A Journey to Incredible Exoplanets

these days any person has the opportunity to follow the progress being made by mankind in space exploration thanks to numerous scientific investigations we've found out that the universe is unbelievably enormous and contains a great number of celestial objects however in all this diversity there are only several hundred worlds that we know of which resemble our planet in the milky way alone the number of exoplanets is supposedly over a trillion and now i invite you on a journey to the most amazing exoplanets ever discovered by now [Music] cosmo the first in outer space [Applause] the first exoplanets were discovered back in the late 1980s since then the number of detected ones has increased hundredfold according to statistics from january 2021 over 4 000 planets in other systems have already been discovered apart from these several thousand candidates likely to be given the status have been registered with sufficient evidence from earth-based observatories most of them are going to become officially confirmed exoplanets the overall number of planets in our galaxy may supposedly be over one trillion from five to twenty percent of these are close to our earth in terms of their size and composition not all of them are in their host stars godilog zones that is not all of them are habitable still according to scientific estimates there are not less than 300 million potentially habitable planets in the milky way exoplanets differ very much in terms of their environment their dimensions may be enormous some even beating jupiter but there are also comparatively smaller ones close to our earth and size some of these bodies are hot consumed with oceans of molten lava whereas others are encased in a shell of permanent ice there are planets out there made entirely of oceans with not a bit of dry land on them while in others sulfuric acid drains or diamond snow are irregular occurrence various techniques are used for discovering other worlds as a rule it is next to impossible to spot an exoplanet by simply looking through a telescope that is why in 2009 kepler was launched the first space telescope designed for searching for planets beyond the boundaries of the solar system the telescope's cameras had 42 charge-coupled devices or ccds with a total resolution of around 96 megapixels with a field of view covering about 25 percent of the sky and coupled with a one and a half meter mirror of the telescope it was able to detect astronomical bodies within three thousand light years from the earth in the three and a half years of productive operations kepler managed to spot over three and a half thousand exoplanet candidates the status of over 2 000 of these has already been confirmed by repeated observations it was in this period that the smallest of known exoplanets today was detected the diameter of kepler-37b is just 35.7 percent that of the earth the telescope was also instrumental in registering several stars and brown dwarfs the transit method was used by kepler in the search for exoplanets this method is based on observing the star's luminosity if the supposed planet passes between the parent star and the observer this will be noticed in the telltale decrease in the star's luminosity the extent of these fluctuations in luminosity directly depends on the ratio of the stars and planets dimensions while their regularity allows one to estimate the object's orbital period the transit method requires accuracy in measurements changes in a star's spectrum account for less than two percent and are usually tenths or even hundredths of one percent ripples in the atmosphere dust and precipitations negatively affect results produced by earth-based telescopes that is the reason why telescopes based on automatic space stations are used for searching for objects beyond the boundaries of the solar system unfortunately in 2013 three and a half years into the mission the kepler space telescope had several major equipment failures in 2018 the spacecraft ended science operations completely kepler was the first spacecraft to be created specifically for looking for exoplanets however most of the objects it managed to spot happen to be too remote and dim to study them in any satisfying detail that is why the next space research complex had slightly different parameters kepler was succeeded by the test telescope launched by nasa on the 18th of april 2018 its main object was searching for rocky exoplanets orbiting the brightest stars within 200 light years from the sun this telescope also used the transit method and here is the spacecraft's brief profile tess is equipped with four refractors with a 24 by 24 degree field of view and a 10 centimeter aperture the spacecraft's peculiar orbit allows it to cover both the northern and the southern parts of the sky which is approximately 85 percent of the entire sky photos are taken by four cameras and the resolution of each camera's ccd is 16.8 megapixels toi 700d is one of the most notable objects discovered by tess this exoplanet became the first object of the kind comparable to the earth and size and which found itself in the habitable zone of its star it orbits toi 700 a red dwarf lying slightly over a hundred light years away from the sun it is a small and rather cold star its temperature is half that of the sun and its mass and radius are just 40 percent those of the sun toi 700 is peculiar for its high stability not a single flare has been registered on it since the beginning of observations a star's stability is a positive feature because bursts of activity are able to divest its planets of their atmospheres and be generally pernicious for potential life on planet surfaces there are at least three planets orbiting toi 700 the one closest to it toi 700b is comparable to the earth in size its mass is approximately 1.07 times that of our planet and its radius differs from that of the earth by not more than two percent unfortunately toi 700b is too close to its host star it is within about 0.06 astronomical units and a year on the planet lasts just 10 days in addition to that chances are it is tidally locked that is it faces the star with one in the same side this means