As a telescope worth tens of billions of dollars, the Webb Space Telescope, currently 1.6 million kilometers away from the earth, has been taking pictures non-stop since it was debugged.
From the initial infrared band test images, to the Webb deep field and color nebulae, to Jupiter with very different colors, The image quality returned by Webb can be said to far exceed the expectations of astronomers, The imaging blur that occurred on the Hubble Telescope did not appear on the Webb Telescope at all.
The latest images taken by the Webb Telescope show that it discovered an almost perfect Einstein ring in the depths of the universe 12 billion light years away from the earth. This result made Einstein's general theory of relativity possible. has once again been proven effective on a cosmic scale, that is, our universe can indeed be bent.
Before the end of the 19th century, the physics of human civilization was actually still in the Newtonian era. At that time, the scientific community's understanding of gravity was still very simple. They only knew that it was "universal gravity" but they did not know how gravity was born. , and what is its specific manifestation in the universe? That's why Einstein came about.
After first solving the problem of the speed of light with the special theory of relativity, Einstein proposed his own concept of gravity, which was later known as the general theory of relativity, in response to the problem of the near motion of Mercury that could not be solved by the astronomical community at that time.
In the general theory of relativity, gravity is no longer an illusory and unknown force, but has become "a geometric fall caused by the distortion of space and time by a mass object" , that is, all objects with mass are governed by gravity, but Compared with the stars in the universe, the mass is too small and the gravity is too weak to be felt.
In the solar system, because the sun accounts for 99.86% of the total mass of the solar system, its gravity has become the strongest. All solar system celestial bodies, including the earth, are orbiting the sun.
When the gravity of a star is so strong, What does the gravity of a galaxy look like in the universe?
Einstein believed that due to the huge mass of a galaxy, its gravity will inevitably severely distort the space-time structure around the galaxy, thereby distorting the light path. The light emitted by other galaxies behind the galaxy will be distorted when passing through the galaxy and become It forms a circular or arc-shaped structure, which is the so-called gravitational lens and Einstein ring.
If the mass of the foreground galaxy is large enough and the space-time distortion caused by it is strong enough, then the galaxy actually creates a magnifying glass in the universe. In this way, the light emitted by the faint galaxy in the background will be absorbed by the foreground galaxy. The gravitational lensing effect magnifies the object from invisible to visible.
When the foreground galaxy completely covers the rear galaxy, and the covered area becomes a perfect circle, the light of the rear galaxy will be refracted and enlarged from around the foreground galaxy , and will also become a circle. This phenomenon It is a low-probability version of gravitational lensing: the Einstein ring.
The Einstein ring 12 billion light-years away was captured by the Webb telescope this time. The photons condensed into this ring actually come from the depths of the universe further away. It’s just that there is just one gap between these photons and the earth. The large galaxy forms the Einstein ring, which would not exist if observed from other directions.
Although humans currently have no substantial technical applications for gravitational lenses and Einstein rings, astronomers believe that in the future we may be able to use gravitational lenses to create natural telescopes.
In other words, search for several galaxies with suitable mass and arrangement in the universe, and then find a suitable angle to place a telescope near the earth or in the solar system to serve as an eyepiece. uses a special telescope that is billions of light years away. Arranged galaxies act as optical systems , using the gravitational lenses caused by their distortion of space and time to observe targets at fixed points. As long as the distance is long enough and the gravity is strong enough, you can even directly see the details of exoplanets.
If you find it difficult to find specially arranged galaxies, astronomers can also use the Earth's gravitational lens to act as an optical system, build a super telescope with an aperture equivalent to the size of the Earth.
