1900: A physics genius wandering around Europe

Chapter 628 Come out! Dark energy! Universal repulsion! Invisible and formless! Unbelievable! Sensational!

What is the driving force behind the accelerated expansion of the universe?
Inside the venue, everyone is eagerly waiting!

Li Qiwei smiled slightly and said:
"Just now when I was down there, I had a conversation with Professor Haier, Professor Dyson and others."

“Some very interesting ideas were put forward.”

“For example, some people believe that accelerated expansion is the cause of gravity.”

"Gravity manifests itself as attraction on a small scale, but as repulsion on a large scale."

"The accelerated expansion of the universe is dominated by this repulsive force!"

Everyone suddenly had strange expressions.

This idea was probably proposed by Professor Haier.

Because he had just used gravity to operate on it.

“But this view is not shared by all of us.”

"A very simple question, what is the boundary between gravity and repulsion?"

"If gravity really has a repulsive side, then this boundary problem is unsolvable."

"But there is one point in this speculation that has been recognized by everyone."

"That is, the reason for the accelerated expansion must be the existence of some kind of repulsive force."

"And this repulsive force must exist independently."

"Because according to the Big Bang theory, the expansion of space is just the aftermath of the explosion and it will definitely not get stronger and stronger."

“So, there must be a [existence] at work.”

"Obviously, we can't see this kind of existence with our naked eyes yet."

"So, some people asked: Could it be caused by dark matter?"

Wow!
Everyone's eyes lit up.

This is a novel answer.

"However, this is also impossible."

“Although dark matter participates in gravity, it is an attractive force, not a repulsive force.”

"Otherwise, the Milky Way and galaxy clusters would have disintegrated long ago, and it would have been impossible for large structures to form in the universe."

Everyone nodded.

We cannot forget the issue of galaxy mass in order to explain the accelerated expansion of the universe.

If we try to give dark matter a repulsive force, the situation will only become more and more complicated.

The big guys in the front row smiled helplessly.

Their guess was shared by Professor Bruce before it was made public.

However, no one complained.

Because those guesses can easily be proven wrong, there is no need to speak them out.

At this time, Li Qiwei continued:

“But the discussion is not without value.”

"At least regarding the causes of the accelerated expansion, we can derive the following key information."

"First, there must be something that can produce repulsion, causing the expansion of space to accelerate."

"Second, the density of this thing will not decrease as space expands, but will remain the same or even increase."

"Because according to Hubble's observation data, the accelerated expansion of the universe is likely to be getting faster and faster."

"So the reasonable explanation is that the more space expands, the more of these things there are, and the greater the repulsive force generated, which can always exceed the gravitational force."

"Thereby causing the expansion of the universe to accelerate."

"Third, this stuff is like dark matter, it is invisible, that is, it has no electromagnetic interaction."

"In addition, it does not have universal gravitation, but universal repulsion. However, this repulsion only acts on space, not on matter."

Wow!
Everyone showed incredible expressions.

Everyone was amazed that Professor Bruce was able to analyze so much in such a short time.

And it is well-reasoned and convincing.

Someone couldn't help but sigh:

"This is Professor Bruce's conjecture!"

"He never speaks of baseless imagination, but rather uses existing reality, his strong logical thinking ability, and his wild imagination to search for possible answers in the void."

"This is the charm of scientific conjecture."

“Human wisdom can be hundreds or thousands of years ahead of the times!”

These words made everyone excited!

Everyone is looking forward to Professor Bruce's next conjecture.

Li Qiwei's eyes were deep and he said calmly:
"Based on the above analysis, I boldly put forward a conjecture."

"I think there is a kind of [dark energy] in the universe!"

Wow!
The whole audience was stunned!
Everyone's eyes widened with disbelief.

Everyone knows what energy is.

What is dark energy?

"Oh my god! Could it be that Professor Bruce is addicted to dark things?"

“What does dark energy mean?”

"Is there a difference between light and dark energy?"

“What is the relationship between dark energy and dark matter?”

For a time, everyone was talking about it.

Haier and other bigwigs were also confused.

