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c) An alien civilization can trivial visit Earth and has been for thousands of years. You make a lot of assumptions how difficult it wouldv be to visit and eve

c) An alien civilization can trivial visit Earth and has been for thousands of years. You make a lot of assumptions how difficult it wouldv be to visit and even why they would be here.

hermitcrab 3y ago
I assume that interstellar travel is really difficult for any civilization. That assumption is based on my knowledge of physics (relativity in particular).
- cronix 3y ago
  > That assumption is based on my knowledge of physics based on your knowledge of known physics. We're still adding to the periodic table...
  - krapp 3y ago
    >We're still adding to the periodic table... That doesn't violate known physics in any way.
    - cronix 3y ago
      Very true, but the point is it just shows there's a lot we don't know still that an advanced civilization might and likely have already discovered and learned to harness/control.
  - glenstein 3y ago
    >based on your knowledge of known physics. Right, and for exactly that reason, it enjoys the advantage over competing theories.
  - dekhn 3y ago
    We're not still adding to the periodic table. https://en.wikipedia.org/wiki/Oganesson https://en.wikipedia.org/wiki/Oganesson , 118, was synthesized in 2002, and confirmed in 2015 and I don't think anybody is actively working on making https://en.wikipedia.org/wiki/Ununennium https://en.wikipedia.org/wiki/Ununennium or https://en.wikipedia.org/wiki/Unbinilium https://en.wikipedia.org/wiki/Unbinilium for lack of resources right now. If somebody is aware of groups actively working to synthesize above 119 please let me know.
- jay_kyburz 3y ago
  Why is it difficult? You just point and shoot. Will take a long time but you will get there in the end.
  - thekevan 3y ago
    I thought that way 3 or 4 years ago. PBS Spacetime has quite a few great videos about that. (Videos by actual physicists and astrologers.)
  - hermitcrab 3y ago
    First you need an incredible amount of energy to get even a modest mass out of the earth's gravity well. Then you you need a truly fantastic amount of energy to get it up to a fraction of the speed of light. Then you need an equally fantastic amount of energy to slow it down again at it's destination. Then you run into time dilation effects, which diminish the usefulness to the sender of any information they are going to get back (due to the delay).
    - jay_kyburz 3y ago
      My point was that you don't need to go fast if you have plenty of time. You just need to get out of gravity which we can do.
      - hermitcrab 3y ago
        Going slowly has it's own issues. If it takes you 100,000 years to cross the space between 2 stars, you are going to need a lot of energy/food to keep your crew/robots/computers going - because there isn't going to be much solar energy available. Also is any civilization going to invest the effort to create a probe/mission that they are not going to hear back from over that sort of time-scale?

c) An alien civilization can trivial visit Earth and has been for thousands of years. You make a lot of assumptions how difficult it wouldv be to visit and even why they would be here.

hermitcrab 3y ago

I assume that interstellar travel is really difficult for any civilization. That assumption is based on my knowledge of physics (relativity in particular).

cronix 3y ago
> That assumption is based on my knowledge of physics based on your knowledge of known physics. We're still adding to the periodic table...
- krapp 3y ago
  >We're still adding to the periodic table... That doesn't violate known physics in any way.
  - cronix 3y ago
    Very true, but the point is it just shows there's a lot we don't know still that an advanced civilization might and likely have already discovered and learned to harness/control.
- glenstein 3y ago
  >based on your knowledge of known physics. Right, and for exactly that reason, it enjoys the advantage over competing theories.
- dekhn 3y ago
  We're not still adding to the periodic table. https://en.wikipedia.org/wiki/Oganesson https://en.wikipedia.org/wiki/Oganesson , 118, was synthesized in 2002, and confirmed in 2015 and I don't think anybody is actively working on making https://en.wikipedia.org/wiki/Ununennium https://en.wikipedia.org/wiki/Ununennium or https://en.wikipedia.org/wiki/Unbinilium https://en.wikipedia.org/wiki/Unbinilium for lack of resources right now. If somebody is aware of groups actively working to synthesize above 119 please let me know.
jay_kyburz 3y ago
Why is it difficult? You just point and shoot. Will take a long time but you will get there in the end.
- thekevan 3y ago
  I thought that way 3 or 4 years ago. PBS Spacetime has quite a few great videos about that. (Videos by actual physicists and astrologers.)
- hermitcrab 3y ago
  First you need an incredible amount of energy to get even a modest mass out of the earth's gravity well. Then you you need a truly fantastic amount of energy to get it up to a fraction of the speed of light. Then you need an equally fantastic amount of energy to slow it down again at it's destination. Then you run into time dilation effects, which diminish the usefulness to the sender of any information they are going to get back (due to the delay).
  - jay_kyburz 3y ago
    My point was that you don't need to go fast if you have plenty of time. You just need to get out of gravity which we can do.
    - hermitcrab 3y ago
      Going slowly has it's own issues. If it takes you 100,000 years to cross the space between 2 stars, you are going to need a lot of energy/food to keep your crew/robots/computers going - because there isn't going to be much solar energy available. Also is any civilization going to invest the effort to create a probe/mission that they are not going to hear back from over that sort of time-scale?