Central Idea

A Star’s Explosive End: About two billion years ago, far beyond our Milky Way galaxy, a huge star exploded into a supernova. This explosion sent out a massive burst of gamma rays, the most powerful type of energy wave in the electromagnetic spectrum.
Gamma-Ray Bursts: These bursts are short-lived but incredibly intense, often associated with the most dramatic events in the universe, like the death of massive stars.

Why discuss this?

These gamma rays travelled across space for billions of years, finally reaching Earth in 2022.
When they arrived, they caused a significant disturbance in Earth’s ionosphere, a layer of electrically charged gases high in our atmosphere.

What Are They? Gamma-ray bursts (GRBs) are incredibly intense flashes of gamma rays, which are the most energetic form of light in the electromagnetic spectrum. These bursts are the most powerful explosions observed in the universe.
How They Occur: They usually happen when massive stars collapse into neutron stars or black holes, or during the merger of neutron stars. These cosmic catastrophes release a tremendous amount of energy.
Duration and Energy: GRBs can last from a few milliseconds to several hours, but they typically last a few seconds. The amount of energy released in this short time can be more than the Sun will emit in its entire 10-billion-year lifetime.
Afterglow: Following the initial burst, GRBs are often followed by an ‘afterglow’ emitted at longer wavelengths (X-ray, ultraviolet, optical, infrared, and radio).

Lasting Effects: The gamma rays disturbed the ionosphere for several hours and even set off lightning detectors in India.
Scientific Importance: Although this burst didn’t harm life on Earth, it showed how sensitive our ionosphere is to space events.
A Rare Event: Such a powerful gamma-ray burst is expected to hit Earth only once every 10,000 years.

Preparing for Future Events: Scientists are studying the potential risks of a similar event happening closer to Earth, within our own Milky Way.
Low Risk: However, the chance of such a dangerous event happening is very low.