Saturday, May 05, 2012

The Universe from Nothing by Lawrence Krauss, 2009

The Universe from Nothing - see 21' for energy in the space between quarks!


Chris Street - 2009 AAI talk that launched Krauss to write 'Universe from Nothing'.
- 10m: good explanation (by superimposing galaxies at different times) of why galaxies appear to expanding at a speed proportional to the distance away.
-16m: we are all stardust, H,He,Li were created in big bang; rest of elements were formed in star exploding; 100,000 galaxies within a dime - 3 stars (not 10) explode every night.
- 18m age of universe 13.72bn
-19.45m - energy of Nothing; if nothing weighs something it contributes a term like this. But 'nothing weighs something' sound ridiculous!
-20m - laws of quantum mechanics & special relativity at extremely small scales, nothing is really a boiling bubbling brew of virtual particles that are popping in and out of existence in a time scale that you can't see them.
- 20m30s - we can't measure virtual particles directly but we can measure their effects indirectly. Empty space is not empty! Empty space is responsible for 90% of your mass.
- 22m energy of nothing Vacuum energy is 10x120 times the energy of all matter in the universe (the worst prediction in all of physics) - if that was the case we wouldn't be here! Something about zero (dont understand)
25m - Options for Universe are open,closed or flat. Weighing the Universe tells us which of these options are true.
28m - x50 is mass of stuff that doesn't shine (dark matter) v normal matter; 90% of universe mass is dark matter. Universe is flat (not open or closed)
32m - in a flat universe the total energy of the universe is precisely zero - gravity can have negative energy which balances out the positive energy of matter. A universe with total energy zero means that only such as universe can come from Nothing. No deity required. Quantum fluctuations can produce a universe from nothing.
40m - why something rather than nothing? The answer is, there had to be. If you have nothing in quantum mechanics you always get something.
41m - before 1998 we assumed that the universe expansion was slowing down; actually found to accelerating. We live in a universe dominated by nothing. 70% of the energy of the universe resides in empty space.
43m - we (galaxies) constitute 1% of a universe that is 70% dark energy and 30% dark matter
45m - the cosmological constant aka energy of empty space is just right for us now; galaxies can form; if the constant had been bigger eg x50 the energy density of matter, then galaxies would never have formed -
46m - anthropic mania: if many universes and the energy of empty space can vary in each one, then only in those that the energy is not much greater than that, will galaxies and us, form.
47m Cosmic natural selection; the laws of physics are just an accident (not fixed and change one paramter); if they were any different we would not be here. No fundamental laws. You may find it repugant but it may true.
49m- string theory - tiny vibrating strings
51m - in a 100 billion years galaxies will be moving away from us at faster than speed of light (its allowed!) and we will not see other galaxies so we will think we are alone in our Milky Way galaxy!

also see Jim Al-Khali's Channel 4 programme, Everything from Nothing.

Link to this 2009 video from a London Atheists post.

Listen to Krauss at 15'39" on Radio 4, The Material World.

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