weaker there's probably a different balance of gases in the air a different makeup of soils Etc but if a microbe can survive the harsh environment of space then it'll probably do just fine under different conditions so long as nothing here is too toxic since we all still have our Optimist hats on let's just say there are no other significant barriers to colonization besides dispersal from here daily in life will spread to all viable corners of the planet and begin its own evolutionary Journey starting from just a microbe over millions to billions of years all the various forms of complex life like plants animals fungi and everything in between would arise the same way it did here on Earth in This Way planetary colonization represents possibly the most extreme example of adaptive radiation there is where an entire ecology develops from a single Source organism and this is actually a good place for us to stop the next star YZ seti hosts Three Rocky worlds which all orbit too close to be considered habitable and then after that were run into Leighton star Tea Gardens star and wolf 1061. all three of which I already covered in my first exoplanets video so now let's take what we've observed and try to come to some conclusions on our Cosmic neighborhood I think the first thing we must all be aware of by now is the clear prevalence of red dwarf stars as it turns out the smaller and mass a star type is the more common it is explaining why over 75 of all the stars in the universe are red Dwarfs with bigger G type 5 stars like ours coming in at only seven percent and the biggest o types being exceedingly rare at 0.0003 on top of that their smaller size and dimmer light makes detecting planets around them far easier than any other star type meaning there's also likely a large bias in our data set towards red systems the second thing I noticed and found surprising was just how many of the planets we've discovered are rocky or terrestrial going into this video I was fully expecting most of them to be gas giants simply because they're bigger and therefore easier to find but it would appear that most star systems feature a balance of Rocky and gaseous planets in fact if we tally up all 114 exoplanets listed on the Wikipedia page 49 of them appear terrestrial 24 were super terrestrial 29 were neptunian 10 were Jovian and only three were super Jovian showing a clear tendency towards smaller planets thinking about it now this just makes sense the same way how small Our Stars are more common than bigger ones of course smaller planets are more common than giant ones lucky for us smaller rocky planets also just so happen to be the only known places to support life making our chances of finding more earth-like planets pretty good lastly I wanted to look into the math a little in total we ended up looking at 12 star systems four of which hosted at least one potentially habitable planet expanding this to the nearest 57 star systems are all the ones listed on the Wikipedia page a total of 14 hosted rocky planets within their habitable zones or roughly a quarter of them well of course this list is constantly being updated if these numbers hold and anywhere near 25 of All Star systems host even potentially viable worlds not only is this a remarkably High number but also means we might not need to look all that far away to find some form of alien life now sure not all of these will be habitable but even if just a fraction or a fraction of a fraction of them are that would still amount to millions of living worlds in the Milky Way alone and I think that's what I find to be the most exciting part of studying exoplanets if we look long and hard enough we're bound to find something with the James Webb Space Telescope in place a new era of exoplanet research is coming and planets like Proxima B Ross 128b and Tau City f are expected to be some of its first targets all that's left for us to do is wait and keep watching the skies [Music] hey everyone thanks for watching if you enjoyed this and want to see more videos like this in the future let me know by leaving a like and seriously leave a comment if you want to see an astro biogeography video I'm sort of just looking for excuses to make one at this point of course if you'd like to ensure that that video gets made you can help support me and the channel by heading over to my patreon lastly you know I gotta say it subscribe so you never miss a video of mine again and I'll see you next time thanks boom done

Channel: Astro Pro

Views: 171,216

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Id: CRhvNWj9pZs

Length: 28min 8sec (1688 seconds)

Published: Wed Oct 12 2022