The scientific community has been left buzzing with the discovery of an ultra-powerful, fleeting burst of high-energy radiation, known as a Gamma-Ray Burst (GRB). Identified as GRB 200826A, in accordance with the date of its detection (26th August 2020), the burst was picked up by NASA’s Fermi Gamma-ray Space Telescope.
Decoding Gamma-Ray Bursts: An Overview
Known as the most potent events in the universe, Gamma-Ray Bursts are detectable from billions of light-years away. Given that a light-year signifies the distance covered by a beam of light in an Earth year – approximately 9.5 trillion kilometers – these bursts are truly astronomical. Depending on whether their duration is more or less than two seconds, astronomers classify them into long or short categories.
Dissecting Long GRBs
Long GRBs are associated with the death of particularly massive stars. When a star substantially larger than the Sun exhausts its fuel, its core collapses abruptly, forming a black hole, an area in space where matter is so dense that not even light can escape its gravitational pull. Amidst the frenzied activity of matter swirling towards the newly-formed black hole, some bits manage to escape via two robust jets that jet out at almost light-speed in opposing directions. When one of these jets is pointed towards Earth, it translates into a GRB. The gamma rays produced during this event are the highest-energy form of light and can last up to minutes. Following such a burst, the disrupted star dramatically expands into what is referred to as a supernova, marking the end of its lifecycle.
Glimpse into Short GRBs
In contrast, short GRBs occur when pairs of dense objects such as neutron stars spiral inward over eons and ultimately collide. Neutron stars are another potential outcome of a high mass star’s evolutionary journey.
Spotlight on GRB 200826A
On August 26, 2020, a sharp burst of high-energy emission was detected, lasting a brief 0.65 seconds. After a long journey through the expanding universe, Fermi’s Gamma-ray Burst Monitor picked up this signal, which was about one second long by then. This burst, which has been speeding towards Earth for nearly half the present age of the universe, is considered the shortest GRB detected to date and is thought to have resulted from the death of a massive star.
Significance of GRB 200826A
The discovery of GRB 200826A is helping to clarify lingering questions related to gamma-ray bursts. Furthermore, it is prompting scientists to revisit all previously known events of this kind and gather additional data, which could shed new light on these incredible cosmic phenomena.
Fermi Gamma-ray Space Telescope: The Eye in the Sky
Originally named the Gamma-ray Large Area Space Telescope (GLAST), the Fermi Gamma-ray Space Telescope is a space observatory designed to perform gamma-ray astronomy observations. Launched in June 2008, it scans the entire sky every three hours and plays a crucial role in probing some of the most extreme phenomena of our universe.
About Gamma Rays
Gamma rays embody the highest-energy light in the universe, capable of having over a billion times the energy of visible light. They are produced by the most energetic and hot objects in the universe. On Earth, gamma rays are generated through nuclear explosions, lightning, and radioactive decay. However, due to their extremely high energy, they pose a threat to life on Earth. Consequently, gamma-ray astronomy is generally conducted with high-altitude balloons or satellites, above the protective cover of Earth’s atmosphere.
