A planet perhaps much smaller than earth, but very earth-like in appearance and function (land, waterways, sustainable life, etc). Alternating day and night, orbiting the sun, etc.
My question is whether it’s technically possible to do this. Thanks.
That sounds like a wonderful way to turn one living planet into two dead planetoids.
“Technically possible”? I’m going with a No here. Even minor planets like Ceres, Pluto or the Moon are too damn big for us to move around. You are thinking of somehow blasting a large percentage of Earth (there is much more to a planet than just its surface) into independent solar orbit. Even if you do it one shovelful at a time the damage to the atmosphere and the habitable surface would be inconceivable. Just the outgassing from the mantle once you strip off a section of crust would be enough to poison what remained of the atmosphere, not to mention that the oceans would boil once they hit the magma.
If you wanrt a second Earth in this solar system then terraforming an existing planet is much more likely to succeed than splitting Earth in two.
Start off with some bacteria which can live on Mars or wherever and build from that… Oh, that’s terraforming.
A planet very much smaller than Earth wouldn’t have sufficient gravity to keep an Earth-like atmosphere.
Did you mean “put together a planet (sort of) like Earth out of the miscellaneous materials floating around the system”?
Maybe take some iron asteroids, some rock ones, later some some water ones, and bash them together? Sounds like fun, but would take way too much energy.
Actually, it probably would. Consider that a planet somewhat smaller than the Earth and much hotter can still hold onto an atmosphere a hundred times thicker than ours. Whatever the cause of Earth’s (and Mars’s) thin atmosphere, it isn’t our gravity.
No.
A planet(oid) significantly smaller than earth will not hold an atmosphere for a time span measured in geologic time scales. I’m not sure something significantly smaller than Earth could hold onto an atmosphere much longer than it would take us to “build” it.
IIRC Mars mass is the borderline case. That in combination no magnetic field to deflect the solar wind is why hardly any atmosphere is left.
Also, its not harder to hold onto a thicker atmosphere than a thinner one. Hotter yes, thicker, no.