After a long flight and debugging, the American space telescope James Webb finally took the latest photos. These photos also aroused the attention and heated discussion of all astronomy enthusiasts. Webb's photos should be said to be really good. According to comments from the Am

After a long flight and debugging, the American space telescope James Webb finally took the latest photos. These photos have also aroused the attention and heated discussion of all astronomy enthusiasts.

The photos taken by Webb should be said to be really good. According to comments from the American astronomical community, the distance taken by Webb has exceeded that of and Hubble . The field of view, clarity, and shooting distance of Webb's photos all surpass Hubble's. But neither the very old galaxies nor the clouds of galaxies in this photo can be directly seen by our naked eyes. Even if we stand where Webber is, our eyes can't see anything like this. Picture, why is this?

The first full-color image taken by the Webb Space Telescope Source: NASA

Because this photo Webb took 12 and a half hours to make a long exposure synthesis. Because Webb does not use all visible light bands, our eyes cannot see such a scene. So why is it easier to see distant stars in the infrared light band?

This principle is quite interesting to talk about. The expansion speed in the early stage of the Big Bang was very large, so the distance between stars increased very quickly. We all have this feeling. When a train goes from far to near, passes by us, and then drives into the distance, if it whistles, you will hear the whistle of this train coming from far away first. It is very strange. It is melodious and low. After the train approaches, the whistle quickly becomes sharp in front of you, and then turns melodious and low as it goes away. This is a Doppler effect of sound wave propagation, and light is a kind of waveform characteristic. Communicators also have such characteristics. If a galaxy is moving away from us, when the light reaches our eyes or observation equipment, its wavelength will also become longer and its frequency will decrease. This effect is similar to the train whistle mentioned above.

Image of the universe observed with the Webb Space Telescope Source: NASA

Then, when we analyze the spectrum, you will find that the light with a longer wavelength will move in the infrared direction. This feature is called red shift , that’s it The entire spectral lines are all shifted to the side of infrared .

Therefore, if you want to see very distant celestial objects, visible light is not very useful. The speed of stars produced by the expansion of the distant universe has caused most of these lights to become infrared light, including near-infrared and mid-infrared light. Even far infrared, you can only see it in this band.

Therefore, a very important piece of equipment carried by Webb is near-infrared and mid-infrared imaging equipment, including spectroscopic instruments in this frequency band. It can be seen from the photos that Weber's imaging ability is still very good, and the combined scene is very beautiful. According to American astronomers, this color is actually post-processed and represents some features. For example, blue galaxies include many stars and have less interstellar dust; while red galaxies are wrapped in thick interstellar dust; green galaxy cluster is rich in hydrocarbons and compounds and other chemicals.

Stephen's Quintuple Galaxy Source: NASA

At the same time, when we look at the photo taken by Webb, we will also find an important feature. You will feel that these galaxies have become a circular layout. In fact, This is not a natural feature, but is due to gravitational lensing.

Because the huge gravitational pull of the huge galaxies that are relatively close to us will form a bending effect on the light passing by the more distant galaxies behind them. After these light rays are bent by the gravity of these relatively nearby galaxies, they then reach our observation equipment. As a result, the distant galaxies we see will be magnified as if they have passed through a lens, and some changes in shape will also occur.As a result, we will see that many galaxies appear to be arranged in a shape that is approximately a circle. Gravitational lensing has a very big benefit. It allows us to see very old stars that are much more distant than our nearby galaxies.

Southern Ring Nebula Source: NASA

Webb is also equipped with the important spectrometer . Through these spectrometers, we can determine which light from distant galaxies is older. Although we have seen galaxies 4.6 billion years ago through Webb's photos, Webb actually found older light through the spectrometer. At least one type of light comes from celestial bodies 13 billion years ago. These lights should be farther away from the formation of the universe. At the beginning, it was no more than a billion years old. This is also the oldest light discovered by humans so far.

So, what do these lights from hundreds of millions of years ago, or even billions of years ago, bring us? These lights must contain ancient signals, but what does that galaxy look like today? We no longer know, because the propagation characteristics of light itself are destined to make a lot of the light we see come from ancient history, but in any case, the environment Webb is in, as well as the imaging and spectroscopy equipment it carries, help Webb Older galaxies and older light were found.

Webb telescope Source: NASA

Let’s talk about Webb’s operating environment. In fact, Webb's ability to have such a good photo imaging, including such observation opportunities, comes from its location - the Sun-Earth L2 Lagrange point. The biggest advantage of this position is that it leaves the sun and the earth behind forever. It always symbolizes the depth of the universe aiming at, and just aiming like this is not enough. Webb is different from Hubble. Hubble is in an orbit around the earth. , the sun's glow will affect its imaging from time to time, because it is equivalent to a background light pollution. In order to completely block the background radiation of the sun, Weber also comes with several layers of sunshade flaps. When this thing is opened, it will shield the sun's rays from behind. Weber is in the shadow of the sun. In such an environment, This allows Webb to receive weak infrared signals from the distant depths of the universe, and it is for this reason that Webb has provided us with such good photos.

Will China have similar photos in the future? I think you don’t have to worry. With the launch of China’s future survey space telescope, we will also have our own launch observation platform, and there will also be photos like this in the visible and infrared bands. The Chinese will see farther and farther from the observation platform in space, and the photos will become more and more realistic and clear.