Lead
In the process of the development of science and technology, people's exploration of the universe has gradually deepened, and telescopes, as an important tool of astronomy, can help people observe farther galaxies and fainter stars, thereby deepening people's understanding of the universe.
However, the telescope on the ground is blocked by the atmosphere, preventing it from being able to perform at its maximum efficiency.
As a result, people want to use the relatively clean environment in space to place telescopes, so as to achieve higher accuracy of astronomical observations.
Thus, the space telescope came into being.
In general, space telescopes have higher observation accuracy and clarity than ground-based telescopes, and they are not disturbed by the atmosphere and can observe objects that ground-based telescopes cannot observe.
So, just how strong are these space telescopes?
What space telescopes are there at present?
1. The difference between ground-based telescopes and space telescopes.
The Earth's atmosphere is important for astronomical observations, absorbing the sun's ultraviolet rays and shorter wavelengths of X-rays, which are harmful to human health.
In addition, the atmosphere is shielded from cosmic rays and cosmic radiation outside the Earth, which is also harmful to humans.
However, the atmosphere can also interfere with astronomical observations, for example, the atmosphere emits light pollution, making very faint objects unable to be observed in areas with high light pollution.
In addition, the refraction and scattering of light by the atmosphere itself can obscure the observed objects.
Moreover, gases in the atmosphere also absorb light, especially high-energy rays such as ultraviolet and X-rays.
Because the atmosphere absorbs these rays, these wavelengths cannot be observed by observation instruments on the ground.
As a result, ground-based telescopes cannot observe light at these wavelengths.
In addition, the absorption of infrared and microwave radiation by the atmosphere is also very severe, so the observations of ground-based telescopes in these bands can also be severely disturbed.
In addition, the absorption of light by the atmosphere also weakens the intensity of light, so ground-based telescopes can only observe objects that are close to it, and objects that are farther away are weakened by light, so they are difficult to observe by ground-based telescopes.
Due to the presence of the atmosphere, the observation range of ground-based telescopes is very limited, so scientists have thought of taking advantage of the characteristics of no atmospheric interference in space to place telescopes to observe objects that cannot be observed by ground-based telescopes, and improve the accuracy and clarity of observation.
Thus, the space telescope came into being.
There is no atmosphere in space, so space telescopes are able to observe objects that ground-based telescopes cannot.
In addition, space telescopes are not disturbed by the atmosphere, so observations are clearer.
Space telescopes have higher accuracy and clarity than ground-based telescopes, so they can observe fainter objects and objects farther away, which broadens the field and scope of astronomy research.
2. The most powerful space telescope in history.
There are several key stages in the development of space telescopes.
The first is the Hubble Space Telescope, the first space telescope, which has a diameter of 2.4 meters.
Although the diameter of the Hubble Space Telescope is only 1/4 of that of the Hubble Telescope, it is not disturbed by the atmosphere, so the observation accuracy and clarity are higher than that of the Hubble Telescope.
As a result, the Hubble telescope is able to observe objects that ground-based telescopes can't, and it is able to observe fainter objects and more distant objects, so the Hubble telescope plays a very important role in the study of astronomy.
The construction and launch of the Hubble telescope is an extremely complex project, it requires the collaboration of hundreds of people to complete, and in the process, it is also very costly.
Therefore, there is only one Hubble telescope, and its use time is very limited, so for a long time, the Hubble telescope has been at full capacity, and scientists have more scientific problems to solve, so people want to build a bigger and stronger space telescope.
There are many factors that need to be considered when building a space telescope, such as the weight of the space telescope, the instruments that the space telescope needs to carry, and the observation range of the space telescope.
Therefore, in the process of building large space telescopes, there is still a need for continuous technical research.
After the Hubble telescope, there are many space telescopes built by people, such as the Spitzer Space Telescope, the James Webb Space Telescope, etc., which are more diameter than the Hubble Telescope.
However, the appetite of scientists does not stop there, they also want to build a bigger and stronger space telescope.
