How Far can We Go?
Turns out that human spaceflight is not perhaps as limited as you might think. But there is a catch. Or two.
We will never be able to explore the whole universe. It is expanding so rapidly (faster than the speed of light at the edges) that we will never be able to visit the whole thing. Which is not really a problem, because we have a whole lot to explore anyway.
But here is the interesting part. With a spaceship which accelerated at a steady 9m per second, or roughly 1g of force, up to the speed of 0.99 the speed of light it would only take 30 years for an astronaut to arrive at the spot as far away as light from our Sun could reach, roughly 15 billion light years. 30 years is incredibly quick, a single lifetime rather than many generations. It means that long distance travel really is possible.
But here is the catch. If you then turned that ship around and headed home, you would have a hell of a time making it back to Earth. At just relativistic speeds if you hit the brakes one second too late you would overshoot the earth by millions of light years.
Or actually, you would overshoot where the Earth used to be by millions of light years. Because if you flew out to the effective edge of the human universe and then flew back you would have spent 60 years exploring. But 70 billion years would have passed on Earth. The Sun would have gone out tens of billions of years before, swallowing the Earth with it, and leaving the bright galaxy you had left only 6 decades before a dark and dust filled emptiness.
So yes, humans could explore to the edge of the universe, but for whom? Personally, I find the fact that it is even remotely feasible for a human to pass 60 years but 70 billion to pass on Earth absolutely staggering. As a reference point, the consensus is the Earth itself is roughly 4.5 billion years old.
As an interesting aside, since my mind tends to jump towards these things, could it not then be possible to spend much less time in space, and instead of exploring - simply fast forward? If it were possible to climb aboard and loop around the universe, coming back in a decade or two but 1,000 or 10,000 or 1,000,000 years ahead - would you take the risk?
We will never be able to explore the whole universe. It is expanding so rapidly (faster than the speed of light at the edges) that we will never be able to visit the whole thing. Which is not really a problem, because we have a whole lot to explore anyway.
But here is the interesting part. With a spaceship which accelerated at a steady 9m per second, or roughly 1g of force, up to the speed of 0.99 the speed of light it would only take 30 years for an astronaut to arrive at the spot as far away as light from our Sun could reach, roughly 15 billion light years. 30 years is incredibly quick, a single lifetime rather than many generations. It means that long distance travel really is possible.
But here is the catch. If you then turned that ship around and headed home, you would have a hell of a time making it back to Earth. At just relativistic speeds if you hit the brakes one second too late you would overshoot the earth by millions of light years.
Or actually, you would overshoot where the Earth used to be by millions of light years. Because if you flew out to the effective edge of the human universe and then flew back you would have spent 60 years exploring. But 70 billion years would have passed on Earth. The Sun would have gone out tens of billions of years before, swallowing the Earth with it, and leaving the bright galaxy you had left only 6 decades before a dark and dust filled emptiness.
So yes, humans could explore to the edge of the universe, but for whom? Personally, I find the fact that it is even remotely feasible for a human to pass 60 years but 70 billion to pass on Earth absolutely staggering. As a reference point, the consensus is the Earth itself is roughly 4.5 billion years old.
As an interesting aside, since my mind tends to jump towards these things, could it not then be possible to spend much less time in space, and instead of exploring - simply fast forward? If it were possible to climb aboard and loop around the universe, coming back in a decade or two but 1,000 or 10,000 or 1,000,000 years ahead - would you take the risk?
Comments
Post a Comment