Interstellar Colonisation

[colinha]

Recently the likelihood of Earth type planets has been shown to be higher than was expected.
Relativistic effects mean that time dilation makes possible journeys of cosmic distances.
For the mathematicians, how long would an interstellar colonisation mission take at an acceleration of 1g to a hypothetical Earth type planet 40 light years distant from the point of view of the colonists.
Is such a mission possible if a source of continuous acceleration ( and deceleration ) is found?

[ChuckFickens]

tooo early!

But very roughly I make it about 15months (assuming that the craft would have to start decelerating at the half way point)

[ChuckFickens]

it would make the directions tricky.

[ChuckFickens]

15years even!

(knew months didn't sound right)

[R1Geezer]

hang on, chuck, 15 years, to a system 40 light years away? so you have warp drive then!

[eltelioni]

The question was "how long .... from the point of view of the colonists". They are traveling fast so they experience time dilation. To an observer on the Earth the journey will take much longer. In the extreme, a photon appears to take 40 years to make the journey, but in its own frame of reference it gets there in no time at all.

[jake-the-peg]

Sorry to disappoint you Colin but it doesn't work.

As you get closer to the speed of light for your time dilation effects the relativistic mass of your spacecraft increases too making it harder and harder to maintain that 1g acceleration.

The energy required to keep it up is impossible

But we'll ignore that because you have so many other problems - not least every speck of dust you hit at that velocity.

say you hit a milligram piece of dust at .9c

that's 36 billion joules of energy about the same as 9 tonnes of TNT - and there's a lot of milligram specs of dust in 40 light years

[mibn2cweus]

Zacsmaster, That calls for a ride in The Way Back Machine . . .

https://www.youtube.com/watch?v=Xki7lbro9_U

http://www.youtube.co...pQ-nw&feature=related

http://www.youtube.co...BTiHg&feature=related

http://www.youtube.co...uGNoM&feature=related

[eltelioni]

Jake - you are a spoilsport. We will ionise the dust particles with lasers then, using a magnetic scoop, we will direct them into our engines and use them as reaction mass. The faster we go, the more dust we will collect. If we carry antimatter to annihilate the dust particles then we have plenty of energy to maintain 1g.
Chuck - how did you calculate 15 years? I have forgotten how to do the maths.

[jake-the-peg]

Ah right anti-matter of course - say while you're at it why don't we all just teleport there ? or would that be silly?

Anti-matter only exists in subatomic particle form I think an anti-hydrogen atom was once achieved for a fleeting fraction of a second but you might as well suggest dilithium crystals as anti-matter

Your problem is still the engineering one of getting the craft to that speed in the first place. Ionising the particles with lasers won't help you either. You'll just collide with the debris!

The question was is such a mission feasible if you had a magic power supply - the answer is no - there are other problems.

Sorry if you don't like it - lots of fun dreaming about visiting other stars but I'm afraid that's what it will always be - the distances involved are just mind numbingly huge.

To date our longest space flight is a little under 2 light seconds and you're asking about something 6 Billion times further .

I'd say that it's like someone who can swim a width asking about swimming the atlantic but at that scale it's not a width of a swimming pool it's about the thickness of a human hair.

Mankind had best start making the most of the planet we have - we are not going to be leaving it

[R1Geezer]

Jake is correct, it seems harsh to the clueless but really the distances are so vast and our speed so small that it will never happen. We may visit other planets in our solar system but that'll be it. Pity because the universe is teaming with life that we have no way of communicating with it.

[rov1200]

I'm surprised why we need to send our rockets into deep galactic space. Why not hitch a ride on one of the passing comets or other space objects that scour the universe by planting a camera on the surface?

[R1Geezer]

oh dear rov, you really need to get your head around it. OK let's look at the the first radio broadcasts, say a century old, so they have been heading out into space for 100 years at the speed of light as an expanding sphere from Earth. so we now have a sphere 200 light years across, tiny, no where near out of our own galaxy which is estimated at 100,000 light years across, see what I mean, so how far into "deep galactic space" do you think we'll get in our primitive rockets, when even at lightspeed we havn't got there? As fo intergalactic space forget it. Again with the comet idea, forget it, they only orbit the sun, well the ones we'd be able to hitch hike on. That's like walking to the front gate in galactic terms.

[mibn2cweus]

Colinha, Killjoy seems to have forgotten about time d i l a t i o n? Expand your m i n d . . .

A uniform acceleration of 1g (9.90665m/s/s) would bring us (coincidently) a distance of 1ly within one year (31556926 sec/year). If one could set sail on a Sun beam on could hope to reach an hospitable planet (the first of many on which to raise a family) in one life time. Remember . . . there is no passage of time at c . . .

One can live a lifetime in a dream . . . I've lived a million years in one trip of the imagination alone. ;o)

But with all due respect to Jake (which is no small sum) we won't get far burning trees.