再见，银河系（Good bye,our galaxy)

The questions I would like to talk about are:

one, where did we come from?

How did the universe come into being?

Are we alone in the universe?

Is there alien life out there?

What is the future of the human race?

Up until the 1920s,

everyone thought the universe was essentially static and unchanging in time.

Then it was discovered that the universe was expanding.

Distant galaxies were moving away from us.

This meant they must have been closer together in the past.

If we extrapolate back,

we find we must have all been on top of each other about 15 billion years ago.

This was the Big Bang, the beginning of the universe.

good bye our galaxy

But was there anything before the Big Bang?

If not, what created the universe?

Why did the universe emerge from the Big Bang the way it did?

We used to think that the theory of the universe could be divided into two parts.

First, there were the laws given its state over all of space at one time.