Some of the farthest cliffs in our solar system act in a way that suggests there are some massive object that we could not see. Planet? Perhaps. But why not a small black hole?
This is a scenario that a couple of scientists describe in a new paper. Of course, they admit that a planet is more likely than an ancient black hole, unlike any we have directly observed. But they just want astronomers to think creatively as they hunt any hypothetical object, often called Planet Nine.
"By focusing solely on the concept of the planet, you limit the experimental demand you are undertaking," says James Unwin, one of the study authors and an assistant at the University of Illinois at Chicago, at Gizmodo. "As you begin to think of more exotic objects, like primordial black holes, you think different ways. We advocate for this, rather than looking for it in visible light, maybe looking for gamma rays. Or cosmic rays. ”
In the past, the Neptune movement of rock objects appeared to be disturbed by something about five to 15 times larger than Earth's mass. Scientists named this object Planet Nine and hunted for it. But this is not the only gravity anomaly on the planet-mass in the galaxy. Scientists have discovered short bases of incoming starlight, perhaps from planet-sized objects bending their gravity. Perhaps they are deceptive planets, or they may be small black holes .
"Primary black holes" is a class of proposed objects formed as a result of the chaotic early days of the universe. Like any other black hole, they would be incredibly dense regions where gravity distorts space so much that light cannot escape. But they would weigh far less than the stars, since they were not formed by stars like the black holes we were actually observing – they would form from places of residual additional density in the rapidly expanding early universe. (And no, they wouldn't make much of a contribution to the dark matter of the mysterious things that seem to represent the lion's share of the mass of the universe.)
Unwin and his associate Jakub Scholz, a junior fellow at the Institute of Phenomenology of Particle Physiology of Physics at Durham University suggested that perhaps the original black hole, played by, interacted with other members of the solar system and was captured in orbit. I asked Uniwn and Scholtz whether such an object would evaporate from small physical effects called Hawking radiation ; they said no, even a black hole with five earth masses would last a very long time, much longer than the epoch of the universe.
If the planet was indeed an original black hole, not a planet-sized mass of regular matter, then it makes no sense to try to find it with typical planet search tools. The figure in the article shared above shows that a black hole of five earth masses can fit in your palm (yes, this meeting would kill you), and a black hole of 10 earth mass would be the size of a ball for bowling. Finding it will require a specialized search for a source-seeking telescope that modern gamma-ray telescopes are not accustomed to seeing – a source of high-energy radiation moving fast through the sky.
Nine-planet hunter Konstantin Batigin does not rule out the idea that it may actually be something more exotic. "Planet Nine can be a five-earth burger and the math will still be right. Of course, a burger has a comparable albedo – or how much light it reflects – on a planet, but a black hole the size of your wallet is a little harder to find, ”he told Gizmodo in an email. He writes that the scenario is a stretch, but not entirely implausible, and the black hole becomes an interesting potential target if Planet Nine is unwarranted in typical deep studies and if the strange movement of trans-Neptune objects persists.
Something causes unexpected behavior in the distant solar system, whatever it may be. The original black hole is not the most obvious, nor the most probable choice – but hey, science is about keeping an open mind and letting experiments refute hypotheses. If there really is a massive object, even if it is a planet, it would be "quite a shock," Scholz says.