Recent content by oracle99

I was thinking of a solar thermal rocket, which can deliver a large acceleration when close to the sun, but fermi is also interesting. https://en.wikipedia.org/wiki/Solar_thermal_rocket The feeling is that these slower proposals will get overtaken later by better designs, so they don't...

Thanks, I was not very clear, yes I meant the threads first post, rather than my last one. .94 c is quite a speed, I think there are practical problems such as the heat generated hitting extremely small particles or atoms at that velocity. One of the articles above mentions using light sails...

I wonder what would be the peak speed in this scenario, as a % of light speed?

For those interested in the practical side of interstellar travel, the Universe Today have a 5 part series covering the history of proposed projects, from using atom bombs in the 50s (!) through to solar/magnetic sails, and "space warps"...

Yes, I suppose its more than a perception, its how the traveller experiences time. If we also place earth in the gravitational well of a black hole, could it be arranged that time elapses at the same rate for the folks back home?

Yes, I understand it is only percieved time elapsed, the traveller cannot actually travel faster than light.

In the original question I made a point if returning the traveller to the original frame of reference, earth. Obviously i bow to your superior knowledge, but maybe there is a misunderstanding? The above calculation says the traveller will see 3.5 years pass when travelling 4 light years..

I understand that the traveller is not literally travelling faster than light, just that you would percieve that, in that time frame. And yes, the practical problems in actually doing it are massive, and even if you are very close to a "perfect" engine, you need to carry insane amounts of fuel...

There is an old joke "you can put a billion dollars worth of plutonium into a suit case, but only briefly.."

So if you travel 3 years you get sqrt(3*3+1)-1= 2.16 light years, about half way to Alpha Centauri, so decelerate is the same, so approx 6 years out, 6 years back, 12 years, from the travelers perspective? oh I see you updated it, that would be earth dwellers time. Thanks! Another little point...

I thought about it in these terms: If you converted the entire mass of the earth into energy, (by E=mc2) that vast amount of energy would still only exert 1G of gravity.

Just a simple little question as my first post here.. Suppose you have a space craft that has an engine that can exert an acceleration of 1G. You fly this to Alpha Centauri accelerating, then halfway turn around and decelerate at 1G, so you have gravity for the whole trip. Once you arrive, you...