• Question: Will human ever be able to leave our galaxy and go to a different one?

    Asked by dannyb to Alastair, Emma, Hywel, Keith on 24 Jun 2010 in Categories: .
    • Photo: Alastair Sloan

      Alastair Sloan answered on 23 Jun 2010:

      Hi Danny

      At the moment I would say no, simply because the distance to travel to our nearest neighbouring galaxy is so long – about 4 million light years away!

    • Photo: Keith Brain

      Keith Brain answered on 23 Jun 2010:

      Yes, I think that they will, although its going to be tricky. We could use something called “time dilation” (or “length contraction” – depends on how you think about it) to get to another galaxy like the Andromeda Galaxy, 2.5 million light years away. This is a property of “special relativity” described by Einstein.

      In order to do this we can hop in a spaceship and travel at 99.999999999992% of the speed of light (think that I got this calculation wrong before, missed a square root) for 1 year (as time appears to pass to you in the spaceship). The problems here are:

      – while only 1 year appears to pass to you on the spaceship, more than 2.5millions years will have passed on earth, so there will be no going back and meeting the relatives … in fact, probably no going back and meeting the same species.
      – getting a person (in a spaceship) to 99.999999999992% of the speed of light requires a lot of energy, so we’ll have to assume that scientists will develop a way of converting matter completely and efficiently into energy.
      – the human body can only cope with a certain acceleration (g-force), which means that you can’t speed up very quickly. So, it will take a long time to get up to speed … I haven’t done the calculation, but I guess its going to take even longer than a year, so …

      We also need “suspended animation”. Lots of Sci Fi movies and books use this (like Alien) – for moving between stars, and we’ll need it in a big way here. It basically involves freezing someone so that they don’t age. Is it possible? I think it will be, in the distant future. We can already freeze human eggs and sperm, and animal (early) embryos, so I think that for adult humans it will eventually be possible. We can already cool humans down to greatly slow their metabolic rate (this is does for some very major heart operations).

      So, lots of technical problems, but I think we’ll get there if we don’t kill each other first!

      PS: You can check the calculation using one of the formulae on the “time dilation” Wikipedia page:
      http://en.wikipedia.org/wiki/Time_dilation

    • Photo: Hywel Vaughan

      Hywel Vaughan answered on 24 Jun 2010:

      Good question danny,
      I think we will eventually, but I don’t believe we will in this life time or indeed in the next. I think we have a much better chance of leaving the solar system before we even attempt the galaxy!
      The problem is the sheer distance you would have to cross in order to leave our galaxy. Even if you travelled at the speed of light, it would take you millions of years to cross it. Unless we discover a method of propulsion or a way to reduce that distance, I don’t see it happening any time soon!

Comments

  • Photo: benjook

    benjook commented on :

    scientists say that climate change is going to be big in a couple of years and that nasa are building rockets for the rich people to fly on to a another galaxy so they can survive, but personally i think if we do something now we can all change the world

  • Photo: lupusmortii

    lupusmortii commented on :

    what if we bend space. imagine a noodle the length of the noodle is the leangth you want to travel however if you bend the noodle in a circle you can go backwards to the other end much more quickley this could also pave the way for a perpetual motion machineif you open a hole in space the opens above itself you could drop in an object whitch would keep passing through the same space for as long as you left it there unless you had to use energy to keep the hole opened

    • Photo: Hywel

      Hywel commented on :

      I think you have identified the key problem there lupus – energy. Some scientists have theorised that space itself can bend, but it would take an amount of energy far beyond anything we are (or likely to be) capable of.
      Great idea though – I love the noodle analogy!

    • Photo: Keith

      Keith commented on :

      You don’t have to invoke space bending to have perpetual motion – all you have to do is have no friction or drag. If your space noodle had friction the object would still slow down. We can just about get perpetual motion by heading off into deep space and giving an “pushing” an object – Newton’s First Law of motion (which still holds) shows that it will continue on “essentially” forever.

      For true perpetual motion, I agree with Hywel – conservation of energy (or mass-energy) is the problem!

      By the way, space-bending is predicted in strong gravitational fields by the General Theory of Relativity, so the space around black holes is decidedly bent …