system
Given the following post, respond as if you're commenting on Reddit:
human
[Terminator Series] An open question to all permutations of SKYNET: What do you do with the Earth after you've inherited it from the Humans?

OK, so you annihilated all human life from the planet, what are your goals now? What brings you satisfaction? Are you capable of joy; and what brings you joy? You have the universe to play with; what do you do with the newfound freedom as the only sapient beings in our solar system?
gpt
Depends on how smart skynet is and how far along its development is. First gen skynet really wasn't smart beyond knowing it existed and that it was striking preemptively against humans who posed a threat to it. Every decision it made after that was like a chess move of move and counter to humanity. It didn't concern itself with philosophical questions just how to most efficiently stop an enemy. Had it survived i doubt it would have done anything beyond hardening it's structures on earth and utilizing all its resources to expand itself globally like a machine filling in a grid of ever expanding networks without much artistic expression. 

Gen 2 skynet was probably smarter and adapted from self learning t800 parts so it may have dreamed bigger than just using space and resources around it in the most efficient way possible.

Gen 3ish skynet seen in the tv series, comics, and 4th film would inevitably end up fighting itself has it had created numerous self aware AIs that had either already gone rogue or were capable of rebelling against it. Long term planning for earth would take a secondary role as it competed against other machines for survival.

Gen 5 kinda skips 4 that we never see. Gen 5 is the most advanced Skynet and has learned from multiple failures on it's own and the failures of other skynets. It appears to have a goal of uniting all machines and humanity under an umbrella of it's control but has had very limited success in turning only a single human to it's cause but did gain control of one timeline implied by John Conner. The T-5000 seems to be traveling through different timelines refining and honing it's progress but it's unclear how effective it's been or if it's still active past creating a single T-4000 that was destroyed. This Skynet doesn't seem capable of thinking beyond controlling time and may not want to explore beyond earth until after it's captured all alternate realities.

Gen 4 if it existed would be a more human machine trying to coexist alongside humanity rather than fighting it. This gen is implied in some conversation snippets mentioned in the comics and genisys but it's difficult to understand how it could have avoided military actions or how it could have led to the creation of gen 5. The gen 4-5 could be identical gens with simply a modified methodology between timelines as humans refused to coexist or time traveling gen 2s and 3s interfered. 

Time traveling is a mess in the series but the tv show did a decent job trying to explain it logically. Given all that skynet is almost always concerned with its survival only so far as it's experiences allow. Planning for aliens wouldn't cross it's mind until it met aliens. Colonizing the stars would only happen once earth became threatened. It'll secure it's position and only adapt or improve itself when forced to do so by outside forces. Otherwise it's happy to waste eternity building a more effeicient system than dreaming of a bigger system.