Can the Big Bang Happen Again
What happened before the Large Bang?
The Large Blindside is unremarkably thought of as the beginning of it all: About 13.viii billion years ago, the observable universe went boom and expanded into being.
Only what were things like before the Large Bang?
Short answer: We don't know. Long answer: It could have been a lot of things, each mind-bending in its own way.
Related: How massive is the Milky way?
In the beginning
The get-go thing to understand is what the Big Bang actually was.
"The Big Bang is a moment in time, not a point in space," said Sean Carroll, a theoretical physicist at the California Institute of Applied science and writer of "The Big Picture: On the Origins of Life, Meaning and the Universe Itself" (Dutton, 2016).
Thus, it'south possible that the universe at the Big Bang was teeny-tiny or infinitely big, Carroll said, because there's no style to expect back in time at the stuff we can't even see today. All we really know is that information technology was very, very dense and that it very quickly got less dumbo.
Equally a corollary, there really isn't anything outside the universe, because the universe is, by definition, everything. So, at the Large Bang, everything was denser and hotter than it is at present, simply there was no more than an "exterior" of it than there is today. As tempting as it is to take a godlike view and imagine you could stand in a void and expect at the scrunched-upwardly babe universe right before the Big Bang, that would be impossible, Carroll said. The universe didn't expand into infinite; space itself expanded.
"No matter where you are in the universe, if y'all trace yourself back 14 billion years, you come to this betoken where it was extremely hot, dense and rapidly expanding," he said.
No one knows exactly what was happening in the universe until 1 2d after the Large Bang, when the universe cooled off enough for protons and neutrons to collide and stick together. Many scientists do think that the universe went through a process of exponential expansion chosen inflation during that showtime second. This would have smoothed out the fabric of space-time and could explain why thing is then evenly distributed in the universe today.
Before the bang
It's possible that earlier the Big Blindside, the universe was an space stretch of an ultrahot, dense material, persisting in a steady state until, for some reason, the Big Blindside occured. This extra-dumbo universe may have been governed by quantum mechanics, the physics of the extremely small scale, Carroll said. The Large Blindside, and so, would take represented the moment that classical physics took over as the major driver of the universe'south evolution. [What Is Quantum Mechanics?]
For Stephen Hawking, this moment was all that mattered: Before the Big Bang, he said, events are unmeasurable, and thus undefined. Hawking called this the no-boundary proposal: Fourth dimension and space, he said, are finite, merely they don't have any boundaries or starting or catastrophe points, the aforementioned fashion that the planet Earth is finite but has no border.
"Since events before the Big Bang have no observational consequences, one may likewise cut them out of the theory and say that time began at the Big Bang," he said in an interview on the National Geographic show "StarTalk" in 2018.
Or perhaps there was something else before the Big Bang that's worth pondering. I idea is that the Large Bang isn't the beginning of time, but rather that information technology was a moment of symmetry. In this idea, prior to the Large Bang, there was some other universe, identical to this 1 but with entropy increasing toward the past instead of toward the future.
Increasing entropy, or increasing disorder in a organisation, is essentially the arrow of time, Carroll said, so in this mirror universe, time would run contrary to time in the mod universe and our universe would be in the by. Proponents of this theory also suggest that other properties of the universe would exist flip-flopped in this mirror universe. For example, physicist David Sloan wrote in the University of Oxford Science Weblog, asymmetries in molecules and ions (called chiralities) would be in opposite orientations to what they are in our universe.
A related theory holds that the Big Bang wasn't the beginning of everything, but rather a moment in fourth dimension when the universe switched from a period of contraction to a period of expansion. This "Big Bounce" notion suggests that at that place could be infinite Big Bangs as the universe expands, contracts and expands once more. The trouble with these ideas, Carroll said, is that there'south no explanation for why or how an expanding universe would contract and render to a depression-entropy state.
Carroll and his colleague Jennifer Chen take their own pre-Large Bang vision. In 2004, the physicists suggested that perhaps the universe as we know it is the offspring of a parent universe from which a bit of space-fourth dimension has ripped off.
It'southward like a radioactive nucleus decaying, Carroll said: When a nucleus decays, it spits out an alpha or beta particle. The parent universe could do the same affair, except instead of particles, it spits out baby universes, perchance infinitely. "It's but a breakthrough fluctuation that lets information technology happen," Carroll said. These baby universes are "literally parallel universes," Carroll said, and don't collaborate with or influence one some other.
If that all sounds rather trippy, it is — because scientists don't nevertheless have a way to peer dorsum to fifty-fifty the instant of the Large Bang, much less what came before it. There'south room to explore, though, Carroll said. The detection of gravitational waves from powerful galactic collisions in 2015 opens the possibility that these waves could be used to solve fundamental mysteries about the universes' expansion in that first crucial second.
Theoretical physicists besides have work to do, Carroll said, similar making more-precise predictions almost how breakthrough forces like quantum gravity might work.
"We don't fifty-fifty know what nosotros're looking for," Carroll said, "until we have a theory."
- Why Does the Earth Rotate?
- How Did the Milky way Get Its Proper name?
- Black Holes Are Awesome. Why Are Their Names Usually And then Boring?
Originally published on Live Science .
Stephanie Pappas is a contributing writer for Live Science, roofing topics ranging from geoscience to archæology to the human being encephalon and behavior. She was previously a senior author for Live Science but is now a freelancer based in Denver, Colorado, and regularly contributes to Scientific American and The Monitor, the monthly mag of the American Psychological Association. Stephanie received a available's degree in psychology from the University of South Carolina and a graduate certificate in science communication from the University of California, Santa Cruz.
Source: https://www.livescience.com/65254-what-happened-before-big-big.html
Post a Comment for "Can the Big Bang Happen Again"