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Yeah, per definition: 1 light year is an unit of length that light travels in one year; equal to just under 10 trillion kilometres (or about 6 trillion miles)
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Originally Posted by elnina
Yeah, per definition: 1 light year is an unit of length that light travels in one year; equal to just under 10 trillion kilometres (or about 6 trillion miles)
Only valid during off-hours (!) or when there is no accident on the way, because of people rubbernecking ...
Does it mean we would need to travel for 4 years at the speed of light, if it were possible, in order to get there?
Well, technically it would take at least slightly more than four years because the speed of light is unobtainable for us non-photons.
The term light-year can be deceptive because at a layman's first glance it intuitively appears to be a measurement of time but rather it is one of distance.
The only thing I can't quite get my head round is that if you can travel at the speed of light, it should indeed take 4 years to get there, at least from the pov of someone based on Earth. But would it take 4 years if you were actually on the spacecraft given that if you are travelling at that speed you could witness a change in Time/Space, so that it just "seems" like 4 years, when in fact it is actually less than that!
Something to do with Einstein's Law of Special Relativity, I think.
The thing is that accelerating to the SoL will take some pretty significant time. It's not like tromping the gas when the light turns green and hitting top speed in a few seconds. The energy it will take to reach the speed of light will be pretty significant. And then, of course, once you get there, you have to decelerate.
The thing is that accelerating to the SoL will take some pretty significant time. It's not like tromping the gas when the light turns green and hitting top speed in a few seconds. The energy it will take to reach the speed of light will be pretty significant. And then, of course, once you get there, you have to decelerate.
Ramp up to the speed of light. At the halfway point turn around and decelerate the rest of the way. I'd guess more like 10 years at least.
Ramp up to the speed of light. At the halfway point turn around and decelerate the rest of the way. I'd guess more like 10 years at least.
So, I guess if you have a known mass of the craft to be used, and a known thrust rate capability, you could calculate how far you can go in acceleration, and at what point you need to begin deceleration.
Problem at this time is the need for fuel, and the mass of the fuel figures in, as well, but then as it diminishes, the rate if consumption has to figure in. Especially in the deceleration stage. So it won't actually be physical half-way point, I think.
Definitely going to be a while before we are truly ready for interstellar travel.
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