At 40 kilometers high, scientists have to put a balloon on the Capital Terrace
Recently, the National Aeronautics Aerospace Agency (NASA) announced a new project that plans to use a balloon to send a 2.5 -meter -high telescope into the flat stratosphere to build an air observatory. The task group recently completed the design of the effective load of the observatory, including telescope, scientific instruments, and cooling and electronic systems. Project engineers will begin integration and testing these subsystems to verify whether their performance meets expectations. If everything goes well, this air observatory will be liter in Antarctica by the end of 2023.
What are the advantages of balloons compared to other observation methods? With the advancement of technology, will this ancient aircraft continue to exist in observation tasks? With these issues, a reporter from the Science and Technology Daily interviewed Professor Wu Qingwen, deputy dean of the School of Physics at Huazhong University of Science and Technology.
The atmosphere of protecting the earth is also an obstacle
There is a thick layer of atmosphere on the surface of the earth. The atmosphere effectively protects the surface of the earth’s surface from cosmic lines, ultraviolet rays, and solar wind particles. The atmosphere is a necessary condition for breeding the life of the earth.
“However, for astronomical observations, the earth’s atmosphere is an obstacle.” Wu Qingwen said. First of all, due to the absorption, reflection, and scattering effect of the earth’s atmosphere on electromagnetic waves, many electromagnetic signals in the universe cannot reach the earth directly. The electromagnetic waves in a few bands can penetrate the earth’s atmosphere. We call these bands “atmospheric windows”. At present, the atmospheric windows on the earth include optical bands, near -infrared bands, and radio -bands. However, it is almost opaque for far infrared, millimeter waves, ultraviolet rays, X -rays and gamma rays.
Wu Qingwen said that each window can bring us rich cosmic information, so in order to understand the universe more deeper, we must cross the barriers of the earth’s atmosphere. In addition, the turbulence of the earth’s atmosphere also causes the image of the celestial bodies to flash, causing image distortion. In order to fundamentally overcome the impact of the earth’s atmosphere on astronomical observations, it is necessary to put the telescope outside the atmosphere.
The main carrier of space detection includes high -altitude balloon, aircraft and rockets. Among them, balloons are an ancient aircraft, which has a history of more than 200 years. The discovery of cosmic rays was the result of the experiment of Austrian physicist Victor Hers in 1912. After the Second World War, materials with light quality, high strength, and advanced performance allowed the empty balloon to achieve large -scale, and could enter high -altitude flat stratums, which greatly promoted observation research such as atmospheric science, space astronomy and cosmic rays.
“High -air balloon can also perform spatial load tests, remote sensing experiments, life science experiments, etc.” Wu Qingwen said that considering that space experiments have high requirements for the maturity of the instrument, because any problem may bring inestimable losses, and high air balloon The detection has the characteristics of low cost, fast -effectiveness, and repetition, so balloon is still the ideal platform for many space and atmospheric science experiments. Because of this, many scientific satellites on the detection instruments will be verified on high -altitude balloon first. For example, the relevant instruments in the “Wukong” dark material detection satellite launched in my country in 2015 and the “Hui Eye” X -ray satellite launched in 2017 have been verified and tested in some balloon flight experiments.
In the past few decades, space astronomy has developed rapidly, and there are space telescopes in most bands. For example, the Hubble Space Telescope in the optical band, the Chandra satellite in the X -ray band, and the Newton satellite, the Fermi satellite in the gamma ray band. These space observation projects have greatly expanded human vision and their understanding of the universe.
Observe stars in infrared bands
NASA plans to use a balloon to send a telescope called ASTHROS, which will be sent to the flat stratosphere for several weeks of observation around 2023. The main observation band is the Asian millimeter wave to the far infrared band. ASTHROS will be the largest telescope with high air balloons in history. The telescope needs to rise to a height of 40 kilometers. Although this height is much lower than the general satellite height, it can avoid the problem of the atmosphere absorption of far -infrared and Asian millimeter bands.
Wu Qingwen said that the infrared telescope detector needs to maintain a very low temperature. Generally, the telescope uses liquid to cool the detector. ASTHROS uses a new way. It uses the electricity provided by solar energy to maintain the superconducting detector close to minus 268.5 degrees Celsius (close to absolute 0 degrees). The weight of the valid load can work for several weeks in the flat flow layer.
“The light of infrared bands can penetrate the dust of the dust, so that some low -temperature celestial bodies that are not visible to the optical band can be seen. Therefore, an important observation goal of infrared band is the star and star formation area. For example, scientists often use infrared bands to observe dust. The central area of the dense galaxy. “Wu Qingwen said.
Therefore, the main scientific tasks of AsthroS are also concentrated on star physics. The instruments they carry can be used to measure the movement and speed of new gases around the star. Three -dimensional information through gas density, speed and motion reveals the star physics generated by large quality stars and supernova explosions, so as to understand the feedback process of the stars, that is, the violent explosion of the stars died dispel the surrounding interstellar media, which can prevent the stars from further from the further stars’ further. form. ASTHROS will also observe the dust and gas quality and distribution around TW of the snake. This may help us understand the formation process of the planet around the star, such as helping understand the formation mechanism of the eight major planets of the solar system. Therefore, Asthros will bring rich star physical information to humans.
Wu Qingwen said that if the experiment is successful, scientists will continue to launch satellites or adopt a larger detection telescope for further in -depth research.
(Reporter Liu Zhiwei News Member Wang Xiaoxiao)
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