-
Asked by zaynahkhan to Simon on 19 Nov 2013.
-
Simon Langley-Evans answered on 19 Nov 2013:
It is thought that most galaxies have a black hole at their centre and that this might be an important element of how galaxies form. The Milky Way has a black hole at the centre.
Other galaxies are a vast distance away. The closest one too us is the Andromeda Galaxy which is 2,538,000 light years away. That means that if you could travel at the speed of light (which you can’t) it would take 2.54 million years to get there! In the spacecraft we have available today it would take 785200000000000 years. Intergalactic travel clearly isn’t possible…
-
Comments
Susan commented on :
Hello zaynakhan!
I wanted to comment on this question, as Simon didn’t mention something really important that would allow us to visit other galaxies: …. time travel!
I am very excited about space travel! But unfortunately, our current fastest spacecrafts don’t go fast enough to allow us to reach the nearest galaxy in a human lifetime.
The fastest that we could ever travel is the speed of light and, as Simon pointed out, even at that speed it would take you 2.54 million years to reach the nearest galaxy.
But Simon didn’t mention the key point of Einstein’s theory: the faster you travel, the slower time moves for you, compared to your friends waiting for you on Earth.
So this means, that if you managed to travel at close to the speed of light, you could travel to another galaxy and back to Earth again within MINUTES according to your watch!
The paradox is that time would move much quicker on Earth, so by the time you got back to Earth, time would have moved on by several million years, so none of your friends and family would be around to greet you anymore.
That is why intergalactic travel probably IS POSSIBLE, but at the moment we haven’t developed good enough technology to allow us to travel fast enough to get there within a human lifetime.
Simon commented on :
Good one Susan. I had forgotten the Relativity problem with travelling at light speed. What you have basically said is that yes, you could travel to another galaxy if you could travel at millions of times the speed of light, but when you got home, everything and everyone you had ever known would be part of the Earth’s fossil record. Theoretically possible, but who would want to do it? Who would want to pay to build a craft that only the occupants would survive to see work?
zaynahkhan commented on :
thank you all for your brillant answers
Susan commented on :
People who didn’t want to come back? I think such a spacecraft could be really useful if we ever want to move our civilisation to a new home in a new galaxy!