What I have always ran through my head in scientific terms is, what would happen if in just one split second, the moon disappeared? Think about that one for a minute. The catastophe's that would follow on a planetary scale would be awesome.
What if for one split second the moon disappeared?
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Cogman
Lifer
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for a split second, the catastrophys would be about the size of a ripple in the ocean. Not much more. only if it where at night would anyone notice. if it dissapeared for longer, maybe a larger wave would be made. but I dont think that it would be mass world wide disasters.
I think he means "disappear and not come back", not "blink out of existence for a split-second". I'm not seeing where the catastrophic destruction comes from. Um, the oceans would pretty quickly slosh back to the midpoint between low and high tides... you might get wet if you're standing on a beach and it's low tide where you are. I suppose it could do things to destabilize the Earth's orbit if the center of mass of the Earth-Moon system suddenly changed, but that's a long-term concern, not a short-term one.
asm0deus
Golden Member
- Aug 18, 2003
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if moons could disappear spontaneously that would be quite a catastrophe already 
Obviously it would have to experience significant trauma to "disappear". Also the word disappear makes your query less profound because it could easily disappear and still have gravitational effects (it disappears everyday because of the earths rotation). It would have to do more than disappear, it would have to disintegrate or become significantly less massive to cause catastrophic effects.
Speaking of awesome catastrophe's isn't there a new movie called the day after tomorrow coming out soon with stuff like that.
Obviously it would have to experience significant trauma to "disappear". Also the word disappear makes your query less profound because it could easily disappear and still have gravitational effects (it disappears everyday because of the earths rotation). It would have to do more than disappear, it would have to disintegrate or become significantly less massive to cause catastrophic effects. Speaking of awesome catastrophe's isn't there a new movie called the day after tomorrow coming out soon with stuff like that.
There's just so much wrong with what sao123 said it's plain funny.
1) Currents, tides, and waves would continue due to gravitational pull from the sun. They wouldn't just suddenly stop. Basic physics dictates that they'd continue in motion for a while. And temperature differentials drive the currents as much as the currents affect temperature differentials.
2) The moon does not have a large gravitational field that steers asteriods into it instead of the earth. The earth's gravitational field is many times that of the moon. The earth protects the moon more than the moon protects the earth. Much more junk has hit the earth than has hit the moon -- it's just that erosion from weather and life has made evidence of impacts on the earth much less prominent than those on the moon.
3) The mass of the moon is not 25% of the mass of the earth. It's closer to 1.23% of the mass of the earth. It's somewhere around 0.0000004% of the mass of the sun. Its disappearance would do squat to the Sun or to the orbit of other planets.
Everything would probably go about the same after some settling of the oceans and earth's core.
1) Currents, tides, and waves would continue due to gravitational pull from the sun. They wouldn't just suddenly stop. Basic physics dictates that they'd continue in motion for a while. And temperature differentials drive the currents as much as the currents affect temperature differentials.
2) The moon does not have a large gravitational field that steers asteriods into it instead of the earth. The earth's gravitational field is many times that of the moon. The earth protects the moon more than the moon protects the earth. Much more junk has hit the earth than has hit the moon -- it's just that erosion from weather and life has made evidence of impacts on the earth much less prominent than those on the moon.
3) The mass of the moon is not 25% of the mass of the earth. It's closer to 1.23% of the mass of the earth. It's somewhere around 0.0000004% of the mass of the sun. Its disappearance would do squat to the Sun or to the orbit of other planets.
Everything would probably go about the same after some settling of the oceans and earth's core.
true. Also, for 1) don't forget that the coriollis effect and winds do much more for ocean currents than the moon. And for 2) earth's atmosphere, not the moon, is what shields us from impacts--most of them burn up before they reach the surface.
The primary effect if the moon disappeared, would be that poets would have to find something else to write about, and I would have to stop burying people in the sand in low tide then leaving them there....I mean....did I say that?
haha, it's still so wrong it's funny.
