Comment by ArtDouce on 14/09/2022 at 14:39 UTC

3 upvotes, 1 direct replies (showing 1)

View submission: Ask Anything Wednesday - Physics, Astronomy, Earth and Planetary Science

Given the limitations of materials and the fact that space isn't actually empty (~1 to as much as 1,000 H atoms per cm^3), how fast would it be possible for a large object (say big enough to carry a reasonable number of people and supplies) to travel through space?

Note our current highest temp material is good to ~4,000 C.

For this question, I think its fair to assume we could possibly double this.

I've read assertions that its C/10, but can't quite work out the math to prove or disprove it.

Replies

Comment by BluScr33n at 14/09/2022 at 23:08 UTC*

5 upvotes, 1 direct replies

Assumptions:

• cylindrical ship of 150m length (should easily fit 100 people)
• interstellar medium with a density of 1 atom per cubic centimeter
• all the kinetic energy from hitting the particles is converted to heat
• constant velocity
• perfect emissivity of spaceship (epsilon = 1)

Using these assumption I used the Stefan Boltzmann law of thermal radiation and the relativistic kinetic energy formula to calculate the temperature of the spaceship due to the collisions with the particles in the interstellar medium. The temperature of the ship turns out to be about ~~1K~~ 1000K for velocities of 0.99c.

disclaimer: this is just a back of the napkin calculation, don't quote me on this

Edit: The temperatures are actually in the hundreds of K