[Music] last week in a NASA press release we learned about an amazing new discovery a nearby red dwarf star was discovered to have not one but seven earth-like planets and any of them may be capable of supporting life the Trappist one planetary system was discovered by dr. Mikhail Gillan and team and reported in the journal Nature the initial discovery of three planets in the system was made in 2015 with the transiting planets and planetesimals small telescope Trappist at the La Silla Observatory in Chile follow up with the spitzer space telescope has now revealed an additional four planets both telescopes used the transit method watching for the dimming of the central star as the planets pass in front of it never before have we seen so many earth-like planets in one place any one of them could bear liquid water maybe even life the Trappist one system lies 39 and a half light-years away in the constellation of Aquarius the star Trappist 1a is an ultra-cool M dwarf star about 10% the sun's diameter and less than 10 percent its mass it's also much colder about 2500 kelvin compared to the sun's 5800 Kelvin the seven planets huddle extremely close to their star all within one fifth of Mercury's orbit that makes a year on a Trappist one planet very short from a day and a half on the innermost Trappist 1b to 3 weeks on Trappist 1h that's a lot of birthday cake the planets live so close together that they all hug on each other gravitationally it's enough to slightly vary the length of their years their gravitational influence on each other allows us to figure out their masses between point four and one point four times Earth's mass this combined with the depth of the eclipses which gives their sizes we can know their densities and so their compositions they are very likely rocky or watery world just like our own the planets have now settled into stable orbital resonances with each other and that's the hint that they may have formed further out and then migrated inwards it's also unlikely that enough material resources would have been available for so much planet forming so close to the star because different chemicals condense at different temperatures planets distance from the star information largely determines the planets chemical makeup if they did form further out then the Trappist one septuplets may have a lot of water and other volatiles maybe the Trappist one planet started out as mixtures of rock and ice however three of them now occupy their star's habitable zone where planet's surface temperature would be just right for liquid water we could estimate the location of the habitable zone for a given star based on the intensity of its photon flux and the effective atmospheric greenhouse gases our solar system's habitable zone extends from roughly one astronomical unit so Earth's orbit to one-and-a-half au so covering Earth and Mars the same calculation for Trappist one forms a smaller thin band in that densely packed system it covers three of the planets Ilan and team have done some climate modeling which indicate that the three innermost planets may be more Venusian so overheated due to a runaway greenhouse effect however that's really hard to predict at this point the outermost planet which over to pass the snow line should be icy however it may be that internal heat left over from formation and generated by tidal interactions with its star and the other planets could warm it to liquid water temperatures as well in fact any of the seven planets could host liquid water should we pack our bags and move to Travis one be like there we've got established that the temperature could be to our liking vines law tells us that the 2500 tells and trappers one star shines brightest at infrared wavelengths it would look pink on the sky to us but there will be no day and night so an eternal sunrise see because the planets are so close to the star they're probably tightly locked like our moon one side of each planet will always face the star the other away there could be okay for habitability if they have sufficiently big atmospheres to mix the heat from their Sun globally these planets would be huge in each other's skies I'm talking no man's sky huge at closest approach some will appear larger than the full moon up to twice their size so they could easily see each other's continents if they have such partial eclipses of the central star by sister planets may be common but there would be no full eclipses the track is one a star is just too close by spanning a whopping five and a half degrees on the sky if you're standing on the innermost planet and a degree on the sky for the outermost for comparison our Sun and Moon span around half a degree on the sky on the inner planet sunny side the star will provide about as much visible light as our Sun planets further out will receive less light but the stars infrared intensity provides the heat needed for liquid water sounds pretty sci-fi awesome but a word of caution being so close to the central star exposes the planets to tellen activity after on earth our distance and our magnetosphere protect us from most of the sun's coronal mass ejections but within a tenth of an au of Travis one a CMEs would be dangerous and tidal locking would weaken the planets protective magnetosphere the Trappist one a wind may have eroded its planets atmospheres just as the Sun did with Mars in addition although this star is now relatively quiet when these M dwarfs are young they are extremely active this planetary system probably had a traumatic year which may not have been ideal for starting life we don't yet know much about what those planets atmospheres are like of a breathable air of a cyanide all sorts of fascinating nasty compounds can end up in exoplanet atmospheres all strongly affecting climate temperature and chemistry the Hubble Space Telescope has confirmed that the a B and H planets don't have hydrogen helium atmospheres which means they aren't gassy planets like Jupiter future spectroscopy from the James Webb Space Telescope will hopefully provide us with atmospheric composition data that may include signatures of chemicals indicative of the presence of biological activity of life finally I mentioned tidal heating good warm traps one H above water's freezing point however tidal forces could pose a serious problem to the inner planets picture IO squished and stretched so vigorously by Jupiter and neighbor Europa that it's a hellish volcano world tidal force between two bodies is proportional to the product of the masses and the inverse cube of their distance there is so much more mass in the Trappist one star planet system than the jupiter io europa system that while the tides are about half the magnitude of iOS on Travis 1h they may be up to a hundred times as bad on Travis one be that could seriously increase temperatures and volcanic activity and make it a real surfing Mecca clearly not all planets in the habitable zone are created equal liquid water is just one item on a long list of requirements for life as we know it tidal locking stellar activity atmospheric composition and volcanism can all turn an earth-like planet uninhabitable but this finding tells us that earth sized planets are probably common around M dwarf stars remember also that a potentially habitable earth-like planet was recently found orbiting the very nearby Proxima Centauri given that M dwarfs are the most numerous stars in the galaxy we may have seen a giant boost in the number of possible homes