A runaway black hole? Hubble captures an unusual feature in deep space

The NASA/ESA Hubble Space Telescope captured an intriguing linear feature so unusual that it was initially thought to be a flaw in the camera's imaging, but further spectroscopic observations revealed it to be a chain of young blue stars stretching over 200,000 light years.

At the lower left tip of the bridge lies a supermassive black hole, which was ejected from the galaxy at the upper right. The black hole compressed gas behind it, leaving a long trail of young blue stars. This unusual event hasn't been observed before and it occurred when the Universe was about half its current age, according to the researchers.

"We noticed an almost straight line of light in the Hubble images that pointed to the heart of a galaxy. As we had never seen something like that before, we decided to investigate it a month later with the Low-Resolution Imaging Spectrometer on the Keck I telescope," said Yale University's Pieter van Dokkum, lead astronomer for the multi-institution research team.

Researchers believe that this intergalactic skyrocket is a result of multiple collisions of supermassive black holes. The first two galaxies are suspected to have merged around 50 million years ago, bringing two supermassive black holes at their centres.

The two black holes whirled around each other as a binary black hole. When the single black hole departed in one direction, the binary black holes moved in the opposite direction.

On the opposite side of the host galaxy, there is a feature that may be indicative of the runaway binary black hole. This is supported by circumstantial evidence that there is no evidence of an active black hole at the galaxy's core.

🆕 Hubble captures a curious linear feature so unusual that it was first dismissed as an imaging artifact from Hubble’s cameras. Nothing like this has ever been seen in the Universe. 😲 Read more here: https://t.co/5SkmKrIndN and 🧵👇 pic.twitter.com/OOHuDgTRf8

— HUBBLE (@HUBBLE_space) April 6, 2023

What's next?

To confirm this black hole hypothesis, the next step involves conducting follow-up observations using the powerful NASA/ESA/CSA James Webb Space Telescope and NASA's Chandra X-ray Observatory.

If confirmed, the discovery would prove a 50-year-old theory predicting the existence of runaway black holes.