Significant Study Uncovers Dark Matter's Influence On Scale Smaller Than Large Galaxies

A research team at Kindai University in Japan's Osaka, led by Professor Kaiki Taro Inoue, has made a significant discovery using one of the world's most powerful radio telescopes, the Atacama Large Millimeter/Submillimeter Array (ALMA) in Chile.

They have found fluctuations in the distribution of dark matter in the universe on a smaller scale than that of massive galaxies. This finding sheds light on the true nature of dark matter, according to the press release shared on the ALMA website.

For the first time, spatial fluctuations of dark matter in the far universe have been detected on scales smaller than 30,000 light-years. This result supports the theory of "cold dark matter."

The dark matter material — believed not to be atoms made up of electrons, protons, and neutrons — that moves far slower than the speed of light with respect to ordinary matter is called cold dark matter.

The research article was published in The Astrophysical Journal on Thursday (7 September).

Dark matter, an invisible substance that constitutes a significant portion of the universe's mass, is believed to have played a crucial role in the formation of celestial structures like stars and galaxies.

Although it is known that dark matter is not evenly distributed but exists in clumps, its distribution on smaller scales remains a mystery.

Observations of gravitational lensing, where the path of light is slightly altered by the gravity of dark matter, have revealed its association with massive galaxies and galaxy clusters.

Gravitational lensing, a concept which has its origins in Albert Einstein's theory of general relativity, can help scientists see cosmic objects that are too far out and faint to observe. 

In their investigation, the Japanese team used the powerful ALMA telescope and focused on a distant quasar (MG J0414+0534) located 11 billion light-years from Earth.

This quasar exhibits a rare quadruple image due to the gravitational lensing effects of a foreground galaxy.

However, the positions and shapes of these images did not align with calculations based solely on the gravitational pull of the foreground galaxy, suggesting the presence of another influencing factor.

The discrepancy in dark matter distribution can be attributed to its effects on a smaller scale, specifically within a range of less than 30,000 light-years.

These findings are said to confirm the existing theoretical model of cold dark matter, as per which clumps of dark matter are not only present within galaxies but also in the spaces between them.

The new research represents a significant step towards verifying dark matter theories and gaining a better understanding of its mysterious nature.