The original statement is correct on a technicality, as Luna 15 wasn't really space junk before it impacted, seeing as it was supposed to land. That said, interesting article. Wasn't aware the...

The original statement is correct on a technicality, as Luna 15 wasn't really space junk before it impacted, seeing as it was supposed to land.

That said, interesting article. Wasn't aware the USSR was operating around the moon during Apollo 11.

Not that much actually. It was, by virtue of its mission, on an orbit that presumably intersected the moons orbit. Coplanarity isn't necessary, but the original trajectory is likely to be at least...

Exemplary

Not that much actually. It was, by virtue of its mission, on an orbit that presumably intersected the moons orbit. Coplanarity isn't necessary, but the original trajectory is likely to be at least somewhat close to the moon's plane. Meanwhile, it is absolutely certain that the lowest point of the rocket's orbit is within the moon's orbit and the highest point is outside the moon's orbit. Which means: This rocket crosses the moon's path once every [insert orbital period here, probably something on the order of 15 to 60 days]. It is in all likelihood not synchronized with the moon, which means the moon is going to be in a different part of its orbit every time they cross paths. [Different from the previous time they crossed paths; not "always different from the place where the rocket is.] So with that, every 15-60 days you're rolling the dice twice (there and back again) on whether the moon is there. After 5 years and something like 60-240 rolls of the dice, you're bound to get a collision eventually.

Consider also that the moon has a width of half a degree of its orbit. I.e. you could only fit 720 moons into the orbit edge-to-edge, and even without the gravity you'd expect a collision probability of 2/720 for every orbit. Gravity just makes it worse "because it makes the moon bigger".

If you want to test it out, download Kerbal Space Program, the layman's intro to orbital mechanics. Build a rocket that takes you beyond the mun such that it is coplanar with the mun. Leave it in that orbit: No inclination, Periapsis of < 100km, Apoapsis of [somewhere behind the mun]. See how many cycles it lives; Observe also that there's a high degree of randomness to the relative position to the mun when you do intersect its orbit. If you wanna go the extra mile, observe what happens when you have a close encounter with gravitational influence: What happens to your probability of collision?

Well, now I wrote all that and saw the other sub-thread. Oh well, maybe someone else finds this interesting. Get well soon. Ü

If this space junk has been in orbit for seven years, it seems likely to me that the gravitational pull of the moon is why it's colliding now, not because it's being randomly tossed in a direction...

If this space junk has been in orbit for seven years, it seems likely to me that the gravitational pull of the moon is why it's colliding now, not because it's being randomly tossed in a direction that happens to be the moon.

Shame on me, I will confess I didn't actually read the article and took "out-of-control SpaceX rocket" to be a newly launched rocket. That makes way more sense. In my defense I do have COVID and...

Shame on me, I will confess I didn't actually read the article and took "out-of-control SpaceX rocket" to be a newly launched rocket. That makes way more sense.

In my defense I do have COVID and am struggling just to exist today.

The original statement is correct on a technicality, as Luna 15 wasn't really space junk

beforeit impacted, seeing as it was supposed to land.That said, interesting article. Wasn't aware the USSR was operating around the moon during Apollo 11.

The USSR had actually launched a lunar impactor all the way back in 1959.

I knew about those. Actually an interesting science experiment, even though it just sounds like a weird cold-war era flex at first.

Update: Space junk piece set to hit the moon is likely from a Chinese rocket, not SpaceX

The probability of hitting the moon given all possible trajectories has to be astronomically small, correct?

Not that much actually. It was, by virtue of its mission, on an orbit that presumably intersected the moons orbit. Coplanarity isn't necessary, but the original trajectory is likely to be at least somewhat close to the moon's plane. Meanwhile, it is absolutely certain that the lowest point of the rocket's orbit is within the moon's orbit and the highest point is outside the moon's orbit. Which means: This rocket crosses the moon's path once every [insert orbital period here, probably something on the order of 15 to 60 days]. It is in all likelihood

notsynchronized with the moon, which means the moon is going to be in a different part of its orbit every time they cross paths. [Different from the previous time they crossed paths; not "always different from the place where the rocket is.] So with that, every 15-60 days you're rolling the dice twice (there and back again) on whether the moon is there. After 5 years and something like 60-240 rolls of the dice, you're bound to get a collision eventually.Consider also that the moon has a width of half a degree of its orbit. I.e. you could only fit 720 moons into the orbit edge-to-edge, and even without the gravity you'd expect a collision probability of 2/720 for every orbit. Gravity just makes it worse "because it makes the moon bigger".

If you want to test it out, download Kerbal Space Program, the layman's intro to orbital mechanics. Build a rocket that takes you beyond the mun such that it is coplanar with the mun. Leave it in that orbit: No inclination, Periapsis of < 100km, Apoapsis of [somewhere behind the mun]. See how many cycles it lives; Observe also that there's a high degree of randomness to the relative position to the mun when you do intersect its orbit. If you wanna go the extra mile, observe what happens when you have a close encounter with gravitational influence: What happens to your probability of collision?

Well, now I wrote all that and saw the other sub-thread. Oh well, maybe someone else finds this interesting. Get well soon. Ü

If this space junk has been in orbit for seven years, it seems likely to me that the gravitational pull of the moon is why it's colliding now, not because it's being randomly tossed in a direction that happens to be the moon.

Shame on me, I will confess I didn't actually read the article and took "out-of-control SpaceX rocket" to be a newly launched rocket. That makes way more sense.

In my defense I do have COVID and am struggling just to exist today.

Hope you feel better soon!

Thanks :)