# Could there be life -- and what sort -- on planet Gliese 581 g? **URL:** \ **Category:** Great Debates\ **Created:** [October 5, 2010, 3:08am UTC](https://boards.straightdope.com/t/could-there-be-life-and-what-sort-on-planet-gliese-581-g/556081 "2010-10-05T03:08:30Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![Sam\_Stone](https://avatars.discourse-cdn.com/v4/letter/s/ecccb3/32.png) [@Sam\_Stone](https://boards.straightdope.com/u/Sam_Stone)\ **Post date:** [October 6, 2010, 1:03am UTC](https://boards.straightdope.com/t/could-there-be-life-and-what-sort-on-planet-gliese-581-g/556081/21 "2010-10-06T01:03:01Z")
> [@Whack-a-Mole](#): > > Not exactly doubting you **Sam** but resolving anything at this distance with a telescope seems inconceivable to me. > > Here is a [picture of Pluto](http://csep10.phys.utk.edu/astr161/lect/pluto/pluto.html) made by the Hubble Space Telescope. Granted Pluto is smaller than Gliese581g is but it is a helluva lot closer. > > I get these new telescopes would be far superior to Hubble but I’d be shocked at them getting a snapshot of a fuzzy blob of a planet around another star much less resolve continents. There’s really no debate about our ability to image a close planet to about 25 x 25 resolution. The Planet Imager is an actual NASA project using proven science. There are certainly technical issues. The glare from the parent star has to be eliminated, which means extending a shield far out from the telescope to occlude the star. Large orbital interferometry arrays have to be aligned and held in station to one another with a high degree of accuracy. There are diffraction problems with super high magnification. But these are all engineering issues, and NASA was on a path with its Origins program (Kepler, Terrestrial Planet Finder, Life Finder, and Planet Imager) to solve these step by step. That program has now been gutted, but other programs are in progress in other countries. Adaptive optics raise the possibility of ground-based interferometry arrays being useful here as well. It’s when you get out to the more speculative resolutions that the science starts to get fuzzy. In theory, you could image something the size of car on a planet ten light-years from here with a big enough telescope array (‘in theory’ meaning by simply working out the calculations for resolution based on aperture size), but practically speaking there are so few photons reaching us from those small objects we may not be able to collect them in any coherent fashion. So there’s definitely a limit to what we can see. ---
**Author:** ![Wendell\_Wagner](https://avatars.discourse-cdn.com/v4/letter/w/8491ac/32.png) [@Wendell\_Wagner](https://boards.straightdope.com/u/Wendell_Wagner)\ **Post date:** [October 6, 2010, 1:29am UTC](https://boards.straightdope.com/t/could-there-be-life-and-what-sort-on-planet-gliese-581-g/556081/22 "2010-10-06T01:29:54Z")
Cisco, there was no consensus that no radio signal would be transmitted more than a few hundred yards at any point in the 1800’s: > **[Invention of radio](https://en.wikipedia.org/wiki/Invention_of_radio)** > > The invention of radio communication was preceded by many decades of establishing theoretical underpinnings, discovery and experimental investigation of radio waves, and engineering and technical developments related to their transmission and detection. These developments allowed Guglielmo Marconi to turn radio waves into a wireless communication system. > The idea that the wires needed for electrical telegraph could be eliminated, creating a wireless telegraph, had been around for a while before ... Basically what happened was that people slowly improved the transmission of radio signals. No one ever said that they couldn’t be sent beyond a given distance. That doesn’t even make any scientific sense. The only question was how strong they would eventually be able to make the transmitters and how sensitive they would be able to make the receivers. Nobody was sure about that. You didn’t say that there were some people who didn’t believe that travel to Mars would ever happen. You claimed, it appears to me, that most people believed that anyone who believed that travel to Mars was possible was insane. That’s simply not true. Most people had thought about the subject. (Lots of people, like me, in the 1950’s watched the film _Invaders from Mars_ over and over.) The consensus of scientific opinion at the time was that it was possible, but it was hard to tell how much money it would cost to get past all the engineering problems that would come up. There was never any scientific barrier to space travel. ---
