Prior to the earth having its problems a wormhole had shown up near Jupiter. Probes through the wormhole showed a number of possible worlds to colonize, then things got ugly here, and other missions are sent out, and Interstellar is basically the final make or break “figure out where we’re going to live” with a library of genetic material mission.
Most of your questions are answered by “wormhole”. I’m not sure what all the complaints are about the movie. I didn’t have a problem with the sound. And as for the characters and plot, it’s a Nolan movie, you either like them or you don’t, and the people who don’t probably should stop whining.
A wormhole near Jupiter? Wouldn’t it have to be opened by something that’s engineered for the task? As for the probes, how long did it take for them to send back the information? Or was it sent back through the wormhole? Was it open for long?
So many questions, and I don’t care to see it.