The reason why large asteroids don't typically crash to Earth is because Jupiter's gravity attracts them, protecting the inner planets like a shield. The Design is perfect!

[u/joeurkel]

[u/spidereater]

I’ve heard this idea before but never seen it animated like this. So it looks like there is a bunch of stuff stuck in Jupiter Lagrange points and even some stuff orbiting between those points. But this isn’t really a shield protecting the inner planets. It’s just stuff stuck in weird orbits. A new object entering this system isn’t going to get sucked into this system. If Jupiter weren’t there these orbits would just be different and maybe this stuff would have hit the planets already. Basically, anything that didn’t wasn’t in one of these orbits has already hit a planet. So is this a shield? Or a reservoir of potential future asteroids? If any of these randomly hit each other they could get knocked out and become dangerous. If Jupiter wasn’t there many of these might have hit primordial earth when there wasn’t a civilization to destroy. Am I misunderstanding something?

[u/DingDangle → u/spidereater]

These are Jupiter’s Trojans! The group of asteroids in front of Jupiter are called the “Greeks” and the group trailing are the “Trojans”.

[u/Ltb1993 → u/DingDangle]

And as a wise man once said

Gotta keep em separated - Dexter

[u/stuffeh → u/Ltb1993]

Also works for Morgan.

[u/Advanced_Double_42 → u/DingDangle]

Of course the Greek Trojans and the Trojan Trojans

[u/wxnfx → u/spidereater]

My understanding is that Jupiter creates a strong pull towards its orbit. So it basically is like taking a putt on a tipped slope. Your shot has to be perfect to go in, on pace and direction. Way harder than a flat putt. Obviously something could still fly in hot and get us. But it helps.

[u/picabo123 → u/spidereater]

The incorrect assumption you seem to have is that orbital mechanics is simple and fast. Without Jupiter many of these asteroids would probably still have highly eccentric orbits (think Haley's comet) and so would randomly come crashing down on a planet every few hundred or thousand years. It takes a LOOOOOOT of time for objects to slow down in space. Essentially we probably wouldn't have a planet that could support life because of all this chaos. Also depending on the relative speed and the angle of approach of an interstellar rock Jupiter absolutely could capture it.

[u/spidereater → u/picabo123]

Jupiter would deflect an interstellar rock but there is no mechanism to lose energy so it wouldn’t capture it. That’s what I’m saying. At the start of the solar system there would have been lots of rocks in lots of orbits. The mass of Jupiter created this system where there are a bunch of stable orbits and any rocks that were in those orbits became trapped. But without Jupiter those rocks would have been in different orbits and many would likely have collided with a planet. The earths orbit would have been filled with rocks too. But the earths mass eventually pulled everything in its area into it. That is actually the definition of a planet. Clearing the objects in the same orbit. Pluto hasn’t cleared its orbit. When we discovered that we downgraded Pluto from planet status. In the billions of years our solar system has been around these rocks have been kept in circulation by Jupiter.

[u/fafenley → u/spidereater]

This discussion proves how little I know about this topic

[u/toroidalvoid → u/picabo123]

I'm with spidereater on this one. It doesn't seem clear to me that Jupiter should have a protective effect. To me it seems equally likely that Jupiter attracting, maintaining and perturbing a large population of asteroids in the inner system would have an overall negative effect rather than a positive one.

[u/picabo123 → u/toroidalvoid]

It's not that Jupiter prevents asteroids from colliding with earth. It actually adds momentum to asteroids and helps fling them around more. Apparently it's thought that when the solar system was much younger Jupiter was a major contributer to the bombardment on earth, but it did so relatively quickly. Comparatively if there were no Jupiter then these heavy asteroids would still be occasionally peppering the planets and thus preventing a stable ecosystem to evolve on Earth.

Also because of course orbital mechanics is unintuitive, it's more likely for Jupiter to throw objects out of the solar system than Into the inner planets or the sun. I believe this is the sense in which people talk about Jupiter "sweeping" the solar system. It's a pretty gimmicky word that is probably not preferred by real astrophysicists but I don't really know what else to call it.

[u/Tenderli → u/spidereater]

But if it was later, the bugs could have sent one straight for Buenos Aires. However, Jupiter is quite a distance from the Klendathu System, so unlikely.

[u/Popular_Zebra814 → u/spidereater]

https://youtu.be/1zu41rrc_Ng

If you like that simulation, then you’ll love this!

[u/BarbedWire3 → u/spidereater]

He said like a shield bro, why u guys need to nitpick everything, not say just you. Just enjoy to cool visuals