• Question: What is energy? Can you define it? Also, how do magnets work? One more: is time travel ever possible and why?

    Asked by 11vinceh to Christina, Colin, Jess, Samaneh, Steve on 17 Jun 2013. This question was also asked by mohamed1.
    • Photo: Steven Gardner

      Steven Gardner answered on 17 Jun 2013:

      Energy is that which gives you the ability to do mechanical work.

      More simply, it’s what you need to move or change a system in some way.

      Permanent magnets work by exposing a specific alloy to a high magnetic field, with gives is a magnetic current that is difficult to remove.

      Time travel is probably not possible, in my opinion. The best argument I’ve heard against it is that if it were possible, where are all the people from the future that have come back to visit us?

    • Photo: Christina Pagel

      Christina Pagel answered on 17 Jun 2013:

      Steve – the people from the future are all hiding!

      seriously though, about time travel, there’s an idea that some things can travel time but you can’t send information between times (because it breaks what’s called the principle of causality – that the cause of something has to predate the effect). But it is a really interesting problem, because there’s nothing (as i understand it) in the laws of relativity or quantum physics (the most successful physics theories ever) that says you definitely can’t time travel. And in fact quantum entanglement says you can change distant objects at the same time – which is time travel in a sense…

      here’s an article about it that explains much better than i can!
      http://gajitz.com/quantum-entanglement-suggests-time-travel-is-possible/

Comments