Scientists may have found one of the strongest hints yet of dark matter, the mysterious substance thought to make up most of the universe, but experts say it is still far too early to declare a discovery.
Nearly a century ago, scientist and astronomers observed that galaxies were spinning so fast they should have flown apart.
To explain this unusual cosmic phenomenon, the scientists proposed “dark matter” an invisible material that doesn’t emit light but has a strong gravitational pull.
In contemporary scientific observation dark matter is believed to make up about 27–85% of the universe’s mass. But this mesmerizing phenomenon till now has not been directly detected.
In a new study, Prof Tomonori Totani of the University of Tokyo analysed 15 years of data from NASA’s Fermi Gamma-ray Space Telescope, which observes high energy light called gamma rays.
He found a faint glow of gamma rays coming from the halo of the Milky Way that cannot easily be explained by known sources like stars or cosmic rays.
Totani says the signal “closely matches” what would be expected if dark matter were made of weakly interacting massive particles (WIMPs).
These hypothetical particles are thought to very rarely interact with normal matter, but could sometimes collide and destroy each other, releasing gamma rays in the process.
The energy of the detected glow, around 20 gigaelectronvolts, fits within the expected range for WIMP self-annihilation.
If correct, the result would suggest dark matter particles are roughly 500 times heavier than a proton, and would be “the most promising candidate radiation from dark matter known to date,” Totani has argued.
Experts say the next step is to look for the same kind of gamma-ray signature in other parts of the universe.
