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How to describe position of our solar system to some ETI in other galaxy?

  1. Sep 18, 2011 #1
    Hi, I am wondering how to describe a position of our solar system to some other extraterrestrial intelligence in some distant galaxy to find us? Is it possible or not?

    i mean if such guidance exist for any galaxy or they have to track back movement of your probe or spaceship etc. and some coordinates are not helpful at all.

    I mean if you want to send a thousand of "near-the-speed-of-light-spaceships" to every direction possible (within 1000x limit) so after a hundred or thousand years they arrive to many galaxies and if the ETI find this probe, how can they track it down to the place of origin?

    What should be on the "ETI-invitation-info-message"?

    Is there a way of universal coordinates/position no matter of where the receiver will be (up,down,left,right,front,back etc.) or this is imposssible to achieve.

    Thanks in advance.
  2. jcsd
  3. Sep 18, 2011 #2


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    The only way I can think of is to describe the initial position of Earth in relation to the rest of the galaxy and hope they can figure out the path we took in our long orbit of the galaxy. By the way, at 99% the speed of light, it would take over 2 million years to reach the NEAREST galaxy to us.
  4. Sep 18, 2011 #3
    Within our own galaxies, I know that the plaque on the Pioneer 11 probe had our position relative to 14 bright pulsars, with the periods of each pulsar written on the plaque in binary.

    Outside of our galaxy, it would be much harder, mostly because as Drakkith said, by the time a probe reached another galaxy, the sun would have rotated so much that any way of triangulating our star would most likely be invalid.
  5. Sep 18, 2011 #4


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    Assuming a 4-5 million year round trip for a probe to reach Andromeda and the ships launched to make it back to the Milky Way, the solar system would have made about 1-2% of it's journey around the galaxy. So for Andromeda the error would not be large, but for further away galaxies it would quickly become much larger.
  6. Sep 18, 2011 #5
    Ah, for some reason I was thinking the sun had an 60,000 year orbital cycle around the Milky Way's core, which now that I think about it is obviously incorrect.
  7. Sep 19, 2011 #6


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    Yep, it takes about 225-250 million years for 1 revolution.
  8. Sep 19, 2011 #7
    thanks guys :smile:
  9. Sep 20, 2011 #8


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    Using pulsars is a very good idea, but, advertising our presence to the universe is probably not such a good idea. Heaven forbid, they might be just like us.
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