Some of the most distant rocks in our solar system act in a way that suggests there’s some massive object out there we haven’t been able to see. A planet? Maybe. But why not a small black hole?

That’s a scenario a pair of scientists describe in a new paper. Of course, they recognize that a planet is more likely than an ancient black hole unlike any we’ve directly observed. But they simply want astronomers to think creatively while hunting for whatever this hypothetical object, often called Planet Nine, might be.

This alternate explanation for ‘Planet Nine,’ proposed by scientists in a new paper, poses some fundamental questions like: Should we visit it?

They were spotted in the act of merging in a galaxy a billion light years away.

NASA has released a stunning image of three black holes about to collide with each other.

The ultra-rare is the best evidence yet of a so-called “triple system” – three active supermassive black holes smashing in to each other.

Each of the black holes is at the centre of its own galaxy.

In a mind-bending new paper, researchers suggest that there could be black holes orbiting the Sun, out past Pluto.

Scientists have long speculated that a “planet 9,” in orbit very far from the Sun, could explain why other bodies in our solar system have strange, hard-to-explain orbits.

Now, a pair of astrophysicists are suggesting a strange twist on that idea: that a black hole — or even a number of them — could be orbiting our Sun right now, way beyond Neptune.

Primordial

This week, a pair of researchers from Durham University and the University of Illinois at Chicago published a paper outlining their theory on the pre-print server arXiv. In it, they suggest that the Sun’s orbit might have captured a free-floating “primordial black hole” — and it, or they, are still out there, circling the solar system.