• Question: is time travel possible on earth and not using space crafts?

    Asked by olisfruit to Chris, Michael, Paddy, Philip on 22 Jun 2011. This question was also asked by bexstar.
    • Photo: Michael Wharmby

      Michael Wharmby answered on 22 Jun 2011:

      Currently, no we can’t do time travel, not in the Back to the Future sense at least!
      We can however do time dilation – different objects experience time differently depending on how fast they are moving. It’s a trick of relativity which I don’t pretend to understand!

      The experiment to do this was to put synchronised atomic clocks on aircraft and fly them around the world and compare the times after the flight with a clock on the ground. Atomic clocks measure time by following the speed of decay of radioactive caesium atoms – there are no moving parts, so any differences in time are due to how the decaying caesium experience time. The flying clocks lost a few nanoseconds (i.e. they experienced time more slowly than the clock on the ground). So in a sense they did travel through time. Sort of.

      More here:
      The experiment in more details: http://hyperphysics.phy-astr.gsu.edu/hbase/relativ/airtim.html
      Time dilation from wiki (there is a full wiki page on it, but it looks horrendous!): http://simple.wikipedia.org/wiki/Time_dilation

    • Photo: Philip Denniff

      Philip Denniff answered on 22 Jun 2011:

      I am but a mere chemist so know nothing of these things. But wouldn’t be great, I could sit the exam again and pass.
      Time travel is easy in science fiction stories, the one I like is the Time Machine by HG Wells http://www.gutenberg.org/ebooks/35 (its only a short story), where just before the inventor sets off he tells his friends not to wait for him if he is late for tea. I wont tell you who sat the tea table.

    • Photo: Chris Jordan

      Chris Jordan answered on 22 Jun 2011:

      We can’t do time travel (except in the normal forwards direction at 24 hours a day) on earth or in space craft. There seems to be no pointers in our current science as to how we could do this either … but something might turn up eventually. And there’s the paradox that if we get time travel in the furture, why don’ t we have future people coming back to see us – except in books and movies?)

    • Photo: Paddy Brock

      Paddy Brock answered on 22 Jun 2011:

      No, I don’t think so, but if you want to know what the earth might have looked like very early on in it’s history, you can visit some recently created volcanic islands. One Galapagos Island (Fernandina) is only ~70,000 years old, so plants and animals are only just beginning to colonise it and it’s mostly black, jagged rock (dried lava). Being there feels very much like you’re going back in time.

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