Could a planet ever be split into two halves?

[Quantum-lept]

True, but wouldn't it be better to use a real-physics scenario rather than contrive something artificial?

Yes, you are correct...my scenario did seem improbable to me, but i was wondering if it was possible somewhere in the universe..maybe it's not since we don't see it. The probability that all the circumstances for such an outcome to occur would be too small...thanks

 

[Quantum-lept]

The size of an object is one thing, but its mass is another, right? So, what if in your story, you had a hollow world, or construct of a similar nature. The upper limit for a mass at L4 and L5 around an Earth-like mass is nothing you would be able to reasonably populate, but if you had a more diffuse mass... then why not?

In nature, this doesn't happen, but there is a reason for the "fi" in sci-fi. For the Dyson Sphere, that is a hypothetical construction of a shell around a star at a distance which would make the inner surface habitable. The upshot would be a vast amount of living space, and the ability to collect the total output of the star around which it was built. The downside would be that I can't imagine how such a thing could ever be constructed, but that wasn't the point. By inverted Dyson Sphere, I meant that instead of surrounding a star and living inside the sphere, your long-lost alien architects build an Earth SIZED world where you live on the outer surface, but which has a mass that would allow it to be stable at L4 or L5. You would have to figure out a way for this body to maintain an atmosphere and gravity, but again, you could attribute that to long lost alien architects, and avoid the "how" by making the sphere impenetrable.

In real life, matter "clumps" to form planets and asteroids or other objects, and it does so without leaving vast unsustainable hollow worlds, but you're going to have to comprom8ise something for the sake of this story; it's just a matter of what.

thanks, this i mostly understand... i sunburn easily, so the Dyson sphere sounds dangerous..(:

but a large sphere protecting a inner smaller one which could be made habitable at L point might be possible in the far future...population of moon under a dome would probably be easier and more cost effective...