**Author:** ![Cisco](https://avatars.discourse-cdn.com/v4/letter/c/ccd318/32.png) [@Cisco](https://boards.straightdope.com/u/Cisco)\ **Post date:** [October 6, 2010, 1:48am UTC](https://boards.straightdope.com/t/could-there-be-life-and-what-sort-on-planet-gliese-581-g/556081/23 "2010-10-06T01:48:44Z")
There was a strong consensus that wireless signals could not be sent beyond a line of sight-- the absolute max theoretical distance being the horizon (which could be increased by raising the height of the broadcast point), so my term “a few hundred yards” might’ve been low, especially by the late 1800s, but Marconi was thought to be nuts for claiming he could send a signal across the ocean. Erik Larsen goes into detail about this in his book Thunderstruck. My other claims might have been similarly short on time frame, but extend them back a few more decades into the past and they hold true. But let me rewind and go back to my original point, which I seem to have done a poor job of defending: I am optimistic that scientific progress will advance, over the next several decades, to the point that planets like Gliese don’t seem so impossibly out of reach for our probes, and possibly even our manned ships. Note, though, that I don’t think we will get there anytime soon at speeds greater than a fraction of C. ---
**Author:** ![Saint\_Cad](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/saint_cad/32/18907_2.png) [@Saint\_Cad](https://boards.straightdope.com/u/Saint_Cad)\ **Post date:** [October 6, 2010, 4:08pm UTC](https://boards.straightdope.com/t/could-there-be-life-and-what-sort-on-planet-gliese-581-g/556081/24 "2010-10-06T16:08:13Z")
Although chlorophyll absorbs some red light, doesn’t anthocyanin do a better job of photosynthesis with red stars? If so, expect a purple planet. ---
**Author:** ![Quartz](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/quartz/32/267_2.png) [@Quartz](https://boards.straightdope.com/u/Quartz)\ **Post date:** [October 6, 2010, 5:00pm UTC](https://boards.straightdope.com/t/could-there-be-life-and-what-sort-on-planet-gliese-581-g/556081/25 "2010-10-06T17:00:08Z")
How do we know that this is a planet and not a planet - large moon system? And how do we know that it’s tidally locked? ---
**Author:** ![Lemur866](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lemur866/32/434_2.png) [@Lemur866](https://boards.straightdope.com/u/Lemur866)\ **Post date:** [October 6, 2010, 6:24pm UTC](https://boards.straightdope.com/t/could-there-be-life-and-what-sort-on-planet-gliese-581-g/556081/26 "2010-10-06T18:24:11Z")
We believe it is tidally locked because any body that close to another massive body would become tidally locked very quickly. It might not be tidally locked, but if it isn’t it would have to have had an impossibly large spin when it formed, or it had some recent impact with another body that gave it some spin. The planet might very well have moons, but we have no way of knowing. ---
**Author:** ![BrainGlutton](https://avatars.discourse-cdn.com/v4/letter/b/82dd89/32.png) [@BrainGlutton](https://boards.straightdope.com/u/BrainGlutton)\ **Post date:** [October 6, 2010, 7:06pm UTC](https://boards.straightdope.com/t/could-there-be-life-and-what-sort-on-planet-gliese-581-g/556081/27 "2010-10-06T19:06:20Z")
> [@Saint\_Cad](#): > > Although chlorophyll absorbs some red light, doesn’t anthocyanin do a better job of photosynthesis with red stars? If so, expect a purple planet. So **that’s** where Barney came from! ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [October 6, 2010, 7:52pm UTC](https://boards.straightdope.com/t/could-there-be-life-and-what-sort-on-planet-gliese-581-g/556081/28 "2010-10-06T19:52:57Z")
