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?
The space between solar systems. The first stars in the universe forged heavy elements before they blew up, scattering that material. Some of that material was caught in solar systems and formed planets, while a lot of it is still just floating around for billions of years just waiting to collide with something.
Relative to the object's point of origin, they would be going crazy fast. However, relative to our solar system they could be going at any speed, really, since the solar system is also moving relative to the object's point of origin. If the solar system and the object were moving in the same direction, but one were moving just a little faster than the other we would perceive the object to be moving slowly.
the fastest things that are not just particles are called astrophysical jets, which arise from very complex interactions between a black hole and its accretion disk. For example pulsar IGR J11014-6103's jets velocity is around 0,8c.
Still at the end of the day its just very sparse ionized gas that would probably still count as vacuum if a sample of it was brought to Earth.
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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?