The Big Burst Theory
- Eduarda Tomio
- Jan 22
- 2 min read
Updated: 11 hours ago
In the late 1960s, extensive technological development occurred in the US and the Soviet Union as they competed and rushed to advance. In the midst of that, while on the lookout for Soviet nuclear testing, US military telescopes captured the most energetic form of light burst in the universe. Now known as "gamma-ray bursts” or GRBs. The process is directly related to black holes.
Credit: NASA's Goddard Space Flight Center Conceptual Image Lab
What are these bursts?
A gamma-ray is the most energetic form of light. So, GRBs are considered the brightest explosions in the universe. Their duration is short, but they emit unimaginable amounts of light. They shine hundreds of times brighter than a supernova, and expel more energy than our Sun will throughout its complete life. They appear to be associated with galaxies with high stellar formation ages, which wouldn't be representative of our current Milky Way. Nonetheless, about 2 billion years ago, our host galaxy could have been home to such processes. Their light emission, like that of pulsars, occurs similarly to that of lighthouses, channeling energy through 2 narrow beams.
GRBs types
Their classification depends entirely on their duration: long- and short-duration. The origin of those different classes may not be the same, but the creation of a new black hole seems to be the outcome of both.
Long-duration: this class accounts for most GRBs (about 70%) and lasts from 2 to hundreds of seconds. Its origin is related to the death of massive stars. The starting mass of the star is 5 to 10 times that of our Sun, and once it runs out of fuel to sustain nuclear fusion, it explodes into a supernova and creates a black hole. A GRB occurs when a newly born black hole begins to accrete surrounding matter, thereby strengthening its magnetic field. It then blasts out two gamma-ray jets at nearly the speed of light.
Short-duration: lasting less than 2 seconds, this class originates from the merger of 2 black holes or a black hole and a neutron star. Those bodies must have been in a binary system for some time prior to the collapse. The resulting impact ejects the neutron star's matter, triggering a GRB. The binary system containing two black holes, on the other hand, wouldn't expel matter. How can it produce a GRB? That is a question that scientists have not yet answered, and that requires ongoing research.
Related links:
https://science.nasa.gov/mission/hubble/science/science-behind-the-discoveries/hubble- gamma-ray-bursts/
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