Timeline for How can I move a planet?
Current License: CC BY-SA 4.0
3 events
| when toggle format | what | by | license | comment | |
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| Jun 1, 2019 at 22:37 | comment | added | Hypnosifl | Let's be generous and say you convert 1% of the mass of the Earth's entire crust to fuel (which would be a lot considering the crust ranges from 5-70 km depth, converting all the mountains on the planet wouldn't get you close) and that the whole crust is 1% of the Earth's mass, in which case 0.0001 of Earth's mass is turned into fuel and expelled & after burning that fuel the Earth is 0.9999 of its previous mass. If the exhaust goes at the speed of light, c, then the shift in velocity is c * ln(1/0.9999) = 0.0001c = about 30 km/s, while escape velocity from Sun at Earth's distance is 42 km/s. | |
| Jun 1, 2019 at 22:23 | comment | added | Hypnosifl | The rocket equation would still apply & doesn't depend on how fast you accelerate, just what your ultimate change in velocity is. If you only use a tiny fraction of the Earth's entire mass (implied by only using a small fraction of the Earth's crust like mountains, keeping in mind that the entire crust is less than 1% of Earth's total mass), your fuel mass is going to be tiny compared to your payload mass, so the change in v will be small even if exhaust velocity is light speed. | |
| Nov 26, 2018 at 15:37 | history | answered | Tom | CC BY-SA 4.0 |