Can Time Travel Change the Course of History?

[QuantumTheory]

Does anyone know why the universe began?
Why did life on Earth began?
Are there any "right " religions?
What happens to you after you die? (Besides the usual process.)
What is the purpose of life?
Why is the sky blue?
Why is the universe black?
Is time travel theortically possible?
Is it impossible to go back in time before you created the time machine?
What would happen to you if you went back in time and killed your grandfather, before you were born?
If you go back in time, can you alter the past? What would happen if you did ? Would there be a different future?

 

[selfAdjoint]

Does anyone know why the universe began?

No.

Why did life on Earth began?

The chemistry was right.

Are there any "right " religions?

Every religion is right to its believers and wrong to everyone else.

What happens to you after you die? (Besides the usual process.)

Anybody who says more than the usual process has a lot of proving to do.

What is the purpose of life?

To continue.

Why is the sky blue?

Interaction of solar photons with electron shell of oxygen molecules.

Why is the universe black?

There hasn't been enough time since it became transparent for light from the most distant regions to reach us. So there's only a finite, not an infinite light reaching us, and it leaves most of the sky black.

Is time travel theortically possible?

Very theoretically, yes. It requires matter with negative energy; such a thing is not exactly impossible, but it sure ain't common!

Is it impossible to go back in time before you created the time machine?

This is a feature of one time travel scheme using wormholes.

What would happen to you if you went back in time and killed your grandfather, before you were born?

It would have to be before his child, your parent, was born to have any particular effect! Several possibilities: The world would change but nobody would realize it, and you wouldn't be in it. Or the world would branch into a universe in which you didn't succeed and one in which you did. Or nature would somehow conspire to prevent you from succeeding. Take your pick.

If you go back in time, can you alter the past? What would happen if you did ? Would there be a different future?

See my reply under grandfathercide.

 

[Evo]

Great post SA.