A team of international astronomers have been hunting for ancient, supermassive black holes -- and they've hit the motherlode, discovering 83 previously unknown quasars.

The universe is full of supermassive black holes, monstrous versions of the humble, everyday black hole, containing masses millions or billions of times that of our sun.

These huge cosmic beasts generate mammoth gravitational effects, so you often find supermassive black holes hiding out at the center of galaxies, orbited by billions of stars.

That's exactly what happens in our home galaxy of the Milky Way.

To find them lurking out in the distant parts of the universe, you need to study the light of accreting gases that swirl around them.

Because we can't see a black hole, but we can see the light, we designate these powerful light sources as "quasars".

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