Is There a Nemesis in the Solar System?

Earth could get tossed out of our solar system into the galaxy itself without a star. Or we could get hit by a comet that gets perturbed by a passing so how close do we need to come to another star for it to be sort of dangerous? We don't really know, but there's actually a lot of really interesting theories that suggest that there might be another star out there which swoops around near our sun and rains down comets on us. People look back at the history of cometary impacts on earth, and they think they might see like a pattern, like a 30 million years cycle. Maybe that's how we got our water. It was one of these comet showers at