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US scientists find potentially habitable planet near Earth
- Encosia 16y agoI find the idea of inhabiting a planet "tidally locked" to its star fascinating. I'd never heard of such a thing until reading that article.
- hugh3 16y agoSufficiently close-in planets inevitably wind up tidally locked to their stars, like the moon is to Earth. And since we're a lot better at observing close-in planets due to their small orbital periods, a helluva lot of currently known planets are tidally locked.
- dasil003 16y agoYeah me neither. Is there any good sci-fi about the concept? Imagine sending a human there, if you could do it in a human life span, I'm sure you'd find volunteers to do it. But what would be the psychological effect of having to live out your life on the terminator in perpetual twilight? Would they eventually go insane and just run into the starlight and cook themselves?
- hugh3 16y agoI think there was such a planet mentioned in one of Asimov's Foundation books. It was a pleasant resort planet, as I recall, with the settlements around the habitable ring having constantly perfect weather. edit: I looked it up: Radole, in Second Foundation. Asimov coined the term "ribbon world" to describe planets like this where the habitable zone forms a ribbon.
- jodrellblank 16y agoSounds like ringworld would be a better fit for that scenario - and vice-versa, even.
- berntb 16y agoFor quite a while, Mercury was thought to be tidal locked. You'll find lots of old SF with that "fact". Edit: Until 1965, see http://en.wikipedia.org/wiki/Tidal_locking#Planets http://en.wikipedia.org/wiki/Tidal_locking#Planets Edit 2: Check Larry Niven's first published short story. http://en.wikipedia.org/wiki/Larry_Niven#Work http://en.wikipedia.org/wiki/Larry_Niven#Work
- dstorrs 16y agoIANAP, but it seems pretty unlikely that this would be possible, at least in any way short of living in underground bunkers. I would expect that either the atmosphere would boil off from the hot side (if there wasn't enough gravity to retain it), or the gravity COULD retain it in which case you would get constant world-wide hurricane force winds.
- hugh3 16y agoIAAP but I'm not so sure what would happen, it's nonobvious. I did find this short article, based on a more thorough research paper from 1997, suggesting it might be possible though: http://www.treitel.org/Richard/rass/tidelock01.txt http://www.treitel.org/Richard/rass/tidelock01.txt In short, not only can such a tide-locked planet maintain an atmosphere, but it might even be habitable over much of its surface, with an active water cycle and maybe even a near-breathable surface.
- dstorrs 16y agoThat is really cool. Thank you for the correction, and for the article.
- Retric 16y agoA tidally locked planet with a significant atmosphere would not heat up as much as you might think. The atmosphere would transmit most of that energy around the planet fairly quickly. Consider the Earth has a circumference of 24,859 miles and the jet stream has been measured at around 247 MPH at those speeds air would circle the earth once every 4 days. However, far more important is radent heating increases as the fourth power of temperature which is why the moon never goes over 123°C even after 24/7 sunlight for several days at a time.
- JoeAltmaier 16y agoMercury. Well, sort of. 3/2 tidally locked (switches sides once a year due to elliptical orbit)
- hugh3 16y agoThis is exciting, if not surprising, news. We knew that potentially habitable planets must be out there somewhere, but I'm still very excited that we now know where the first one is. Expect to hear the name "Gliese 581g" a lot more in the future, because this will be the standard hypothetical nearby life-bearing system people will be talking about for years to come. Habitable and only twenty light years away? The tidally locked nature of the planet is a bit of a bummer, though. If there were water on the surface, I wonder what would happen to it. Will there be a liquid-water ring, or will the water inevitably wind up getting stuck on the cold side, never to remelt? Perhaps a constant system of glaciers flowing from cold side to hot side, melting, blowing to the cold side and snowing down again?
- barrkel 16y agoThe way I see it, a tidally locked planet is an easier find, because of the high variance in surface temperatures. Relatively rotating planets will have far narrow variances, making most of them uninhabitable based on temperature.
- nebula 16y agoI'm sorry how does the variance in surface temperature help us find it?(especially with current technology). As I understand it pretty much all the exoplanets so far have been found using Doppler shift. The size of the planet, more precisely the mass, and its distance from the star would influence the magnitude of the shift and hence detectability.
