Chapter 366 Sky Eye No. 1

Primordial gravitational waves refer to the extremely rapid expansion of the universe in the early days of the Big Bang, from about 10^-332 seconds after the birth of the universe.

During this process, the universe as a whole expanded at a speed many times faster than the speed of light - of course, this is only an expansion at the spatial level, not superluminal motion of matter, so it does not violate existing theories.

At this stage, the gravitational waves released by the superluminal expansion of the universe are called primordial gravitational waves.

Primordial gravitational waves have special significance. Through some complex mechanisms, existing theories can regard the existence of primordial gravitational waves and the existence of gravitons as the same issue.

That is, there is no need to directly observe gravitons. As long as it can be confirmed that primordial gravitational waves really exist, it can be confirmed that gravitons really exist.

Now, the question becomes, how to confirm whether primordial gravitational waves really exist?

Fortunately, this problem can be solved through observation, but it is more difficult.

Because the wavelength of primordial gravitational waves is too long and the frequency is too low. Its wavelength is even as long as the observable universe, that is, the wavelength is as long as tens of billions of light years.

As early as the first-level civilization stage, humans have confirmed the existence of gravitational waves and have actually detected gravitational waves.

However, the gravitational waves detected by early humans have extremely high energy, extremely high frequency, and extremely short wavelength. They are usually some violent physical processes such as black hole mergers, black holes swallowing neutron stars, and neutron star collisions.

For example, the double black hole merger event that has been detected.

About 1.3 billion light-years away from the solar system, a black hole with a mass of 36 times the mass of the sun and a black hole with a mass of about 29 times the mass of the sun are madly rotating around each other and eventually merging into a large black hole.

In simple calculations, the mass of this merged large black hole should be the sum of the masses of the two small black holes before the merger, that is, 65 times the mass of the sun.

But the final result after the merger is only about 62 times the mass of the sun.

Where did the missing mass of about 3 times the mass of the sun go?

The answer is that it radiated to the entire universe in the form of gravitational waves.

In this instant, the gravitational wave radiation power of the merger of the two black holes is as high as 3.6*10^49 watts, and its instantaneous power is even 10 times more than the total visible light radiation power of the entire observable universe.

Such an intense gravitational wave radiation event has a frequency of about 250HZ, which means 250 vibrations per second.

The transmission speed of gravitational waves is the speed of light, so the wavelength of this gravitational wave radiation is about 1,200 kilometers.

The LIGO detector used to detect this gravitational wave radiation event observed a length change of less than one ten-thousandth of the diameter of a proton because of this gravitational wave, thus confirming the existence of this gravitational wave.

However, gravitational waves with a wavelength as short as 1,200 kilometers are already so difficult to detect, so how can the primordial gravitational waves, which have a wavelength equivalent to the entire observable universe, that is, about 96 billion light years, be observed?

Faced with this kind of gravitational wave, humans who have developed to the peak of the third-level civilization and have many means of gravitational wave detection cannot detect it.

At this stage, humans have built laser bases tens of millions of kilometers apart in the galaxy.

For gravitational wave detectors, it can be simply assumed that the longer the arm length of the detector, the higher the detection accuracy.

The laser gravitational wave detectors built in interstellar space and tens of millions of kilometers apart are equivalent to arms as long as tens of millions of kilometers - in comparison, the arm length of the detector that detected the gravitational waves of black hole mergers was 4 kilometers - and they could not detect the original gravitational waves.

However, humans also have a gravitational wave detection method with higher detection accuracy, the pulsar timing array detector.

Pulsars are a type of neutron star. It has extremely strong radiation and extremely stable rotation.

The electromagnetic waves emitted by high-speed rotating pulsars will sweep across the earth at a fixed frequency like the light of a lighthouse.

People regard pulsars as laser bases for laser array interferometers to detect the existence of gravitational waves.

