# How far could material from Earth or Mars be transported due to asteroid impact?

NASA has issued reports to the effect that small bits of Mars have come to Earth due to asteroid impacts - asteroid hits Mars, chunks are ejected into space far enough to eventually fall into Earth's gravity well. The reverse is also plausible - material from Earth could have been transported to Mars the same way.

That said, my question is: how far could such transport reach through the solar system? Could material ejected from an early Earth have made it as far out as Jupiter? What about material from Mars?

## 2 Answers

It is possible for dust and debris to travel basically anywhere in the solar system, given lots and lots of time.

The first major hurdle to this travel is that the impact needs to accelerate the debris to a speed higher than the planets escape velocity. In the case of Mars, that's a speed of about 5km/s. Any debris traveling under this speed will eventually fall back down and land on Mars. Anything higher will drift off into interplanetary space.

Once in interplanetary space, there is a set of pathways known as The Interplanetary Transport Network, which are very low-energy routes between bodies in the solar system. With a small bit more speed than the escape velocity it is possible for the debris to enter a path in this network, and eventually arrive at some other planet in the solar system. The only cost is time; it can take millions or billions of years on some routes.

In an even bigger collision, and in some gravitational slingshot scenarios, the debris can reach the sun escape velocity, and head off into interstellar space.

There is no limit in either direction.

Kim has shown that matter can leave the solar system.

In the opposite direction, towards inner planets, it's a matter of angular momentum with respect to the Sun. Since objects move slower the farther out they are, it's easier for them to lose all their momentum in a collision. Then the Sun's gravity pulls them inwards nearly radially. It's slow, but given enough time, such an object crosses all inner planet's orbits and hits the Sun. If it didn't collide with another body. (This assumes the original body was close to the ecliptic plane and the collision didn't change that too drastically.)

In other words, there are no conservation laws that prohibit rocks from leaving or entering the Solar System as far as they like. Those laws only restrict the time frame and the velocity.

This opens up the (slim) possibility that we might find some Pluto/Sedna/Quaoar debris on Antarctica :-)

• Collisions of this nature are very likely to change the orbital plane. Why wouldn't it? There are no forces to constrain collision debris to a particular direction. Sep 28, 2016 at 10:14
• Also, it is incorrect to say that it is easier for objects to lose all their momemtum in a collision. It just depends on which angle they are hit at. If they are hit from behind, they will accelerate and move to a further out orbit, if they are hit from the prograde direction they will slow down, and move to a smaller orbit closer to the sun. In fact, it is only the FAR side of the orbit which will be lowered towards the sun, making the orbit more elliptical. It is not conceivable that the object can be STOPPED, so it falls straight down and hits the sun. Sep 28, 2016 at 10:36
• @Innovine My description is imprecise, sorry. What I meant to convey was that in a collison not the whole body would be stopped, but that it is likely that some of the zillions of debris rocks, each with its own random momentum, there could be some with near zero momentum.
– Jens
Sep 28, 2016 at 11:35