Black Holes are not Totally Black
Black holes are regions in space where gravity is extremely strong, and nothing, including light, can escape their gravitational pull. While black holes are often described as "totally black," they can emit X-rays and produce light. The glow that often surrounds a black hole is found to be caused by gas that is pulled into the black hole.
Scientific Findings
The black hole is found to have no colour. Yet, an image of a black hole taken by scientists shows a massive orange and yellow glow surrounding a smaller black space in the middle. This is actually the material pouring into it that becomes superheated gas. This gas is thought to change colour as it gets closer to the black hole. Like the Sun when it sets behind clouds in the evening, light from the superheated material will have to travel through more gas on its way to instruments on Earth. So the effect will be to change the colour and appearance of the material around the black hole.
Black Holes could be Bright
Despite the name, not all black holes are black. While black holes come in many different sizes, the biggest ones are at the centres of galaxies, and are still growing in size. If material such as gas, dust or stars gets too close to a black hole, it gets sucked in by the enormous gravitational force. As it falls towards the black hole, it heats up and becomes incredibly bright. The light produced by these “bright black holes” can span the entire electromagnetic spectrum, from X-rays to radio waves. Another name for the bright black holes at the centre of galaxies is “active galactic nuclei”, or AGN. They can shine trillions of times brighter than the Sun, and can sometimes even outshine all the stars in its galaxy.
Extracted from:
https://www.forbes.com/sites/startswithabang/2019/07/10/sorry-black-holes-arent-actually-black/?sh=74bb3e2c5c02
https://www.bbc.com/news/science-environment-49571917
https://theconversation.com/some-black-holes-are-anything-but-black-and-weve-found-more-than-75-000-of-the-brightest-ones-169938
