What happened before the Big Bang?

[bekdik]

not that big bag!

Have you seen his big bag?

 

[martin]

Interesting read so far, thanks for posting!

 

[Tassidar]

I was thinking on the easiest way to explain this and asked somebody who knows 10 x more than me on this subject, to put it into laymans terms that I even I could understand (Especially since we argue about these things all the time) So this is my wifes edited reply via email to me (Oh and before anyone asks.. this is her field of work and study)

"Okey dokey...

First on the space/time issue: In Einstein's Special Relativity (1905) he showed that space and time are not absolute - that is, what I call "space" or "time" can be different to what you call "space" and "time", and will be if we are moving at different velocities.

Further, he showed that time and space are not separate. Time is the 4th dimension that we move in, just like the three space dimensions are x, y, and z (or left/right, forward/backward, up/down). The thing that makes time different from space is that we can only move in one direction in time... We can only move forward in time. Whereas in space we are free to move left OR right, forwards OR backwards, up OR down. This is why we perceive the time dimension to be different to the space ones.

On the black holes: In Einstein'd General Relativity paper (1915) he went on to show that gravity is geometry. That is, just as you can explain the "centrifugal force" by noting that you are in a rotating reference frame (as opposed to one at rest), gravity can be explained by noting that you are no longer in "flat" spacetime, but rather in spacetime that is curved.

The thing about black holes is that they curve spacetime so much, that you have to exceed the speed of light to escape them." Like you said, "imagine rolling balls around a curved sheet. The deeper the curve, the faster you have to roll the ball to get it out of the dent. For a black hole, the dent is so steep that you would have to roll the ball faster than the speed of light to get out of it, which of course is impossible.

However, going faster than the speed of light is only necessary for leaving the black hole. You don't have to go anywhere near the speed of light to fall in it, so your mass would not get infinite." (Your point 3)

"Onto falling into black holes... Let's say that I'm an astronaut falling in towards a black hole, and you are on a spaceship watching me. I have a watch on my arm, and you have a clock on your spaceship. We start off with both our clocks synchronized.

As I get closer to the event horizon, the black hole's gravity is starting to distort space. Light bouncing off me has to fight against the gravity to get back to you on the spaceship, so I appear redder to you", again as you said. "However, the gravity is only affecting MY time on MY watch - you are safely away from the black hole, so to you it looks like my clock is running slow. However, to me, it looks like my clock is running perfectly normally, and yours is the one that is slow. Time does NOT actually slow down, it is only an affect of how we measure it (in curved spacetime) that makes it appear so.

I would get very stretched out, this is called spaghettification. What happens is that (imagine I'm going into the black hole feet first) the gravity pulling on my feet is much much stronger than the gravity pulling on my head. This is because of the "steepness" of the black hole's gravitational "well". Anyway, I'd be stretched out longer and thinner as I approached the BH, until I got torn apart. Not a pleasant experience Ironically, it would be "safer" to go into a really massive black hole, since the gravitational slope is shallower. If I chose a black hole of about 10 million times our sun's mass, I would feel only slight spaghettification forces - not enough to kill me

As I approach the event horizon, I become almost invisible as the light bouncing off me loses most of it's energy in it's escape. For you watching on the spaceship, my watch runs slower and slower as I approach the black hole, until it appears to stop completely at the event horizon. You would not see me cross the event horizon, I would appear to hover outside it for infinite time."

Thanks for the clarification.

You would not see me cross the event horizon, I would appear to hover outside it for infinite time.

Could you explain why this happens, I would think that you would fade away.

 

[Kalvaer]

My personal take on it.....

You would be watching me and my clock would be getting slower and slower to the point that it actually appears to have stopped (or moving so slowly that you would not be able to actually see any change in it for years to come). It might actually tick over a second in 50 years but you wont be around to see it. Just the same way as I would appear to be just sitting there frozen in space instead of fading away of course. I would also be getting almost invisible. You wont be able to detect the light in the visible spectrum, but should be able to detect me in infrared

Of course all of it is theoretical. I know I personally wouldn't want to be the first one to test it out and jump into a black hole.

EDIT: Oh BTW.. I'll double check with my better half tonight to see if my logic is right