Submitted by darthatheos t3_10ve1np in space
[deleted] t1_j7hwnqn wrote
Reply to comment by moral_luck in Rolls-Royce Nuclear Engine Could Power Quick Trips to the Moon and Mars by darthatheos
How many megajoules per kg is it?
moral_luck t1_j7i2c65 wrote
Einstein's most famous equation (E=mc^(2)) limits energy density of any fuel to 9 x 10^(10) MJ/kg
And that would be an antimatter reactor. Physics means no fuel can have infinite density.
[deleted] t1_j7i5cy1 wrote
Light. Zero mass. Lots of energy.
moral_luck t1_j7i7wee wrote
Where did the light come from?
SowingSalt t1_j7jjchk wrote
Therefore in the ratio mJ/kg, light is undefined and cannot be on the chart; which was the original point.
moral_luck t1_j7hz7ym wrote
Solar energy is hydrogen fusion, deuterium–tritium fusion is about 338,000,000 MJ/kg.
But we don't have the technology to create miniature suns in our rockets.
BTW, U-235 fission has an energy density of about 144,000,000 MJ/kg.
Another source puts the energy density of the sun's core around 6.43 x 10^(8) MJ/kg, or 643,000,000 MJ/kg.
The second source is titled The Source of Solar Energy.
[deleted] t1_j7i5md1 wrote
That's fusion reactors not solar energy on the surface of the earth
moral_luck t1_j7i7uhl wrote
Where does the solar energy on the surface of the earth come from?
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