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The Big Bang theory of the origin of our universe is widely accepted by the physics community. The idea that our universe started out as some infinitesimally small point, which expanded out to what we see today, makes a lot of sense. Except for one small thing. That initial point, called a singularity by physicists, is a physical impossibility. According to the models we have today, the temperature of the universe at that first moment would have had to be infinite, which mathematically makes no sense. Also, the singularity doesn't do a good job of explaining where all the matter and energy we see today in the universe came from. So, physicists are increasingly starting to look at other branches of physics to see what they can do to replace the singularity with a more reasonable proposition, one which can actually be explained by existing science.
Dr. Robert Brandenberger, from McGill University, is one of these researchers. He works in a field called string gas cosmology. This field uses the ideas of string theory (in which everything in the universe is composed of minuscule, sub-atomic, undetectable strings), to try to explain the early universe. According to his premise, our universe began as a very dense, very hot soup of these strings, which eventually started expanding, replacing the Big Bang singularity, and grew into what we see today.
Dr. Paul Steinhardt, from Princeton University, and Dr. Justin Khoury, from the Perimeter Institute in Waterloo, Ontario, have a different model. In their picture, our universe has been around forever, trapped in a multi-dimensional structure called a brane. This brane occasionally bumps into another brane, and when that happens, there's a giant explosion of energy and matter inside the brane itself. This causes the brane to expand, which, from inside, looks just like the Big Bang. But it avoids the singularity, since the whole universe never shrinks down to an infinitely small size.
Dr. Sean Carroll, a researcher at the California Institute of Technology, isn't convinced by either of these models. His view of the origin of the universe is that it's the offspring of another, older universe. He believes that tiny quantum fluctuations in space-time of old universes cause the spontaneous beginning of rapid expansion, called inflation, and the birth of a new entire cosmos.
Dr. Robert Brandenberger, from McGill University, is one of these researchers. He works in a field called string gas cosmology. This field uses the ideas of string theory (in which everything in the universe is composed of minuscule, sub-atomic, undetectable strings), to try to explain the early universe. According to his premise, our universe began as a very dense, very hot soup of these strings, which eventually started expanding, replacing the Big Bang singularity, and grew into what we see today.
Dr. Paul Steinhardt, from Princeton University, and Dr. Justin Khoury, from the Perimeter Institute in Waterloo, Ontario, have a different model. In their picture, our universe has been around forever, trapped in a multi-dimensional structure called a brane. This brane occasionally bumps into another brane, and when that happens, there's a giant explosion of energy and matter inside the brane itself. This causes the brane to expand, which, from inside, looks just like the Big Bang. But it avoids the singularity, since the whole universe never shrinks down to an infinitely small size.
Dr. Sean Carroll, a researcher at the California Institute of Technology, isn't convinced by either of these models. His view of the origin of the universe is that it's the offspring of another, older universe. He believes that tiny quantum fluctuations in space-time of old universes cause the spontaneous beginning of rapid expansion, called inflation, and the birth of a new entire cosmos.
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