that the planet is likely to be scorching hot the planet lying further from its star toi 700c is thought to be a mini neptune its mass may be from 5 to 13 times that of our earth and its radius is 2 or 3 times that of the earth it takes toi 700c 16 days to complete one orbit around its host star located closer to the star than the inner border of the habitable zone it must be too hot for life to originate and evolve there toi 700d is the third and at this point the remotest planet in the system discovered by now it takes 37.4 days to complete a full orbit which by the way lies along the inner edge of the habitable zone the mass of toi 700d hasn't been gauged precisely and may be anything from one to three times that of the earth at the same time the planet's radius is just 20 to 30 percent bigger than that of the earth toi 700d is thought to be a rocky world but its exact composition is not yet known the amount of energy received by the planet from its star is 86 that of the amount we receive from the sun assuming the planet's atmosphere is similar to ours the steady state temperature on the surface of toi 700d is estimated at 268.8 kelvin or 4.3 degrees celsius below zero however due to the greenhouse effect or other features of the atmosphere we may not know yet this figure may shift either up or down there is no precise data on the eccentricity of toi 700d but it is thought to be small at around point eleven as the planet's orbit finds itself at the inner edge of the goldilocks zone the planet's eccentricity however small may incidentally turn out to be perceptible when the planet comes too close to its star from time to time thus actually leaving the habitable zone still with the year on the planet lasting slightly over one earth month such unfavorable periods are expected to be rather short if there are living creatures on toi 700d then they might be able to weather the harsh spells in a state of anabiosis alternatively they could adapt or migrate to less inclement areas even though the data acquired by spectral analysis of toi 700d can't be enough for making conclusions there is a chance that there is liquid water on the planet's surface then there is bound to be the greenhouse effect too which will help the surface temperature to reach favorable values as i've already mentioned toi 700d along with the other known planets in the system is highly likely to be tidally locked to its star if this is the case there should be a stark difference in temperatures between the sunny side and the shadow side this contrast could be leveled off by dance atmosphere but that would cause powerful hurricane winds although the main mission of tess has been accomplished by now it still has enough resources to carry on operations the telescope will continue taking snapshots of the sky including the milky way plane which is the most challenging direction for observation over 2 100 exoplanet candidates have been discovered by tess in the course of the main mission not less than 66 of them have already been confirmed apart from that six supernovae flares have been registered three exo comets identified and a great number of photos taken of small bodies in the solar system the latters were not objects of the main mission but are of course of scientific interest toi 700d is still guarding its mysteries and waiting for its explorers great hopes are placed on the new orbital telescope james webb which may help investigate this world and a number of other ones the new telescope is supposed to provide images of not only exoplanets lying closest but also detect their moons and carry out spectral analysis of their surfaces the launch of the telescope is planned for the 31st of october 2021. if all goes according to plan first data will be available as soon as next year will we ever discover a world that could rightfully be called the second earth and if we do will we be able to reach it distances in space are just too much for humans could it be that we're confined to the limits of our system forever allowed only to gaze at the vast infinite universe several centuries ago it was quite unimaginable to admit of discovering exoplanets however everything changed in 1992 as the polish astronomer alexander vostin was studying the pulsar psr 1257 plus 12 it was noticed that its pulsation period was irregular which was accounted for by the influence of two planets with a mass four times that of our earth this hypothesis was later confirmed which led to the conclusion that the first planetary system beyond ours had been discovered there are three objects in that system two of which have a mass similar to that of the earth and are comparatively close to their pulsar in the constellation virgo due to the fact that it is rather remote from us and the conditions for sustaining life are poor the psr-1257 plus 12 system is of little interest to scientists although its discovery led us to believe that the search for earth-like worlds may eventually be a success just three years later the first exoplanet orbiting a sun-like star was discovered 50 light years away from the earth and was dubbed 51 pegasi b just several years later the number of confirmed exoplanets counted dozens and today 4173 exoplanets in 3096 different planetary systems unknown to science in addition a great number of earth-like objects is still awaiting the confirmation of their status which is possible after a secondary registration with telescopes on earth the number of celestial objects of this kind in the entire milky way may well be over a hundred billion with about one-fifth of them bearing resemblance to our earth interestingly most of the discovered earth-like exoplanets are located not very far from our system ros128b this planet was discovered in 2017 by european scientists with the help of the high accuracy radial velocity planet searcher or halves at the observatory in chile the object is located in the single star system ros 128 which is the 13th closest star to us the object is a faint red dwarf with a mass of 0.15 that of the sun it was possible to discover this planet thanks to its gravity which leads to minor variations of the stellar spectrum of its parent star while