Chapter 230: War Suspicion

In that era, many countries had this kind of laser interferometer space antenna, among which China had two sets, one was called Taiji and the other was called Tianqin.

The third type is the pulsar timing array.

As the name suggests, it is a method of measuring gravitational waves using a pulsar array.

The so-called pulsar is actually a type of neutron star, that is, a rotating neutron star. The characteristic of a pulsar is that it will continuously emit electromagnetic pulse signals, which will come out from the two poles to form two radiation cones.

The powerful electromagnetic pulse signal of the radiation cone sweeps across the starry sky like a flashlight. If its polar radiation cone does not coincide with the rotation axis, then it will shake in the starry sky like a regularly shaking flashlight. If the radiation cone happens to sweep across the earth, people will observe that the neutron star exists in the form of a pulsar.

Another characteristic of pulsars is that their period is very stable, especially pulsars with a rotation period of milliseconds are extremely stable.

Therefore, people came up with this gravitational wave detection method based on the characteristics of pulsars.

That is, according to the millisecond pulsars observed at different positions, they are formed into an array, and then the time when each pulse reaches the earth is measured very accurately with an astronomical telescope.

After that, if a gravitational wave signal reaches the earth, it will have different effects on pulsars at different positions and distances in the pulsar array.

Gravitational waves are ripples in space-time. Changes in space-time ripples will affect the arrival time of pulsar pulses, causing different changes in the pulse period and arrival time.

By analyzing the changes in pulse arrival, the position of the changing pulsar, and other information, people can find that gravitational waves are coming.

The range of gravitational waves detected by this method is nanohertz gravitational waves, that is, the range of 10 to the -9th power of Hertz.

In that era, the Chinese pulsar timing array was FAST-the Sky Eye.

Well, there is actually another method called polarization measurement of microwave background radiation. Its principle is to use the two special polarization modes of gravitational waves themselves to achieve this. One of these two special polarization modes is called E film and the other is called B film.

However, this method is used to detect primordial gravitational waves. If primordial gravitational waves exist, they will leave marks in the cosmic microwave background radiation. People can judge whether it is E-mode or B-membrane through the marks left by it, and then know whether primordial gravitational waves exist.

Of course, now that the new humans have become a starship civilization and are still sailing at a constant speed of 30% of the speed of light, they naturally cannot use pulsar timing arrays to detect gravitational waves.

The laser interferometer gravitational wave observatory cannot be used either, after all, it is placed on the ground.

So only the laser interferometer space antenna is left.

According to this principle, when sailing, the new human warships will deliberately arrange the warships carrying detectors in groups of three to keep the same direction of movement and synchronized speed, so that their spatial positions are fixed.

In this way, every three warships carrying such detectors in the constant speed sailing stage can form a set of laser interferometer space antennas.

The gravitational waves detected by the new humans now are obtained through this array.

Because the fleet had just entered the uniform speed phase, scientists initially thought that the warships carrying the detectors had not yet adjusted the synchronization.

But after discovering that almost all arrays detected the same gravitational wave signal, they realized that it was indeed a gravitational wave signal.

The space-time deformation caused by gravitational waves is actually very weak, that is, stretching or squeezing, and its deformation amplitude is generally only 10-21.

And its signal source can also be divided into many types.

The first thing people think of is the merger of stellar-level compact celestial bodies, such as the merger of two neutron stars and the merger of two black holes. The gravitational wave frequency generated by this type of gravitational wave source is relatively high, generally in a few hertz, tens of hertz or even hundreds of hertz.

The second is the merger of two white dwarfs. The mass of white dwarfs is not as large as that of neutron stars and black holes, and the rate of their merger is not that fast, so this type of gravitational wave source also has a relatively low frequency.

The gravitational wave source with a smaller frequency is the merger of supermassive black holes in the center of distant galaxies. For example, the Milky Way and the Andromeda Galaxy will collide in about 3.7 billion years. If there is a civilization outside the local galaxy group, they will detect this type of gravitational wave source in a few years.

And gravitational waves with lower frequencies are primordial gravitational waves.

With this knowledge accumulation, new human scientists can determine the type of source by analyzing the frequency of gravitational waves.

The new human scientists quickly obtained the gravitational wave source data from the laser interferometer space antenna array, and then drew corresponding conclusions based on these data.

"General, if the data is correct, then this gravitational wave source must be produced by the merger of massive stars. As for its location."

It was Gander who spoke. The moment he confirmed that the gravitational wave signal was received, he notified Yue Yuan, and he was also talking to Yue Yuan at this moment.

Speaking of the location, Gander stopped talking and pointed to the star map on the big screen.

"Is this Sirius?!" Yue Yuan quickly recognized the marked position on the star map,

because Sirius is very close to the sun, only 8.6 light years away, and the sun can be seen on the large-scale star map. On the human star map, the sun, which has been destroyed to the point where nothing is left, is naturally marked out specially.

But Yue Yuan looked at the star map and had a question in his mind, that is, there is no natural massive star merger event in Sirius.

In other words, something big should have happened there.

Just when Yue Yuan was about to ask a question, a member of the astronomy team hurriedly floated towards Gan De and shouted: "Professor Gan, the data has changed. You see, there is more than one source of gravitational waves, and its frequency has increased sharply in a very short time!"

Gand quickly took the latest detection results, and after a few glances, his face showed a solemn look.

He looked at Yue Yuan and said: "General, it seems that the gravitational waves detected before were not produced by the merger of massive stars, but by some kind of man-made... aliens. If so, then I dare to conclude that the gravitational wave signal from that direction will have new changes!"

Sure enough, as soon as he finished speaking, a message came from the observation center, saying that the frequency of gravitational waves had changed again. In just one minute, the frequency of the gravitational wave signal source soared to a very high level and then dropped sharply.

It is totally out of the range of normal natural phenomena.

"It seems that some advanced civilizations are fighting somewhere. I don't know what weapons can cause such a large disturbance in space and time." After seeing the detection results, Yue Yuan also made a judgment in his heart, but for a moment, he didn't know what to do.

Humans haven't run far, and such a thing happened. It's really terrible.