Gravity is affected by mass AND distance, the moon has significantly less mass than earth (<2%), but the radius is also much smaller, therefore gravitational effects are ~25% of what one experiences on earth. Look up the equations rather than making poorly founded assumptions (hint, it's the one with G, m1, m2 and r).
the moon has 1/6 of the gravity of earth AT THE MOON"S SURFACE. The earth has a significantly greater effect on other objects passing nearby than the moon does. Instead of the moon shielding the earth, the earth makes a great shield for the moon since it's not only larger, it's got a stronger gravity pull.
You managed to mention most of these principles haphazardly in your post, however you failed to apply them where appropriate.
Gravity is affected by mass AND distance, the moon has significantly less mass than earth (<2%), but the radius is also much smaller, therefore gravitational effects are ~25% of what one experiences on earth. Look up the equations rather than making poorly founded assumptions (hint, it's the one with G, m1, m2 and r).
the moon has 1/6 of the gravity of earth AT THE MOON"S SURFACE. The earth has a significantly greater effect on other objects passing nearby than the moon does. Instead of the moon shielding the earth, the earth makes a great shield for the moon since it's not only larger, it's got a stronger gravity pull.
You managed to mention most of these principles haphazardly in your post, however you failed to apply them where appropriate.
hahaha, that's right, real research on what would happen if the moon disappeared.
Like the great experiment of '63 where NASA moved the moon beyond the solar system and measured the effects:roll:
well I'm guessing the effects wouldn't be instant but isn't the moon that helps keep the earth geologically active? I mean isn't that why mars is dead now and earth is still active? mars has a moon but its much much smaller.
DrPizza
Administrator Elite Member Goat Whisperer
Uhh, who managed to get into Sao's account? I don't recall him making horrible mistakes like the ones above. Oh well, I suppose we all make them sooner or later... I know I've made my share.
Anyway... as far as the moon protecting us from asteroids, I'm not sure about that. It's obvious that the moon protects us from stuff coming at us that hits the back of the moon. However, wouldn't there be objects that would have *just* missed the earth but whose paths were deflected into the earth by the moons gravitational field? I'd love to see confirmation some place on this.
Also, while the tides certainly are caused by the moon's gravitational field, I think it's effects on the major currents in the ocean are very minor. (think about it... the tide comes in, the tide goes out, but the gulf stream keeps on going and going and going - it certainly doesn't reverse its path everytime the moon goes by (or rather the earth spins)
sao123
Lifer
- May 27, 2002
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Hi guys... (you are indeed correct Dr. Pizza) I see my former roomate has been using my account again while I was away with my new wife....too lazy to create his own maybe?? (note to change password)
Anyways, I remember having this discussion with CTHO9305 way way back, after all I am a computer science / math individual having little background in astro physics. my former roomate is a Astro - Metero - Geo Physics smacktard.
Heres what I know...Kevin is wrong...Scott is right.
The moon has 1/81 of the mass of the earth.
It stands to reason in my mind that tidal influence has little value towards deep see currents as those are primarily part of the earths heat pumping mechanism.
This theory of his seems to have some value, although not as severe (in my mind) as stated. I think it would take a planetary ejection of something the mass of saturn or uranus to cause such a destabilization. Which would "as a result" create the center rotation point of the solar system somewhere outside of the center of the sun, causing the enitre system to wobble and fall apart.
However, since the idea is correct that the earth moon system revolve around each other around some point within the earth, the moon suddenly disappearing could cause the earth to wobble causing a disruption in local weather and climactic patterns. After all...wouldnt an ejection of the moon move the point of revolution of the earth moon system outside of the earths surface? On a monthly basis, the earth would seem to move closer and further from the sun within its orbit? (think of 2 kids holding hands and spinning real fast then they let go and fly apart...they both wobble in a new orbit)
As far as the moon shielding earth from meteors, probably only by a sweeping monthly orbit. Catches anything in its path or orbit before it can get to earth...but I remember reading that that was jupiters roles in the solar system protecting the innter planets...not the moons (or if so...only on a much smaller scale)
Anyways, I remember having this discussion with CTHO9305 way way back, after all I am a computer science / math individual having little background in astro physics. my former roomate is a Astro - Metero - Geo Physics smacktard.
