How can you be unaffected by others?

This is a form of symbiosis known as commensalism.

commensalism

Possibly. It is a philosophical question and we don't (probably will never) know for sure.

Probably because of climate change

You don't even have to go to other galaxies to find other suns. There are somewhere between 200 and 400 billion other stars right here in the same galaxy that we live in. In fact, our own Sun is a...