• Question: is it possible to time travel? what is the science behind it?

    Asked by Lydz to Frank, Ian, Isabel, Zena on 18 Mar 2015.
    • Photo: Isabel Pires

      Isabel Pires answered on 18 Mar 2015:

      If you consider Einstein’s Theory of General Relativity, travelling into space is actually travelling in time forward to the future!
      According to this, if I were to travel away from Earth (lets say to Saturn) and back, the journey would have only lasted a few years (according to my clock) but on return to the Earth, thousands of years had passed (according to Earth time clocks). The time passed depends, or is relative, to what point you use as a reference, either my clock or Earth time clock. It is complicated, right? I still get confused by it…

      Travel back in time is harder to explain… As Steve Hawking said, the reason we have not seen any “time tourists” from the future, should mean that it is not , in fact, possible. But scientists do have different theories about this…

    • Photo: Zena Hadjivasiliou

      Zena Hadjivasiliou answered on 18 Mar 2015:

      Just to add to what Isabel said, travelling into time according to Einstein’s theory depends on the speed at which something is moving. For example, time moves very slowly for a spacecraft that moves very very fast. So if I got in an spacecraft that was sent into space and travelled at very very high speed when I get back to the earth I will be younger than all my friends that now have the same age as me! It is mad to try and understand this! But in reality, it is very hard to make spacecrafts that move fast enough for this to happen, or for a person to be able to travel at such high speeds!