> [@](#): > > Kepler doesn’t work that way. Kepler uses a wide-field imager to study a field of about 150,000 stars at the same time. Computers are then used to analyze the brightness of each star, looking for signs of planets occluding the star and lowering its brightness. Kepler is not designed for high-resolution imaging of single stars. Even at that, only about 1% of planetary systems are aligned in such a way that Kepler could learn anything at all about them. The technique is only practical when you’re looking at a large enough set of stars that 1% becomes significant. And while the cancellation of SIMS and TPF is unfortunate, nobody was really surprised about the cancellation of the Planet Imager. There are always pie-in-the-sky missions being proposed several generations past anything we currently have, with no real expectation of getting them funded. The idea is more that, if you make a proposal sufficiently grand, then even after it inevitably gets cut back heavily, you’ll still have something worthwhile. Even if the funding situation went perfectly, you’d probably have learned enough from earlier-generation missions that the previous plans would be horribly obsolete. ---
**Author:** ![ITR\_champion](https://avatars.discourse-cdn.com/v4/letter/i/c67d28/32.png) [@ITR\_champion](https://boards.straightdope.com/u/ITR_champion)\ **Post date:** [October 6, 2010, 9:38pm UTC](https://boards.straightdope.com/t/could-there-be-life-and-what-sort-on-planet-gliese-581-g/556081/29 "2010-10-06T21:38:01Z")
Another factor that would be required for complex life is some protection from radiation. To go by the example of our solar system, that doesn’t seem to happen too often. Different types of radiation are present, some from the sun and some ambient in space. We can only survive here because of a combination of atmospheric protection and magnetic fields. ---
**Author:** ![Cisco](https://avatars.discourse-cdn.com/v4/letter/c/ccd318/32.png) [@Cisco](https://boards.straightdope.com/u/Cisco)\ **Post date:** [October 6, 2010, 9:40pm UTC](https://boards.straightdope.com/t/could-there-be-life-and-what-sort-on-planet-gliese-581-g/556081/30 "2010-10-06T21:40:29Z")
> [@ITR\_champion](#): > > Another factor that would be required for complex life is some protection from radiation. To go by the example of our solar system, that doesn’t seem to happen too often. Different types of radiation are present, some from the sun and some ambient in space. We can only survive here because of a combination of atmospheric protection and magnetic fields. That would only apply to surface life. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [October 7, 2010, 12:45am UTC](https://boards.straightdope.com/t/could-there-be-life-and-what-sort-on-planet-gliese-581-g/556081/31 "2010-10-07T00:45:52Z")
> [@](#): > > Another factor that would be required for complex life is some protection from radiation. Eh, it’s only what, thirty years since Chernobyl? And yet, there’s a species of fungus which not only lives in the main reactor core, but actually feeds on the radiation. If life can adapt that well to an environment like Chernobyl that quickly, then I’m sure it could adapt to life on a flare-prone red dwarf planet given billions of years. ---
**Author:** ![Polycarp](https://avatars.discourse-cdn.com/v4/letter/p/82dd89/32.png) [@Polycarp](https://boards.straightdope.com/u/Polycarp)\ **Post date:** [October 7, 2010, 12:51am UTC](https://boards.straightdope.com/t/could-there-be-life-and-what-sort-on-planet-gliese-581-g/556081/32 "2010-10-07T00:51:20Z")
> [@BrainGlutton](#): > > > [@Cisco](#): > > > > \*(countdown to new name: 3, 2, 1 . . . ) > > How about “the planet Claire”? “Gliese is the world. It’s the time, it’s the place, it’s got motion.” - Jacobs and Casey, 1971, rev. ---
**Author:** ![Whack-a-Mole](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/whack-a-mole/32/141_2.png) [@Whack-a-Mole](https://boards.straightdope.com/u/Whack-a-Mole)\ **Post date:** [October 7, 2010, 1:35am UTC](https://boards.straightdope.com/t/could-there-be-life-and-what-sort-on-planet-gliese-581-g/556081/33 "2010-10-07T01:35:33Z")
> [@Cisco](#): > > But let me rewind and go back to my original point, which I seem to have done a poor job of defending: I am optimistic that scientific progress will advance, over the next several decades, to the point that planets like Gliese don’t seem so impossibly out of reach for our probes, and possibly even our manned