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Peat02 t1_jdo3zaz wrote

Reply to comment by sithelephant in [NASA on Twitter] Newly-discovered asteroid 2023 DZ2 will pass Earth more than 100,000 miles (161,000 km) away–about half the distance to the Moon–making its close approach at 3:51 p.m. EDT (12:51 p.m. PDT) by ICumCoffee

Wouldn't this be based on the volume of the lunar diameter sphere and the percentage that the earth makes up of that volume rather than the diameter?

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za419 t1_jdo52fp wrote

We'd have to do some orbital mechanics on this one. Most things in the solar system are roughly coplanar on the ecliptic, so the real shape is probably a section of the sphere a few degrees wide.

Or we could probably just guess and multiply the space available by a substantial number, because even that section is going to be pretty tall compared to the Earth. Space is big.

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Monnok t1_jdodiq3 wrote

Your Earth-volume : lunar-orbit-volume ratio works for the likelihood of finding the asteroid inside or outside of the Earth at any given moment.

But we can assume the object has an entire path of moments passing straight through on [basically] a line. An asteroid “looking ahead” directly at the round perimeter of the Earth might briefly occupy some point “in front” of the Earth before collision… but that’s still a collision path. And it’s never gonna get to any points on the other side. What it “sees” just is a flat disc in a flat disc. It’s either heading through the empty part or not.

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