Lawrence Krauss: Life, the Universe and Nothing

[Arm0r]

Very interesting watch if you're into this sort of thing.


http://www.youtube.com/watch?v=rdvWrI_oQjY

[[BTF]Defiant!]

Saw him deliver this live a few years back.

[Arm0r]

I also enjoy Michio Kaku's opinion on such things but there is a question to be had.


http://www.youtube.com/watch?v=6GooNhOIMY0

Lawerence Krauss says in his seminar that the universe will eventually expand faster than the speed of light making reaching other systems impossible, Michio Kaku on the other hand says that if you reach type 2 civilization status that nothing in the universe can run you extinct...but if the universe expansion progresses to faster than the speed of light, how can a civilization ever hope to survive that?    The civilization in question would have to advance to the level of faster than the speed of light which when we look around us looks pretty impossible with our laws of nature.   In fact the expansion of space itself is the only known thing that will breach and surpass the speed of light.

 

[kren.Z]

If you liked that video then you'll like Brian Greene's Quantum Leap
http://www.youtube.com/watch?v=8eZqQUdWURs&feature=related. It's basically the same thing but focuses more on quantum physics than cosmology.

Lawerence Krauss says in his seminar that the universe will eventually expand faster than the speed of light making reaching other systems impossible,

I just think a theory is missing.

One of the interesting things discussed in that video is a phenomena known as quantum entanglement. It's basically a system of 2 electrons and measurements on one electron has an instantaneous effect on the state of the other electron regardless of the distance between the two. It's gets really interesting when you read some of the correlations between quantum physics and the structure of life and DNA, i.e. quantum entanglement, information theory and the double helix etc..

[QwazyWabbit]

First point, the theory states that the velocity of the expansion of space increases without limit. This means that there will come a time when the most distantly observable point will recede from the observer so fast that even light cannot traverse the space between them fast enough, and since the expansion is uniform, that the "horizon" of that observable universe will begin to shrink, meaning that less and less of the universe is observable. This is what he meant by our unique time in the history of the universe, we can still see the evidence of the big bang. Eventually we won't be able to see it. Furthermore, as the universe ages, eventually the horizon will be so close that inhabitants of a galaxy will only be able to see their own galaxy and nothing else.

Second point, quantum entanglement is not instantaneous. It propagates at the speed of light. But an observer at A changing the state of particle A entangled with B cannot receive a report from observer B at faster than light speed. This is Einstein's time-like and space-like phenomenon. Nothing at A can change anything at B if light cannot get there.

[reaper]

He says he knows the shape of the universe from recording angles of microwave radiation. I think it's a very impressive calculation, knowing the radiation all around (created from a plasma wall at the start), should of centralized mass at certain times, so you have angles to expect to record (from these large masses, 100,000 light years apart (the age of the universe)) - based on the curvature of the universe as a whole. 

I think it's a huge stretch to say we know the shape of the universe though.  There could be a meta universe, it could be governed, or just plain wrong.  The theory is far from supported, since you're basically trying to piece a puzzle together with what little scraps you have.  It's also interesting we can't see past where the microwave's are sourced from (the edge of the universe), and the theory says the microwaves sourced here were curved by space on the whole from the edge of the universe, therefore the universe is this shape.  It's interesting, but all totally unknown in my opinion.