- barrkel 16y agoIt doesn't help you find it. What it does is widen the acceptance criteria. Instead of needing to find a rotating planet exactly in the "Goldilocks zone", any planet whose surface is hot on one side but cool on the other, such that the range of temperatures in some part of it lies in the zone, is acceptable, because you can suppose a zone of habitability on the edge of light and shadow. I'm guessing that's easier because if the planet is a bit too hot on average, you can shift the zone into the shadow; and if it's too cool on average, you can shift the zone into the light. If the planet rotates, you've got a bigger problem, especially if it's too hot, because you need to find / build shade.
- rubashov 16y ago> Gliese 581g, has a mass three to four times that of Earth > The surface gravity would be about the same or slightly higher than Earth's I'm confused. Maybe it's way less dense than earth, so on the surface you're far from the center of gravity?
- hugh3 16y agoThe density is unknown, but we assume it to be rocky because... well, at 2 Earth masses there's not much else it could be made of. It can't be ice because it's too warm, and it can't be gas because gas planets that size won't hold together. But by my calculations a four Earth-mass planet with the same density as Earth should have gravity of about 1.73g. (using http://www.ericjamesstone.com/weird_stuff/gravitator.htm http://www.ericjamesstone.com/weird_stuff/gravitator.htm) Which is not that similar to Earth gravity, but not too far off either, in the scheme of things.
- astrofinch 16y agoPotentially habitable planets that have less mass than Earth does are inherently more difficult to detect, am I right?
- ugh 16y agoYep. But we are getting closer.
- ww520 16y agoThat's a very cool calculator. I tried to work out the math based on sphere volume: V=4/3 x PI x R^3. Earth Mass Radius Surface Gravity 1X 6378km 1.00g 2X 8035km 1.26g 3X 9198km 1.45g 4X 10124km 1.59g 5X 10906km 1.71g If it's 2X or 3X, it's just adding 30% to 40% body weight. For 4X or 5X, it's like adding 100lb to an 150lb body. We have plenty of people in the 250lb to 350lb range and they have no problem in mobility. Human body can handle the load. It might still be helpful to have exoskeleton help.
- jarin 16y agoThat is great, but have they determined whether or not it has unobtainium deposits yet? On a serious note, how is it that the planet has 4 times the mass of Earth but the surface gravity is "the same or slightly higher" than Earth's?
- ramchip 16y ago> On a serious note, how is it that the planet has 4 times the mass of Earth but the surface gravity is "the same or slightly higher" than Earth's? It could be bigger than Earth: http://www.wolframalpha.com/input/?i=surface+gravity+of+4+earth+mass+and+2+earth+radius http://www.wolframalpha.com/input/?i=surface+gravity+of+4+ea...
- patrickgzill 16y agoMy first thought was "use big heat pipes to transfer heat from the hot side to the cool side".
- hugh3 16y agoIndeed, anyone living there would not have an energy problem at all.
- tocomment 16y agoOr a system of shades orbiting the planet, or stationed between the planet and its sun. But by blocking sunlight the overall temperature of the planet would get colder. Perhaps it has a large habitable moon that does rotate?
- fleitz 16y agoSweet, it's only 20 light years away. A quick 10 month journey at warp 3.
- nfg 16y agohttp://en.wikipedia.org/wiki/Time_dilation http://en.wikipedia.org/wiki/Time_dilation
- akozak 16y agoClearly fleitz is assuming he'll be a passenger.
- hugh3 16y agoTalking about warp factors and talking about time dilation don't go well together, unfortunately. The Star Trek universe is, as best I can figure out, nonrelativistic.
- texel 16y agoThis is a bit of hand waving (which is OK because we're talking about imaginary sci-fi constructs) but it was my understanding that since warp drive bends space around you, you're not actually going anywhere near the speed of light, and therefore you experience time similarly relative to people at rest.
- hugh3 16y agoI'd have to see that on a Minkowski diagram before I believed it made sense.
- waterlesscloud 16y agoTwo words- Minkowski Compensators.
- olegkikin 16y agoThe fastest space craft we have (twin Helios probes) travels at 250 000 km/h (20 light years) / (250 000 km/h) = 86,340 years
- hugh3 16y agoUnfortunately the Helios probes can only get up to that sort of speed because they're going downhill (ie towards the sun). Going uphill to get out of the local gravity well is harder. At Voyager 2 speeds it takes 340,000 years.
