Exoplanets: Are We Close To Finding A New Earth? | Answers With Joe

you know how hard it is to keep you alive our universe as we understand it is an infinite expanse of mostly empty space coursing with cosmic rays that would kill you within 15 seconds and in that infinite expanse out of billions of galaxies there's one galaxy with one nondescript star with dozens of celestial bodies around it only one of which has a large stabilizing moon and a magnetic field protecting it from the cosmic rays just far enough away from the star for liquid water to form liquid water that will kill you you can't live on it you can't drink 96.5% of it it's uninhabitable in toxic to humans and there's a lot of it 71% of the earth's surface is water so much that we have an actual water hemisphere literally one half of our planet is almost totally covered in water if an alien approached the Earth from this angle they'd think that we didn't have any land at all but even on the 29% of the planet that we can live on there are huge swathes of it there just let's just say not very comfortable so we have this tiny fraction of the planet that we can live on but even then all we can do is live on this sliver along the surface if we go up only five miles we'll die from lack of oxygen if we dig down only three miles we'll die some extreme temperatures or get crushed by ocean pumping the entire human race exists in this one eight mile zone and for hundreds of thousands of years we thought that's all there was today we mathematically understand that there must be somewhere out there another planet like ours and so far we found 3,400 exoplanets just another 10 billion to go Josh trap instead asked can you do a video about exoplanets up until 1995 exoplanets were just kind of a theoretical thing but all that change with a discovery the first exoplanet 51 pegasi B or 51 peg for short now there were a couple of planets that were discovered earlier in 1992 but they orbited around a pulsar so that didn't really count and they were still trying to figure out for sure whether or not they were legit or not but 51 pegasi is a sun-like star so it's definitely counted what it didn't do was make any sense at all it came to be known as a hot Jupiter meaning it was a jupiter-sized planet that orbited extremely close to the star so close that it orbited the star every four days you would not want to go to their the thinking at the time was that it was impossible for a planet that size to form that close to the star but since then they've actually found a lot of hot Jupiters and scientists now believe that they do form out in the solar system just like Jupiter did but then move inward over time in fact it's now hypothesized that the only reason Jupiter didn't have the same fate was because the gravitational effect of Saturn in the outer gas giant of course if Jupiter hadn't moved in the way those hot Jupiters did it would have eventually either crashed into Earth or flung Nets out of the solar system but instead it stayed in this nice little place out there basically becoming the solar system's vacuum cleaner eating up all the comments and asteroids that could have possibly hit us man we got lucky we just found one planet and already we gained a whole new understanding of our own solar system that's how you science people 51 peg B was discovered by a technique called radial velocity as many of you know when a planet orbits the star the planet's gravity affects the Stars position ever so slightly same is true with the earth and the moon so when viewed from above the planetary planet looks like the star as a tiny wobble this is radial velocity but even if you're viewing the orbital plane more heads on you can still see radial velocity by measuring the differences in the Stars wavelength thanks to the Doppler effect when the star wobbles away from you the light slightly red shifted when it wobbles towards you the slightly blue shifted the rating characteristics of the wobble can tell us a lot about the planets size and density and perturbations in the wobble indicate the presence of multiple planets according to NASA at the time of recording the 639 planets have been found using the radial velocity method thing is this method is mostly successful for finding big jupiter-sized planets because the play has to be that big in order for its gravity to affect the start enough to be detectable if we want to find other planets like Earth we've got to try something different so in 2009 the Kepler space telescope would launch with a specific purpose of finding transits transits occur when the orbital plane of a star just happens to line up edge on with our perspective and one of the planets passes in front of the star this gives the brightness of the star very slightly but by measuring the duration of the transit and the amount of the light dim you can learn a lot about the planets size density and distance from the star and through Estero spectroscopy we can tell whether the planet has an atmosphere and even the composition of elements in the atmosphere by how the light interacts with that atmosphere as it passes through and that can give us an idea of what the conditions on the planet are like this is the upside of transit photometry it gives us a much better picture of what these planets are like and it makes it possible for us to find small rocky planets more like earth here on earth we witness transits of Venus and Mercury which are actually surprisingly rare the next Venus transit isn't going to be until 2117 I wish I'd known it was such a big deal when it hasn't back in 2012 what does happen a lot more drunk this is the downside of the transit message because the vast majority of orbital planes aren't likely to line up just perfectly so that we can view them in this way but even still the Kepler space telescope has been able to confirm the discoveries of 2335 exoplanets xxx which are roughly twice the size of earth small rocky and then the habitable zones of their stars and that's just what Kepler in total 2732 planets have been found using the transit method and here comes the mind blow considering how rare transits are and extrapolating up from that data scientists now believe that there's an average of one point six pan at per star in the Milky Way galaxy at four hundred billion stars in the Milky Way galaxy that comes out to 640 billion planets ten billion of which are expected to be earth-like