This is a two part question… the first part is probably very answerable to anyone who knows a bit about science (not me), whereas the second is plain stupid… but where better to ask than here?
Ok, lets say I’m on top of a 1000 foot skyscraper (or hovering up there… I’m a God or something) and in each hand is a marble.
Marble A is like any generic marble, but marble B weighs the same as the earth, or even two earths, yes lets go with that… all contained in that little ball.
If I dropped both at the same time… do they both behave as if I dropped any two marbles of differing weights, or does the fact one of them is ridiculously heavy alter anything like speed, acceleration, terminal velocity etc compared to the normal one?
The second question is simply; what would happen when marble B hits the ground?
Would its sheer weight cause the marble to penetrate through the ground like a bullet through wet paper, leaving only a marble shaped hole?
Would that weight cause a catastrophic amount of damage to the surrounding area?
How far would that marble travel? Would it go through the core? Would it come out the other side? If so how far would it then travel… upwards? Would it be subject to the laws of gravity… I have no idea how this works…
Would it even knock the earth out of its orbit or cause the extinction of all life…
Help me out here please… my brain can’t fathom the logic.
with a marble that size you cannot simply ignore the gravity generated by the object you are “dropping”.
In simple terms, marble A would “drop” sideways to the surface of marble B then marble B and the earth would move toward each other by an amount relative to their sizes.
My intuition suggests an acceleration greater than that of a regular item dropped from, say, The leaning tower of Pisa, but intuition is sometimes not a great guide in these situations.
Someone better at the physics will be along shortly to do the maths.
With out doing math and physics, i’d say if you drop marble B, you better be god, because the building you are standing on is about to not be there any more.
marble A we can just forget about entirely, in a few seconds it will be of 0 importance.
If marble B weighs in at 2 earths, and is marble sized, marble B has an insane gravitational field, may as well rephrase to what if i took a black hole disguised as a marble and threw it at the earth.
I am also assuming that because you are God, you are preventing marble B from already wrecking the place by holding it in your all powerful hand, somehow shielding earth from its already lethal by being that close nastiness?
Marble B is not very far off being a black hole. Let’s say your god-like grip is preventing it from influencing the surrounding matter until you let go. The moment you do anything within a 1 km radius is going to accelerate towards it at several million meters per second squared, including the crust of the earth. Anything within a 10 km radius, hundreds of thousands of meters per second squared. Anything within a 100 km radius, a few thousand meters per second squared. Only at distances well above 1000 km do we even need to bother with acknowledging there’s another Earth’s gravity in the equation.
What naita said. Basically, marble B will rip up the Earth, and probably form the core of a new planet made up of marble B plus the matter that used to make up the original Earth.
I calculated the potential energy of the set up*, 2 Earth mass marble, etc. and if I’ve done several conversions, etc., right I get about 10[sup]19[/sup] Hiroshima bombs of energy. Or the total output of the Sun over about a year.
Not all of which gets converted into kinetic energy, but still, better bring sunscreen.
The “1000 ft” height doesn’t make any difference. It’s center of mass to center of mass and the radius of the Earth swamps that in a situation like this.
Anyway, I kind of predicted people would raise the gravity issue and other such problems a marble with that density would immediately create… but I’m more interested in the actual weight of the marble and what would happen to the earth when they collide, in terms of actual solid object vs solid object.
How about, if in my God like powers, I turned off the marble’s gravitational field, so it was just a heavy ass marble?
Or to think about it another way…
Scaling it down a bit, if I gave the marble the weight of say, Mount Everest - I imagine that would cause quite the impact when dropped from 1000ft…
So using that same way of thinking about the questions, ignoring gravitational and other such things that get in the way of such stupidity… scale it up to 2 earth weights…
In laymen terms, what would happen to the ground at moment of impact?
I came up with this question when I was a little boy, hence the silliness.
At the density of that marble, the “solidness” of the Earth would be difficult to distinguish from a hard vacuum, and the marble would slip through solid rock straight to the core of the Earth easier than a lightsaber through butter.
I don’t know what speed it would reach (but the math is fairly simple, someone else’ll probably do it) but it would whip through the core of the Earth and out the other side, rising until it reaches zero velocity, where it will fall back through the Earth again. Repeat however many thousands of times it takes for the minuscule effect of friction to slow the marble until it settles in the core, then this will happen.
(You might want to give this a try, though I can’t vouch much for it because I haven’t read it since it was originally published in the 1980s and it probably has been visited by the suck fairy.)
Okay, I missed this part the first time. This makes no sense. You are saying “what if object x has property y, but you disable property y.” It is like saying, oh (thinking of an an analogy) how hot would eating a 2 million Scoville pepper feel if you removed all the capsicum? If you turned off a marble’s gravitational field then it is by definition no longer heavy-ass. (And, since those two Earth masses were no longer being held in place, the whole thing would explode in a flash that would be detectable many millions of light years away.)
Okay, then if you don’t want to use real world logic at any stage, then the question lacks any meaning at all. Using fantasy logic at every stage, when the marble hits the ground it will turn into a mountain-sized purple hamster that sings My Way in a perfect initiation of Frank Sinatra.
I confess this confuses me, too. I’m no great physicist, but my understanding is that gravity involves a mutual attraction. If some amount of mass is not affected by gravity, then it’s just a big (or little) floaty thing. If you’ve got some idea about unidirectional gravity, that’s gotta be explained before the question can be answered.
The marble has inertial mass of two planets, but the gravitational mass of a marble: half an ounce or so.
It can’t happen, but the answer is pretty obvious once you decree that it has happened. The question isn’t nonsensical, conceptually, just impossible, pragmatically.
It’s a little like asking, what if a spaceship could go faster than the speed of light? There are lots of very clear answers. (One of them entails time travel paradoxes!)
You can not with your God like powers turn off the gravity, unless you want to interject divine intervention into the equation, to which the answer is, You are God, what ever you wish to happen will
Mt Everest?
Easy, now you have made an asteroid impact that avoids the whole decel and heat on hitting the atmosphere thing.
I dont know how to avoid the gravitational thing, it’s the natural way of things
But if i try and pretend the object lacks it’s own gravitational field, at least lacks one that equates to it’s mass, you still have a horrendous impact, the kinetic energy of earthX2 falling from 1k feet is still there.
And said marble is not going to give way because all that mass is condensed to the size of a marble, and here is where i cant pretend the gravity of the thing, and the intense pressures, and all the energy that is crushed down into that little size exists, but i’m no physicist.
See here is the problem i am seeing.
If this object has no gravitational field of it’s own, once you take your God Hand off of it, the is no rule in the universe to convince that mass to remain in that compressed state, and it is going to explode, and earthX2 expanding from marble size to earthX2 size, with no nuclear reactions what so ever, just pure kinetic explosion, is going to be absolutely devastating.
If you manage by divine intervention to have it hit earth before that happens, well imagine making a mud ball, then taking a basketball, deflating it and smashing it to the size of a BB, then poking it into the mud ball, then instantaneously re-inflating it to basketball size.
You can not fall to divine intervention for all aspects of this, or the answer again is going to become “What does God wish to happen?”
At some point you have to take your finger off of things, and then the laws you as God used to make everything are going to resume.