ships. Note, though, that I don’t think we will get there anytime soon at speeds greater than a fraction of C. I agree that people thought we could never do the stuff we have done. I just recently saw quotes from people (notable scientists) who said going to the moon was utterly impossible as late as the late 50’s. Obviously they were proven wrong. However, the problems to get to the moon were engineering problems and solvable. I think the difference here is we are bumping up against the limitations of physics. Today scientists have a firm grasp of physics in all its flavors and the very real limitations imposed by the very laws of the universe. There is no sidestepping that. Is it possible some new breakthrough will be made showing new possibilities for space travel and/or communication? Sure and I certainly hope so. As it stands though that seems unlikely. I pray someone will find a way to access hyperspace or make a warp drive or open wormholes or dimension doors or whatever. I really hope the universe allows such things else we are pretty stuck in our lonely solar system. As it stands though, barring a dramatic (and that is putting it lightly) revelation in physics and how the universe works there is no reason to believe we will be any closer to getting to Gliese (or any star) than we are today. We already can conceive of wild possibilities for such a trip because we know with great precision what a chemical rocket will do or how an Orion type ship might work or an ion drive or solar sail. Even with the will to build such things their limitations will not change in the future. You can only do so much with a rocket and a billion years of scientific advancement will not change that. To be clear, I am an avid sci-fi buff and love space and dream that someday we can really get out there. Few things would make me happier. I really harbor an abiding hope that some grand revelation will occur opening the way for us somewhere down the road. The universe is an amazing place and I have no doubt it still has surprises in store for us. Just the realist in me can’t help but be skeptical. ---
**Author:** ![Cisco](https://avatars.discourse-cdn.com/v4/letter/c/ccd318/32.png) [@Cisco](https://boards.straightdope.com/u/Cisco)\ **Post date:** [October 7, 2010, 1:56am UTC](https://boards.straightdope.com/t/could-there-be-life-and-what-sort-on-planet-gliese-581-g/556081/34 "2010-10-07T01:56:34Z")
What is the physical barrier to achieving, say, 0.5 C? That would get us there in about 40 years, by my rough estimation-- well within a human being’s lifespan. ---
**Author:** ![Whack-a-Mole](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/whack-a-mole/32/141_2.png) [@Whack-a-Mole](https://boards.straightdope.com/u/Whack-a-Mole)\ **Post date:** [October 7, 2010, 2:24am UTC](https://boards.straightdope.com/t/could-there-be-life-and-what-sort-on-planet-gliese-581-g/556081/35 "2010-10-07T02:24:58Z")
> [@Cisco](#): > > What is the physical barrier to achieving, say, 0.5 C? That would get us there in about 40 years, by my rough estimation-- well within a human being’s lifespan. Nothing outright prevents it beyond a practical matter. If you want to build a rocket to accelerate you to that speed (and then presumably decelerate you at the other end) it’d be an absurdly huge rocket. I do not know the math but you’d need a constant burn for days likely. The Space Shuttle burns all its fuel in about 2 minutes to give you an inkling of the scope of the problem. So, not a actual impossibility but a practical impossibility. Could we do it? I suppose. We could level Mt. Everest by hand with the will and enough time. Doesn’t mean anyone will ever do it though. ---
