Incredibly bright and energetic, gamma ray bursts are mysterious signals blasting in from the deepest reaches of space, and although they've been studied for decades, we still don't have much of an idea about what causes them. In order to help unlock the secrets, researchers have managed to recreate mini gamma ray bursts in the lab for the first time.
Gamma ray bursts are among the most violent events in the universe, sometimes brighter than the Sun and outputting as much energy in a few seconds as the Sun has in its entire lifetime. But it's the "burst" that's the problem – these events are over in the blink of an eye, so there's no time to train telescopes on them to figure out exactly where they're coming from.
So far, the leading theory is that gamma ray bursts are created when jets of particles are ejected from black holes or cosmic collisions. For this to work, scientists say that these beams would be mostly made up of electrons and their antimatter equivalents, positrons, and they'd have to generate strong magnetic fields around themselves.
Since gamma ray bursts take place millions or even billions of light-years away, they're tricky to study, so a research team led by scientists at Queen's University Belfast went about recreating them here on Earth. Making events that energetic required the most powerful laser in the world – the Gemini laser in the UK.
The researchers fired the Gemini laser onto "a complex target" and were able to successfully recreate some of the major characteristics of a gamma ray burst. Long-lasting magnetic fields were able to be generated, confirming the strength and distribution that would be expected.
"We thought that the best way to work out how gamma ray bursts are produced would be to mimic them in small-scale reproductions in the laboratory – reproducing a little source of these beams and look at how they evolve when left on their own," says Gianluca Sarri, lead researcher on the study. "During the experiment, we were able to confirm that the current models used to understand gamma ray bursts are on the right track, predicting the right mechanisms for the magnetic field generation and gamma-ray emission."
The experiment can teach us about more than just gamma ray bursts themselves. As with any mysterious celestial phenomenon, it may be tempting to jump to the "aliens" conclusion, but gamma rays almost certainly have a natural explanation. That said, understanding them could help us cut through the cacophony of space signals and single out any actual ET communications that might be out there.
"If you really want to search the universe for alien transmissions, you first need to make sure all the natural emissions are understood so that they can be ruled out," says Sarri. "Our study helps towards understanding black hole and pulsar emissions, so that, whenever we detect anything, we can determine straight away if it can be explained naturally or if it has come from an alien civilization."
The research was published in the journal Physical Review Letters.
