Cosmic Explosions, Expanding Universe, and Earth's Peril: Frequently Asked Questions Answered by an Astronomer
In the vast expanse of the universe, one of the most enigmatic phenomena that scientists have been trying to decipher are gamma-ray bursts (GRBs). This month, we delve into the world of GRBs, a subject of intense research by researchers like Dr. Chryssa Kouveliotou, a prominent figure in the study of transient phenomena.
GRBs are incredibly powerful events, their energy transformation resulting in heat, rotational velocity, magnetic energy, and more. A significant fraction of this energy propels fast-moving jets or beams of outflowing plasma, creating the gamma-ray bursts we observe.
These bursts, despite their power, are remarkably rare, even rarer in galaxies like ours. They can be produced by the deaths of massive stars or the mergers of binary neutron stars. When a large enough star collapses, only the central core initially forms a black hole, which is only a few miles across.
One of the most intriguing aspects of GRBs is their ability to challenge our understanding of the Big Bang theory. Gamma-ray bursts from 13 billion years ago can still be seen, defying our intuition about the origins of the universe.
The Big Bang theory assumes a symmetrical and infinite universe, with no special centre. However, the expansion of the universe means that, under certain definitions, faraway galaxies are receding from us faster than the speed of light. But it's essential to note that it's the space between us and the distant galaxy that's expanding, not the galaxies themselves.
Gravity causes material to fall into the black hole, but the star's rotation initially draws it into a disc around it. The exact process of how energy is transformed into a gamma-ray burst is still being researched, but it's thought to be the result of the star's magnetic field being wound up like a rubber band, throwing out matter when it unwinds.
While GRBs are not a significant immediate threat, it's crucial to improve our understanding of them to identify potentially threatening systems nearby. If a GRB were to occur in the Milky Way, it could pose a threat to life on Earth.
For those with questions about the universe, we invite you to email us at contactus@our website. Your queries could be featured in a future issue. Remember, the more we understand about the universe, the more we can appreciate its awe-inspiring mysteries.
This article appeared in our November 2022 issue.
