Thursday, January 26, 2012 |
First aired on Quirks & Quarks (21/1/12)
Where did the universe come from? In other words, why is there something rather than nothing? Renowned cosmologist Lawrence M. Krauss tackles this question and some of the paradoxes it raises in his latest book, A Universe from Nothing.
In a recent interview with Quirks & Quarks, Krauss told host Bob McDonald that "the new discoveries in cosmology make it more and more plausible that the universe came from nothing."
In his book, Krauss discusses the fact that there's actually a lot to that "nothing." The concept, which comes from Aristotle and other philosophers, is of "empty space, darkness with nothing in it." But thanks to quantum mechanics and relativity, we now know that "empty space is actually a boiling, bubbling brew of virtual particles that are popping in and out of existence in a time scale so short you can't measure them." But we can measure their effects indirectly, and so we know they are there. "So empty space isn't so empty," Krauss said.
He went on to say that "because of those quantum fluctuations, the universe can actually create something from that kind of nothing." This may seem like a violation of the conservation of energy. But, as Krauss explained: "Gravity has the unique property of producing both negative and positive energy -- negative energy due to the gravitational attraction of particles. So you can actually produce two particles, say, a particle and anti-particle pair, and if the gravitational energy is strong enough so that the negative energy counters the positive energy of their mass, you can produce them with impunity."
Moreover, it turns out that "one of the remarkable properties of our universe that we've measured in the last decade is that the total energy of our universe we think is essentially zero. It's consistent with a universe that was created from nothing."
Krauss pointed out that most of the energy of the universe resides in empty space, and that this dark energy is causing the universe to expand. A 100 years ago, we thought there was only one galaxy, but modern astronomy has revealed there are now 400 billion in the visible universe. As the universe expands, it pushes all those other galaxies away from us, so in the very distant future they will eventually be too far away to see. So, ironically, it will actually look like there is only one universe -- which was how we thought of it 100 years ago.
What we now know as a result of particle physics and cosmology has affected our understanding of the past, the present and the future. "Because of the energy of empty space and dark matter, everything we can see in the universe is just a bit of cosmic pollution in a sea of dark matter and dark energy. We are much more insignificant than we once thought we were," Krauss said.
But that's no reason for dismay, according to Krauss. "We have this amazing, fortuitous chance to have consciousness, to have evolved on this planet, and be able to understand and appreciate and enjoy the amazing properties of the universe, and make the most of our brief moment in the sun," he said.
There are several theories about what happened before the Big Bang. One is that our universe spontaneously arose from nothing; another is that time itself, just like space, arose out of the Big Bang. But the other possibility is that there is a multi-verse, and there are universes being created and dying at any given moment.
"We don't know, but all of them point to the remarkable possibility that you don't need a creator for creation," Krauss said.
The universe continues to surprise us, he added. And as a physicist, the celebrated scientist has found that "the two most exciting states to be in are being wrong and being confused. Because it means there's more to learn. And I can tell you I'm often both."
A Universe from Nothing
by Lawrence M. Krauss
Buy this book at:
From the publisher:"'Where did the universe come from? What was there before it? What will the future bring? And finally, why is there something rather than nothing?' Lawrence Krauss's provocative answers to these and other timeless questions in a wildly popular lecture now on YouTube have attracted almost a million viewers. The last of these questions in particular has been at the center of religious and philosophical debates about the existence of God, and it's the supposed counterargument to anyone who questions the need for God. As Krauss argues, scientists have, however, historically focused on other, more pressing issues -- such as figuring out how the universe actually functions, which can ultimately help us to improve the quality of our lives..."