Hawking’s paper was published in the Journal of high energy physics, which proposed a new theory for the origin of the universe. It is worth noting that this is different from Hawking’s unbounded universe theory.
Just 10 days before Hawking’s death, he and Thomas herto, Professor of theoretical physics at the University of Leuven in Belgium, completed the revision and submitted the paper “a smooth exit from external expansion?”.
In addition to being a great physicist, Hawking also made outstanding contributions in many fields.
One minute background review: the big bang and the multiverse
It all started with a big bang, bang! （that all started with a big bang，BANG！）
Just like the theme song of the big bang, many scientists believe that our universe originated from a big bang. But what happened after the explosion?
In physical cosmology, a theory holds that from 10 seconds after the big bang to 10 to 10 seconds, the universe expands like a balloon at a faster speed than the speed of light, which is called “cosmic expansion”.
After the “expansion of the universe”, the universe will continue to expand, but the speed will be much slower, and the planets will be formed.
Our universe seems to have entered a stable state. But many theories believe that in some parts of the universe, expansion will continue, that is, “eternal expansion”.
Because the expanding area will expand and self replicate at a very fast speed.
Therefore, if the rate of expansion attenuation is slower than that of the formation of new expansion zone, there will always be new expansion zone.
These expansions will then form different pocket universes, forming a “multiverse”, and our universe is just one of them.
Hawking said in an interview in 2017:
“The conventional theory of eternal expansion predicts that the universe is an infinite fractal, with different pocket universes embedded in the expanding ocean. The laws of physics and chemistry in one pocket universe are different from those in the other. These different pocket universes form a multiverse. “
Set a limit for infinity
But I’ve never been a fan of this multiverse theory. Because, this means that the number of pocket universes is almost infinite, and this theory can not be verified.
Hawking added. That’s why he and Thomas herto tried to put forward a new theory of multiverse interpretation, and their new ideas were recorded in the paper a smooth exit from external expansion.
According to AVI Loeb, chairman of the Department of astronomy at Harvard, Hawking and Thomas herto solved the original mathematical and philosophical bottleneck problems mainly through mathematical methods, and put forward the prediction that “the universe that can be formed has certain limitations”.
When we go back to the development of the universe and reach the critical point of eternal expansion, the well-known concept of time will lose its meaning.
Thomas herto said that they set the infinite expansion at the critical point at the beginning of time, which is the boundary of everything.
It is worth noting that this is different from Hawking’s unbounded universe theory, which predicted that if we go back to the beginning of the universe, we will see the universe closed like a hemisphere.
“Now, we have to say that our past has boundaries.” They predicted that from above this boundary, the big bang formed a series of universes with specific structures.
If this theory holds, it means that our universe and other pocket universes are probably formed from that critical point.
Moreover, we may be able to find gravitational waves that match the expansion traces of the universe as an argument, which becomes an arguable hypothesis.
However, herto also said that the existing equipment has not been able to detect such evidence.
Therefore, he hopes that the future development of science and technology will bring more advanced instrument technology, which can further study the theory.
Xiaobian thinks that in the future of mankind, someone may carry on this research, find out the supporting arguments, and lead mankind to explore a small part of the vast universe.
But so far, this is more like an imaginative hypothesis left by Hawking, a small seed, and the question mark in the title of the paper is also like an invitation to the world.
Perhaps we should be inspired by the fact that Hawking was busy revising his papers on the origin of the universe ten days before he died.
Follow your heart, even if it seems as if you want to study the origin of the universe and go back to the beginning of time.
What do you think? Welcome to comment area.