From UPSC perspective, the following things are important :
Prelims level : Neutrino, Supernovae
Mains level : NA
This newscard is an excerpt from the original article published in The Hindu.
Another space-based abstract terminology has appeared in TH.
What is the news about?
- Many stars, towards the end of their lifetimes, form supernovas – massive explosions that send their outer layers shooting into the surrounding space.
- Most of the energy of the supernova is carried away by neutrinos – tiny particles with no charge and which interact weakly with matter.
- Researching the mechanisms of the so-called Type II supernovas, a team from IIT Guwahati has come up with new insights into the part played by neutrinos in this dramatic death of massive stars.
What are Neutrinos?
- Proton, neutron, and electron are tiny particles that makeup atoms.
- The neutrino is also a tiny elementary particle, but it is not part of the atom.
- Neutrino has a very tiny mass, no charge and spins half.
- It interacts very weakly with other matter particles.
- Neutrinos come from the sun (solar neutrinos) and other stars, cosmic rays that come from beyond the solar system, and from the Big Bang from which our Universe originated.
- They can also be produced in the lab.
- Neutrinos come in three ‘flavours’, another name for ‘types’, and each flavour is associated with a light elementary particle.
- For instance, the electron-neutrino is associated with the electron; the muon-neutrino with the muon and the tau-neutrino with the tau particle.
What is Supernova?
- All the stars burn nuclear fuel in their cores to produce energy.
- The heat generates internal pressure which pushes outwards and prevents the star from collapsing inward due to the action of gravity on its own mass.
- But when the star ages and runs out of fuel to burn, it starts to cool inside.
- This causes a lowering of its internal pressure and therefore the force of gravity wins; the star starts to collapse inwards.
- This builds up shock waves because it happens very suddenly, and the shock wave sends the outer material of the star flying. This is what is perceived as a supernova. This happens in very massive stars.
Try this PYQ:
Q. Which of the following is/are cited by the scientists as evidence/evidence for the continued expansion of the universe?
- Detection of microwaves in space
- Observation of redshirt phenomenon in space
- Movement of asteroids in space
- Occurrence of supernova explosions in space code
(a) 1 and 2 only
(b) 2 only
(c) 1, 3 and 4
(d) None of the above can be cited as evidence
The Type-II Supernova
- In stars that are more than eight times as massive as the Sun, the supernova is accompanied by a collapsing of the inner material of the dying star – this is also known as core-collapse supernova or Type II supernova.
Role of neutrinos
- The collapsing core may form a black hole or a neutron star, according to its mass.
- As they spew out of the raging supernova, the neutrinos can change from one flavour to another in a process known as neutrino oscillations.
- Due to the high density and energy of the supernova, it generates neutrino oscillations happening simultaneously over different energies (unlike normal neutrino oscillation), termed collective neutrino oscillation.
- The oscillation result may dramatically change when one allows the evolution with the angular asymmetry, the oscillations can happen at a nanosecond time scale, termed fast oscillation.