Dark Matter
GS Paper – 3 Space Technology
Why in the news?
In the United States, a highly sensitive experiment called LUX-ZEPLIN (LZ) was recently utilised to find dark matter in the universe.
Previously, scientists discovered that out-of-plane bending in barred galaxies can be explained by dark matter halos when researching how the form of dark matter impacts the velocity of stars in the centre of particular galaxies (stellar bars).
What exactly is Dark Matter?
Dark matter is made up of particles with no charge.
As a result, these particles are “dark” because they do not emit light, which is an electromagnetic phenomenon, and “matter” because they have mass like conventional matter and interact via gravity.
The visible cosmos we see is the consequence of different interactions between the four fundamental forces operating on particles, which are as follows:
- Strong nuclear force
- Weak nuclear force
- Electromagnetic force
- Gravitation
Only 5% of the observable universe is made up of matter, with the remaining 95% made up of dark matter and dark energy.
So far, gravitational force is poorly understood due to its incredibly weak force, which makes it difficult to detect any particle that interacts with gravitational force.
What exactly is Dark Energy?
Dark Energy is a proposed form of energy that acts in the opposite direction of gravity, exerting a negative, repulsive pull.
It has been proposed to explain the observable characteristics of distant types of supernovae, which show that the universe is expanding at a faster rate.
Dark Energy, like Dark Matter, is inferred rather than directly detected from studies of gravitational interactions between astronomical objects.
What exactly is the distinction between Dark Matter and Dark Energy?
Dark matter is an enticing force, a cosmic mortar that ties our universe together.
This is due to the fact that dark matter interacts with gravity while not reflecting, absorbing, or emitting light. Dark energy, on the other hand, is a repulsive force, a type of anti-gravity that inhibits the expansion of the universe.
Dark energy is by far the more powerful of the two, accounting for roughly 68 percent of the total mass and energy of the universe.
Dark matter accounts for 27% of all matter. The remaining 5% is all of the regular matter we see and interact with on a daily basis.
This also serves to accelerate the expansion of the cosmos.
What is the Evidence for Dark Matter?
There is substantial indirect evidence, as evidenced by numerous levels such as distance scales, for example:
For example, when you move from the galaxy’s core to its outskirts, the observed plot of star speeds and their estimated figure diverge significantly.
This means that the galaxy has a substantial amount of dark matter.
Other examples of distance scale:
There are numerous levels to observe the universe, such as electrons and atom nuclei, galaxies, galaxy clusters, and even larger distances where the entire universe can be mapped and analysed.
Bullet clusters of galaxies are produced by the merger of two galaxies; according to physicists, their merger can only be explained by the presence of dark matter.
What particles are utilised to observe dark matter?
Neutrinos would have been highly beneficial in detecting dark matter, but they are too light and so ineffective.
Several more things have been hypothesised, including the Z boson’s supersymmetric companion, a particle that mediates the electro-weak interaction.
However, no suitable particle has yet been discovered that can interact with gravity and be detected with current technology on Earth.