The principle is very simple. The radiation interval of a pulsar is extremely stable. If a gravitational wave passes through, the radiation interval of the pulsar will change very slightly. By measuring this change, the properties of the gravitational wave can be measured.

In this way, the distance between the earth and the pulsar used as a clock can be equivalent to the arm length of the gravitational wave detector.

As a result, humans have achieved the goal of upgrading the arm length of the gravitational wave detector to hundreds or even thousands of light years.

From the initial arm length of 4 kilometers, to the later arm length of tens of millions of kilometers, and then to the current arm length of thousands of light years, humans have achieved a huge leap in the ability to detect gravitational waves, and the detection accuracy has increased by more than a thousand times.

But... unfortunately, even if the detection accuracy has been improved so much, it is powerless in the face of monsters such as primordial gravitational waves whose wavelengths have reached the order of magnitude of the diameter of the observable universe.

To detect primordial gravitational waves, we need to find another way and a new detection method.

Han Yang found a method that theoretically has the ability to detect primordial gravitational waves.

Because the universe expanded at superluminal speed in the early stages of the Big Bang, and primordial gravitational waves can only be transmitted at the speed of light, they were "sealed" in the cosmic microwave background radiation.

The cosmic microwave background radiation can be simply regarded as the first ray of light since the birth of the universe, and can be called the "primordial light".

It is a kind of electromagnetic radiation that fills the entire observable universe, with a temperature of about 2.725 degrees Kelvin.

If primordial gravitational waves exist, they must have become part of the cosmic background radiation.

And everything that exists will inevitably leave traces. Through sociological means rather than scientific means, Han Yang has already known that primordial gravitational waves do exist, so this trace must also exist.

Therefore, Han Yang found the ultimate means to complete the quantization of gravitons: by detecting the cosmic microwave background radiation, find the impact caused by primordial gravitational waves and separate it.

This is also an extremely difficult thing. After all, even if this impact does exist, it must be extremely small. To detect it, it is necessary to have detection equipment and means with an almost incredible sensitivity.

However, even if this is extremely difficult, it is still possible to achieve, unlike the other methods, such as directly observing gravitons and observing primordial gravitational waves through gravitational wave detectors, which are not possible at all.

After digesting and absorbing all the scientific data purchased from the Yunguang civilization, Han Yang confirmed that he now had the possibility of theoretically manufacturing observation equipment with high enough accuracy.

Of course, it was only in theory. It was still extremely difficult to turn theory into practice and truly manufacture such detection equipment.

In other words, simply manufacturing such detection equipment was not difficult at all - for human civilization, which already had such powerful engineering power, it was possible to push a planet, so what kind of equipment could be difficult for humans?

To be more precise, it was the most difficult to build such equipment.

This involved a lot of theoretical calculations.

People must first confirm what kind of parameters are needed to have the possibility of detecting such an impact, and then study how to achieve such parameters, what materials and structures to use, and so on.

Based on this goal, the human scientific community and Han Yang simultaneously carried out a lot of calculations and research, and conducted experiments again and again.

In this process, countless extremely difficult scientific problems emerged. Although the powerful mathematical tool of Roche analysis has greatly improved efficiency and reduced difficulty, the human scientific community still shows signs of being unable to cope with it.

There is no way. In the past hundreds of years, they have been accustomed to learning existing knowledge and then making micro-innovations and applied research based on existing knowledge. Now they have to explore the unknown field by themselves - there is no way, there is really no such thinking and consciousness.

Han Yang knows that scientific research talents who truly possess this kind of scientific thinking and consciousness can only be slowly cultivated from the next generation.

Generally speaking, ordinary civilizations will not have this opportunity. Because the internal and external environment does not allow it.

Only humans who exist on their own have this opportunity.

The human scientific community can only do some auxiliary work, and the key core of this work falls on Han Yang.

Fortunately, Han Yang at this stage has gone through several major upgrades before and has enough confidence to face this problem.

