Astronomers from Tel Aviv University have looked far out into space – and thus far back in time – to learn that the most massive black holes – called super-massive black holes – began growing at a very fast rate when the universe was only about 1.2 billion years old.
That’s in contrast to two to four billion years year old, as suggested by earlier studies. And it’s in contrast to approximately 13 to 14 billion years old for the age our universe at the present time. We’re not talking about about ordinary black holes that collapsed from massive stars. These are super-massive black holes of the type believed by astronomers to reside in the centers of most galaxies.
Super-massive black holes vary in mass from about one million to about 10 billion times the mass of our sun. Our own Milky Way galaxy is thought to have a super-massive black hole in its center. It would be invisible, except for its effects on the space surrounding it. On the other hand, when the universe was young – when massive black holes were first forming – they might have been more directly visible.
That’s because black holes in the young universe might be radiating fiercely due to the infall of gas from surrounding space. The Tel Aviv astronomers used some of the largest ground-based telescopes in the world, coupled with advanced instrumentation, to peer deep into space at black holes that were active when the universe was 1.2 billion years old.
These very distant and young black holes are relatively small, but – as matter falls into them – they are growing fast, these astronomers say.
Deborah Byrd created the EarthSky radio series in 1991 and founded EarthSky.org in 1994. Today, she serves as Editor-in-Chief of this website. She has won a galaxy of awards from the broadcasting and science communities, including having an asteroid named 3505 Byrd in her honor. A science communicator and educator since 1976, Byrd believes in science as a force for good in the world and a vital tool for the 21st century. "Being an EarthSky editor is like hosting a big global party for cool nature-lovers," she says.