In addition to the worldâ€™s largest radio telescope in Guizhou, you also need to understand these

According to Xinhua News, the world's largest single-caliber, highest-sensitivity radio telescope (FAST) independently developed by China was completed and put into use on September 25.

It is understood that this radio telescope in the mountainous area of â€‹â€‹Longnan, Guizhou Province was assembled from 4,450 triangular receiving panels, with an aperture of 500 meters and a total area of â€‹â€‹30 football stadiums. Can receive electromagnetic signals 13.7 billion light years away, the error does not exceed 1 mm. It is the largest radio telescope in the world.

As a specialized device for detecting electromagnetic waves emitted by celestial bodies outside the Earth, the radio telescope has always played a crucial role in the research and development of outer space and astronomy. Therefore, in addition to our country, all other countries and regions in the world have also built a variety of radio telescopes or arrays of radio telescopes. Lei Feng Network (search "Lei Feng Network" public concern) here for everyone to make an inventory of foreign radio telescope to see what they look like.

Â American Arecibo Radio Telescope

Before FAST was established in China, the worldâ€™s largest single-caliber radio telescope was the Arecibo radio telescope at the Arecibo Observatory in Puerto Rico. The initial diameter of the telescope was 305 meters and was later expanded to 350 meters. It was jointly managed by the Stanford International Research Center, the National Science Foundation and Cornell University.

Arecibo was built and put into use in 1974. To celebrate the completion of the construction, the staff used Arecibo to send a series of electromagnetic signals to the globular cluster M13 25,000 light-years away from the earth. It was later called the Arecibo message. This information contains commonly used human decimal figures, DNA structure diagrams, human appearance and solar system composition.

Â German Effelsberg radio telescope

Before the construction of Arecibo in the United States, the Effelsberg radio telescope in Bonn, Germany, which was formally put into use in August 1972, was the worldâ€™s largest rotary parabolic radio telescope. Effelsberg is 100 meters in diameter and belongs to the Maxwell Planck Institute for Radio Astronomy. It can observe radio wave radiation of 90 cm to 3.5 mm.

Â US Green Bank Radio Telescope

The Green Bank radio telescope in Green Bank, Virginia, USA was built and put into use in 2002 and is part of the National Radio Astronomy Observatory. It is reported that the Green Bank telescope also has a diameter of 100 meters and a reflection area of â€‹â€‹more than 9,000 square meters, equivalent to the size of a standard American football field. At the same time, the accuracy can distinguish one millionth of a watt of electromagnetic signals, which is equivalent to a falling snowfall. Energy released to the ground.

It is worth mentioning that due to the existence of the Green Bank telescope, astronomers and locals who came to the town had to disable mobile phones and other wireless devices. Even electromagnetic appliances, including microwave ovens, were banned. This town of Green Shore is also known as "the quietest town in the United States."

Â French Nancay radio telescope

The Nancay radio telescope, located on the outskirts of Paris in France for the first time, was formally completed in 1964. President De Gaulle personally laid the foundation for himself. Compared with the conventional spherical arc single-beam radio telescope, Nancay is unique in that it is composed of two oppositely standing meshed metal rod arrays, one of which is 200 meters high, 40 meters wide, and the other is With a height of 300 meters and a section of 35 meters, it can be tilted when extreme weather is encountered. Radio waves are received by the two arrays and processed by interference to the data center between the two receivers.

Â US VLA array

The Very Large Array (VLA) on the San Agustin Plain in New Mexico is the world's largest array of synthetic aperture radio telescopes, consisting of 27 25-meter receivers. Each receiver weighs 230 tons and is 2124 meters high. It is mounted on rails and can be arranged in different shapes according to different receiving tasks. The receiving array was affiliated with the National Radio Astronomy Observatory. Construction began in 1973 and it was formally put into use in 1980. The VLA can work in 6 different bands with a resolution of up to 0.05 arcseconds (ie, 1/60th of a degree).

Astronomers have made a number of major discoveries with VLA, such as the micro-quasars in the Milky Way, the Einstein ring around distant galaxies, and the radio-band counterparts of gamma-ray bursts.

Â Japan's Nobeyama Radio Wave Observation Station

The Nobeyama Radio Wave Observing Station is located in Nanmu Village, Nagano Prefecture, Japan. It is 1,350 meters above sea level and is a branch of the Japanese National Astronomical Observatory in the Japanese Alps. The station has three sets of equipment: a 45-meter-diameter millimeter-wave single-antenna radio telescope, a millimeter-wave observation array composed of six 10-meter radio telescopes, and a solar observation array composed of 84 small receiving antennas ( The figure shows 84 small receiving antennas).

Â Australian radio telescope array

25 km west of Narrabri, New South Wales, Australia is lined up with the Australian Telescope Compact Array (ATCA) at the Paul Wilder Observatory in Australia. The array consists of six 22-meter-diameter radio receivers of the same type, weighing 270 tons each. Like the U.S. VLA, each receiver is mounted on a rail and can be arranged in different angles and shapes as needed. Five of the receivers can move freely over a 3 km long track, while the sixth is located at the western end of a 3 metre long main track.

In addition to independently completing space missions, ATCA is also able to work with the 64-meter aperture telescope at the Australian Parkes Observatory and the single 22-meter aperture butterfly receiver at the Kunambara Observatory in New South Wales to form a super. Observed arrays with long baseline interference can have the equivalent resolution up to the equivalent of a single-caliber radio telescope with a bore diameter equal to the distance between the two sites.

Â VLBA and EVN radio observation networks

In addition to the single-caliber radio telescope and various arrays mentioned above, similar to the long baseline interference technology used by ATCA in Australia, astronomers in the United States and Europe have also established VLBA and EVN radio observation networks.

Among them, VLBA refers to Very Long Baseline Array (VLBA), which consists of 10 radio telescopes distributed remotely in the U.S. National Radio Astronomical Observatory Array Operation Center remotely distributed in various regions of the United States. These 25-meter-diameter observatories are Dispersed in several states such as Hawaii, California, Arizona, and Washington, DC in the United States, they formed an ultra-large observation array with a maximum length of 8,611 kilometers through long baseline interference technology.

VLBI refers to Very Long Baseline Interferometry. EVN is the European VNBI network (European VLBI Network), which is a radio observation network composed of European countries through long baseline interference technology. However, the EVN has developed to the current network observations. The members are not only European, but even the VLBA of the United States and many of our countryâ€™s space stations have also joined the EVN.

For example, the 40-meter radio telescope of the Yunnan Observatory belonging to the Chinese Academy of Sciences joined the EVN Joint Observation Network in June 2009. In the subsequent interference test with the 100-meter radio telescope of Effelsberg in Germany, the relevant interference waveform was successfully obtained. In addition, the Shanghai Sheshan Observatory, also affiliated with the Chinese Academy of Sciences, has also conducted observational tests in conjunction with EVN.

Â to sum up

The observation aperture of astronomical telescope determines its resolution. The larger the aperture is, the more available data can be obtained, but the single aperture cannot be infinitely large. The current 500-meter FAST in Guizhou of China is already the largest in the world. Under such realistic conditions, more and more observation stations distributed in various countries and regions have already started frequent international cooperation. They use long-baseline interference technology to connect observation points in different regions and form an equivalent between the two places. The distance from the single-beam radio telescope greatly enhances the observation of radio waves. Therefore, in the field of space exploration and development, in addition to building its own infrastructure, opening the door and vigorously developing international cooperation across regions is the future development trend.