NASA's James Webb Telescope is now scheduled to launch in March 2021, foreign media reported on Jan. Before that, the project went through years of delays and billions of dollars in funding. Despite the waste of time and money, the telescope will become the undisputed \"king\" of the infrared band, allowing us to reach the remote corners of the universe for the first time.
From the first galaxies formed after the birth of the universe to the possibility of extraterrestrial life, the James Webb Telescope, for about $9.7 billion, will be our only hope for a better understanding of everything in the universe.
Although the James Webb Space Telescope (JWST) is regarded as the \"successor\" to NASA's legendary Hubble telescope, this is not the case. Hubble is primarily an optical telescope capable of capturing the same wavelength range as the human eye, extending only slightly to the infrared and ultraviolet wavelengths. In its essence, the Hubble telescope is like a giant, orbiting eyeball that keeps sending back shocking images. And if your sense of light is as powerful as it is, you can see these amazing sights yourself.
But not the James Webb telescope. It will be observed entirely in the infrared band, barely touching the most \"red\" band the human eye can see. In other words, it will study a universe that is almost invisible to humans.
One of the main reasons why the James Webb telescope is designed this way is that infrared observations from the surface are difficult. To make precise observations and measurements, astronomers must ensure that the night sky is absolutely clear, but light pollution on the ground severely limits the conditions.
Infrared pollution is more ubiquitous because any object with temperature emits infrared light. The human body can produce infrared radiation of 100 watts. The Earth itself is high in heat and is bright in the infrared. Even the telescope itself emits infrared radiation at room temperature.
In short, we are not completely unable to carry out infrared astronomical observations from the ground, but are only extremely difficult. So we chose to place the James Webb telescope in space.
To ward off the effects of Earth's infrared light, the James Webb Telescope will operate 1.5 million kilometres from Earth. Although far from the earth, the sun is also a problem. You must have felt the sun burning outside in the summer. It was infrared radiation. Even millions of kilometers away from Earth, the sun's heat is not to be underestimated.
To this end, infrared space telescope designers can take several countermeasures. One of the most common is the use of active cooling systems to reduce the temperature of the telescope to levels suitable for observing the infrared band. This is a good way to use it in other infrared space telescopes. But it also limits the telescope's working life, as astronomical observations cannot continue once the coolant is exhausted.
Therefore, the James Webb telescope will find a way out, equipped with an expensive giant'space umbrella'. The umbrella,22 meters long and 11 meters wide, is made of five layers of material with extremely high reflectivity, each less than the diameter of human hair. This huge \"parasol\" will keep the telescope in the shade all the time, with temperatures no more than -223 degrees Celsius, and is suitable for observations in the target infrared band.
All in all, the James Webb telescope is so bulky that it won't fit with a single rocket. In addition to the giant umbrella, its main mirror has a diameter of dami, far more than any rocket currently in use. Since the mirror cannot be \"glued\" to the rocket's side, smart NASA engineers have decided to split it into 18 smaller hexagons so it can be stuffed into the rocket with folded umbrellas and the rest of the telescope.
If all goes well, a few days after the launch of the James Webb telescope, it will fly towards the observation point, spread the mirror and the umbrella in place, and then begin the observation mission.
And its observations will be stunning. One of the telescope's main observational targets will be the early universe, just a few hundred million years after its birth. The first stars and planets once shone brightly in the visible-light band. But over the past 13 billion years, the universe has gradually expanded, causing the wavelengths of these rays to pull longer, eventually leaving visible light and falling into the infrared light band, just within the ideal range of observations for the James Webb Telescope.
The James Webb Telescope will look at all the \"icy\" objects in the universe, including the protoplanetary disk surrounding the primary star, the molecular cloud, the comet, the Kuiper belt and so on.
The telescope will also use a special device to block light from some distant stars, capturing any celestial bodies, such as exoplanets, that pass in front of those stars. The planets are so bright in the infrared that through the light they emit, we can analyse the chemicals and elements in the planet's atmosphere, perhaps to find signs of life.
In short, from searching for extraterrestrial life to uncovering the truth of the dawn of the universe, the James Webb Telescope will surely live up to our years of waiting. (Leaves)