1900: A physics genius wandering around Europe

Chapter 335: Cosmological constant! Stop the universe from expanding?

The importance of general relativity to astronomy cannot be overstated in any language.

Throughout the 20th century, physicists' research directions can be summarized into two.

One is extremely small, the other is extremely large.

Extremely small refers to various microscopic particles.

They are the most basic particles that make up everything in nature.

The physical theory that studies them is quantum mechanics.

And the maximum refers to the entire universe.

Among them, general relativity is the most important theory for studying the universe.

Relativity includes special relativity and general relativity.

Maxwell's electromagnetic theory + quantum mechanics + special relativity form quantum electrodynamics.

This theory is specifically about the study of electromagnetic force.

Quantum mechanics + general relativity form the theory of quantum gravity.

The goal of this theory is to unify gravity into the four fundamental forces.

Of course, there was no good progress until Li Qiwei's later generations.

This shows the status of relativity in the field of physics.

Early astronomy was almost entirely based on the theory of general relativity.

In the later stages, the macro and micro are actually indistinguishable from each other.

Because what physicists study is how microscopic particles formed the universe we have today.

That's another topic.

More knowledge reserves are required.

Now, astronomers have only just got their tools, and astronomy has not yet begun to flourish.

All the astronomers present at today's meeting believed that it was prepared for astronomy.

During this period, several conferences have been held in the field of astronomy on general relativity.

Because general relativity is so important to astronomy.

The five major predictions have a fatal attraction to every astronomer.

Many bigwigs and young scholars are flocking to it.

Of course, this does not mean that all astronomers agree with the general theory of relativity.

There will always be people who question or doubt the relationship between general relativity and the universe.

American astronomer Levitt is one of them.

At this moment he stood up.

He knew that his doubts would definitely cause an uproar.

"You must be kidding. So many physics experts have not questioned it. What can you, an astronomer, question?"

Although the topic given by Bruce in today's meeting is questioning the general theory of relativity.

But the bigwigs present were very self-aware.

Those were Bruce's humble words. General relativity has already reached the pinnacle of physics theory.

Anyone who wants to question it will probably make everyone despair.

But Levitt did it anyway.

He is also considered a big shot in the current field of astronomy.

What he cared about was never personal honor, but the future of astronomy as a whole.

For this reason, Levitt felt it was his responsibility to speak out about his doubts.

He recalled the time when Bruce visited him.

At that time, Bruce was already a leader in the physics community.

Every move he made attracted the attention of countless physicists.

But for other fields, especially astronomy.

Bruce's influence was much smaller.

So Levitt did not attend the lecture at Princeton.

This is the thing he regrets the most.

And now, he will no longer let himself regret it.

Eddington, Schwarzschild, and Hubble all looked toward Levitt.

I have great admiration for this senior.

"Since the advent of general relativity, people in the field of astronomy have gotten a little carried away."

"Everyone just wants to use general relativity as a tool, but is unwilling to think about the theory itself."

"Professor Levitt is indeed worthy of being a leader in the field of astronomy. He has never lost his original intention."

At this moment, everyone became excited.

Everyone wants to see what kind of questions this great astronomy expert will ask.

Li Qiwei also looked at him with a smile. He didn't have a deep impression of this big man in his memory.

However, this does not mean that he will look down on anyone.

Leaving one's name in history certainly means being awesome, but not having one's name in history doesn't mean that one's achievements are meaningless.

If we really look into it carefully, the emergence of general relativity in real history is also full of twists and turns.

There are many people whose achievements and contributions are not well known.

At this moment, facing the gaze of everyone in the auditorium, Levitt was slightly moved.

However, he soon became resolute and said:
"Hello, Professor Bruce, I'm Levitt."

"You made five major predictions in your paper on general relativity."

"The fifth prediction is that the universe is expanding."

"According to the results of the Bruce field equations, the universe may be expanding."

"My question is about the expansion of the universe."

"Is it possible that your field equations are wrong and you should add a cosmological constant?"

