Was the universe created with a Big Bang 13.7 billion years ago, or has it been expanding and contracting for eternity? A new paper, inspired by alternative explanations of the physics of black holes, explores the latter possibility, and rejects a core tenant of the Big Bang hypothesis.
The universal origin story known as the Big Bang postulates that, 13.7 billion years ago, our universe emerged from a singularity — a point of infinite density and gravity — and that before this event, space and time did not exist (which means the Big Bang took place at no place and no time).
There is ample evidence to show that the universe did undergo an early period of rapid expansion — in a trillionth of a trillionth of a trillionth of a second, the universe is thought to have expanded by a factor of 1078 in volume. For one, the universe is still expanding in every direction. The farther away an object is, the faster it appears to move away from an observer, suggesting that space itself is expanding (rather than objects simply moving through space at a steady rate). [Big Bang Theory: 5 Weird Facts About the Universe's Birth]
Another key piece of evidence is the cosmic microwave background (CMB), which is thought to be heat left over from this great cosmological event. It can be observed in every direction and has no single origin point. Scientists think the CMB began propagating through the universe about 380,000 years after the Big Bang, when atoms began to form and the universe became transparent, according to the European Space Agency.
However, there is no direct evidence of the original singularity. (Collecting information from that first moment of expansion is impossible with current methods.) In the new paper, Brazilian physicist Juliano Cesar Silva Neves argues that the original singularity may never have existed.
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