Gamma ray bursts, powerful flashes of light, are the brightest events in our universe that last no longer than a few seconds or minutes. Some are so bright that they can be observed with the naked eye, like the GRB 080319B burst detected by NASA's Swift GRB Explorer mission on March 19, 2008.
But, despite their intensity, scientists do not know the reason for the appearance of gamma-ray bursts. Some people generally believe that these are messages from alien civilizations. And so scientists managed to recreate a mini-version of gamma-ray bursts in the laboratory, discovering a completely new way of studying their properties. The results were published in Physical Review Letters.
One of the reasons for the occurrence of gamma-ray bursts is that they are somehow born in the process of ejection of jets of particles created by massive astrophysical objects such as black holes. This makes gamma ray bursts extremely interesting for astrophysicists. Studying them in detail could reveal the key properties of black holes in which these flares are born.
The rays emitted by black holes are mainly composed of electrons and their "antimaterial" companions, positrons. All particles have antimatter, which are identical to them in everything except charge. Such beams must have strong magnetic fields. The rotation of these particles in the field gives rise to powerful bursts of gamma radiation. At least that's what our theories predict. But nobody knows how these fields should be born.
Unfortunately, there are several problems in studying these surges. They not only live very little, but - and this is the most problematic - and are born in distant galaxies, sometimes a billion light-years from Earth.
Therefore, you rely on something that is incredibly far away, appears by accident and lives for a few seconds. It is like trying to figure out what a candle is made of, having only the sparks of candles that light up from time to time thousands of kilometers away.
The most powerful laser in the world
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Recently, it has been suggested that the best way to figure out how gamma-ray bursts are born is to simulate them on a small scale in a laboratory by creating a small source of electron-positron beams, and see how they develop, on their own. Scientists from the USA, France, Great Britain and Sweden have managed to create a small version of this phenomenon using the most powerful lasers on Earth, such as the Gemini laser belonging to the Rutherford-Appleton Laboratory in England.
How powerful is the strongest laser on Earth? Take all the solar energy that covers the entire Earth and squeeze it down to a few microns (the thickness of a human hair) and you get the power of a Gemini laser shot. By striking a complex target with a laser, scientists were able to release ultra-fast and dense copies of astrophysical jets and create ultra-fast animations of their behavior. The result is startling: Scientists have taken a real jet that stretches for thousands of light years and squeezed it down to a few millimeters.
For the first time, scientists were able to observe key phenomena that play an important role in the creation of gamma ray bursts, such as the self-generation of magnetic fields that last for a long time. This made it possible to confirm some major theoretical predictions about the strength and distribution of these fields. Our current model, which is used to understand gamma ray bursts, is on the right track.
This experiment will be useful not only for understanding gamma ray bursts. Matter, composed of electrons and positrons, is an extremely interesting state of matter. Common matter on Earth is made up mostly of atoms: heavy, positively charged nuclei surrounded by clouds of light negatively charged electrons.
Due to the incredible difference in weight between these two components (the lightest nucleus weighs 1,836 times more than an electron), almost all phenomena that we experience in our daily life stem from the dynamics of electrons, which react much faster to any input from outside (light, other particles, magnetic fields, and so on) than nuclei. But in an electron-positron beam, both particles have the same mass, so the discrepancy in the reaction time is completely eliminated. This leads to many fascinating consequences. For example, sound would not exist in the electron-positron world.
Why should we even worry about such distant events? In fact, there is why. First, understanding how gamma-ray bursts are born will allow us to understand a lot more about black holes and open a big window to understanding how our universe came to be and how it will evolve. Secondly, there is a more subtle reason. SETI - Search for Extraterrestrial Intelligence - searches for messages from alien civilizations, trying to capture electromagnetic signals from space that cannot be explained in a natural way (mainly radio waves, but gamma-ray bursts are also associated with this radiation).
Of course, if you point the detector into space, you get a lot of different signals. But in order to isolate the transmission of intelligent beings, you first need to make sure that all natural sources are known that can and should be excluded. The new study will help us understand emissions from black holes and pulsars, so when we stumble upon them again, we know they are not aliens.
Ilya Khel