But they were still relatively calm.

Professor Bruce would never shoot without a purpose.

Li Qiwei smiled lightly and continued:

"The dark energy I'm talking about is a completely different form from the matter or energy we know."

"I named it dark energy because I don't know the nature of what's causing the accelerated expansion of the universe."

"But whatever its nature is, it will manifest as an energy effect."

"Just like dark matter can participate in gravitational interactions, it is also a form of energy."

"Dark energy has a repulsive effect and is evenly distributed throughout the universe."

"Its density does not decrease as space expands."

"So the larger the space, the more dark energy there is; and the more dark energy there is, the faster the expansion of the universe will be, forming a cycle."

"It is precisely because of the existence of dark energy that the universe is expanding at an accelerated rate."

"This is my conjecture about the driving force behind the accelerated expansion of the universe."

quiet!
Deathly silence!

After hearing this explanation, everyone felt confused.

Not only is it not clearer, it is even more confusing.

“Is this still the universe I live in and know?”

"I don't understand, Smecta."

However, the bigwigs are full of doubts.

Compared to dark matter, dark energy is full of mysteries.

Before Eddington took the stage, the crowd couldn't help asking questions.

Someone asked:

"Professor Bruce, is there any relationship between the dark energy and dark matter you mentioned?"

“Is it possible that dark energy is the energy form of dark matter?”

"Just like ordinary matter turning into ordinary energy?"

Li Qiwei replied:
"No!"

"Dark matter and dark energy are two completely different entities. There is no connection between them as you said."

"Although neither of them participates in electromagnetic interactions, so they cannot be detected by the human eye or instruments."

"But one of them manifests as attraction, and the other manifests as repulsion. There is no transformation relationship."

"Besides, dark matter is real and exists."

"Dark energy is rather special, and its nature cannot be studied for the time being."

Someone then asked:

"Professor Bruce, energy is a very abstract concept. It has no entity itself and must rely on material basis to exist."

"Then what substance does dark energy rely on?" Everyone nodded. This is a very good question.

Li Qiwei said:
“That’s why I named it dark energy.”

"We don't know how this energy works yet."

“Maybe it doesn’t need a medium.”

"Or maybe this medium is like dark matter and cannot be observed."

"It needs to be emphasized again that dark energy is not necessarily matter or energy, it is an unknown form."

Now everyone was completely confused.

Dark energy is really weird.

Moreover, most people present could not accept the existence of dark energy as they could accept dark matter.

Although dark matter is equally mysterious, it at least participates in gravity, so we can just treat it as ordinary invisible matter.

Air is also invisible, but that does not hinder the fact that air exists.

But dark energy is different.

As Professor Bruce explains, its nature is not even clear.

This is a little hard to believe.

Li Qiwei looked at everyone's expressions and felt deeply moved.

Even in later generations, dark energy remains one of the biggest unsolved mysteries in cosmology.

Although the existence of dark energy has been recognized by the academic community.

But its nature remains unclear and there are many speculations.

For example, some people believe that dark energy is vacuum zero-point energy.

The larger the space, the more vacuum zero-point energy there is, which is consistent with the properties of dark energy.

Some people believe that dark energy is a substance even more magical than dark matter.

Normal matter, antimatter, and dark matter all have gravitational force, while dark energy has universal repulsion.

This statement is similar to Haier's point of view and is difficult to verify.

There is also a view that dark energy is actually a kind of spatial structure, and like the mechanism behind quantum entanglement, it is the underlying rules of the universe.

Finally, there is a most popular view that dark matter is the cosmological constant Λ.

In the gravitational field equation, Λ represents the repulsive force, which counteracts the gravitational force of matter.

But this statement still does not explain the nature of dark energy.

In short, there are too many speculations in the scientific community about dark energy, and there is no conclusion yet.

Any researcher can propose possible conjectures based on his or her own thinking.

But there is no doubt that dark energy exists, and many phenomena have proven it.

Ordinary people have more wild imaginations about dark energy.

In many science fiction novels about cultivating immortals, the essence of spiritual energy is interpreted as dark energy.