observing these variations harps is able to spot planets around stars in this particular case it took the telescope approximately 10 years to collect sufficient data before discovering this planet this effort paid off ros-128b became the second earth-like exoplanet lying closest to us it is located 11 light years away from the earth in the constellation virgo apart from that astronomers claim it to be the most moderate of all known exoplanets due to its mass its temperature and its rather calm parent star it takes this planet 10 days to orbit its star it finds itself in the habitable zone since the temperature of the photosphere and luminosity of ros 128 are low it is also classified as an earth-like type of planet and at the moment ros 128 b is one of the most likely candidates to be a potentially habitable exoplanet besides research done in 2018 confirmed that its climate is favorable enough to sustain life another exoplanet on the list of earth-like objects located closest to us is gliese 667cc this celestial body is part of the triple star stellar system gliese 667 in the constellation scorpius it consists of two orange dwarves and one red dwarf the first two components a and b lie 12.6 astronomical units from each other with the third component orbiting them at a distance of 230 astronomical units the earth-like planet in this system was discovered on november the 29th 2011 in the geneva observatory with the help of the doppler method the object is 22.7 light years away from the earth and is the second exoplanet orbiting its host star the mass of gliese 667cc is about 3.8 times that of the earth while its temperature range may be rather similar to the terrestrial one modeling at the planetary habitability laboratory managed by university of puerto rico reveals that the average surface temperature of the atmosphere of gliese 667cc must be approximately 27 degrees celsius the planet receives about 90 percent of energy compared to that received by the earth from the sun also gliese 667cc is almost certain to be locked in its orbit that is it faces its star with one on the same side if the planet's orbit does not curve too little and if its mass is not too big the greenhouse effect produced by the rather dense atmosphere must be quite sufficient to create favorable conditions for primitive life forms the next deserving object in our list is hd85512b an exoplanet orbiting the orange dwarf hd85512 in the constellation velar its star is a single k-type main sequence star with the mass 0.69 that of our sun as for its age it is more than 5.6 billion years old the exoplanet discovered close to it is located 36 light years away from the earth and its mass is 3.6 times that of our planet at the same time hd-85512b may be one of the smallest planets in the habitable zone it was spotted in august 2011 with a harps telescope the supposed steady state temperature of its surface is something around 25 degrees celsius if the planet's atmosphere is identical to that of the earth its surface temperature should reach 78 degrees celsius it is also highly probable that there is liquid water on this celestial body which is why for some time it was believed to become the most likely place where life would be discovered first apart from the objects mentioned there is a number of other celestial bodies in space located quite close to us which also boasts some unique features many of them may well contain various life forms and maybe not quite as far from us as we would imagine however we should bear in mind that some half a century ago man did not possess a tenth of information known to us today and in the future the progress of our discoveries is going to escalate even more dramatically for example on december the 18th 2019 the k-op space telescope was successfully launched in orbit by the european space agency it is specifically aimed at exploring exoplanets using the transit method it may be this spacecraft is to contribute to the list of earth-like exoplanets and it may become the telescope to first discover alien life forms in the universe science does not stand still and every new day bears witness to the fact that mankind continues to actively stride forward if this progress does not lose its momentum sooner or later we are bound to find an answer to the eternal mind perturbing question are we alone in the universe and i hope the answer we get will prove that life is not a mere accident but a logical consequence of the evolution in our universe [Applause] the discovery of this object was made with the kepler space telescope whose mission was to look for exoplanets the kepler star system became the 90th object spotted by the telescope that is where the catchy nickname kepler-90 comes from let's take a closer look at it kepler-90 is a yellow dwarf of spectral type g0v both its mass and radius are approximately 1.2 times those of the sun as for the surface temperature it equals 6080 kelvin or 5800 degrees celsius the estimated age of the star is 2 billion years this makes it 2 times younger than our sun which formed about 4.6 billion years ago it was possible to gauge the star's age by analyzing its spectrum which helps establish the stage of the star's evolution another method instrumental for the purpose is observing stars lying closest to the object under scrutiny incidentally kepler-90 is too dim to be seen with the naked eye its luminosity meanwhile is approximately 1.7 times as intense as that of the sun located in the draco constellation it is approximately 2840 light years away from our system incidentally the object is hardly notable for its properties it is quite an ordinary main sequence star without any particularly exciting features it's the number of planets discovered in its system so far that makes it really stand out the only other system where we could observe as many as eight planets had been only our solar system before kepler 90 had been spotted the sun held the first place in terms of the number of planets with the following champions as the runners-up the system's trappist-1 [Music] hd10180 and hr-8832 each of them has seven detected planets at first glance kepler 90 might probably look like our solar system