Black holes may have helped light up the universe

Black holes may have helped light up the universe



Around 13.7 billion years ago, it’s thought that the universe exploded into existence in a phenomenon that’s come to be known as the Big Bang – and then, all went dark.

With hot, thick gas swirling about the newborn universe, light remained trapped for as many as one billion years, until the cosmos finally expanded and filled with light-emanating objects.

Just how this transformation occurred, however, has long remained a mystery.

Now, a new study has found that black holes may have been responsible for filling the early universe with light, as they violently flung out matter and tore through the surrounding clouds.



In the new study, researchers from the University of Iowa observed unusual activity in a nearby galaxy that could help to explain the processes that helped to illuminate the universe.

‘The observations show the presence of very bright X-ray sources that are likely accreting black holes,’ says Philip Kaaret, professor in the UI's Department of Physics and Astronomy, and corresponding author on the study.

‘It’s possible the black hole is creating winds that help the ionizing radiation from the stars escape.

‘Thus black holes may have helped make the universe transparent.’

The researchers investigated a galaxy called Tol 1247-232, which sits roughly 600 million light years away.

It’s one of just three nearby galaxies known to emit ultraviolet light, and in May 2016, the researchers observed a single X-ray source with fluctuating brightness within a star-forming region of the galaxy.

This, they say, indicates that the source was not a star.



‘Stars don’t have changes in brightness,’ Kaaret says.

‘Our sun is a good example of that.

‘To change in brightness, you have to be a small object, and that really narrows it down to a black hole.’

Black holes are known to swallow everything in their vicinity.

But, the researchers say they may also be able to eject matter in jets, as a result of the accelerated rotational energy of the black hole itself.



They compare this process to the movement of a figure skater twirling with outstretched arms.

‘As matter falls into a black hole it starts to spin and the rapid rotation pushes some fraction of the matter out,’ Kaaret says.

‘They’re producing these strong wings that could be opening an escape route for ultraviolet light.

‘That could be what happened with the early galaxies.’

The researchers plan to conduct further studies on this galaxy, as well as others, to better determine if black holes may have driven the illumination of the early universe.