The Cubic Kilometre Neutrino Telescope or KM3NeT is deployed under the Mediterranean Sea to detect high-energy neutrinos, also known as ghost particles.
But why are neutrinos called ghost particles?
Why in the news?
Scientists have deployed telescopes under the Mediterranean Sea to detect the high-energy neutrinos also known as ghost particles. 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 much like the IceCube Neutrino Observatory, which can detect high-energy neutrinos from deep space but is under the frozen ice in the Antarctic rather than being in the water.
Key Takeaways:
Neutrinos are tiny particles, very similar to electrons, but without any electric charge. They are miniscule subatomic particles that hardly interact with anything. This means that they can travel massive distances undisturbed and that in turn means that it is much easier to trace them back to their source, helping us understand more about the distant universe.
They were first detected in 1959, though their existence was predicted almost three decades earlier, in 1931. They are one of the fundamental particles the universe is built of, and are the second most abundant subatomic particles after photons.
Not all neutrinos are important to study. Scientists are more interested in studying the super-fast, high-energy neutrinos that have come from far, far away. They are called Astrophysical neutrinos. Such neutrinos are rare and mostly originate from exotic events such as supernovae, gamma-ray bursts, or colliding stars.
Astrophysical neutrinos come in three different “flavours”: electron, muon and tau. The last has proven to be especially difficult to observe and detect, earning the moniker of “ghost particle.”
To detect high-energy neutrinos, there is a need for a large volume of optically transparent material in a place where it is extremely dark. “The location needs to be dark because the detectors look for flashes of Cherenkov radiation: light that neutrinos produce when they interact with a water or ice molecule,” according to a report by Cosmos magazine.
KM3NeT
KM3NeT is a deep-sea research infrastructure in the Mediterranean Sea, comprising a neutrino telescope with a volume of at least one cubic kilometre.
It uses Cherenkov radiation to study neutrinos. As a European research infrastructure, it is located in the Mediterranean Sea and involves collaboration among multiple countries.
These flashes help scientists trace the path of that neutrino, giving them details about its source, the amount of energy it contains, and its origins.
Although both frozen ice and deep sea waters provide conducive conditions for detecting high-energy neutrinos, experts suggest that underwater neutrino telescopes could be more efficient than IceCube.
That is because water scatters light less, which gives a more accurate idea about where the detected neutrinos came from. The one disadvantage is that water absorbs light more and as a result, there will be less light to examine.
IceCube Neutrino Observatory in Antarctica uses “strings” (cables) of digital optical modules (DOMs) to detect neutrinos. It has over 5,150 DOMs embedded deep within Antarctic ices. The reaction of neutrinos with the ice produces charged particles that emit blue light. This is registered and digitised by individual DOMs.
IceCube Neutrino Observatory
It is a device located at the Earth’s South Pole that detects subatomic particles called neutrinos. Built and maintained by the IceCube Collaboration, it consists of approximately 350 physicists from 58 institutions across 14 countries, led by the University of Wisconsin–Madison. IceCube collaborators address several big questions in physics, like the nature of dark matter and the properties of the neutrino itself.
Dark Matter
Everything we see – the planets, moons, massive galaxies, you, me, this website – makes up less than 5% of the universe. About 27% is dark matter and 68% is dark energy. While dark matter attracts and holds galaxies together, dark energy repels and causes the expansion of our universe.
Dark matter is a form of matter that scientists believe accounts for nearly 85 per cent of all the matter in the universe. It gets its “dark” moniker from the fact that it does not interact in any way with electromagnetic fields, including light and radio waves. It does not absorb, reflect, or emit radiation, which makes it nearly impossible to detect. This is why no experiment has directly detected dark matter successfully.
Even though dark matter does not directly interact with light, it does have mass.And when there is a large amount of mass, it can bend the space-time continuum, and therefore, light. This “gravitational lensing” done by many galaxies also points towards the evidence of dark matter.