in miniature however on closer inspection the following principal differences will change the observer's mind about it for a start the smaller planets are closer to the star with the bigger planets lying further and following bigger orbits as we know it's quite the other way round in the solar system with the giants close to the star and the smaller planets located further away admittedly it is too early to claim this with absolute certainty and the number of planets we know of in the kepler system may increase as scientists make progress in their observations another principal difference from our system shows in the planet's mutual proximity the earth and the other planets in our system on the other hand are located further away from each other and also all the eight known planets in the kepler-90 system orbit their star within just one astronomical unit another important difference is the fact that six internal planets in the kepler-90 system are either super earths or mini neptunes in size while its two outer planets are gas giants the two planets in the system lying closest to their host star dubbed kepler-90b and kepler-90c may probably be called our earth's analogues however their temperatures are considerably higher than on mercury or venus that is the two planets closest to their host star in our solar system this is the case on account of their proximity to their system's center kepler-90g and kepler-90h are the objects lying furthest from their apparent star both of these bodies are gas giants their dimensions must be comparable to those of jupiter the system leaves the general impression of being extremely compact even kepler-90h the remotest planet in the system lies approximately as far as the earth does from the sun also as i've already mentioned this remotest planet is also the largest in the system and a year on it is almost as long as a year on our earth 331 days to be more exact all these planets were discovered not so long ago with the latest of them kepler-90i spotted as recently as in 2017. it was possible to detect it with the transit method that is by observing sharp changes in the host's star's luminosity when one or several planets pass across its disk and block a certain portion of its rays normally visible to us this method is quite productive for large celestial objects lying close to a star however if a planet is remote from it fluctuations in the stars luminosity and other incidental factors interfere with observations these problems may be dealt with in two ways namely by prolonging observation periods and by sorting data with the help of statistical algorithms and artificial intelligence systems in fact the latter helped the team of scientists studying kepler-90 in discovering the eighth planet in the system a specially trained neural network was instrumental in pinpointing one more planet in the kepler-90 system and defining its parameters the newly spotted object was given the temporary designation kepler-90i located between kepler-90c and d this celestial object orbits its star within less than 15 days and its radius is 1.32 that of the earth kepler-90i is three times closer to its star than mercury is to the sun that is why its surface temperature is rather high approximately 427 degrees celsius just to compare this value is quite close to the surface temperature venus which is 477 degrees celsius kepler-90i resembles our earth very much in terms of its chemical composition size and mass its orbital period is 14.4 earth days as the planet lies too close to its parent star it cannot realistically support life the discovery of this celestial object prompted a lot of questions on the part of the scientific community it still remains to be found out how such a large and complex planetary system managed to remain so compact and stable at the same time also astronomers assume there might be more planets out there orbiting kepler-90 which still remain to be discovered the search for other bodies in this system is still on as for the other known planets in the system the parameters of each are unique in their own way let's have a look at them starting with the planet closest to its star the radius of the one nearest to its parent star kepler-90b measures about 1.3 times that of the earth and its orbital period lasts for seven days just like all the other objects in the system except kepler-90i it was detected back in 2013. the planet coming next orbiting its parent star slightly further away than kepler-90b is kepler-90c its radius is slightly smaller measuring 1.19 times that of the earth and as for its orbital period it is 8.7 days the fourth known object in terms of its closeness to its star is kepler-90d with its radius measuring 2.87 times data the earth it orbits kepler-90 within a period of 59.7 earth days kepler-90e holds the fifth place its radius is 2.66 that of our planet and its orbital period may reach 91.9 days kepler-90f comes next its radius is 2.88 times that of the earth and its orbital period is 124.9 earth days after kepler-90f comes kepler-90g with a radius measuring 8.1 times that of the earth its orbital period is 210.5 days and its mass is approximately 0.8 times that of jupiter last but not least but definitely the remotest from its star at this point kepler-90h has a radius measuring 11.3 times that of the earth its orbital period is 331.6 earth days and its mass is about 1.2 times that of jupiter as this object's orbit lies approximately as far from its star as that of the earth from the sun assumptions about the presence of hypothetical moons in its environs may prove to be true if there are any located close to kepler-90h that are similar to titan or ganymede in their parameters conditions on these moons may be realistically suitable for life these hypothetical celestial objects might have some really incredible features as their planet lies in the habitable zone of its star some of these moons may well resemble our earth for all we know just as you are watching this video on the cosmo channel and your life may be dawning on a moon of the far away gas giant [Applause] kepler-90h is a kind of landscape one would see in the least harsh part of a planet dubbed by