Why scientists are installing underwater telescopes to detect ‘ghost particles’

Sub: SCI

Sec: Space Sector

Context:

Scientists are deploying two telescopes to detect high-energy neutrinos, also known as ghost particles, under the Mediterranean Sea.
The two telescopes are part of the Cubic Kilometre Neutrino Telescope or KM3NeT.
While one of the telescopes will study high-energy neutrinos from space, the other will examine neutrinos from the atmosphere.
These telescopes are similar to the Ice Cube Neutrino Observatory in Antarctica, which detects high-energy neutrinos from deep space, but KM3NeT will be under the sea instead of ice.

What are neutrinos?

Neutrinos are tiny subatomic particles, very similar to electrons, but without any electric charge.
They were first detected in 1959, although their existence was predicted earlier in 1931 by physicist Wolfgang Pauli.
They are one of the fundamental particles the universe is built of, and are the second most abundant subatomic particles after photons.
They are extremely difficult to detect due to their weak interaction with matter, even though billions pass through every cubic centimetre of space each second.

High-Energy Neutrinos and their importance:

High-energy neutrinos, which come from distant cosmic events like supernovae or gamma-ray bursts, are super-fast, particularly rare and of great interest to scientists because they can offer insights into regions of space obscured by dust.
For example, region around the centre of the Milky Way is often obscured by cosmic dust, which absorbs and scatters visible light. Neutrinos, however, are not affected by dust, making them an ideal tool to study these otherwise hidden phenomena.

Neutrino Detection Mechanism:

Neutrino telescopes rely on detecting Cherenkov radiation, flashes of light produced when neutrinos interact with water or ice molecules.
This light is detected by sensors, allowing scientists to trace the path of the neutrino and learn about its source, energy, and other properties.
The location for these telescopes must be dark and have optically transparent material to capture these flashes.

Why Underwater Neutrino Telescopes:

While both ice and water are suitable for neutrino detection, experts suggest that underwater telescopes, like those in KM3NeT, might be more efficient than Ice Cube because water scatters light less, although water absorbs light more, limiting the amount of light available for detection.