From UPSC perspective, the following things are important :
Prelims level : GRB Explosions
Mains level : Various interstellar phenomena
The emission from the most notable Gamma Ray Burst (GRB) explosion away from 4.5 billion light-years has been traced by Indian researchers.
What are GRB Explosions?
- GRBs are immensely energetic explosions that have been observed in distant galaxies.
- They are the brightest and most energetic electromagnetic events known to occur in the universe.
- Bursts can last from ten milliseconds to several hours.
- After an initial flash of gamma rays, a longer-lived “afterglow” is usually emitted at longer wavelengths (X-ray, ultraviolet, optical, infrared, microwave and radio).
- The intense radiation of most observed GRBs is thought to be released during a supernova or superluminous supernova as a high-mass star implodes to form a neutron star or a black hole.
What makes GRB special?
- The explosions are both extremely energetic (a typical burst releases as much energy in a few seconds as the Sun will in its entire 10-billion-year lifetime) and extremely rare.
- All observed GRBs have originated from outside the Milky Way galaxy, although a related class of phenomena, soft gamma repeater flares, are associated with magnetars within the Milky Way.
- It has been hypothesized that a gamma-ray burst in the Milky Way, pointing directly towards the Earth, could cause a mass extinction event.
Answer this PYQ in the comment box:
Q.Which of the following is/are cited by the scientists as evidence/evidences for the continued expansion of universe? (CSP 2012)
1. Detection of microwaves in space
2. Observation of red shift phenomenon in space
3. Movement of asteroids in space
4. Occurrence of supernova explosions in space
Select the correct answer using the codes given below:
(a) 1 and 2 only
(b) 2 only
(c) 1, 3 and 4
(d) None of the above can be cited as evidence.