This is a highly entertaining and mind-stretching talk by Lawrence Krauss from 2009. The title is "A universe from Nothing," and I'm still trying to wrap my head around it. Enjoy. Here are a few of Krauss' quotes from his talk: The universe is flat, It has 0 total energy, And it could have begun from nothing. (min 40) Why is there something rather than nothing? There had to be. If you had nothing in quantum mechanics, you’ll always get something. It’s not simple. . . but it’s true. (Min 41) We live in a universe dominated by nothing. 70% of the energy in the universe resides in empty space. And we don’t have the slightest idea why it’s there. (min 42). We now know that “we are more insignificant than we ever imagined. If you get rid of everything we see, the universe is essentially the same. We constitute a 1% bit of pollution in a universe that’s 30% dark matter and 70% dark energy. We are completely irrelevant. (min. 43). There may be other universes that aren't conducive to life, and lo and behold there isn't life in them. That's a kind of cosmic natural selection. (min 46:00). [History of string theory in 10 seconds.] (min 49). Strive for cosmic humility. The recognition that we don’t know far more than we know. (min. 50). Galaxies are moving away from us at an increasing rate of speed. In 100 billion years, “all evidence of the big bang will disappear.” Scientists living then will derive a picture of the universe that is completely wrong. They will derive a picture of the universe being one galaxy surrounded by empty space that is static and eternal. Falsifiable science will produce the wrong answer. (min. 52). We live in a very special time: The only time when we can observationally verify that we live at a very special time!” (min 52). The universe remains mysterious, and that is great (min 53).