scientists as super earth and the closest potential candidate suitable for searching for alien life forms but let's be consecutive the recent past heralded a boom in discovering exoplanets there are 4 370 exoplanets discovered in over 3 000 planetary systems so far in addition to these more than 3 000 objects are awaiting confirmation of their exoplanet status most of them are large bodies gas giants super jupiters and super earths this is accounted for by technical features of the technologies used for the purpose it is easier to look for massive bodies with a short orbital period than to try to spot smaller planets similar to the earth or mars in terms of dimensions there are among exoplanets those that may realistically harbor life there are dozens of these objects scattered in space and they understandably draw scientists close attention today we're going to look at one of these objects which is an exoplanet dubbed gliese 832c in fact this exoplanet is one of the most likely places where alien life forms will eventually be detected this exoplanet orbits a star called gliese 832 which lies 16 light years away from the sun and is part of the gru's constellation gliese 832 is a dim red dwarf whose luminosity is just 0.7 percent of that of the sun both its mass and diameter are approximately two times smaller than those of the sun and its temperature reaches about 3300 degrees kelvin that is the reason why the habitable zone of this planet is within quite a short range from its star due to tidal forces the planets lying in the habitable zone of gliese 832 will be tidally locked to their star that is will face the star with one side only just as it is the case with the moon and the earth and mercury and the sun there are two confirmed planets orbiting gliese 832 the jupiter-like planet glieser-832b was discovered first astronomers announced the event in 2008. with the mass two-thirds out of jupiter the planet orbits parents start a distance of an average 3.4 astronomical units completing a full orbit every 9.4 earth years the discovery of the other confirmed planet glieser 832c was announced in 2015 by an international team of scientists headed by robert wittenmeier it got an exceptionally high rating for its similarity to the earth 0.81 to be more exact which instantly attracted both scientists and reporters it was also nicknamed the second earth even though the two planets parameters are rather different either way this is one of the planets closest to the earth with such a high earth similarity index the mass of glieser 832c is five and a half that of the earth it takes the planet 35 earth days to complete a full orbit around its parent star moving at a distance of an average 0.16 astronomical units this is six times less than the distance between our earth and the sun its orbit's eccentricity is rather high with the planet regularly leaving the habitable zone and then re-entering it this must cause sharp temperature leaps and drops on its surface gliese 832c is estimated to receive approximately as much energy flux from its parent star as does the earth from the sun the average surface temperature on the planet is 253 degrees kelvin or 20 degrees celsius below zero it is also suggested that due to the atmosphere which is likely to be quite dense the temperature on the planet may be considerably higher however it is not easy to claim this with certainty as gliese 832c lies quite close to its star and so chances are it is firmly tidily locked to it in this case there should be a substantial temperature difference between its sunny side and shadow side which should regularly cause hurricane winds if the atmosphere really is dense it's worth mentioning that in 2017 following observations astrophysicists from the university of texas at arlington the usa put forward the hypothesis that there may be a third planet in the glieser 832 system its mass could be 1 to 15 earth masses and it could follow a stable orbit around the center of the system 0.25 to 2 astronomical units away from it at the moment the planet is being searched for let's imagine what gliese 832c would look like assuming life were possible on this planet first of all we wouldn't help noticing its gravity which would be strikingly higher than that on our earth since the planet's diameter is not yet known the gravity force cannot be calculated exactly still it would be a rocky planet similar to our earth and earth-like planets in terms of its density so its gravity force would be likely to reach two to four hundred percent that of the earth this would lead to the relief leveling out meaning that the mountains would not be so high and the ocean is not so deep this in its turn would enhance the area of warm water which is favorable for life due to a dense atmosphere and a comparatively dim sun the landscape on gliese 832c would be of a reddish hue and in general the planet would be submerged in semi-darkness since the planet is likely to face its star with the same side at all times the temperature on the sunny side should be high and the temperature on the shadow side quite low in the ring-like area at the border between them the temperature should be moderately comfortable although due to regular heating of the planet the atmosphere would be constantly in turmoil which should result in strong winds in addition high objects of relief potentially able to dissipate some of the force of hurricane air currents fail to form on account of high gravity conditions as the orbit of gliese 832c is small and elongated seasons on this planet should change every week it will be winter on gliese 832c at the furthest point from its parent star and summer at the closest approach the tilt of the rotational axis with respect to the ecliptic plane will not be of such importance as it is in the case of the earth the change of season will depend exclusively on the planets getting closer to or away from its parent star the most favorable conditions for life to develop on gliese 832c are likely to be in the ring-like area at the border between the light and the dark sides of the planet it is here that most liquid water will accumulate and rain down from clouds formed on the warm