Question: Will human ever be able to leave our galaxy and go to a different one?
Alastair Sloan answered on 23 Jun 2010:
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!
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:
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!