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Space Science

What Does Sunset On an Alien World Look Like? 94

Posted by Soulskill
from the forgot-my-camera dept.
The Bad Astronomer writes "Using real data from Hubble Space Telescope of a planet orbiting another star, exoplanetary scientist Frédéric Pont created a lovely image of what sunset would look like from HD209458b, nicknamed Osiris, a planet 150 light years away. The Hubble data gave information on the atmospheric absorption of this hot Jupiter planet, and, coupled with models of how the atmosphere was layered, Pont was able to create a realistic looking sunset on the planet. The big surprise: the star looks green as it sets! Sodium absorption sucks out the red colors and blue is scattered away, leaving just the green hues to get through. It's a lovely application of hard scientific knowledge."
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What Does Sunset On an Alien World Look Like?

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  • it's located someplace that we're not going to be able to verify the results.

    • by Ardeaem (625311) on Monday January 09, 2012 @04:16PM (#38641270)

      it's located someplace that we're not going to be able to verify the results.

      The laws of physics work the same way there that they do here...you don't actually have to go there to know how light will pass through the atmosphere...

      • by na1led (1030470)
        No one knows what Pluto looks like, but somehow we know what another planet looks like from hundres/thousands of lightyears away? Makes no sense to me.
        • by dave420 (699308) on Monday January 09, 2012 @04:35PM (#38641580)

          We are talking about how a star (which we can clearly measure) interacts with an atmosphere (which, again, we can clearly measure). Nothing as small or dark as Pluto needs to be measured to figure out what the "sunset" looks like. Comparing the two is highly specious. Not being able to directly image a dark, tiny rock is a lot different to being able to detect the atmosphere of a planet and the output of a (relatively) very bright star.

          I guess it's best to leave this stuff to the professionals ;)

          • Re: (Score:2, Interesting)

            by icebike (68054) *

            We can barely measure the star, and we certainly can't measure the atmosphere with any degree of certainty from 150 light years away. At best we can achieve is a few spectroscopic measurements of the absorption of upper atmosphere. This work is based on suspect modeling which in turn is based on a very tiny amount of data and nothing about the surface layers of the atmosphere.

            Professionals indeed.

        • by Joce640k (829181)

          No one knows what Pluto looks like, but somehow we know what another planet looks like from hundres/thousands of lightyears away? Makes no sense to me.

          If you'd bothered to look at the picture before posting you'd know there's no 'planet' in it.

          You don't even have to read this one, just look at the picture.

          • by na1led (1030470)
            They show a picture of a Jupiter type planet. How the hell can they tell with any amount of accuracy? There are still mysterious things about the planets in our own backyard we're not sure of.
            • by avgjoe62 (558860)

              Maybe you should have RTFA and not just looked a the picture. The picture attached to the article shows a view of the star as seen from the planet, NOT a picture of the planet itself. They even explain that the star looks the way it does because the apparent size of the star means that it displays every color absorption at once instead of changing color gradually as Sol does here on Earth.

              I can see why you would assume that was a picture of the planet, but you're wrong.

      • by hedwards (940851)

        Don't get me wrong, they're probably correct, but then again because of the location we can't verify that the results are correct and that there isn't something else going on that changes the results. One thing about science is that without verification you don't know if an as yet unknown effect or situation is going to make for an unexpected result.

      • by Culture20 (968837)

        it's located someplace that we're not going to be able to verify the results.

        The laws of physics work the same way there that they do here...you don't actually have to go there to know how light will pass through the atmosphere...

        How do you know the laws of physics work the same way there without being able to verify the results?

      • Re: (Score:1, Insightful)

        by UnknownSoldier (67820)

        > The laws of physics work the same way there that they do here...

        And your proof is ... ?

        • by dkf (304284)

          The laws of physics work the same way there that they do here...

          And your proof is ... ?

          You can't draw any conclusions at all without that assumption. It's nearly as fundamental as assuming that there's an objective observable universe at all...

      • Unless vernor vinge was correct
        http://en.wikipedia.org/wiki/A_Fire_Upon_the_Deep
      • by Gr8Apes (679165)

        it's located someplace that we're not going to be able to verify the results.

        The laws of physics work the same way there that they do here...you don't actually have to go there to know how light will pass through the atmosphere...

        Not exactly... all I get are Server 500 errors. That's not what I pictured an alien sunset looking like.

        • by gnapster (1401889)

          Not exactly... all I get are Server 500 errors. That's not what I pictured an alien sunset looking like.

          The slashdot effect works the same way there that it does here. You don't actually have to go there to know that making the slashdot front page will cripple their servers.

      • by Brain-Fu (1274756) on Monday January 09, 2012 @04:56PM (#38641896) Homepage Journal

        The laws of physics work the same way there that they do here

        That is a metaphysical assumption of physics, not an observed fact. We won't know that for sure until we go there.

        Of course...it is probably true.

      • by mcgrew (92797) * on Monday January 09, 2012 @05:09PM (#38642080) Homepage Journal

        Indeed; they could easily figure out what a sunset would look like on one of Jupiter's moons by sending a probe. But the picture wouldn't look like what was predicted by computer model; I've never seen two sunsets that were exactly alike. Latitude, temperature, air pressure, etc -- there are too many variables. When I was stationed in Thailand in the Air Force I saw what I would have thought were breathtakingly beautiful sunsets at a certain time of year that contained all the colors there were, including green. You don't get sunsets like that this far north.

      • by Skapare (16644)

        We know what the atmosphere on Earth is like VERY well, and yet we cannot get a single image that shows what a sunset always looks like, because details of the atmosphere change, every day, everywhere. I very much doubt it is that simple on any distant planet.