side ice caps on the dark side will also melt in the border zone thus supplying still more water it goes without saying that it is water that is key to developing life the change of seasons will be likely to play the same role as lunatids on our earth with areas alternately submerging and re-emerging this process of water getting mixed with substances dissolved in it is a good prerequisite for life to originate and develop there is a good chance of life originating in water and probably staying in it without later spreading to land the ocean reduces the effect of gravity and protects its potential inhabitants from sharp temperature changes and hurricane winds as for frequent and sharp changes of seasons hypothetical organisms on gleesa 832c may learn to lapse into a state of anabiosis in order to weather unpleasant although short periods of high and low temperatures alternatively they may choose to emigrate to a comfortable temperature zone from the sunny side to the shadow side and back again for example if a space probe ever reaches the surface of gliese 832c to investigate the area what would it see there assuming life did originate on this planet as the gravity forces are rather strong there the potential inhabitant should be a thick set chunky figure boasting a robust skeleton and powerful muscles plants on gliese 832c would be dark in order to attract as much light as possible they should also be quite low and likely to be creeping or moss-like with strong roots able to stand winds it is highly likely that rather than chlorophyll some other molecules should be important for photosynthesis the planet's dense atmosphere may become a habitat for bizarre life forms floating in air currents single-celled microorganisms for instance may float in this dense atmosphere following air currents while capturing light and nutrients dispersed in the air because of a dense atmosphere high clouds and a dim sun the surface of gliese 832c would be a rather dark place life forms would have to adapt to these conditions vision would probably not play the decisive role in their existence if it evolved at all alternatively its spectrum may be limited to the infrared range be it as it may all these speculations remain conjectures and ideas even though they're based on good physical laws and assumptions i wonder which of these suggestions you would call realistic and which of them bordering on fantasy or perhaps gliese 832c is not habitable at all let us know in the comments and let's keep in touch this object is a single star with a planetary system and there are at least three celestial bodies within the habitable zone now let's look at it in more detail the distance between trappist-1 and our sun is 39 and a half light years the object was discovered in the period from 2016 to 2017. this single star is a red dwarf of spectral type m8v as for its dimensions it is only 12.1 percent of our sun's radius just to compare it isn't in fact much larger than jupiter the mass of trappist-1 is 27 000 times that of our earth but at the same time is 0.08 the mass of our sun with the average temperature reaching 2500 kelvins its luminosity is 1900 times weaker in comparison with that of the main star of our system the orbital period of trappist-1 is 3.3 days as for its age it is seven and a half billion years which makes it almost three billion years older than the sun the distance between this star and us is diminishing as it is slowly but surely drifting towards our system this object aroused interest largely following the discovery of its planetary system back in 2016 whose three components were spotted by transit method with the help of an automated 0.6 meter telescope in the european southern observatory or the eso in chile the planets were initially dubbed trappist-1b trappist-1c and trappist-1d however further investigations revealed that the presumed location of trappist-1d was described incorrectly following that four more earth-like objects were discovered by astronomers with the help of the spitzer space telescope these were dubbed trappist a f g and h thus the total number of planets in the system reached seven and on the 13th of april 2016 the parameters of these celestial objects were defined in more detail all the seven exoplanets are identical to our earth in terms of their dimensions with their radii ranging from 0.71 to 1.13 that of our planet planets b and c orbit their parent star in the periods of 1.51 and 2.42 days respectively initially according to astrophysicists both of these planets were comparable to venus in all but exceptionally high temperatures however after their mass and density had been measured it was trappist-1 that could be called venus's analog trappist-1b the second closest planet to its star is likely to contain a large amount of water and other volatile elements the new data enabled scientists to find out more about the other discovered planets too it takes trappist-1d 4.05 days to orbit its star its radius is 0.77 that of the earth the orbital period of trappist-1e is 6.1 days its radius is 0.92 that of the earth the orbital period of trappist-1 f may last up to 9.2 earth days its radius is 1.04 that of the earth the orbital period of trappist-1 g is 12.3 days and its radius is 1.13 that of the earth last but not least trappist-1 h is the seventh object and is the furthest from its star with a rotation period of 18 days and a radius of 0.7 that of our planet it should be mentioned that the initial estimates of the object's masses were likely to be rather conservative due to the analysis of the density of the first six planets it was later ascertained that they contain a big amount of water and other volatile elements which makes them considerably lighter than thought previously as for the furthest of them e f g and h for all we know they may consist entirely of water only trappist-1c boasts a mass bigger than initially estimated which may be indicative of over 50 percent of iron in its composition of the seven planets known to be located in the trappist-1 system three of them find themselves within the habitable zone namely d e and f speaking about the rest of them following the estimates of its density