At first, one might object to the notion of a multiverse, because it seems to violate known laws, such as the conservation of matter and energy. However, the total matter/energy content of a universe may be very small. The matter content of the Universe including all the stars, planets and galaxies, is huge and positive. However, the energy stored within gravity may be negative. Now, if you add the positive energy due to matter to the negative energy due gravity, the sum may be close to zero! In some sense, such universes are free. They can spring out of vacuum almost effortlessly.
In fact, to create a universe like ours may require a ridiculously small net amount of matter, perhaps as little as an ounce. This idea of creating a universe from nothing was first introduced by physicist Edward Tyron of Hunter College of the City University of New York, in a paper published in Nature Magazine in 1973. He speculated that the universe is something "which happens from time to time" due to quantum fluctuation in vacuum.
This theory help us to answer very practical questions about the universe. For example : Why doesn't the universe spin? Everything we see around us spins, from tops, hurricanes, planets, and galaxies, to quasars. It seems to be a universal characteristic of matter in the universe. But the universe itself does not spin. When we look at the galaxies in the heaven, their total spin cancels out to zero. If the universe did spin, then time travel would become commonplace and history would be impossible to write.
The reason why the universe does not spin may be that our universe came from nothing. Since the vacuum does not spin, we do not expect to see any net spin arising in our universe. In fact, all the bubble-universes within the multiverse may have zero net spin.
Why do positive and negative electrical charges balance out exactly? Normally, when we think of cosmic forces governing the universe, we think more about gravity than the electromagnetic force. Although, we take for granted, the cancellation of positive and negative charges is quite remarkable, and has been experimentally checked to 1 part in 10^21. If there were just 0.00001% difference in the net positive and the negative electrical charges within our body, we would be ripped to shreds instantly, with our body parts thrown into outer space by the electrical force.
The answer to these enduring puzzles may be that the universe came from nothing. Since the vacuum has net zero spin and charge, any baby universe springing forth from nothing must also have net zero spin and charge. There is one apparent exception to this rule that the universe is made of matter rather than antimatter. Since matter and antimatter are opposites, we might assume that the big bang must have created equal amount of matter and antimatter. The problem, however, is that matter and antimatter will annihilate each other on contact into a burst of gamma rays. Thus, we should not exist. The universe should be a random collection of gamma rays instead of teeming with ordinary matter. If the big bang were perfectly symmetrical (or if it came from nothing), then we should expect equal amounts of matter and antimatter to be formed. So why do we exist? The solution proposed by Russian Physicist Andrei Sakharov is that the original big bang was not perfectly symmetrical at all. There was a tiny amount of symmetry breaking between matter and antimatter at the instant of creation, so that matter dominated over antimatter, which made possible the universe we see around us.
If the Universe came from "nothing", then perhaps nothing was not perfectly empty but had a slight amount of symmetry breaking, which allows for the slight dominance of matter over antimatter today. The origin of this symmetry breaking is still not understood.
In fact, to create a universe like ours may require a ridiculously small net amount of matter, perhaps as little as an ounce. This idea of creating a universe from nothing was first introduced by physicist Edward Tyron of Hunter College of the City University of New York, in a paper published in Nature Magazine in 1973. He speculated that the universe is something "which happens from time to time" due to quantum fluctuation in vacuum.
This theory help us to answer very practical questions about the universe. For example : Why doesn't the universe spin? Everything we see around us spins, from tops, hurricanes, planets, and galaxies, to quasars. It seems to be a universal characteristic of matter in the universe. But the universe itself does not spin. When we look at the galaxies in the heaven, their total spin cancels out to zero. If the universe did spin, then time travel would become commonplace and history would be impossible to write.
The reason why the universe does not spin may be that our universe came from nothing. Since the vacuum does not spin, we do not expect to see any net spin arising in our universe. In fact, all the bubble-universes within the multiverse may have zero net spin.
Why do positive and negative electrical charges balance out exactly? Normally, when we think of cosmic forces governing the universe, we think more about gravity than the electromagnetic force. Although, we take for granted, the cancellation of positive and negative charges is quite remarkable, and has been experimentally checked to 1 part in 10^21. If there were just 0.00001% difference in the net positive and the negative electrical charges within our body, we would be ripped to shreds instantly, with our body parts thrown into outer space by the electrical force.
The answer to these enduring puzzles may be that the universe came from nothing. Since the vacuum has net zero spin and charge, any baby universe springing forth from nothing must also have net zero spin and charge. There is one apparent exception to this rule that the universe is made of matter rather than antimatter. Since matter and antimatter are opposites, we might assume that the big bang must have created equal amount of matter and antimatter. The problem, however, is that matter and antimatter will annihilate each other on contact into a burst of gamma rays. Thus, we should not exist. The universe should be a random collection of gamma rays instead of teeming with ordinary matter. If the big bang were perfectly symmetrical (or if it came from nothing), then we should expect equal amounts of matter and antimatter to be formed. So why do we exist? The solution proposed by Russian Physicist Andrei Sakharov is that the original big bang was not perfectly symmetrical at all. There was a tiny amount of symmetry breaking between matter and antimatter at the instant of creation, so that matter dominated over antimatter, which made possible the universe we see around us.
If the Universe came from "nothing", then perhaps nothing was not perfectly empty but had a slight amount of symmetry breaking, which allows for the slight dominance of matter over antimatter today. The origin of this symmetry breaking is still not understood.
*This is an excerpt taken from Michio Kaku's book Parallel Worlds: A Journey Through Creation, Higher Dimensions, and the Future of the Cosmos
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