"This constant can be zero or a positive or negative number."

"In short, with this cosmological constant, we can offset certain forces and make the universe static."

"Because the fact that the universe is expanding is beyond human imagination."

"If the universe is expanding, is it space itself that is expanding?"

"But space itself is empty, how can it expand?"

boom!
Levitt's question shocked everyone in the audience.

This is simply a brilliant and bold idea.

He actually wanted to add a constant to the Bruce field equation so that the calculated universe would no longer expand.

It’s so terrifying!

"Oh my God, there is indeed no shortage of geniuses in the world. Astronomers are the ones who understand general relativity the best."

"Professor Levitt is worthy of being a veteran in the field of astronomy. He sees the essence of the problem directly."

"He did not become a puppet of general relativity, but instead used a critical attitude to think about it. This is really worth learning from."

"."

For a time, everyone praised Levitt.

This is a really good question.

Einstein even started calculating on the spot.

He discovered that adding a cosmological constant could actually curb the expansion of the universe.

"hiss!"

"We really can't underestimate the heroes of the world."

"There's something about this Levitt."

Eddington and the other two were full of admiration.

They also have talented people in the field of astronomy.

Who says astronomy is the same as biology?

We are different!
Faced with everyone's surprise and discussions, Li Qiwei remained calm.

There was still a smile on his face, as if what Levitt asked was not a fatal question but simple arithmetic.

Everything is under control.

In real history, after Einstein proposed the field equations, he discovered that each solution to the equations represented a different universe.

But no matter which cosmological model, expansion will always occur at some point in its evolution.

This puzzled Einstein, and he also thought that the universe could not expand, which was a bit too unbelievable.

So he added a constant to his equation to adjust for the expansion of the universe.

Various facts in later generations have proved that Einstein was wrong.

The universe is expanding, and it is expanding at an accelerating rate!

The expansion rate has exceeded the speed of light.

Now, the general theory of relativity published by Ridgway has made up for all the defects and can be called the most perfect general theory of relativity. This is also the reason why no one raises any questions.

If we can still find faults with this, it would be incredible.

After more than a hundred years of testing, the correctness of general relativity has become unbreakable.

There is no way anyone could prove it wrong.

But now, I didn’t expect that the inertia of history is so great.

Li Qiwei abandoned the cosmological constant, but unexpectedly it was picked up by someone else.

He smiled and said:

"Professor Levitt, your question is very interesting."

"To be honest, when I wrote the field equations, I actually had the same idea as you."

Wow!
The crowd was instantly shocked.

Everyone was surprised that Bruce had already thought of this.

"Yes, given Bruce's talent, there's no way he wouldn't think of this."

"It seems that this problem has been solved. No wonder Bruce is so calm."

"It turns out he's already several steps ahead of us."

Levitt was also moved. He didn't expect that the question he had been thinking about had already been thought of by the original author.

He gave a wry smile.

It turns out that not everyone can scam Professor Bruce.

He is horrible.

Looking at everyone's surprised expressions, Li Qiwei continued:
“But I found that this is actually wrong.”

"Because my field equations were derived step by step, it is not a hypothesis."

"So, what the final result is like represents what my general theory of relativity is like."

“Adding an artificial constant will only destroy the real truth.”

"According to the principle of Occam's razor, do not multiply entities unless necessary."

"For my interpretation of the universe, I trust my field equations."

Wow!
Li Qiwei's determination and confidence shocked everyone present.

He has absolute confidence in his theory.

Because the universe is expanding, it is not speculation but an inevitable consequence of the Bruce field equations.

If even the equations are wrong, then it means that there is something wrong with the foundation of general relativity.

This is something Bruce absolutely cannot tolerate.

At the same time, this also gives everyone a reminder.

If one day someone can prove that the universe is not expanding, it would mean that general relativity is wrong.

That would be an earth-shattering event that would shock the entire world.

Li Qiwei smiled and said, "I know that some of you are already thinking about questioning the general theory of relativity by proving that the universe is not expanding."

