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B Could we shade the Earth from the Sun to save Earth?

  1. Sep 12, 2017 #21
    No need for the first ftp:// just sayin
  2. Sep 13, 2017 #22
    Earth could be shaded one day as a byproduct of other things- https://en.wikipedia.org/wiki/Space-based_solar_power
    So if your wondering.....if everyone has the same standard of living as Canadians, they would consume 20kw energy pp and at 10B future population that is 200TW global energy. This would require 142 000km 2 collecting area (at 100% efficiency) and block out .1% of all sunlight earth receives(less on a practical level).
    * It would be self defeating in some way, as you are emitting energy in infrared, that goes to Earth, as well as beaming the energy down to earth.....unless you beam that energy somewhere else......
  3. Sep 15, 2017 #23


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    Hear hear. I have often advocated painting the Sahara Desert and other open spaces with white paint or covering it with reflective foil. You could miss the difficult bits like mountain sides and big rocks. Still, a 10% portion of the Earth's surface would need a lot of paint. It makes me laugh to read stuff that people write about "terraforming Mars" when you realise that the idea of terraforming Earth is constantly being rejected. It would be cheaper than doing Mars AND we would all benefit from it!
    Manufacturers could pay a tax which would correspond to a certain area (10m2, say, of the Earth being rendered reflective for every kg of carbon produced in the manufacture of every item.
  4. Sep 18, 2017 #24
    I appreciate all the posts. It turns out that this is in part an old idea. There is a Wikipedia site named Space sunshade but these solutions are all in response to Global Warming not extending the life of the planet when the "habitable zone" no longer includes Earth. So from that perspective, it seems to be a new idea. I think that in the near future we could develop the technology to do this and maybe every 5 or 10 years send up a L1 station that would block or reflect enough solar energy to keep pace with this natural increase. The result would be an Earth with basically the same climate we have today a billion years in the future.
  5. Sep 18, 2017 #25
    Since Sun's evolutionary luminosity increase is very slow, it might make sense to move Earth farther from the Sun.

    One way which seems possible is to place an asteriod very slightly closer to Earth than L4 Lagrange point, so that it slowly "falls towards Earth" - which in turn, exerts a force on Earth which, over many years, slowly widens its orbit. Install high-Isp engines (such as ion engines) on that asteroid to keep it from drifting relative to Earth.
  6. Sep 18, 2017 #26

    I like Serena

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    How about changing the weather so that we have clouds by day, and open sky by night?
  7. Sep 18, 2017 #27


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    Lovely for astronomers. :smile:
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