Are There Other Earths?

summer 2017 Arecibo Puerto Rico astronomers using the iconic radio telescope witnessed a repetitive signal it's radiating from the direction of the Virgo constellation it has all the characteristics of intelligence it seems to be coming from a small red dwarf star named Ross 1:28 and it's just 11 light-years away one of our nearest cosmic neighbors [Music] [Applause] [Music] 50 300 kilometers to the south on a Chilean mountaintop the 3.6 meter less iya Observatory is completing more than a decade of monitoring that same star in those data a stunning detection [Music] there is an earth-sized planet orbiting ross 128 [Music] and it resides in the habitable zone where life sustained by liquid water is possible now wielding sensitive new instruments planet hunters are suddenly finding thousands of new worlds all over the sky but have any of them sprung to life [Music] or are we on earth loan orphans of the universe [Music] look up at the night sky hit any star according to astronomers it probably has several planets in orbit around it and there are many more stars out there and BPI the most common star type in the universe is the red dwarf also known as the Class M star they're hard to see small lightweight cool and faint but these conditions actually make it easier to find exoplanets orbiting around them because red dwarfs are petite the wobbling motion caused by their planets gravitationally tugging on them is larger so it's simpler for instruments to detect because they're low in mass the planet's orbit close in there years go by in just a few days so it's easier to see the wobble pattern repeating and passes across the face of the star called transits happen much more often [Music] because they're cool and faint there's less glare so planets are plainer to perceive [Music] Proxima Centauri our stellar next-door neighbor is just such a red dwarf it's puny just 12% the mass of the Sun and less than 14% is big it's only about 1% is bright so it's relatively cool only about 3,000 Kelvin our Sun is nearly 6,000 Kelvin and after extensively studying the star for more than 16 years astronomers have confirmed at least one small planet Brosnan Proxima Centauri be [Music] it's at least 1.3 times more massive than Earth probably dense and rocky like our world which would make it about 10% bigger it orbits its parent star once in a little more than 11 days revolving at the distance where water could be liquid as well as solid and gas just like Earth but there's a problem with that star like many red dwarfs Proxima Centauri has a stormy temperament large flares blasting x-rays bathing its system of worlds in deadly radiation eroding away any life supporting atmospheres they may have and there are problems with that newly found planet although it's in the so called Goldilocks zone Proxima B orbits only 7.2 million kilometers from the source of that radiation that's 21 times closer to its star than we are 2 hours because Proxima B doesn't rotate it may have no magnetic field nothing to ward off the onslaught of lethal energy to anyone standing on the surface of that world the irate red star would look ten times larger than our Sun does to us more concerns the planet doesn't tilt like ours and its orbit seems to be nearly circular which means it doesn't have seasons Earth's changing climate and relatively rapid rotation of day into night likely stimulates the continual evolution of life próxima B is much less dynamic it's probably in tidal lock with its star like our moon it always shows its parent body the same face so it may have a warm day side which would bear the brunt of the flares coming off the star and a cold frozen night side the view from that night side would be dominated by two dazzling stars Alpha Centauri a and B forming a triple system with Proxima each tens of times brighter than any stars in the night skies of Earth but there may be no one there to see them [Music] [Music] if you go a little further out from earth the news gets better Ross 1:28 only 11 light-years from us is one of the quietest red dwarfs known it discharges hazardous radiation much less often than its sister M stars the high accuracy radial velocity planet searcher or harps has been looking at Ross 1:28 coming through ten years of data astronomers recently confirmed a rocky planet gliding along in the stars temperate zone dubbed Ross 1:28 be the small dense planet looks to be one point 35 times the mass of Earth much like Proxima B and similar to the planet at Proxima Ross 128 B orbits about 20 times closer to its calm and cool star than does earth to our hotter Sun it's year is just nine point nine days long this planet may offer the closest most comfortable environment of any exoplanet found so far but that's not conclusively proven the Ross world maybe more like Venus holding a high-pressure atmosphere that's too hot for life and what about that intriguing Arecibo radio signal the celebrated Green Bank telescope in West Virginia and the SETI Institute s' Allen telescope array in Northern California both took a long hard look the repeat signal wasn't seen again researchers best guess is that was most likely a reflection of pulses from one or more communication satellites in geostationary orbit around Earth but though there's no proof of intelligence astrobiologists remain enthusiastic this they say is the right kind of place to look for life small red M dwarfs live hundreds of times longer than sun-like stars if primitive life can get a toehold on a world near one there's a plenty of time for evolution to learn to cope with harsh conditions red dwarfs are opening up new possibilities of finding habitable worlds just when planet discoveries around more familiar stars seem to be shutting them down [Music] scientists will invent different schemes for detecting alien planets most successful so far at least in terms of raw numbers is two tasks a Space Telescope with persistently staring at a rich patch of stars to engine start one