UPSC Prelims 2015 Q30: Science & Technology – Physics
In the context of modern scientific research, consider the following statements about
‘IceCube’, a particle detector located at South Pole, which was recently in the news:
1. It is the world’s largest neutrino detector, encompassing a cubic kilometre of ice.
2. It is a powerful telescope to search for dark matter.
3. It is buried deep in the ice.
Which of the statements given above is/are correct?
- (a) 1 only
- (b) 2 and 3 only
- (c) 1 and 3 only
- (d) 1, 2 and 3
Answer: (d) 1, 2 and 3
Explanation
IceCube
IceCube is a neutrino observatory at the Amundsen-Scott South Pole Station, completed in 2010.
| Statement | Verdict | Fact |
|---|---|---|
| 1. It is the world's largest neutrino detector, encompassing a cubic kilometre of ice | Correct | About one cubic kilometre of clear Antarctic ice |
| 2. It is a powerful telescope to search for dark matter | Correct | It looks for neutrinos produced when dark matter particles annihilate |
| 3. It is buried deep in the ice | Correct | Sensors sit between about 1,450 and 2,450 metres below the surface |
How it works:
| Step | Detail |
|---|---|
| Neutrino hits ice | Produces a charged particle |
| Blue flash | The particle gives off Cherenkov light |
| Sensors | Over 5,000 optical modules record the flash |
India's planned detector is the India-based Neutrino Observatory in Tamil Nadu.
Answer: (d) 1, 2 and 3.
Why each option is right or wrong
- (a) Incorrect. It is also buried deep in the ice and is used to search for dark matter.
- (b) Incorrect. Statement 1 is also true: it is the world's largest neutrino detector.
- (c) Incorrect. Statement 2 is also true: it helps search for dark matter.
- (d) CORRECT. IceCube is the largest neutrino detector, searches for dark matter, and lies deep in ice.
Key point
IceCube (South Pole, 2010): cubic-kilometre neutrino detector buried 1.5 to 2.5 km in ice; detects Cherenkov light; also searches for dark matter.
Remember
IceCube = neutrino detector under South Pole ice.
Common mistakes
- Doubting statement 2; IceCube's own science goals include dark matter.
- Confusing IceCube (neutrinos) with LIGO (gravitational waves).
- Thinking the detector sits on the ice surface.
Exam tip
Neutrino detectors are always buried: under ice, rock or water, to block other particles.
Sources
- IceCube Neutrino Observatory — About IceCube
- Tata Institute of Fundamental Research — India-based Neutrino Observatory: Project Report