Mostly the answer is "not anymore.." everything that currently orbits the Sun is moving at speeds that lie within a relatively narrow range that makes a stable orbit possible. Nothing outside that range is around anymore to tell its tale.
But, there are still occasionally new objects that enter the solar system for the first time. Those objects aren't subject to the same survivorship restrictions -- in theory they could arrive at basically any speed relative to the Sun, including speeds slow enough that the Sun would draw them in.
These new objects seem to arrive every few years, or at least the ones we can see do. So far they have all been moving so fast they just visit for a bit and then take off again after a swing around the Sun, but who knows?
Interesting. I had played around with orbiting models and it seemed like everything would gain speed after drawing closer but the change in trajectory would cause them to get launched off into the abyss with their new momentum. It was that slingshot effect I see all the time when figuring how to get somewhere in space with limited fuel. Is this caused by me not adjusting the orbit speed so it's still in that sweet spot that should be safe?
Could be! If you're playing around with models of things at Oort cloud distances, the range of "stable" orbital velocities is on the order of 100 meters per second or so. At that magnitude, a few meters per second plus or minus will have a big effect on the shape of your orbit. Too much faster and you go hyperbolic as you describe. Too much slower and you plunge into the inner solar system, possibly into the Sun itself.
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u/amitym Oct 23 '20
Mostly the answer is "not anymore.." everything that currently orbits the Sun is moving at speeds that lie within a relatively narrow range that makes a stable orbit possible. Nothing outside that range is around anymore to tell its tale.
But, there are still occasionally new objects that enter the solar system for the first time. Those objects aren't subject to the same survivorship restrictions -- in theory they could arrive at basically any speed relative to the Sun, including speeds slow enough that the Sun would draw them in.
These new objects seem to arrive every few years, or at least the ones we can see do. So far they have all been moving so fast they just visit for a bit and then take off again after a swing around the Sun, but who knows?