If there is a prototype of the Red Coast Base in "The Three-Body Problem", it may be hidden in this coniferous forest.

When you think of the mysterious "Red Coast Base" in Liu Cixin's "The Three-Body Problem", does this image come to your mind?

On the black soil of Northeast China, in the dense coniferous forest, stands a huge parabolic antenna...

In fact, there is such a place in real life, but it does not stand on a high peak like the "Red Coast Base". Instead, it is a real existing and operating telescope that is closest to the description of the Red Coast Base - the Jiamusi 66-meter radio telescope of the China Xi'an Satellite Tracking and Control Center.

Figure 1 The Jiamusi 66-meter radio telescope surrounded by forests (Photo: Lv Binghong, Xi'an Satellite Tracking and Control Center)

The Jiamusi 66-meter radio telescope, as the name suggests, is a 66-meter radio telescope located in Jiamusi City, Heilongjiang Province. But more often, people call it the deep space antenna.

Where does the “Deep Space Antenna” come from?

Those who are familiar with the lunar exploration project may be familiar with the term "deep space exploration". However, the moon is only the outpost of deep space exploration. We will also explore Mars and even more distant targets in the future. When we explore the moon and even Mars, we need to control the probe and receive the data sent back by the probe, and all of these require the use of "deep space antennas".

As you can imagine, to communicate with distant probes, we need not only a loud voice, but also good and sensitive ears. The Jiamusi 66-meter deep space antenna, as Asia's largest fully movable antenna, takes into account both "loud voice" and "good ears". However, this voice and ear are not for sending and receiving sound waves, but for sending and receiving electromagnetic waves. The Jiamusi 66-meter deep space antenna can use electromagnetic waves to communicate well with the lunar probe, and is one of the main equipment of my country's lunar exploration project.

Figure 2 Jiamusi 66-meter deep space antenna and observation room (Photo: Lv Binghong, Xi'an Satellite Tracking and Control Center)

Figure 3: Staff members are operating the telescope in the observation room (Photo: Lv Binghong, Xi'an Satellite Tracking and Control Center)

Is it an “antenna” or a “radio telescope”?

Whether it is the Jiamusi 66-meter deep space antenna or the well-known Guizhou "Sky Eye" telescope FAST, they can all be called "antennas", but "pretentious" astronomers generally call antennas used for astronomical observations "telescopes". In addition, the electromagnetic wave frequency band of the antenna is the radio band, so it is specifically called a "radio telescope".

Artificial signals, such as those from mobile phones, satellites, and deep space probes, are usually much stronger than the celestial signals that astronomers want to observe, so antennas that are generally used to receive artificial signals do not need very sensitive "ears". But the Jiamusi 66-meter antenna is different. Its goal is the more distant sea of ​​stars! In order to be able to communicate with deep space probes that will be launched farther in the future, the Jiamusi 66-meter antenna's ability to listen to signals is comparable to that of a radio telescope, and therefore has the ability to conduct astronomical observations. In fact, it is also conducting astronomical observations. So it can also be called the "Jiamusi 66-meter radio telescope."

I am a pretentious person, so I like to call it the Jiamusi 66-meter Radio Telescope.

It is worth mentioning that, because general astronomical observations only require receiving signals, domestic radio telescopes, except for the one in Jiamusi, do not have the ability to transmit signals. So, if you want to ask which cosplay Red Coast base is the best, the Jiamusi 66-meter radio telescope is the best choice!

Figure 4 The Jiamusi 66-meter radio telescope under the stars (Photo: Lv Binghong, Xi'an Satellite Tracking and Control Center)

Pulsars—Maybe They Can Take Us Further

The main astronomical observation target of the Jiamusi 66-meter radio telescope is pulsars. You say it is a deep space station, how can it observe pulsars? Not to mention, if we want to conquer the more distant sea of ​​stars, we may have to rely on pulsars.

Our previous popular science articles (https://mp.weixin.qq.com/s/y5Y3uLPl4XRkd36nIyZaBg and https://mp.weixin.qq.com/s/udGn8VC45n3SQNVGCbueHw) introduced that pulsars are neutron stars that periodically sweep the Earth with their radiation beams as they rotate. Imagine a lighthouse, with a beam of light constantly sweeping around. If we stand in a position that happens to be swept, we can periodically feel the light. Pulsars are lighthouses in the universe.

Figure 5 Schematic diagram of a pulsar. The upper part shows a rotating neutron star (purple ball) and its two radiation beams (yellow beams). The red dots in the lower part indicate the brightness of the neutron star we see at the corresponding moment. The yellow curve is the brightness change of the neutron star during one rotation.

(Image source: http://www.ligo.org/science/Publication-S6VSR24KnownPulsar/)

If our probe flies out of the solar system and goes to the distant interstellar space where the antenna on Earth can no longer communicate with it, how can the probe that loses ground control reach its destination smoothly? One possible solution is to let the probe use pulsars for autonomous navigation.

Before using pulsars for navigation, it is necessary to use ground-based radio telescopes to carefully observe pulsars, identify which pulsars are suitable for navigation, and create a "file" for each pulsar that can be used for navigation. These files are the maps that future interstellar probes will need to use for interstellar travel. Although the probes in interstellar travel are no longer controlled by humans on Earth, they can observe pulsars on their own and then determine their position in space based on the "maps" they carry with them.

In a recent scientific research advance, astronomers from the National Astronomical Observatory of China used the Jiamusi 66-meter radio telescope to observe 10 pulsars and analyzed their "interstellar twinkling" phenomenon.

Many people may have seen this scene: sunlight shines through clear water to the bottom of the water, and as the water surface fluctuates, the light and shadow on the bottom of the water also shake and change.

Similarly, the electromagnetic waves emitted by pulsars, when irradiated to the earth through the interstellar medium, will also change in brightness with the fluctuations of the interstellar medium. We call this phenomenon "interstellar scintillation". From observations, we can see that the brightness of electromagnetic waves of different frequencies from pulsars changes over time (see Figure 7).

Figure 7 Interstellar scintillation of pulsar B0355+54 observed by the Jiamusi 66-meter radio telescope (PFWang et al. 2018). The color represents the brightness of the pulsar radiation, the horizontal axis is time, and the vertical axis is the frequency of the electromagnetic wave.

In-depth processing of these changing data can not only obtain some information about the interstellar medium, but also infer information such as the lateral velocity of the pulsar. The motion information of the pulsar is also indispensable in the "map" of interstellar navigation.

The real-life version of "Red Coast Base" carries mankind's yearning for the universe

Unlike the Red Bank Base in the novel "The Three-Body Problem", the Jiamusi 66-meter radio telescope is not used to directly establish contact with extraterrestrial civilizations, but to help human spacecraft fly to farther space. But like the Red Bank Base, the Jiamusi 66-meter radio telescope also carries the infinite yearning of human beings for the universe!

Figure 8 Group photo of some staff members of Jiamusi Deep Space Station

References:

1. Jiamusi Deep Space Station successfully completed the near-moon braking mission of the "Queqiao" relay satellite https://mp.weixin.qq.com/s/saOhD1ZK8XywQPqjh8GCkw

2.Xu, Dezhen, et al. "First geodetic VLBI sessions with the Chinese Deep Space Stations Jiamusi and Kashi." Advances in Space Research 58.9 (2016): 1638-1647.

3. Wang, PF, et al. "Jiamusi Pulsar Observations: II. Scintillations of 10 Pulsars." arXiv preprint arXiv:1808.06406(2018).