Dark energy is invisible, colorless, and tasteless, and it fills the entire universe. It has an energy effect and is very consistent with the setting of aura.

It is believed that dark energy can generate all matter in the universe.

Some science fiction novels believe that dark energy is actually energy from another universe that spreads into our universe.

and many more.

Regardless, anyone with an interest in science can come up with an opinion about the nature of dark energy.

Moreover, this almost involves metaphysical propositions, and the gap between ordinary people and top scientists is infinitely narrowed.

Maybe one day, someone will have a sudden inspiration and figure out the nature of dark energy.

By then, a Nobel Prize in Physics will be inevitable.

At this moment, facing the questions of everyone present, Li Qiwei was temporarily unable to explain the nature of dark energy.

It is said to be temporary because his theory of everything has not yet been broken through.

Once the breakthrough is made, even a small amount of dark energy will be no problem at all.

Everyone also understood that even with Professor Bruce's ability, he was temporarily unable to imagine the nature of dark energy, which shows how mysterious it is.

But this does not affect everyone's interest in studying dark energy.

Hubble, in particular, felt that he had found his next life goal.

“Explore the nature of dark energy!”

At this time, Eddington asked another question:
"Professor, if dark energy really exists, what is its relationship to the Big Bang theory?"

Wow!
This may be the issue that everyone is most concerned about.

Li Qiwei knew what everyone was worried about.

He thought for a while and said:

"I would say that the existence of dark energy does not overturn the Big Bang theory."

"Dark energy is a type of energy associated with the vacuum of space, and its amount depends entirely on the size of space."

"Based on this, we can redescribe the Big Bang theory to include dark energy."

"Dark energy appeared along with dark matter and ordinary matter energy very early in the explosion."

"By the way, I think the proportional relationship between them is a good research topic."

In later generations, scientists calculated that the energy in the universe is roughly composed of the following parts:
Dark energy: 68%; dark matter: 27%; ordinary matter: 5%; photon radiation energy: 0.01%.

"Because the space is smaller at this time, gravity dominates and the expansion of the universe slows down."

"However, although the expansion rate is slowing down, the space of expansion is gradually increasing."

"And the more space there is, the more dark energy there is."

"Until a certain point, the repulsive force of dark energy becomes stronger than the gravitational force."

"Then, the universe was taken over by dark energy and began to expand at an accelerated rate."

Wow!
Everyone exclaimed!

After adding dark energy to the Big Bang theory, there is no sense of incongruity.

It even fills in the gaps of the Big Bang theory.

"My God!"

"The Big Bang theory is indeed the theory that transcends all other theories."

"Dark matter and dark energy can be perfectly integrated by it."

This beauty of logic and science makes everyone intoxicated.

In later generations, scientists proved through observation and calculation that the universe began to expand at an accelerated rate about 50 billion years ago.

If the entire history of the universe is condensed into one year, then the accelerated expansion began in late July.

Moreover, there is an even more terrifying fact.

Ridgeway added:

"The expansion of the universe is not only accelerating, but it is likely to be exponentially accelerating."

"It started out slowly, then grew faster and faster, bursting through the sky, and even surpassing the imagination of the human mind."

"A universe of infinite size!"

Wow!
Everyone was shocked when they heard this.

Hubble just proposed the theory of the Big Divide Universe, which also believes that the acceleration is getting faster and faster.

But compared with the index, it's not good enough.

There is a well-known fable.

It is said that a king wanted to reward the craftsman who invented chess.

So let the other party put forward a condition.

"The reward I want is insignificant," said the craftsman.

"Put one grain of rice on the first square of the chessboard, two grains of rice on the second square, four grains of rice on the third square, and so on."

The king laughed after hearing this, thinking that the reward was too simple.

However, when he discovered that 64 trillion grains of rice were needed on the 2000th grid.

He probably wanted to kill the craftsman outright.

This is the power of exponentials.

At this moment, everyone was filled with infinite curiosity about dark energy.

Where does energy come from?

How can it increase infinitely?

But all of this seems to be unsolvable today.

(End of this chapter)