- olegkikin 16y agoFurtunately, once you leave the sun's gravitational pull (enough), you can accelerate at a constant rate. So "even" if you accelerate at 0.1g, you can reach 0.7c in 100 years. So if we had such an engine and an energy source, we could get to that planet in 200-300 years. The cool thing is, technology innovations are accelerating as well, so we will develop better engines faster than the old ones will arrive to the destination. It's a cool race.
- avar 16y agoYou might not need an engine on the craft, just a big reflector and a tightly focused beam on some planetary body that bombarded it with photons. The problem then would be slowing down at the other end though.
- herdrick 16y agoThis was announced a year or two ago, right - is there anything new there? EDIT: OK, that was Gliese 581 C. This is the new best hope.
- nohat 16y agoIt's amazing to watch the increasing habitability of newly discovered extra-solar planets. Remember a few years ago when a super jovian was an exciting discovery? Sure it was an easy assumption: planets ought to be common, if our system had 9 (yes back before poor pluto was demoted). The spector of the anthropic principle was always there though. Now, to see the discoveries mount - as fast and earthlike as our instruments are capable? That's exciting. Hell, 20 light-years? That's not so far away from the planned orion interstellar trip.
- avar 16y agoPhil Plait just posted a writeup about this: http://blogs.discovermagazine.com/badastronomy/2010/09/29/possible-earthlike-planet-found-in-the-goldilocks-zone-of-a-nearby-star/ http://blogs.discovermagazine.com/badastronomy/2010/09/29/po...
- hartror 16y agoHis write up is far more suitable for the HN audience, has plenty of science, grains of salt and uses the very scientific word "probably" a lot (that isn't a joke).
- BrandonM 16y agoHis write up is far more suitable for the HN audience, has plenty of science, grains of salt and uses the very scientific word "probably" a lot (that isn't a joke). I agree. I submitted the link fully expecting that it would simply vote up someone else's submission, but apparently it hadn't been submitted yet. Now it has been: http://news.ycombinator.com/item?id=1742200 http://news.ycombinator.com/item?id=1742200
- chegra 16y ago"Time dilation would make it possible for passengers in a fast-moving vehicle to travel further into the future while aging very little, in that their great speed slows down the rate of passage of on-board time. That is, the ship's clock (and according to relativity, any human travelling with it) shows less elapsed time than the clocks of observers on Earth. For sufficiently high speeds the effect is dramatic. For example, one year of travel might correspond to ten years at home. Indeed, a constant 1 g acceleration would permit humans to travel as far as light has been able to travel since the big bang (some 13.7 billion light years) in one human lifetime. The space travellers could return to Earth billions of years in the future. A scenario based on this idea was presented in the novel Planet of the Apes by Pierre Boulle." - http://en.wikipedia.org/wiki/Time_dilation#Time_dilation_and_space_flight http://en.wikipedia.org/wiki/Time_dilation#Time_dilation_and...
- ugh 16y ago"A scenario based on this idea was presented in the novel Planet of the Apes by Pierre Boulle." — also The Forever War by Joe Haldeman: http://en.wikipedia.org/wiki/The_Forever_War http://en.wikipedia.org/wiki/The_Forever_War
- warfangle 16y agoAlso, A World Out of Time, by Larry Niven - where a ramjet pilot returns to earth, only to find it ruined and way too hot: http://en.wikipedia.org/wiki/A_World_Out_of_Time http://en.wikipedia.org/wiki/A_World_Out_of_Time
- albahk 16y agoThis is old news - James Cameron already made a documentary about this place. edit: My point here, not well made, was that the potential of a discovery of this magnitude, i.e. a virgin planet capable of sustaining humans etc will eventually be exploited and ruined much the same way we have done to earth. The earth or this new planet is not the problem, but the way we exist on it.
- anigbrowl 16y agoIf you were meant to live in perfect harmony with nature, you'd be a tree.
- malloreon 16y agoTime to blow this popsicle stand! So long, suckers!
- ankimal 16y agoI wonder if we ll reach it on a speed-o-light craft or teleport to it?
