Physicists have long believed that the universe is almost the same in any direction, and now they have found a new way to test this hypothesis: by examining the shadow of a black hole.
If the shadow is smaller than the existing physics theory predicts, it can help prove a distant concept called the bumblebee gravity, It describes what will happen if the universe’s seemingly perfect symmetry is not so perfect after all.
If scientists can find a black hole with such a small shadow, it will open a door to a new understanding of gravity, which may explain why the universe is expanding faster and faster.
But to understand how this bumblebee idea came about, let us delve into some basic physics.
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Look in the mirror
Physicist’s love symmetry; After all, it helps us understand the deepest secrets in the universe. For example, physicists have realized that if you conduct experiments on basic physics, you can move the test equipment to other places and get the same results again (that is, if all other factors such as temperature and gravity Strength, remain unchanged).
In other words, you will get the same results no matter where you experiment in space.Through mathematical logic, this directly leads to Law of conservation of momentum.
Another example: if you run the experiment and wait a while and then run it again, you will get the same results (again, all other conditions are the same). This symmetry in time directly leads to the law of conservation of energy-energy will never be created or destroyed.
There is another important symmetry that forms the basis of modern physics. To commemorate the physicist Hendrik Lorentz (Hendrik Lorentz) figured out all this in the early 1900s, he called it “Lorentz” symmetry. It turns out that you can experiment and experiment, and (under all other conditions are the same) you will get the same results. You can also increase the experiment to a fixed speed, still Get the same result.
In other words, all other conditions are the same-yes, I repeat it often because it is important-if you experiment in a completely static state and do the same experiment at half the speed of light, you will get the same the result of.
This is the symmetry revealed by Lorentz: the laws of physics are the same regardless of position, time, direction, and speed.
What do we get from this basic symmetry?Well, for starters, we got Einstein’s whole special theory relativity, It sets a constant speed of light and explains how objects traveling at different speeds link space and time.
Special relativity is so important to physics that it is almost a meta-theory of physics: if you want to concoct your own view of how the universe works, then it must be compatible with special relativity.
Physicists have been working hard to create new and improved physics theories, because ancient theories such as general relativity cannot explain everything in the universe, such as what happens. General relativity describes how matter distorts space and time, particle physics The standard model is also unexplainable. In the center of a black hole. One very juicy place to look for new physics is to see if there are any precious concepts that may not be as accurate under extreme conditions-precious concepts like Lorentz symmetry.
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Some gravity models believe that the universe is not completely symmetric after all. These models predict that there will be additional components in the universe, forcing it to not fully observe Lorentz symmetry. In other words, there will be a special or privileged direction in the universe.
These new models describe a hypothesis called “hornet gravity.” Its name comes from the assumption that scientists once claimed that bumblebees should not fly because we don’t understand how their wings generate lift. (By the way, scientists have never really believed it.) We don’t fully understand how these gravitational models work and how they are compatible with the universe we see. However, they are there, facing the earth. Just stare at the viable options of our new physics.
One of the most powerful uses of the Hornet gravity model is that it can potentially explain Dark energy -The phenomenon that causes the observed accelerated expansion of the universe. It turns out that the extent to which our universe violates Lorentz’s symmetry can be linked to the effect of accelerating expansion. And since we don’t know what is producing dark energy, this possibility is indeed very attractive.
So you have a new theory of gravity based on iconic ideas such as symmetry violations. Where will you verify the idea? You will reach a place where gravity is stretched to its absolute limit: a black hole.In this new study, it has not been peer-reviewed and will be published online to the preprint database in November 2020 arXiv, The researchers did just that, looking at the shadow of a black hole in an imaginary universe modeled as realistic as possible.
(please remember The first picture of a black hole M87, was it produced by Event Horizon Telescope a year ago? The incredibly beautiful in the center of the bright ring, the dark void is actually the “shadow” of the black hole, and the area absorbs all the light from behind and around. )
In order to make the model as realistic as possible, the research team placed a black hole in the background of the expansion of the universe (as we observed) and adjusted the degree of symmetry violation to match the scientists’ dark energy behavior. measuring.
They found that in this case, the shadow of the black hole looks 10% smaller than the shadow in the “normal gravity” world, providing a clear way to test the gravity of the bumblebee. Although the current image of the black hole M87 is too blurry to distinguish the difference, people are working hard to take better pictures of more black holes, thus exploring some of the most profound mysteries in the universe.
Originally published in “Life Science”.