Fast radio burst

Context: In a study, astronomers have reported a fast radio burst (FRB) whose characteristics are different from almost all other FRBs previously detected, except one.

• FRBs are bright flashes of light that appear for a few milliseconds and then vanish. Since the first FRB was discovered in 2007, 140 more were discovered until June 2021
• The new study in Nature describes FRB 20190520B, first discovered in 2019, is idifferent is different from other FRBs, it emits frequent, repeating bursts of radio waves. And between bursts, it constantly emits weaker radio waves.
• Only one FRB has been previously observed to behave this way. Called FRB 121102, that was discovered in 2012.
• Calling the behaviour strange the US National Radio Astronomy Observatory (NRAO) stated that the discovery raises new questions about the nature of these mysterious objects and also about their usefulness as tools for studying the nature of intergalactic space.

What are Fast Radio Bursts?

• Fast Radio Bursts are brief (few millisecond) bursts of radio waves coming from far beyond our Milky Way galaxy.
• The phenomenon was first reported in 2007
• A defining property of these bursts is their dispersion the bursts produce a spectrum of radio waves, and as the waves travel through matter, they spread out or disperse with bursts at higher radio frequencies arriving at telescopes earlier than those at lower frequencies.
• This dispersion allows researchers to learn about two important things:
• They can measure this dispersion to learn about the stuff that radio bursts pass through as they travel toward Earth
• They can indirectly determine how far apart things are.

Origin of FRBs:

• FRBs have been spotted in various and distant parts of the universe, as well as in our own galaxy. Their origins are unknown and their appearance is highly unpredictable.

Previous Year Questions

Q.1) Which one of the following is a reason why astronomical distances are measured in light-years? (2021)

1. Distances among stellar bodies do not change.
2. Gravity of stellar bodies does not change.
3. Light always travels in a straight line.
4. Speed of light is always same.

Source: Indian Express