3 ms·

Interesting. I'd not considered the loss of mass as a means of propulsion. Obviously there was the kinetic energy transfer but the impact ejacted some of the

by prism56 7mo ago

Interesting. I'd not considered the loss of mass as a means of propulsion. Obviously there was the kinetic energy transfer but the impact ejacted some of the asteroids mass opposite to it's trajectory further increasing it's trajectory change. Cool demonstration, hopefully not needed one day.

messe 7mo ago
That's how rockets work.
- prism56 7mo ago
  Yeah, I sort of meant in the context of an object losing its mass, it's seldom used on earth as the effects are small but on the timescale/distance/speeds of an asteroid it could have noticeable effects. Rockets are using mass loss but there's more going on with the rapidly expanding gas causing the increased impulse.
  - fc417fc802 7mo ago
    Rockets are able to optimize due to dealing with a gas. It's still just pushing off of a disconnected mass. You go one way the lost mass goes the other. If you think about it that's how a cannon works. The projectile gets pushed forwards and the barrel gets pushed in the opposite direction. Some of the larger ones can push their launcher back quite a bit more than you might expect. My point is that this is actually a common failure of intuition. We tend to think of larger objects on earth as fixed and in our day to day life on dry land they often are (at least more or less) due to static friction. A slightly more interesting observation (I think) is that if the bodies don't achieve escape velocity relative to one another then the forces all cancel out in the end. It just might take an arbitrarily long time in the case of similarly sized masses.
alhirzel 7mo ago
It's the butterfly effect. After the momentum exchange (the rocket slamming, stuff being ejected in the impact, etc), the entire system was left with different properties. From now on, the equation F=Gm1m2/r^2 will have a different m1, and you can sum the equation over all m2 (literally every other massive object in the universe).
dylan604 7mo ago
When the impact happened the news articles seemed to imply some surprise about that as well which seemed strange to me. I just wrote it off to the journalist just not being up to speed on the subject matter. The size of the debris field trailing also seemed to be a surprising result.

by prism56 7mo ago

messe 7mo ago

That's how rockets work.

prism56 7mo ago
Yeah, I sort of meant in the context of an object losing its mass, it's seldom used on earth as the effects are small but on the timescale/distance/speeds of an asteroid it could have noticeable effects. Rockets are using mass loss but there's more going on with the rapidly expanding gas causing the increased impulse.
- fc417fc802 7mo ago
  Rockets are able to optimize due to dealing with a gas. It's still just pushing off of a disconnected mass. You go one way the lost mass goes the other. If you think about it that's how a cannon works. The projectile gets pushed forwards and the barrel gets pushed in the opposite direction. Some of the larger ones can push their launcher back quite a bit more than you might expect. My point is that this is actually a common failure of intuition. We tend to think of larger objects on earth as fixed and in our day to day life on dry land they often are (at least more or less) due to static friction. A slightly more interesting observation (I think) is that if the bodies don't achieve escape velocity relative to one another then the forces all cancel out in the end. It just might take an arbitrarily long time in the case of similarly sized masses.

alhirzel 7mo ago

It's the butterfly effect. After the momentum exchange (the rocket slamming, stuff being ejected in the impact, etc), the entire system was left with different properties. From now on, the equation F=Gm1m2/r^2 will have a different m1, and you can sum the equation over all m2 (literally every other massive object in the universe).

dylan604 7mo ago

When the impact happened the news articles seemed to imply some surprise about that as well which seemed strange to me. I just wrote it off to the journalist just not being up to speed on the subject matter. The size of the debris field trailing also seemed to be a surprising result.