    • For a while. Have a little faith, we'll get there some day. Or at least our distant descendants.

      • by hedwards (940851)

        It's a 150 light years away, we're not talking about a few thousand years worth of developments there. We would need to get very close to the speed of light for it to take a reasonable period of time to get there. And even at half the speed of light you're looking at having to wait 300 years for the probe to get there and an additional 150 years for the first results to come back.

        In the meantime you'd have a probe operating independently and being bombarded by cosmic rays. Hopefully nothing went wrong as we

        • by grumbel (592662)

          We would need to get very close to the speed of light for it to take a reasonable period of time to get there.

          Depends on how much in a hurry you are. With a Project Orion type spacecraft you could get there in a few thousand years. And while that sounds like a long while, humanity has already build things that latest that long, i.e. the pyramids.

        • Since this planet has a green sun, the photosynthetic life there can't be green, or it would reflect away all the light. They said the blue is all scattered away, meaning the plants would likely be red.

          Obviously this planet is Gallifrey complete with red fields and Timelords, and TARDISes etc.

          With TARDISes, 150 light years is no obsticle at all.

    • by viking099 (70446)

      It should be simple enough to test his method. Use it to make illustrations for Earth, the Moon, and Mars. That should give us some indication as to its accuracy.

    • It would be interesting for this guy to calculate the same thing on a planet/moon we *can* visit (Titan or Mars, for example), then see how his prediction stacks up to the real thing. If they match, cool. If not...well, iteration is a time-honored scientific and engineering principle, no?
    • by wzzzzrd (886091)
      Just wait until they discover global warming on this exoplanet, then it miraculously becomes science.
  • by Anonymous Coward on Monday January 09, 2012 @04:15PM (#38641254)

    ...they get overloaded servers there too. :P

  • by Anonymous Coward

    It would look something like this [abcnews.com]

  • Only if these aliens use the same light spectrum as we do, and use the same photo standard as we do.....and if and only if they actually SEE with the same organs as we do.
    • by gman003 (1693318)

      The question wasn't "what do aliens see on a sunset on their world?", but "what would we see on a sunset on an alien world?"

    • Re:Only if... (Score:4, Insightful)

      by Victor_0x53h (1164907) on Monday January 09, 2012 @04:27PM (#38641466)
      I see what you're going for there, but the image would be of "a sunset on an alien world", not "a sunset on an alien world as observed through the eyes of an alien". I know this is Slashdot and reading articles isn't kosher, but I thought it was ok to at least read the post's title.
    • by gstoddart (321705)

      Only if these aliens use the same light spectrum as we do, and use the same photo standard as we do.....and if and only if they actually SEE with the same organs as we do.

      Um, no ... since you clearly didn't read TFA, here you go:

      STIS covers visible wavelengths, and HD209458 is bright enough that the precision of the spectrum is sufficient for a precise translation into colours perceived by the human eye

      So, the article is showing what this would look like to human eyes.

      This in no way attempts to talk about w

    • by gl4ss (559668)

      it's a hot jupiter planet, doubt there's any life there.

      you'd think the guy would have started with what does sunset on jupiter look like tho

    • by AK Marc (707885)

      only if they actually SEE with the same organs as we do.

      If they see with the same organs I do, I'm asking for my eyes back.

  • by Anonymous Coward on Monday January 09, 2012 @04:17PM (#38641298)

    It looks to me like the sunset has a striking resemblance to a 500 error.

  • Does that mean we have to be on that other world to view it?

  • by Anonymous Coward

    I just added .nyud.net [nyud.net] to the end of the domain name and I could read the article and see the pics.

  • by nwf (25607) on Monday January 09, 2012 @04:30PM (#38641510)

    It looks like an Internal Server Error? I would have thought it would be more interesting than that. The more things change, the more they remain the same.

  • How?

  • by Anonymous Coward

    No need to travel light years far for an exotic sunset. Mars has blue sunsets:

    http://mars.jpl.nasa.gov/MPF/ops/ss24_0.jpg

    I suppose it's just whatever your atmosphere decides to refract. Ours is red-orange-yellow. Mars has blue. This one has green. And I suppose there are even purple sunsets somewhere.

    • by Arrepiadd (688829)

      Part of the color comes from what you have on the atmosphere, as different molecules absorb at different wavelengths and, as a consequence, only let go everything else. It is also due to the light the star itself emits.

      But the most important part is how thick the atmosphere is. There is a phenomenon called Rayleigh scattering [wikipedia.org] that correlates how much the light is scattered the wavelength. It basically says that the thicker the atmosphere, the more light is scattered and the more you see the reds, as opposed

  • Aaaaaand slashdotted.

    Slashdotted a planet 150 lights years away. The power of /. has no limit.
  • Seeing as this alien world would be at least a handful of light years away, I imagine that the setting of our sun looks like any other distant star setting across the horizon. ;-)

  • by Kozar_The_Malignant (738483) on Monday January 09, 2012 @05:46PM (#38642624)
    Sadly, the image seems to be obscured by smoke from the smoldering server.
  • by PPH (736903) on Monday January 09, 2012 @05:47PM (#38642648)

    I've always been too in busy in the back seat of a car with some alien babe parked at the viewpoint when they happen.

    - Captain Kirk

  • Hmmmm, the sun is the star that the earth revolves around. Our sun would just appear as a star in their sky. I would therefore imagine that the sunset on a distant planet would look much like the setting of any star in our sky, not too spectacular.

  • as any human viewer would be squashed into a fine film to possibly view this phenomena. Who cares?
  • Bluish Green.

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