**Author:** ![Zany\_Zeolite\_Zipper](https://avatars.discourse-cdn.com/v4/letter/z/4af34b/32.png) [@Zany\_Zeolite\_Zipper](https://boards.straightdope.com/u/Zany_Zeolite_Zipper)\ **Post date:** [October 7, 2010, 3:11am UTC](https://boards.straightdope.com/t/could-there-be-life-and-what-sort-on-planet-gliese-581-g/556081/36 "2010-10-07T03:11:59Z")
> [@Sam\_Stone](#): > > > [@Locrian](#): > > > > Does anyone know if Kepler is being sent out there for some more photos? It may not be calibrated correctly, but can we get some better pics of the planet’s surface any time soon? > > > > From its description, it is quite possible there’s some type of life on there. I would think there’s some type of plant life. > > > > Incredible. > > In the distant future, we could build telescope arrays of hundreds of Hubble-sized mirrors spaced several hundred kilometers apart, which would allow us to resolve planets around the nearest stars to maybe 100 X 100 pixels. It would look something like [this](http://awlyatyarazz.files.wordpress.com/2008/02/earth.thumbnail.jpg) (that’s a 128 X 128 thumbnail of earth). > > That’s probably the best we could ever hope for in our lifetimes. In the distant future, gigantic arrays the size of Earth’s orbit, along with adaptive computer analysis might allow us to image details on the nearest planets down to a few hundred meters in size. But at that resolution you start running into physical limits (there just aren’t enough photons to measure). :eek: When I perfect my carbon neutral sex-bot and rickshaw driver, I am giving all of the profits to you to make this happen. I have never wanted to leave my profession more than after I saw that picture. If we could get down to even that resolution, we could prove intelligent life, by looking for the alien equivalent of Vegas in the night sky. ---
**Author:** ![Bryan\_Ekers](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bryan_ekers/32/183_2.png) [@Bryan\_Ekers](https://boards.straightdope.com/u/Bryan_Ekers)\ **Post date:** [October 7, 2010, 3:26am UTC](https://boards.straightdope.com/t/could-there-be-life-and-what-sort-on-planet-gliese-581-g/556081/37 "2010-10-07T03:26:50Z")
> [@Zany\_Zeolite\_Zipper](#): > > If we could get down to even that resolution, we could prove intelligent life, by looking for the alien equivalent of Vegas in the night sky. Weell, maybe not _Vegas_ but I otherwise agree. ---
**Author:** ![Lumpy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lumpy/32/446_2.png) [@Lumpy](https://boards.straightdope.com/u/Lumpy)\ **Post date:** [October 7, 2010, 3:49am UTC](https://boards.straightdope.com/t/could-there-be-life-and-what-sort-on-planet-gliese-581-g/556081/38 "2010-10-07T03:49:01Z")
About Venus’s atmosphere: paradoxically, it’s so thick because Venus has _lost_ so much atmosphere. More specifically, it’s lost most of it’s hydrogen, including hydrogen photodissociated from water vapor. Water is essential to allow carbon dioxide to bind with silicate rock into carbonate minerals. If all the limestone and other carbonate minerals in the Earth’s crust released their carbon dioxide, Earth would have an atmosphere like Venus. ---
**Author:** ![Sitnam](https://avatars.discourse-cdn.com/v4/letter/s/6a8cbe/32.png) [@Sitnam](https://boards.straightdope.com/u/Sitnam)\ **Post date:** [October 7, 2010, 2:10pm UTC](https://boards.straightdope.com/t/could-there-be-life-and-what-sort-on-planet-gliese-581-g/556081/39 "2010-10-07T14:10:05Z")
Gliese 581’s rotation is in sync with its orbit so one side always faces Gliese and one side doesn’t. So I’d imagine even if there was breathable air and you were standing on the twilight edge you’d feel arctic chills or oven heat depending on which way the wind was blowing. ---
**Author:** ![Half\_Man\_Half\_Wit](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/half_man_half_wit/32/21766_2.png) [@Half\_Man\_Half\_Wit](https://boards.straightdope.com/u/Half_Man_Half_Wit)\ **Post date:** [October 7, 2010, 2:20pm UTC](https://boards.straightdope.com/t/could-there-be-life-and-what-sort-on-planet-gliese-581-g/556081/40 "2010-10-07T14:20:01Z")
I posted this somewhere before, but [here’s](http://kencroswell.com/reddwarflife.html)a good article on the possibility of life on tidally locked planets orbiting red dwarfs. Seems it’s much more promising than people used to think it was, the main reason for the new views being better computer simulations – the article cites that even a planet having an atmosphere of a density of only 15% of that of the Earth’s would have sufficient convection to keep the gases from freezing out on the dark side. [Previous page](https://boards.straightdope.com/t/could-there-be-life-and-what-sort-on-planet-gliese-581-g/556081.md?page=1) [Next page](https://boards.straightdope.com/t/could-there-be-life-and-what-sort-on-planet-gliese-581-g/556081.md?page=3)