So, after years of research and development, scientists built a space telescope with an aperture of 6.5 meters, which is the James Webb Space Telescope.
The James Webb Space Telescope can only be assembled in space due to its large size, which is a very complex project.
After years of research and development, the James Webb Space Telescope was finally launched on December 25, 2021, which is the largest and most powerful space telescope built in human history.
The James Webb Space Telescope is three times the diameter of the Hubble Telescope, so its observation accuracy and clarity are higher than that of the Hubble Telescope, it can observe objects that the Hubble Telescope cannot observe, and it can observe the distribution of dark matter that the Hubble Telescope cannot observe, as well as the laws of their motion, etc.
3. The structure and function of the James Webb Space Telescope.
The James Webb Space Telescope is a very complex instrument that consists of many parts.
Its primary mirror has a diameter of 6.5 meters, which is three times larger than the diameter of the primary mirror of the Hubble Telescope, so it is able to observe objects that are fainter and more distant than the Hubble Telescope.
The primary mirror is a very large mirror, and if it is a monolithic mirror, then it will be very heavy so that it cannot be fired, so scientists have adopted the method of dividing the primary mirror into 18 small mirrors and then assembling them.
As a result, each small mirror weighs a lot less, so they can be assembled in space.
If 18 small mirrors are directly assembled together, there will be a beam difference between them during the observation process, which will affect the accuracy and clarity of the observation.
Therefore, in order to avoid the beam difference, the scientists eliminated the beam difference by adjusting the shape of each small mirror.
In addition, since the shape of small mirrors must be very precise, they are also very difficult to manufacture.
The primary mirror consists of 18 small mirrors, which are supported by the primary mirror bracket, and the main mirror bracket is made of more than 30 support rods, which are made of carbon fiber, which is very light in weight, so the weight of the primary mirror bracket can be reduced when carrying out the launch.
In addition, carbon fiber has another advantage, that is, its expansion coefficient is very small, so the primary mirror bracket will not be deformed due to the influence of temperature difference after being exposed to solar radiation.
The primary mirror consists of 18 small mirrors, each of which is very precisely shaped, so that a sophisticated instrument is required to inspect them during the assembly process.
Therefore, scientists have built a special inspection instrument to detect the shape of small mirrors, which consists of many parts, including laser emitters, mirrors, photodetectors, computers, etc.
By adjusting these parts, you can make the detection instrument emit a laser beam, and then, the laser shines on the small mirror, the small mirror will reflect the beam, through the photodetector, you can detect the offset of the beam, so as to judge whether the small mirror has deviation.
In addition, the primary mirror also needs to have a stable optical path, so as to ensure that when the light falls on the primary mirror, there will be no change in the optical path, which will affect the observation accuracy and clarity.
For this purpose, scientists have designed an optical path stabilizer close to the primary mirror, which is composed of some small mirrors, mirrors and photodetectors, which can adjust the direction of the optical path to ensure that the direction of the optical path does not change when the light falls on the primary mirror.
In addition, in order to ensure the cleanliness of the primary mirror, the scientists also coated the primary mirror with a layer of silver.
In addition, in order to avoid the influence of the sun's radiation on the primary mirror, a protective shield is also made around the primary mirror, which can block the primary mirror when the primary mirror is not working, so as to reduce the sun's radiation.
In addition, the light emitted by many celestial bodies is invisible, such as infrared light, ultraviolet light, etc., which is harmful to human eyes, so scientists have also added a filter to the front of the primary mirror, which can block some harmful light to humans.
In addition, due to the extremely low temperature in space, the telescope's instruments are susceptible to the cold, so scientists have also added heating equipment to the telescope's launch capsule to ensure the normal operation of the instruments.
epilogue
The launch of the James Webb Space Telescope is of great significance to human astronomical research, which will help mankind to explore the mysteries of the universe more deeply, and in the process of exploring the universe, there may be more major discoveries about the origin and evolution of the universe.