planet b is thought to contain either a small nucleus or else a considerable amount of volatile elements due to high temperatures of 127 and 69 degrees celsius above zero on the surfaces of planets b and c respectively water is not likely to remain in its liquid state there and is bound to float about as vapor as for planets g and h they're too remote from their central star to be potentially habitable however according to models suggested at cornell university the habitable zone of trappist-1 may well be wider and allowing for volcanic hydrogen potentially acting as a greenhouse gas there may be four planets within the habitable zone rather than three the density of trappist-1 f is rather low too and so it may well turn out to be an all-ocean planet here are the temperatures for all the planets in the system the steady-state temperatures are given without including incident light dispersion and greenhouse effects just to compare the steady-state temperature on our planet in the same conditions would measure four degrees above zero and on mars 47 degrees below zero in november 2017 it was posited that the activity of the star didn't allow its planets to form and maintain their own atmosphere it is accounted for by the fact that trappist-1 goes through periods of active flares which may negatively affect the nearby celestial bodies and thus render them uninhabitable for living organisms as we know them interestingly the planets are located much closer to each other in comparison to our systems planets the planet mercury which is the closest one to the sun is located 0.39 astronomical units from it while the distance between trappist 1b and its parent star is just 0.01 astronomical units as trappist-1 is a rather dim star it is no easy matter to explore it red dwarfs like that are quite widespread across the universe accounting for most of the galaxy's stellar matter plasma ejections on these stars are a rare occasion although astronomers believe that there may be giant cold areas and compact hot areas with temperatures upwards of 4 000 kelvins on the surface of trappist-1 if this conjecture proves to be true scientists will proceed to confirm that the system's planets are constantly bombarded by powerful ultraviolet and x-ray radiation which is able to destroy their atmospheres and render their surface completely sterile the reason for that lies in the fact that none of the microorganisms known on the earth are able to withstand intensive radiation emanating from flares of this kind including the most radiation resistant bacteria dana caucus radiodurans nevertheless in december 2017 atmosphere was proven to persist even in periods of high activity of stars which implies that planets g and h may potentially have their own atmospheres at the moment astrophysicists idea is to use more up-to-date telescopes for studying the matter for example the james webb space telescope whose launch is planned for march 2021 today the trappist system presents a great interest for the global scientific community and even though it is highly unlikely that any advanced civilization will be discovered on its planets we cannot ignore the fact that life forms in the universe may be extremely diverse and may differ from our perceptions of life as we know it which implies that not all intelligent organisms are supposed to follow the scenario of our planet if science manages to find out more details about this system in the nearest decades many conjectures and doubts we have today about trappist-1 will most likely be cleared [Applause] systems with this number of stars are rather rare what we see while observing the stars are generally binary systems that is systems consisting of two objects as for multiple systems that is those made up of three or more stars they are by far rarer there are two varieties of multiple systems namely optical and physical objects and optical systems are located far from each other but seen from the earth they appear to be just one star objects and physical systems meanwhile are actually close together and are bound by gravity most physical multiple systems consist of just three objects it is triple systems that account for about 70 percent of all systems of this kind known to us today the caster system however is noticeably different from the majority each of the three main stars in this system is a binary star thus the total number of stars in caster is six it is also highly unlikely that there is stars in areas unobservable to us in caster's vicinity which are gravitationally bound to this sextuple system the more components a multiple system contains the fewer such systems there are in space this means that systems consisting of three and more stars must be extremely rare in the universe it goes without saying that we're far from possessing all data about multiple systems statistics that is why we can't but admit that in theory there may be systems with still more components somewhere in deep space getting back to the caster system this is the second brightest object in the constellation gemini it is beaten only by pollux an orange hued giant star in terms of luminosity in our sky caster holds the 23rd place the system is 50.88 light years away from our earth and its age is estimated at approximately 200 million years it was discovered back in the 17th century and even then it was classified as a binary system and later astronomers managed to spot several other objects physically bound to it the first and the main component of the system was dubbed caster aa this is a main sequence star of spectral type a15 it is about twice as heavy as our sun and its radius is also two suns radii the surface temperature on caster reaches approximately 9140 degrees kelvin at the same time the object's luminosity is 30 times that of our sun the second component's designation is caster ba it is of spectral type a25m and its mass is 1.7 times that of the sun with its radius measuring 1.6 that of the sun caster ba orbits its companion starcaster a a it takes the two objects about 350 years to complete a full orbit around each other it was later found that the eclipsing variable star yy geminorum is also physically bound to caster