An international team of researchers created a few weeks ago a mini burst of gamma rays in the laboratory to study their behavior, and potentially understand where these rays projected into the cosmos come from.
Bursts of gamma rays, intense explosions of light, are the brightest events ever observed in the Universe. These only last a few seconds or minutes. Despite their intensity, the source of these gamma-ray bursts remains mysterious. To try to find out more, researchers have recently achieved the feat of creating — in the laboratory — a mini version of these gamma rays. The details of this study were published in the journal Physical Review Letters.
One of the potential sources of these gamma rays could be black holes. Thus, studying these rays would then make it possible to evaluate certain key properties of the objects from which they come. The beams released by the black holes would for the most part be composed of electrons and their “antimatter” companions, positrons (all particles have antimatter counterparts identical to themselves, but with an opposite charge). These beams must have strong and self-generated magnetic fields and the rotation of these particles around the fields could then release powerful gamma rays according to current theories.
The problem is that researchers do not really know how these fields would be generated. Another problem, and not least, these beams come from distant galaxies, sometimes located billions of light years away from Earth. It has recently been concluded that the best way to determine the production of gamma-ray bursts is to imitate them by reproducing them on a small scale in the laboratory. To study their evolution, it would be enough to reconstitute a source — on a smaller scale — of these electron-positron beams.
Therefore, a group of researchers recently succeeded in creating this first small-scale replica, using one of the most intense lasers on the planet — the Gemini laser — located in the Rutherford Appleton laboratory in the United Kingdom.
To give you an idea of the intensity of this laser, take all the solar energy that hits our planet and concentrate it in a beam of only a few microns thick (the thickness of a human hair). By firing this laser at a target, the researchers were able to measure these gamma rays and copy them to study their behavior. They then for the first time were able to observe some of the key phenomena that play a major role in the creation of these gamma-ray bursts, such as the automatic generation of magnetic fields.
The scientists were able to confirm some major theoretical predictions of the strength and distribution of these fields. In short, this experience confirms that the processes currently used to study and understand gamma-ray bursts are on the right track. One might wonder why is it important to worry about events so far away? First, because knowing how gamma-ray bursts are generated will allow us to better understand black holes, and thus broaden the field of research on the birth of our Universe and its evolution.
But there is a more subtle reason. SETI, in charge of capturing messages from extraterrestrial civilizations, focuses primarily on electromagnetic signals from space that can not be explained naturally –it focuses mainly on radio waves, but gamma rays are also associated. So, in order to isolate any “smart” transmissions, you must first make sure that all natural emissions are fully explained so that they can be excluded.