- tocomment 16y agoDo you guys think we'll come up with a catchy name for this planet (or future "habitable" planets discovered?) Any idea how that naming process would work? I can't imagine seeing "Gliese 581g" in headlines for years to come.
- rblion 16y ago"we’ve almost totally depleted this planet, we can just go to this one that is 21 light-years away."
- tectonic 16y agoFrom http://blogs.discovermagazine.com/badastronomy/2010/09/29/possible-earthlike-planet-found-in-the-goldilocks-zone-of-a-nearby-star/ http://blogs.discovermagazine.com/badastronomy/2010/09/29/po... "But perhaps the most interesting and exciting aspect of all this is what it implies. The Milky Way galaxy is composed of about 200 billion stars, and is 100,000 light years across. The fact that we found a planet that is even anything like the Earth at all orbiting another star only 20 light years away makes me extremely optimistic that earthlike planets are everywhere in our galaxy. 20 light years is practically in our lap compared to the vast size of our galaxy, so statistically speaking, it seems very likely it’s not unique. I don’t want to extrapolate from a data set of two (us and them), but if this is typical, there could be millions of such planets in the galaxy. Millions."
- tocomment 16y agoA couple more questions. Would the presence of a magnetic field affect habitability? If so how? How likely is a planet this size to have a magnetic field like Earth's? Say we did colonize this planet, would be be able to launch crafts into orbit from the surface? It seems like our rockets can barely escape Earth's gravity?
- dbrannan 16y agoVoyager 2 (man's fastest space craft) is traveling 35,000 miles per hour / 60 = 583 miles per second. 187,000 miles per second equals the speed of light. Light can travel 57,395,520,000,000 miles in one year (roughly 5.7 trillion miles). So, in 21 years that would equal 57,395,520,000,000 miles x 21 years, or roughly 120 trillion miles. Thus, if Voyager 2 was our space craft we'd have 583 miles per second x 60 seconds x 60 minutes x 24 hours x 365 days x 21 years to get 386,095,248,000 billion miles towards our new planet. There is a huge gap between 386 billion and 120 trillion miles, like 311 times. That means it would take us roughly 310 x 21 years = 6528 years to get there using current technology. I just don't see us going there as being very practical. -------- EDIT: I'm getting down voted for doing the math! Seriously?
- waterlesscloud 16y agoIf only it were possible to increase the speed of spacecraft somehow.
- mfukar 16y agoWow. I'd never thought I'd see Voyager 2 being cited as the state-of-the-art.
- sgt 16y agoWe just need to put our heads together and create a warp drive. Come on people, let's do it. It must be possible! "Warp drive by 2030" - next Obama speech.
- jasonkeene 16y ago"EDIT: I'm getting down voted for doing the math! Seriously?" "35,000 miles per hour / 60 = 583 miles per second." I stopped reading right there, please actually do the math if you do the math.
- Pistos2 16y agohttp://www.google.com/search?q=57395520000000%20miles%20per%20year%20*%2021%20years%20%2F%2035000%20miles%20per%20hour http://www.google.com/search?q=57395520000000%20miles%20per%... ((57 395 520 000 000 (miles per year)) * (21 years)) / (35 000 miles per hour) = 3 928 593.15 years
- christangrant 16y ago"The planet is tidally locked to the star, meaning that one side is always facing the star " How is the gravity about the same as earths if the planet does not spin, or is the planet spinning at the same rate that it is revolving around it's star, like the moon. So I guess gravity does not just come from the centripetal force. Are there any other forces that contribute to planetary gravity? If not the planetary year should be very small. ...rambling
- jcl 16y agoGravitational force is dependent on mass, not how much an object is spinning.
- christangrant 16y agoSo centripetal force is independent from planetary gravitational force...
- shajith 16y agoDoes anyone know if the "Message from Earth"[1] sent towards Gliese 581c can conceivably be received at this new planet? If there is intelligent life in that system capable of detecting and transmitting signals of that form (NOT assuming that by any stretch), a response is due in ~2049. While we're on that topic, wouldn't such a hypothetical civilization already have discovered other electromagnetic radiation from our system by now? Or does it have to be a focused high-power signal as this one? [1] http://en.wikipedia.org/wiki/A_Message_From_Earth http://en.wikipedia.org/wiki/A_Message_From_Earth