zero and liftoff of the Delta 2 rocket with Kepler on a search for planets in a Sun way like our own launched in 2009 the remarkable Kepler mission watches for the slight dimming of a star when a planet sails across its space along the line of sight between the telescope and the target star Kepler astronomers and citizen scientists have spotted several thousand new planets using this transit technique thousands more are waiting to be confirmed by seeing them pass a second or third time establishing the planets orbital period so the longer humanity looks the more worlds will probably see in slower wider orbits more distant from their Suns the searches to date have mostly netted large diameter planets most of them very close to their stars big world's transiting often are beginning to divulge the secrets of their atmospheres astronomers are practicing on these worlds learning to spot molecules like methane nitrogen carbon dioxide water and oxygen which could be products of active life so-called biomarkers [Music] a surprising number of these globes are truly gigantic super Jupiter's between eight and fourteen times heavier than our own Earth and Venus are up to a thousand times smaller and 2,500 times lighter in weight altogether much more difficult to spot some planets lead truly bizarre lives like this extra hot gas giant HD 1897 33 B it orbits so close to its turbulent star that periodic flares tear off large chunks of its atmosphere researchers call this a torch orbit NASA Swift satellite and the Hubble Space Telescope watched as the planet temporarily grew a tail like a comet big as it is over millions of years this huge world will erode away some worlds like scorpion 1b inhabit multiple star systems feeling the complex gravitational interactions of two three or more massive bodies and this one age IP 1304 t4b is an immigrant planet it came in with its parent star from outside our galaxy [Music] this dramatic diversity among exoplanets as astronomers scratching their heads but planet hunters believe they've barely scratched the surface of the skies hidden treasures one quick way to tell if a planet might be earth-like is to check the color of the light bouncing off of it if you look in a color space earth sits off on its own a lone wolf away from its solar system siblings some researchers rate worlds with an earth similarity index the ESI a number ranging from zero nothing like earth to one exactly like earth to qualify as a true twin to ours it's not enough for a planet to be the same mass or the same size or even in the habitable zone [Music] in 2007 the harpes team at La SIA picked up the first evidence of a planet in the habitable zone of its star a red dwarf named Gliese 581 six times more massive than Earth and rotating so slowly it's days perhaps seventy of our days long Gliese 581d made globally warm itself with greenhouse gases so it could be an ocean planet the first one spotted if so it probably began as an ice giant further out in the system kepler-22b was the first exoplanet that mission scientists found in the temperate zone of a star like ours that star is just slightly smaller than ours but the planet is bigger about two times Earth's diameter [Music] the transit method isn't very good at pinning down planetary masses so we don't yet know how it weighs in compared to earth researchers speculate it may be a Waterworld a deep global ocean clinging to a massive rocky core 22 light-years out in another direction gliese 667cc swings round a cool red m-dwarf in just 28 days at that distance the star looks three times wider than our Sun does to us and you'd see two other prominent lights in that sky the star has two nearby sisters the planet is massive maybe five times Earth's mass standing on its surface if it has one you'd weigh one and a half times what you do at home but it's possible you'd feel right at home in other ways the Lisa 667cc could be habitable 10% larger than our planet kepler 186f lives just within the outer edge of its stars Goldilocks own that star is a red dwarf about 500 light-years distance for larger hot and presumably lifeless planets ride closer into the dwarf 186f is roughly earth sized perhaps just 11% larger but it's probably colder than Mars [Music] in 2013 a pair of planets surfaced in the Kepler data 62e and 62f circle their cool star in orbits where plenty of water could flow the inner one is likely a totally wet world the outer a super-earth one and a half times our size could be cooler and drier now imagine a cloudy world where you wait at least twice what you do on earth kepler 452b sometimes called Earth's cousin is probably rocky like us and 1.6 times our size but it may be up to 5 times more massive 1,400 light-years from us it orbits a g-type star very much like our Sun it's 20 percent brighter but the planet rides a bit further out from its star the kepler 452b liyan and a half years older than ours evolution has had more time to work [Music] it was long thought that the most likely place for life would be an earth-like planet circling a sun-like star but in 2017 a system full of surprises came to light a tiny star not much bigger than Jupiter hosting seven rocky planets all about the same size and mass as Earth [Music] the Trappist one planetary system takes its name from the project that discovered it transiting planets and planetesimals small telescopes it's a pair of surprisingly petite robotic scopes they're perched on a Chilean mountain but controlled from Belgium [Music] NASA's Spitzer infrared Space Telescope helped confirm the find when a star isn't bright a small earth sized world transiting across its surface makes a big difference a proportionally larger drop in the light curve 40 light years out the ultra-cool dwarf named Trappist 1a glows a deep red it's just 11% the diameter of our parent star so it puts out merely 5/100 the sun's light though it's dim the dwarf provides more than enough energy to set up a habitable zone and at least three of the newly