it is a star of spectral type m .55 a its mass is 0.62 that of the sun and its radius is 0.76 that of the sun that made it the third component in the system so it was rightfully designated caster ca this star follows an elongated elliptical orbit around the system's bary center scientists estimate its orbital period at 14 000 years as for its location it is approximately 1 100 astronomical units away from its two companions each of these stars is binary which means that each of them has a secondary companion of its own let's look at them caster a b is strongly bound to caster a and its mass is about half that of the sun caster bb is a starved spectrotype m25 and its mass is also about half that of the sun caster cb is a starved spectrotype m .55e and is slightly heavier at 0.57 sun's mass and with a radius of 0.68 that of the sun [Music] caster cb is almost identical with caster ca in its properties as the surface temperature of both is approximately 3820 degrees kelvin and their luminosity is less than 10 percent that of the sun all the six stars orbit around a common center of mass or barry center and their overall luminosity is 52.4 times that of the sun caster a a and caster ba are white stars interestingly the former is 30 times and the latter 14 times brighter than the sun by contrast castus ca and castus cb are typical red dwarfs according to scientists caster a a and caster ba are supposed to remain in the main sequence stage for at least several hundred million years the red dwarves meanwhile like caster ca and cb have a much longer expected lifespan this is due to the slow process of thermonuclear fusion of hydrogen and so they may last from several billion to tens of trillions of years scientists are currently busy looking for exoplanets in the caster system however so far they have not been able to discover as much as a hint of exoplanets in the system perhaps the system is too young to have produced any or else more advanced methods of detection are called for it is too early to speak about other physical properties of these stars it is quite difficult to study them because they are optical doubles and seen from the earth only seem to be close whereas it is an illusion that is why special spectrometers are necessary to take care of accurate measurements we can see all the six stars from our earth as a single object and it is located in the northern hemisphere in the constellation gemini the best time to observe them is in winter and spring it is easy to locate cast in the sky as it is bright enough and can be found near a well-known asterism called the winter circle or the winter hexagon this asterism is made up of pollux capella aldebaran rigel sirius and procyon it is best seen in the night sky in northern latitudes in the winter time february is the best month to observe caster and pollux it's worth mentioning that caster is a star system that leads a group of at least 16 celestial bodies the point is that these stars move together and have similar velocities and their rage is similar that is why they have been dubbed by scientists as the caster moving group or cast a stream it includes such well-known astronomical objects as fomalhaut vega alderamin alpha libri and others the question of caster's stellar evolution still remains open as i've mentioned before most telescopes are incapable of revealing finer details of these stars as they are too close together as seen from the earth according to some scientists systems of this kind are formed as a result of a big star split into two components by centrifugal force others claim that they originate when one star gravitationally captures the other there is also a theory of compound nucleus formation that suggests a molecular clouds fragmentation with stars forming as a result then there is a theory involving proto-stellar discs that suggests sudden cooling of gas in a massive protostellar disk so several stellar companions may simultaneously originate in one and the same plane following the disk's fragmentation be it as it may most facts indicate that multiple systems originate in one place rather than from scattered sources in the case of the caster system its components are believed to have been formed out of one molecular cloud in the same period where a hypothetical exoplanet to find itself in the caster system its inhabitants would have enjoyed rather bizarre natural phenomena for example the planet would receive light from several stars at the same time so there would be several sunrises and sunsets a day at least it seems bizarre and exotic to us as we live in the light of only one star if the sun had a companion with similar parameters the earth would get twice as much heat and light with all that it implies and the sky above us would have a totally different aspect and it is hard to imagine what a sky with several stars like our sun would look like this mind-boggling sight is straight from a world of fantasy but that's what we would see if we were to find ourselves in the caster system in this film i have told you about many notable exoplanets still our trip is admittedly quite brief to cover all the fascinating worlds mankind is now aware of would literally take infinite time even as we speak about them the rate at which we get information about them grows incrementally it is these unusual exoplanets that draw the attention of the entire scientific community and it is these celestial bodies that will become new objects of more detailed investigations and research and so we'll definitely be getting back to them in our new videos to bring you the latest updates [Music] you

Channel: Kosmo

Views: 908,212

Rating: 4.8236895 out of 5

Keywords: planets, exoplanets, space, cosmos, life, closest exoplanets, nearest exoplanets, universe, stars, video about space, aliens, extraterrestrial, kepler-90, kepler, tess, toi, gliese, journey to exoplanets, life in the universe, life on other planets, mars, earth, solar system, film, video, closest stars, nearest stars, cosmo, kosmo, science, ufo, moon, satellite, mysteries, riddles, habitable zone, great filter, fermi paradox

Id: DJWtZFooKaE

Length: 60min 50sec (3650 seconds)

Published: Fri Apr 30 2021