now for the sake of thoroughness there are a few other methods that scientists have used to find exoplanets and one of them is called gravitational microlensing a gravitational lens is a relativistic effect with a gravity of an object in the foreground bends the light of a distant star behind it we mostly use this with galaxy clusters that can also be used to discover planets we discovered forty-seven planets this way so far another called astrometry it's similar to radial velocity effect but the wobble is in relation to other stars so far only one plan than bound this way and just in case you notice all of these methods are actually indirect you're not seeing the planet itself you're seeing that planets effect on the star or the star's light so you might be wondering why can't we just take a picture of a planet well we have direct imaging a planet is very difficult because the star is so bright that it's hard to discern the planet from the star especially at the distance that we're dealing with but there are ways to put a proverbial thumb over the star so we can detect the light bouncing off the planet or the thermal signature of the heat that the planets absorbing from the star and we found 43 planets this way so far we've actually taken pictures of 43 planets outside of our solar system the diversity of planets we found so far is mind-blowing from hot Jupiters the hot Neptune's - puffy planets which are a lot like Jupiter but far less dense planets like JD 1214b which are thought to be water worlds completely surrounded by ocean - a planet we discovered in 2011 that we think might actually be made out of diamond even rogue planets floating around throughout the galaxy not attached to any solar system probably flung out by those hot Jupiters as they were making their way into the solar system but of course what we're really interested in is other planets like Earth and for that scientists have come up with something called the earth similarity index or the ESI and it looks like this there's a link in the description if you want to figure them mess up but it measures planets from zero to one with one being completely similar to earth and one of the most promising what we found so far is Kepler 438 B it's 12% bigger than Earth gets 40% more light and it's a rocky planet in the habitable zone the only thing is it stars a very active dwarf star that throws off massive solar flares so unless it has a strong magnetic field like we do it's probably not suitable for life Kepler 442 B is only one point three times the size of Earth it orbits its star every 112 days and has an average temperature of around negative 40 degrees Celsius now that's cold but it's actually colder on Mars so this planet is more likely to have life than MRSA then they've Gliese 667c which was discovered in 2012 it's actually quite a bit bigger than the earth but it has an average temperature of around 5 degrees Celsius which is plenty warm enough for liquid water to form but the most recent discovery that's captured our imagination is the Trappist one system you probably heard about it it was first discovered by the Trappist telescope in Chile and then later studied by the Spitzer and Hubble Space Telescope but this system has seven rocky planets in it seven and as many as three of these planets trap this one de and F all fall in the star's habitable zone and it's a tiny star system really closer in size to Jupiter and its moons and what's so cool about is if you were standing on one of those planets you would be able to see all the other planets as big as the moon in the sky and you could travel between the planets in just a matter of days unfortunately being so close to their star means that these plants are likely tidally locked meaning one side faces the planet at all times like the moon doesn't us which kind of puts a damper on things because that makes it very unlikely for life to form but still if we were to go there it might be kind of comfortable for us and it's also still just an amazing discovery to find that many earth-like planets in one star system now there are new discoveries happening all the time and there's far too many to mention in one video already so if you're watching this in the future which you are and there's one of the planets that I didn't mention that you want to give a call out talk about it in the comment this by the way is just the beginning with new projects like the James Webb Space Telescope coming up in the next few years we are going to make discoveries that are going to absolutely explode our understanding of planets in our galaxy the universe is a harsh cold empty place that is not coming to life but somehow this little planet earth created a nice little sanctuary that made our existence possible it was incredibly unlikely but the fact that it happened once means that maybe it happened again and if we're lucky we might find another sanctuary soon all right guys thanks for watching please like and share to help spread this video around in it this is your first time here I invite you to check out some of my other videos you might like it I talked about a lot of similar topics and if you do like them maybe subscribe I do this every Monday big things as always do the answer files on patreon I want to take a second and call out some new people who have joined the the crew this week we have Steven Q's Andre Wetzel Tom Cummings and Rob C odo actually up to his pledge a little bit and I want to thank him for that if you'd like to join them and get special perks like being able to see my secret vlogs that's only two patreon viewers you can go to patreon.com/scishow answers with Joe and as always this videos fine by ganker boy calm do you get regular canker sores and mouth ulcers you need to fix your mouth canker boy is a daily supplement that keeps those bad boys from happening you can do a risk-free trial at canker boycott all right thanks again for watching you guys have an eye-opening week and I will see you next Monday love you guys take care

Channel: Joe Scott

Views: 312,369

Rating: 4.9221601 out of 5

Keywords: answers with joe, exoplanets, astronomy, kepler 438b, kepler 442b, Gliese 667c, Trappist-1 system, kepler space telescope, radial velocity, planet transit, transit of venus, rogue planets, Earth, gravitational microlensing, astrometry, transit photometry

Id: 6S_T__cFsj4

Length: 10min 40sec (640 seconds)

Published: Mon Jul 10 2017