Researchers studied if stupendously large black holes make up dark matter. They looked at ancient light from the early universe to see if these massive objects existed. The study showed no evidence of them. Findings will appear in Physical Review Letters on October 26, suggesting other candidates might exist instead.
Dark matter is believed to make up about five-sixths of all matter in the universe.
It was first proposed decades ago to explain why galaxies don't fly apart at their observed rotation speeds.
The idea is that this unseen substance's gravitational pull helps keep galaxies intact.
However, the exact nature of dark matter remains a mystery.
The study's authors looked into the possibility of "stupendously large black holes" as a potential source of dark matter.
These hypothetical objects would be heavier than entire galaxies and are extremely difficult to detect in the vastness of space.
However, no such black holes have been found so far, with the largest known black hole weighing about 36 billion times that of our Sun.
The researchers examined the light from the universe's early days, known as the cosmic microwave background.
This ancient light provides a snapshot of how matter was distributed in the infant universe.
The study found that this cosmic microwave background isn't "grainy" like it would be if stupendously large black holes were a major part of dark matter.
The researchers clarified that their findings don't rule out the existence of stupendously large black holes, but rather suggest they don't make up a large part of dark matter.
They also hinted at the possibility of exploring smaller black holes, akin to asteroids, as potential candidates for dark matter.
Their study will be published in the journal Physical Review Letters on October 26.