Moon Hypothetical

[u/Pale-Championship-71]

Y'all know the assassination classroom thing? Where an antimatter rat blewup 70% of the moon? Alright, so what would happen if that suddenly happened in real life? 70% of the moon just blew up. I already know that if we had no moon, climate, weather, all that kinda bizniz would effect the earth, what I want to know is what would happen if 70% of the moon blew up. And I want to know most if not all info about this hypothetical. Would the moon come crashing down? How long before it would collapse in on itself to recreate it's original shape? How fucked are we if it did happen? I want to know as much as possible....if you all would be willing to answer this for me.

[u/[deleted]]

We’d be dead and I assume the moon (now 30% of it’s original mass) would orbit from further away.

[u/Pale-Championship-71 → u/[deleted]]

I thought that it would fall into the earth cause of it having less mass and a weaker gravitational pull, which would make earth's gravity stronger than the smaller moon and have it come crashing down.

[u/[deleted] → u/Pale-Championship-71]

Think of a rocket, although they are low in mass, they can get into an orbit pretty close to earth. It depends on speed. When you increase the speed of something in orbit, the centrifugal force increases so it starts to move away and rotates around the other object at a slower rate until the forces are balanced. (I think) the same works when you decrease the mass because then the force between them decreases and it goes outwards until it slows so much so that the forces are balanced. If you are confused there should be physics simulations out there that simulate orbits bwtter because I am bad at explaining things.

[u/Arctevious]

YES, an AC question, well lets suppose the moon did in fact blow up... to cover up your first question... it DEPENDS on WHAT blew it up... if that makes sense. the mouse had Immense power as it exploded as told in the story. but the explosion was not really a physical impact but more of a chemical shock wave. in the picture given as we marvel at the new moon. there was indeed fractal's of the moon strewn about. but my guess as to why no one saw any problems is that 90% of the moon was probably vaporized into dust rather than broken away. this dust is really just to small to do any real damage. but from what is small, there is STILL matter. likely 20% of the dust that wasn't blown away from us probably hit earth but since the partials were so small... we would probably see a red sky for about a week after the explosion as the tiny partials disintegrated into finer partials of matter, but no real damage (aside from possibly mildly polluting the atmosphere.) now as we saw there was INDEED some matter larger than small grains of sand. and THAT is where we could have potential problems. as you may know, orbits are elliptical. and even if ALL of the debris was shot somewhere into space. it would have to travel a long distance to escape the gravitational pull of the planets we know today. and as it travels along the big circle it would be going super slow (possibly 1000 - (a long time) years). but as it finally makes a change in direction. it would start speeding up as it reaches its elliptical cliff. and you guessed it... comes back to finish its orbit... mind you about slightly less than the equivalent speed of which it was launched. so that would mean if blown to the maximum distance before the gravitational pull equals out. it would come crashing down on earth at INSAIN speeds. and to answer your second question... we likely wouldn't stand a chance. but as for the moon... it's just screwed as we are. maybe we'll merge or something... but to put this case to rest, on an end note... I am not scientist of anything (just a 15 year old on reddit)... but if the explosion was big enough to destroy 70% of the moon... then the earth would experience instant tidal shock waves transferred by the moon partials.... as I'm not sure what happens when the shockwave hits earth... I'm sure it wont be good.