Astro News
DARK MATTER
What is Dark Matter?
An intangible substance that constitutes 85% of all matter in our Universe. However, the twist is that we do not know what it is made of and neither have we seen it. We just know that it exists!
The gravity of dark matter is what "drives normal matter (gas and dust) to collect" according to NASA. This gravitational influence is what creates star clusters and galaxies.
How did we discover it?
We owe the discovery to Swiss Astronomer, Fritz Zwicky. According to observation, galaxies seemed to be moving faster than we could account for by the gravitational pull of stars and planets. Therefore, there just had to be more mass in the universe in order to explain this phenomenon. Hence, Zwicky birthed the concept of dark matter, separating this substance from ordinary matter. Upon research furthered by other scientists, the studies seemed to support this hypothesis. Consequently, the scientific world was convinced that the existence of dark matter played a crucial in the formation of astronomical objects in our universe.
How can one detect Dark Matter?
There is still no way to physically observe this mysterious substance. However, we can detect its existence by observing the warped background around massive galaxy clusters and reverse-engineer these distortions. Through mathematical models and simulations, we can predict the locations and properties of the densest concentrations of matter in the cluster. Thus, we can usually expect to find dark matter in massive halos that surround galaxies. They seem to bind other galaxies together and keep stars in orbits while also existing in the centre of galaxies where the concentration of ordinary matter is the densest.
SOME FACTS TO NOTE!
The reason why dark matter is invisible is because it does not interact with light! This substance does not absorb, emit or reflect light wich makes it impossible to detect.
Dark matter is also used to explain temperature fluctuations in cosmic microwave background radiation!
It is theorised that it could consist of particles that do not interact with light. But in order for them to form current observed structures, they must be very heavy particles because otherwise they would not clump together.
There is yet to be experimental evidence regarding the detection of dark matter. We are unsure if dark matter is also effect by gravity, electromagnetism, strong and weak forces. It may be possible that it is actually influenced by a fifth force that we are yet to identify.
A RECENT DISCOVERY!!
Astronomer Tomonori Totani, from the Department of Astronomy at the University of Tokyo, claims that he has captured an image of dark matter using the Fermi Gamma-ray Space Telescope!
This picture seems to be that of halos of gamma-rays from the centre of the Milky Way Galaxy and it must be noted that the photograph is not in visible light!
“A part of the Fermi data showed a peculiar excess that our model couldn't explain, leading me to suspect it might be due to radiation originating from dark matter,” says Totani.
There is currently great debate surrounding this find within the scientific community where some researchers are criticising his potentially biased analysis of the data.
There is lots of evidence that is needed to back up this discovery made just a week ago! Therefore, it will take some time for other astronomers to research his findings and produce their own results.