What if we could travel at 0.9c?

If we could travel at up to 90% of the speed of light, how would our lives be different?

I am making the assumption that it is fairly easy to travel at these speeds, so we don’t have to worry about the cost of building rockets and the like.

We could travel around the earth faster. While travelling between places close together at 0.9c would be a bit impractical – overshooting would be far too easy, and crashes would be very dangerous – , we could certainly set up a transit system between countries that was a lot faster than flying. It would be a lot easier to get to the other side of the world, so we could take more oppertunities to explore, and places would feel closer. I’d expect that would eventually mean places becoming more similar as we build greater links and closer contact between people on different continents who currently can’t physically meet each other without hours worth of travel.

We could reach other planets easily. On average (it depends on the comparitive parts of orbits we’re in) it would take less than 4 1/2 minutes to reach Mars, and slightly under 4 1/2 hours to reach Neptune. That gives possibilites for lots of interesting research, or building facilities there – offices, running tracks (Mars Olympics, anyone?), laboratories, or whole cities, if we didn’t just use the places as a massive landfill site.

Alternatively, we could do a lot more exploration of further afield – a one way trip to alpha centauri would take about 4 3/4 years. Not exactly short, but enough that we could send expeditions. It would still, however, take thousands or millions of years to reach the centre of our galaxy, or to reach the Andromeda galaxy, respectively, so there are many places still out of reach.

At least, that’s the time it would take when watching from Earth. At more than about 0.1c, we have to start taking in to account relativistic effects. Someone travelling at 0.9c relative to Earth will see the distances they are travelling appear to shrink, while people watching them from Earth will see time appear to go slower for the travellers than on Earth.

If you were on a ship travelling at 0.9c to alpha centauri, you would see the distance between earth and alpha centauri (ignoring acceleration – this is a blog and I’m not a physicist) as only about 1.9 light years. So in the journey there you would only experience about 2.1 years. If you stayed there and explored a little and then came back, you would find that everyone on earth had aged about 5 years more than you had, which could be…interesting. There probably would be seme people willing to go that far and have the catch up to do when they returned, so we could get some interesting data.

If you tried to travel to the centre of the galaxy, however, you’d still be experiencing about 13000 years while doing so, so exploration there is still out.


What if we could travel at the speed of light?

Then we get to rewrite physics. Yay!


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