Beyond the Kuiper Belt, wherein lies our friend Pluto, there exists what we now know as the Oort Cloud, named after astronomer Jan Oort who theorized its existence.
The Oort Cloud is thought to be the region from where long-period comets come barreling toward our sun, make a tight U-shaped curve, and then fly way out again, only to return later.
Trillions of chunks of ice float around out there, far far away. But, as pointed out, some of them get perturbed and are flung inward on their spectacular comet slingshot.
So what perturbs the Oort Cloud? Theories abound, including the existence of one or more really large objects too far away to be seen.
The Earth has seen a series of mass extinctions in the course of its 4.5 billion years existence, thought to be caused by uncomfortably large comets smashing onto the surface. Something may be out there throwing stuff at us.
It turns out, looking at our own galaxy, more than half the stars seem to be part of a binary, trinary or quaternary system. Essentially more than one star orbiting each other. A solo star is more of the exception than the norm. Could we have a sister star?
You can’t make this stuff up.
Maybe something big is out there. Maybe it and our sun orbit each other over millions of years. Does the sun have a companion out there somewhere? Could there be a brown dwarf, too dim for us to see, disturbing the Oort Cloud?
These are real questions astronomers are asking themselves. Although you wouldn’t be able to see it in visible light, such a body would still emit enough heat to be detectable in the infrared spectrum.
Alas, no nemesis dwarf star has been found to date.
That leaves us with another planetary size object that could be flinging comets toward us. We still don’t know.
But something does seem to dislodge stuff thought to be floating in the Oort Cloud and send them on a wildly oliptical orbit around the sun.
They have a wild ride.