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I want to add a planetary propulsion to Earth, to be able to move it at subluminal speeds.

I found this document , taken from What is the largest planet size that can be pushed out of orbit?. I want to rely on big reactors, such as those described in the movie "Wandering Earth". In this movie, planetary reactors are constructed in the northern hemisphere and around the equator.

Where should I put reactors geographically speaking on Earth to steer it ?

Let us imagine here that energy requirements and technologies available don't restrain any propulsion system from being applied.

EDIT: Reactors would be added on an exterior shell supported by massive pylons connected to Earth, not directly on Earth.

Elyo
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  • Your biggest problem is that the earth is not "solid" in the way that reactors can push it. When you try to push it, it will deform. The mantel will move. Even the continental plates will buckle, break, and shift under pressure. With all the earthquakes and volcano eruptions that will happen because of that push means that I would not want to live on such a planet. – David R Jul 17 '22 at 13:36
  • So, If I wanted to do this, that would mean geologically terminating Earth before, making it a dead solid rock ? The structure I was thinking about was making a big bubble around Earth with gigantic pylons connecting it to the surface and deep below into the mantle and putting the reactors on that shell, making the pylons so that it would spread the efforts on the surface equally, would it work? – Elyo Jul 17 '22 at 13:45
  • I wonder what acceleration your proposed thruster system would provide to Earth. If anything less than 1G total (at full power), you won't break the crust. But if you'd want to move Earth, you would either need engines on every side, or first stop Earth's spin. – Vesper Jul 18 '22 at 13:40
  • @Vesper and stopping Earth Spin would mean destroying everything on the surface. As I was imagining it, I would build a shell around Earth fixed to the crust. This topic is somewhat linked to a post I made about making the Sun go supernova. Indeed, I want to use Earth as an ark for humanity, with a planetsized warp drive, and to move it to a good orbit around a new star, I need subluminal engines. This is part of my "research" to build my own sci-fi universe for my drawings. – Elyo Jul 18 '22 at 18:40
  • Well you don't need to instantly stop a planet's spin, decelerating its rotation could take years. Yet, preserving life while despinned planet accelerates, and then while it travels between stars would take some serious efforts. Doable IMHO, at least while a civ can move a planet, it can heat it enough to not freeze, and make a rotating light to emulate Sun is not a hard task compared to giving planet subluminal thrusters. – Vesper Jul 27 '22 at 15:57

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The moon.

training droid https://starwars.fandom.com/wiki/Marksman-H_combat_remote

I humbly submit the Moon would look like the training droid from Star Wars. There are many benefits. The moon is less mushy than Earth and much more of it is not under deep water. People will not complain that a giant thruster got put in the wildlife reserve. The moon is not a lava Cadbury egg like the Earth and so no worry that enthusiastic thrustering will cause molten goo to erupt. The moon is rich in helium isotopes that could be used to power fusion thrusters. It is rich in rocks that one could hurl into space as reacton mass to propel the moon along ... hmm; one might need some math to make sure those rocks did not wind up on Earth.

The moon pulls the earth and it pulls on every bit of the earth because gravity is that way. So less worry about asymmetric forces tearing earth bits off or pushing them into the gooey center.

Your moon would swing wide at the desired part of the orbit and coax the earth along. Presumably in a progressively wider orbit around the Sun because the alternative was considered and does not end well.

Willk
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  • I realize that putting pylons inside earth crust would just tear it apart. So your solution is to move the moon and drag the Earth along the way ? Or just take the Moon ? – Elyo Jul 17 '22 at 14:14
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    @Elyo - I am intrigued by the idea of putting the thrusters on the moon and then making off with it, leaving the Earth in the lurch. Ho ho! But the OP wanted to move the earth and this scheme already strays from some of the OP "Where should I put reactors geographically speaking on Earth". However I say the top line has trump and that asks about planetary propulsion more generally. Related: https://en.wikipedia.org/wiki/Moving_Earth where a similar scheme using asteroids is mooted. – Willk Jul 17 '22 at 15:10
  • Thank you for the link. The problem with using asteroids to slightly move the Earth via gravitational interactions is, that it's way too slow. – Elyo Jul 17 '22 at 16:13
  • I picture the scene where it is proposed the Moon be used to gently drag the Earth off iinto space. The reply: "Moon, schmoon. Bah. So little. Is Mars busy?" – Willk Jul 17 '22 at 16:28
  • If you're going to fly the moon around, beware of running into Martin Landau. – Tom Jul 17 '22 at 17:13
  • @Tom what do you mean ? Like a Landau oscillator ? – Elyo Jul 17 '22 at 18:05
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    @Elyo - a sweet sweet reference to Space 1999. And betraying a good understanding of what that show was all about,, and given that it has never been rerun (and I was watching for it), a fairly advanced age on the part of Tom since it was on TV back in 1975. A schoolmate of mine circa 1977 had a Space 1999 lunchbox and we discussed what that show might have been about. Tom that Grecian Formula is working wonders for your beard. – Willk Jul 17 '22 at 18:12
  • @Willk I've got news for you: Amazon Prime has both seasons of Space 1999 pretty cheap. And thank you, I think my beard and moustache are very nearly at peak Grecian sweetness. – Tom Jul 17 '22 at 18:59
  • I wonder if the Moon would be enough to actually propel Earth to the required orbit by gravity pull. If, for example, you would be able to make Moon run along a shifted orbit, like if you take a ball on a rope and spin it slightly so that the rope would form a cone with opening faced towards the ground, the one the ball would move along relative to Earth placed in the cone center, this would provide a net momentum for gravity force to provide acceleration to Earth, but maybe energy or mass consumption ratio won't allow for the Moon to stay in there long enough. – Vesper Jul 18 '22 at 13:48