What is Dark matter and where can you find them?
Dark matter is part and parcel of our universe. Our Universe is unlimited and weird. Being mysterious many unexpected things happen every moment. Whatever the Universe has been exploited by the humans of this Earth is very minimal and handful.
What is Dark matter?
Dark matter is part and parcel of our universe. Our Universe is unlimited and weird. Being mysterious many unexpected things happen every moment. Whatever the Universe has been exploited by the humans of this Earth is very minimal and handful. Our astronomers, cosmologists, and scientists know some things about stars, planets, constellations, galaxies, galactic clusters, comets, satellites, etc.
Earlier it was believed that the Universe consisted of only one galaxy which is ours Milky Way. But after astronomer Edwin Hubble discovered the mechanism to measure the distances of faraway celestial bodies, now astronomers suspect that the Universe contains billions of galaxies.
One galaxy may contain trillions of stars, forget about the number of planets and satellites. It is estimated that our Universe originated about 13.4 billion years ago and Milky Way is 10 billion years old now.
It is observed that rotating body movement is regulated by the gravitational forces of the body at the center. The speed of the rotating body depends upon the distance from the object at the center.
The speed of the rotating object decreases with the increase of the distance from the center. A bright example is there in our own solar system. Mercury, the nearest planet ( distance 69.146 million km from the Sun) of the solar family moves 47km per second, whereas our mother Earth (distance 151.44 million km from the Sun) orbits Sun at a speed of 30km per second.
Fritz Zwicky, the Swiss American cosmologist, in early 1930, during studying the Hubble observatory of the Coma cluster of galaxies, noticed that the stars at the periphery of the galaxy, are not being thrown away into the universe beyond the Milky Way galaxy under the influence of some unseen elements, rather keeping them bound together. Such an anomaly was not observed earlier. Zwicky opined that the yet unobserved type of mass is Dunkle Materie or dark matter. He published his finding in 1933 in the Swiss Physical Society journal.
What is dark matter and why it is not visible?
Normal matter is visible due to the presence of charged particles like electrons and protons. Activities like reflection, refraction, absorption, etc are integral parts of visible matter. But dark matter is a celestial body and a property of the Universe occupying space.
It is an invisible and dense body other than known matter. It is composed of particles that don’t absorb, reflect or emit light but light can pass through it. Unlike other known matter, it can’t be detected by electromagnetic radiation or touched. Scientists assume that dark matter consists of WIMPS (Weakly Interacting Massive Particles ).
The strange matter has gravitational force, which keeps the stars and galaxies together. It is presumed that about 26.8 % of dark matter constitutes the universe, whereas normal matter’s contribution is about 4.9 % and dark energy constitutes the rest 68.3 %. Albert Einstein was the first on Earth to observe that empty space is not empty. It has some energy and the energy is the property of space, which is believed to be expanding the Universe.
The universe is originated 13.4 billion years back out of nothing for an unknown reason, infinitely beginning with smaller than an atom and it expanded infinitely within a few seconds, this unusual event is BIG BANG. At the advent of the Universe, Cosmic Microwave Background (CMB) radiation was also created and is present till now. Hindu mythology says Universe is created as Lord Vishnu wishes.
When was the dark matter created?
In the earliest, the entire Universe was filled with hot clouds of normal matters and dark matters. In due course of time normal matter settle down in stars, planets, satellites, comets, asteroids, etc.
Dark matter was created, with the creation of the universe left unattended due to its unknown characteristics.
It is scattered unevenly throughout the Universe without being detected till Zwicky’s discovery. Dark matter has gravitational force and mass but is not affected by temperature and pressure although light can pass through it.
Research is still on about this mysterious matter. COSINE-100 International team in South Korea and ANAIS-112 at Canfranc Underground Laboratory (LSC), Spain conducting experiments on the dark matter for years together could not find, any concluding evidence of dark matter in spite of following the same technology of DAMA/ LIBRA experiment in Italy. DAMA/LIBRA, Italy experiment, claimed in 2018 that the researchers had found physical evidence of dark matter in the form of flashes of light in sodium iodide crystals. They believed that the flashes were evidence of dark matter colliding with atoms in the crystals.
It is now observed that the dark matter and normal matter ratio in the Universe are 6:1, but over several decades physicists around the world trying to find the physical evidence of dark matter, and left with not having much success.
An international team of physicists, published a paper on a new theory, in the journal Physical Review Letters, in which they suggest that dark matter came from regular matter and dark matter is capable of creating more dark matter from regular matter. Now dark matter still remains an illusion for many but its existence can’t be ruled out. Whatever facts we know about Universe and dark matter are the tip of the iceberg.