What will happen to our motion when the Earth stops suddenly?

Anyway, I saw the end of Earth on Doctor Who, and nobody was living there anymore; all the people had migrated out and colonized new solar systems. Nobody fried, nobody froze and nobody was flung off into space...

...except Saint, who didn't look a day older...

 

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So we need to adjust our atomic clock to count our calendar's days?

 

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Not me; my atomic clock just had its 2000-year tune-up, running like a well-oiled kitten.

 

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They had atoms 2000 years ago?

Oiled cats run faster?

I have so many questions.

Where can I buy one of your time machines? Buh-dump

 

If time is not absolute according to theory of relativity, then how can we measure the age of the universe?
Because the big bang says space is expanding in every direction with speed faster than light.

 

Not quite. Locally, it can't expand faster than light. But from our perspective (if we could see it, which we can't) it seems to be expanding faster than light, since not only are we going in the opposite direction, space itself is expanding between us.

We can measure things and then express time in whatever reference frame we like. If you choose a different frame (a frame moving at a different speed than we are) you will see different result. But we can accurately express time in _our_ frame.

 

A-- 10Kkph --B-- 10Kkph --C-- 10Kkph --D-- 10Kkph --E-- 10Kkph --F-- 10Kkph

The above very rough example shows a number of galaxies labeled A,B,C, etc. The numbers in between them indicate the speed in which one galaxy is moving away from the galaxy next to it. If we were galaxy A, then the next galaxy B is moving away at 10,000 kilometer per hour, C is moving away from B at 10,000 kph and so on... From our frame of reference, C is moving away from us at 20,000 kilometers per hour, D is 30,000 kilometers per hour and so on...

Therefore, if we add together the various speeds of the many galaxies that are between us and those billions of galaxies light years away, the speed of the furthest galaxies away from us appear to be moving faster than light even though those furthest galaxies may only be moving at 10,000 kilometers per hour from their frame of reference.

Is this right or am I way off track?

 

yes, you make sense.

 

Does the moon spin about its own axis and revolve around the Earth too?

 

It does both. It spins around its axis once a month and also orbits the Earth once a month - thus keeping one face towards the Earth at all times.

 

the moon is moving closer or farther from the Earth?
is the moon habitable?

 

Moving towards at the moment (for the next day or so), but on average it moves away at not quite 4 cm per year.

It is habitable only if you bring a habitat with you, but then most anywhere is habitable.

 

Very slowly moving away.

Not in the way you are thinking.