“I want to say that everyone is welcome to try, because your final result is certain.”

"The universe must be expanding."

"As for how to prove that the universe is expanding, I think that's a matter for you astronomers."

The humorous words caused a burst of laughter.

This was followed by thunderous applause.

Everyone was impressed by Li Qiwei.

Although Levitt's doubts are novel, they lack evidence after all.

And Li Qiwei's answer was impeccable.

Because all the results are calculated based on the Bruce field equations.

The field equations are derived based on two basic principles and Riemann geometry.

The logic is rigorous and flawless.

In fact, Levitt's question is the same as questioning whether light can bend.

As long as it can be proved that light is not bent, the general theory of relativity can be denied.

But no matter what, his concept of the cosmological constant still left a deep impression on the bigwigs.

This is a very profound reflection on general relativity, and it is worth learning from for everyone.

Li Qiwei continued, "We can continue to think along the lines of Professor Levitt's question."

"Gravity causes celestial bodies in the universe to attract each other and tend to gather together."

"And the results of the field equations show that the universe is expanding."

"Then there must be an expansion force that can offset the gravity, or even be greater than the gravity, so that the universe can expand."

"So what is this force?"

"These are questions that I think the future of cosmology will need to address."

"I hope you can join me in promoting cosmology. One day, we will have a correct understanding of the nature of the universe."

boom!
The astronomers present were extremely enthusiastic.

Li Qiwei described to them an extremely bright future.

Before cosmology even began, it had already attracted the bigwigs present.

Eddington, Hubble and Schwarzschild were extremely excited and looked at each other.

They feel that their future career direction has been determined.

That's cosmology!

Levitt looked at the young scholars around him, their faces full of admiration and worship.

Suddenly I felt deeply moved.

There has never been a day when astronomy has attracted so much attention from the world as it does today.

The whole world is now speculating when astronomers will be able to prove the correctness of general relativity.

Because the five major predictions of general relativity are all related to astronomy.

Therefore, it is natural for people to think that only astronomers can complete the proof.

As a big name in astronomy, Levitt naturally knows that many people are currently trying it quietly.

Young astronomers are especially active.

This is a quick path to fame.

No matter how many ordinary papers you publish, they are not as good as verifying one of the predictions.

Once a breakthrough occurs, it will definitely be an event that shocks the world.

I will immediately become a rising star in the astronomy world.

"Perhaps by then, Professor Bruce's reputation will rise again."

“It’s truly known to everyone.”

Levitt immediately regained his spirits. No matter what, this was a great thing for astronomy.

He will only give his full support.

"Thank you very much for your answer, Professor Bruce."

"I really hope someone can prove the five major predictions as soon as possible, especially the expansion of the universe, which is so important."

Li Qiwei suddenly said with a malicious tone: "I believe that day will not be too far away, Professor Levitt."

"I feel like Hubble has a good chance of proving it."

"He's a really good lad, very creative."

boom!
As soon as he finished speaking, there was an uproar in the conference hall.

Professor Bruce actually praised Hubble again in public.

This is already the second time.

"Wow, Hubble is really loved by Professor Bruce."

"Oh my God, if Professor Bruce praised me like this, I should be able to graduate with a Ph.D. tomorrow."

"You just think this is a good thing, but what a lot of pressure Hubble has to bear."

At this moment, Hubble's blood was boiling and he felt like he was about to explode.

It was an indescribable feeling.

It seemed as if the eyes of the whole world were on him.

Hubble was in a state of extreme excitement.

Instead of feeling any pressure, he took a deep breath and fell into absolute calm.

"I absolutely cannot let Professor Bruce down."

At this moment, another person suddenly stood up.

Eddington and others exclaimed that it was another great astronomy figure, the Dutch astronomer Kapteyn.

In real history, his and Levitt's work laid the foundation for Hubble's future achievements.

Everyone was curious, did this big shot also have doubts about the general theory of relativity?

(End of this chapter)