New Light On Dark Matter

Scientific research is unearthing new understanding on an old mystery

- Akshit Sangomla

Deciphering the true nature of the mysterious dark matter—that constitutes 27 per cent of the Universe—has eluded scientists since it was discovered by Fritz Zwicky in 1933. Dark matter attracts everything through gravity; it competes with the equally mysterious dark energy that pulls apart everything in the Universe. These two competing forces shape the Universe at the largest scale. Dark energy, which constitutes 68 per cent of the Universe, is also the most plausible cause for the observed accelerated expansion of the Universe. This means that all the stars, planets and other celestial bodies—visible to us—make up only 5 per cent of the Universe. The rest is yet unknown. But new scientific evidence is now interpreting this mystery.

To explain current observations of the Universe, scientists say dark matter exists, but it does not emit, absorb or reflect light. This makes it difficult to detect. The only way that its existence can be inferred is through the gravitational pull it exerts on other matter in the form of stars, planets and other celestial objects.

That’s why astronomers look at galaxies and clusters of galaxies—the grandest structures of the Universe—to understand dark matter: what it is and why it exists in the first place. matter, and this increases the dark matter concentration in these clusters.

This, in turn, makes it easier for astronomers to search. Another place scientists have been looking is deep under the Earth’s surface where they have been detecting possible particles that could make up dark matter in Xenon tanks—the largest propellant tank made by humans—and even in rocks.