Question: do you understand about when time started or when it will end or how long the sky goes on for?!

Anna Scaife answered on 19 Nov 2014:

Hey Anna – time as we understand it started with the Big Bang – that’s our zero point. It was 13.8 billion years ago.

Some theories say that our Universe will expand forever, which means that time must be infinite. But there are other theories that say our Universe will eventually collapse back in on itself and end in a Big Crunch. I guess at that point we can probably say that time has ended… but then there are *other* theories, which say our Universe expands and collapses over and over again in cycles. In that case I don’t know whether we’d consider time to have ended and started again and again or if we can think of it as just one long infinite amount of time…