大象传媒

Black hole discovery could unlock a mystery of the universe

black-hole.Image source, NASA/ESA/N. Bartmann
Image caption,

An artist's impression of a supermassive black hole that is inside the core of a vigorously star-forming "starburst" galaxy.

For a long time, scientists have wondered how supermassive black holes in space reached their colossal size - now, a new discovery could provide some answers.

Astronomers have observed a fast-growing black hole which they believe could be an important "missing link" between galaxies that produce lots of stars like our Sun and the first supermassive black holes.

The researchers used old data from the Hubble Space Telescope to make their big discovery.

Image source, NASA/ESA
Image caption,

A team of astronomers have discovered a unique object in the distant universe that could be a crucial link between young star-forming galaxies and the earliest supermassive black holes

The black hole, which has been nicknamed GNz7q, is believed to date back to only 750 million years after the Big Bang, which is commonly thought to have taken place 13.8 billion years ago.

An old image taken by the Hubble telescope showed ultraviolet (UV) and infrared light coming from GNz7q, the types of radiation expected from materials that are falling into a black hole.

"GNz7q is a unique discovery that was found just at the centre of a famous, well-studied sky field - it shows that big discoveries can often be hidden just in front of you," said Gabriel Brammer, an astronomer from the University of Copenhagen and co-author of the study.

And astronomers believe that this discovery could help answer a big question about the universe - how did supermassive black holes, weighing millions to billions of times the mass of our Sun, get to be so huge so fast?

What are black holes, supermassive black holes and quasars?

Black holes are formed when a dying star collapses inward under the pressure of its own weight. This leads to something called a supernova, a star's extremely powerful explosion.

Black holes are places in space where the pull of gravity is so strong that even light can't escape it! This is what makes them invisible.

Supermassive black holes are millions, or sometimes even billions the size of our Sun. Astronomers believe they can be found at the centre of all large galaxies, including our own: The Milky Way.

Quasars are incredibly bright objects in space powered by black holes which give off large amounts of light and energy.

Every large galaxy has a supermassive black hole at its centre and unsurprisingly, given their name, they are properly massive!

Supermassive black holes are so gigantic that they have a mass of more than one million stars the size of our own Sun.

Mass is how much stuff something is made out of and black holes have LOTS of stuff in them tightly packed together.

Media caption,

How does a black hole 'burp'?

Brammar says that scientists think supermassive black holes first began in the cores of starburst galaxies.

Starburst galaxies produce lots of stars really quickly meaning they contain all the ingredients that make up stars like our own Sun.

As those ingredients of swirling dust, energy and gas flow into a black hole in the middle of a galaxy - that gas and energy becomes very, very hot creating an incredibly bright jet of light at its centre, known as a quasar.

Somewhere in-between the two phenomena occurring, these black holes are thought to grow incredibly in size.

And, while scientists have an understanding of how starburst galaxies began and how quasars are formed, they previously had little understanding of what happens in-between.

That is until now and the discovery of GNz7q - which Nasa says provides the "missing link" between the two - and can help explain the origins of supermassive black holes.

Now the team hopes to search for similar objects using the new James Webb Space Telescope to work out how common the fast-growing black holes really are.