Whenever someone talks about sending robots to extra-solar planets by accelerating them close to the speed of light (perhaps using lasers) - for example I believe Hawking suggested this. It always occurs to me that they will be travelling through a very sparse gas of hydrogen (1 atom per cubic centimetre).
For a slow spaceship this would be essentially a vacuum, but for a spaceship travelling at, say 0.5c, it would feel like billions of hydrogen atoms hitting the spaceship at velocities of 0.5c.
Assuming that the spaceship can withstand 3000 degrees F. I wonder if a spaceship would simply melt when travelling at 0.5c due to collisions with hydrogen atoms.
I find it strange that this issue never seems to be talked about in popular articles about interstellar travel. Perhaps it is not a big issue as I made out?
Anyway, my question is: What temperature and force would the spaceship experience when travelling at 0.5c in interstellar space due to the sparse hydrogen atoms in empty space?
