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EndoExo t1_jefyxhm wrote

Reply to comment by kuahara in TIL: About Earth trojans. Two asteroids that share our orbit, leading us around the sun. by RevolutionaryAd94

If they're in our orbit and orbiting the sun at the same rate, there's no chance of them hitting us. We keep the same distance apart at all times. It's asteroids crossing our orbit that have a chance to hit us.

But it's not actually in the exact same orbit. It moves around a Lagrange point where the Earth-Sun gravity interaction creates a stable zone to hang out with us while we move around the Sun.

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Bruce-7891 t1_jeg1tvy wrote

This makes more sense. Doesn't the speed of the orbit and mass of the object have to be a certain ratio for it not to get sucked into the star or ejected into space? It would have to be a planet sized asteroid. The title is a little misleading.

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EndoExo t1_jeg6a2v wrote

They're not planet-sized. Wiki says one is about 300m and another 1.2km. Everything in an orbit is traveling the necessary speed for that orbit, otherwise it wouldn't be an orbit. In most cases, an object in the same orbit around the Sun as Earth would eventually be pulled into a different orbit by Earth's gravity, but these asteroids are moving around a Lagrange point where the gravity of the Earth and the Sun kinda cancel out for orbital purposes.

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