• Question: do black holes help you with the theory of time travel

    Asked by anon-206139 to Zoe, Kai, Jose Eliel, Hannah, Hamid, Claire on 12 Mar 2019. This question was also asked by anon-206140.
    • Photo: Jose Eliel Camargo Molina

      Jose Eliel Camargo Molina answered on 12 Mar 2019:


      Hi!

      So, as far as we know time travel backward (as in going to the past) is not possible. But obviously, time travel forward (to the future) happens all the time (pun intended).

      Black holes are essentially super massive objects that are also small. So they have a huge gravitational force. General relativity (the theory describing how gravity works) tells us that any object with mass creates a curvature (a sort of stretching) in spacetime.

      Spacetime is just the combination of space (think your room) and time into the same structure (Here is a good video about it: https://www.youtube.com/watch?v=ScdLqAA_64E). Think of it as a flipbook (those little books that if you flip through it quickly you see an animation). A flipbook is an object that has space (each page with a drawing) and time (each page corresponds to a moment in time).

      A black hole with all its incredible amount of mass takes that spacetime around it and stretches it out, which means that crazy things can happen: Time can speed up, things get stretched out … and so on.

      Earth is already capable of doing it! The clocks in GPS satellites have to be adjusted to be in sync with the ones on Earth, as being further away they feel much less of that stretching caused by Earth’s gravity. The clocks in the GPS satellites appear to run about 38 microseconds faster each day than the clocks on earth. Isn’t that crazy? The coolest thing is that we can use math to calculate this and can correct and account for it and still get accurate results of your position (this is happening in your phone too!!)

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