In this process, Han Yang first confirmed the external environment required to build this detection equipment.

The lower the various interference radiations, the better.

This environment is different from the neutrino detector that requires extremely low background radiation. Neutrino detectors can be built deep underground, shielding almost all external radiation. But at this moment, if this kind of detection equipment is built underground, even the cosmic microwave background radiation will be shielded, so what can it detect?

It is necessary to keep other types of radiation as low as possible, but not affect the cosmic microwave background radiation.

The only place that meets this detection condition is far away from stars and other celestial bodies.

The reason is simple. Stars are the most numerous and most extensive sources of strong radiation in the universe.

In addition to stars, other celestial bodies with strong radiation are not acceptable. Black holes, neutron stars, white dwarfs, especially these extreme celestial bodies that are in the process of accretion, the farther away the better.

Han Yang finally chose a place about 16.2 light years away from the solar system.

There, the nearest star is 5 light years away. And the surrounding stars are red dwarfs and yellow dwarfs with low radiation power, and there are no supermassive stars such as blue giants.

The address is selected, and the next step is to combine the specific local environment to make a detector structure that can better adapt to the local environment.

Of course, before that, Han Yang had to confirm what standards this detector needed to meet.

Combined with existing scientific data, that is, although I don’t know what kind of detection standard can detect this effect for the time being, I already know which detection standards cannot detect this effect.

In this way, the performance lower limit was confirmed.

Then through a large number of calculations, by solving a series of extremely complex equations - the mathematical tool of Roche analysis played an important role in it. Many complex equations that could not be solved before were solved under the application of this new mathematical tool.

Of course, this process is still not enough to rely solely on Han Yang’s own computing power. This is not that Han Yang can’t calculate it himself, but it is too wasteful.

For this kind of calculation, you can just write a program and hand it over to a special supercomputer to do it, without wasting your own computing power.

So, a dwarf planet located at the edge of a distant galaxy, about 200 billion kilometers away from the sun, was chosen by Han Yang, and he started to build a large-scale supercomputer center directly there.

One of the major indicators that restrict the performance of supercomputers is heat dissipation. Because this dwarf planet is far away from the sun, the surface temperature is as low as minus 260 degrees Celsius, which just meets the heat emission of supercomputers.

On this dwarf planet, Han Yang mobilized the engineering capabilities of mankind, plus his own engineering capabilities, and built tens of thousands of supercomputer centers in just a few years. The computing power of each supercomputer center, although not as good as Han Yang's own, is also limited.

These tens of thousands of supercomputer centers were running at full power, and began to calculate the complex calculation problems submitted by Han Yang and the human scientific community. The heat released even caused the surface of the dwarf planet to rise from more than 260 degrees below zero to two or three degrees above zero, melting all the solid gases on the surface of the planet, such as dry ice, methane, solid hydrogen and oxygen, and directly giving the dwarf planet a thin layer of atmosphere.

Fortunately, with the atmosphere, the planet radiated more heat energy outward, barely achieving a balance between heat generation and heat release, and the planetary temperature did not rise again, allowing the supercomputer to continue to operate on this planet.

Under the full-scale calculation and verification, a series of extremely precious scientific data output finally allowed Han Yang to slowly form the basic concept of this detector in his mind, and initially figured out how to build it and what performance indicators to achieve.

After figuring this out, the hundreds of millions of tons of materials that were specially transferred back to the construction site of the fifth-level civilization aerospace mothership could be put into use.

After two years, the giant cosmic microwave background radiation detector named "Sky Eye No. 1" by Han Yang was finally built.

Under the vast universe and the reflection of thousands of stars, one side of this giant detector is like a smooth mirror, completely reflecting the appearance of the universe.

Behind its smooth mirror surface are equipment after equipment, which are connected by various pipes and complex cables. There are hundreds of thousands of large and small equipment.

The cross-sectional area of ​​this detector is also 4.6 square kilometers.