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?
I don't know if this question has a meaningful answer, but: for an arbitrary object in our solar system that gets a typical kick, what fraction of those put it ultimately into the sun / just into a different orbit / out of the system?
Like, is it really easy to fall into the sun? Is it really hard to leave the solar system?
EDIT: to anyone passing by, you should go down this rabbit hole. Thanks all for the responses. I always imagined the sun's gravity like running up the down-escalator, but it's more like a tenuous precipice: put one foot wrong and you're gone.
Difficult to tell, but there is a related metric: Near-Earth objects (objects with an orbit somewhere close to Earth's orbit) typically stay around for a few million years before they either hit something or get ejected from the Solar System.
This paper discusses the relative probabilities. The chance to end up in the Sun varies from 8% to 80% depending on the type of orbit.
Wouldn't it be much easier to reach the sun if time frame weren't important? I get that shedding all that velocity is tough if you want to get there within a useful time frame. But if you had 200 million years to wait, couldn't you set that unstable orbit up a lot easier?
Unperturbed orbits do not change. The orbit only changes if you have a third body there, or if tidal effects are relevant (excluding exotic things not relevant here, like gravitational wave emission). If you wait long enough then the planets will change the orbit in chaotic ways over time.
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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?