discovered planets orbit within it Trappist 1f is likely the best positioned for life the red Sun in its sky would look larger than ours does to us but less than 100 as bright it could be warm there though like tussling siblings seven world so near to one another probably jostle one another's orbits they try to keep in resonance their orbital periods pulled into hole number relationships but those gravitational tugs could power up tight keeping these worlds warm mixing the chemistry's that lead to life the Trappist one system has had a long time to brew the little star could be more than twice as old as our Sun and it could live at least ten times longer like Ross 1:28 Trappist one is a quiet dwarf it's ultraviolet radiation wouldn't strip the atmospheres of the planets in its habitable zone for perhaps 15 billion years [Music] the search for nearby worlds that may be like our own is accelerating large arrays of millimetre and submillimetre wavelength dish antennas like this one in the hive cold Atacama Desert are revealing how baby planets grow within the dust disks of young stars the giant Magellan telescope at loss arena Chile with a segmented primary mirror twenty four and a half metres across and the extremely large telescope also in Chile but at Cerro Amazonas with its nearly 40 meter wide aperture and laser guided adaptive optics will try to take direct images of exoplanets at least five times sharper than the Hubble Space Telescope [Music] their monster mirrors take years to cast [Music] cool [Music] and polish above Earth's atmosphere nasa's transiting exoplanet survey satellite tests will search all over the sky looking at the brightest and nearest stars at least 200,000 of them with the objective of spotting earth sized and super earth sized planets europe's plateau satellite will investigate as well new space-based observatories like the James Webb Space Telescope and the wide field Infrared Survey telescope should be able to identify the composition of many exoplanets atmospheres they'll look for telltale signs of biology the exhalations of life in the gases around these worlds like a small bird flying near the landing lights of a large airplane planets moving near stars are tough to see astronomers are now perfecting devices called coronagraphs which simulate the effect of an eclipse blocking out the glare of nearby stars to reveal planets they may host if an alien world is young and bright enough and far enough away from its star such instrumentation can directly image it these sensitive detectors may be able to make out what's in the atmospheres of the nearby habitable zone dwelling earth-sized worlds like Ross 128 B Proxima B and the Trappist one planets evolution of biology on earth dramatically changed our planet's atmosphere setting up a feedback loop making conditions even more hospitable to life with a similar level of technology to our own astronomers on any of those alien planets could tell that we are a living world [Music] on the scale of human distances even the closest stars are almost unimaginably far away humanity's farthest rocket-powered probes are only now just leaving the solar system after four decades but a bold plan to dispatch a fleet of tiny low-mass nanoprobes across the interstellar abyss due Proxima Centauri has just been launched driven by a constant coherent column of light from a square kilometer phased array of 10 kilowatt lasers together pumping out about a hundred gigawatts the swarm of sales would be propelled outward from earth fast enough to fly by the nearest star system in about 20 years aboard each light sail rides a tiny package of science instruments including cameras plus communications module a miniscule radioisotope battery and a photon thruster for maneuvering all weighing no more than a few grams they're called star chips a thousand such craft would be deployed at a time it's a long way to travel and plenty can go wrong including impacts of interstellar dust cosmic rays and atoms of hydrogen commands could be sent as modulating information on the power beam and findings would be uplink to earth by a compact laser using the sail area as an antenna this audacious concept its first phase privately-funded could return close-up images and sensor data of Proxima Centauri be the first mission to an exoplanet in the last few years astronomers have had to completely change the way they think about worlds around other stars [Music] once assumed to be rare exoplanets turn out to be extremely common small dense worlds like ours orbiting in the habitable zones of stars are showing up more often in astronomical searches [Music] unexpected lakes and seas in our own solar system suggest that supportive conditions exist in astonishing locations [Music] ultra cool dwarf stars may actually be better at building oceans on their planets than stars like our Sun [Music] ultraviolet light from flaring dwarf stars could stimulate the complex chemistry needed to jumpstart biology life may spring up in places that are nothing like our planet and to them we may look like the surprising outlier but we evolved on earth will we ever find any other world as beautiful [Music] [Music] [Music]

Channel: SpaceRip

Views: 1,439,026

Rating: 4.6916604 out of 5

Keywords: Alien life, exoplanet, SETI, astrobiology, Kepler Mission, HARPS, Kepler Space Telescope, ESO, NASA, Goldilocks zone, habitable zone, Arecibo, La Silla, European Southern Observatory, planet-hunter, red dwarf, Super Earth, transit, radial velocity, wobble method, are there other earths, alien life documentary 2018, life on other planets, alien planet, other earths, black hole, the universe

Id: _f2I_PoTGLU

Length: 35min 23sec (2123 seconds)

Published: Thu Jan 04 2018

Reddit Comments

[u/yeahbuthow]

Other earth like planets? Almost impossible that there aren't any. Other earths? Depends on how deep you want to look at the various types of multiverse.

Quick summary of the 4 levels of multiverse

[u/Holeshot75]

Well that was neat.