Heres what I know...Kevin is wrong...Scott is right.
The moon has 1/81 of the mass of the earth.
It stands to reason in my mind that tidal influence has little value towards deep see currents as those are primarily part of the earths heat pumping mechanism.
This theory of his seems to have some value, although not as severe (in my mind) as stated. I think it would take a planetary ejection of something the mass of saturn or uranus to cause such a destabilization. Which would "as a result" create the center rotation point of the solar system somewhere outside of the center of the sun, causing the enitre system to wobble and fall apart.
However, since the idea is correct that the earth moon system revolve around each other around some point within the earth, the moon suddenly disappearing could cause the earth to wobble causing a disruption in local weather and climactic patterns. After all...wouldnt an ejection of the moon move the point of revolution of the earth moon system outside of the earths surface? On a monthly basis, the earth would seem to move closer and further from the sun within its orbit? (think of 2 kids holding hands and spinning real fast then they let go and fly apart...they both wobble in a new orbit)
As far as the moon shielding earth from meteors, probably only by a sweeping monthly orbit. Catches anything in its path or orbit before it can get to earth...but I remember reading that that was jupiters roles in the solar system protecting the innter planets...not the moons (or if so...only on a much smaller scale)
What is it do you suppose that keeps the earth in such a stable rotation? Granted the earth "swings" to and fro on it's 21.5 degree axis but if there were no moon to keep her stable the earth instead of spinning like a well balanced top it would imediately begin to spin just a toy top that looses speed and starts to wobble uncontrolably. Ifthe moon just flat disappeared the seasons would be no more, there would be climatic changes that would make Global Warming look like bambi and in a quite a short amount of time humanity would be extinct.
i mean if it were to dissapear completely, not just for a microsecond then reappear. definitely be some major tidal waves happening there. quite possibly some earthquakes too as the sudden change in gravity would cause some major shifting in solid ground too. prolly enough to release some stress along faultlines.
dont know about the moon keeping the earth stable tho. i'd say the earth is wobbling BECAUSE of the moon, not in spite of it. mind u, if it were mid wobble and the force that caused that wobble were to dissapear, the momentum of that wobble could indeed continue in it's direction at that moment and turn the world upside down or something. dont know how that woudl effect life on earth tho. our day/night schedule woudl change but i dont know how much. interesting point in any case.
i mean if it were to dissapear completely, not just for a microsecond then reappear. definitely be some major tidal waves happening there. quite possibly some earthquakes too as the sudden change in gravity would cause some major shifting in solid ground too. prolly enough to release some stress along faultlines.
dont know about the moon keeping the earth stable tho. i'd say the earth is wobbling BECAUSE of the moon, not in spite of it. mind u, if it were mid wobble and the force that caused that wobble were to dissapear, the momentum of that wobble could indeed continue in it's direction at that moment and turn the world upside down or something. dont know how that woudl effect life on earth tho. our day/night schedule woudl change but i dont know how much. interesting point in any case.
sao123
Lifer
- May 27, 2002
- 12,653
- 205
- 106
(password changed...)
Now back to business...
To the above poster who mentioned volcanic activity....
Might you be suggesting that the moon creates tidal currents within the liquid rock of the earths magma similar to that experienced in the oceans?? interesting. Could this be a cause for volcanic activity(prediction assistance)...
Could this also be a major factor in plate tectonics movement?? the plates are known to float, but i dont know if its known why they move...if the underlying magma rock is experiencing tidal currents frequently...2x per day like the oceans, this could help explain the 2 inches per year the plates move...
Thoughts please??
Now back to business...
To the above poster who mentioned volcanic activity....
Might you be suggesting that the moon creates tidal currents within the liquid rock of the earths magma similar to that experienced in the oceans?? interesting. Could this be a cause for volcanic activity(prediction assistance)...
Could this also be a major factor in plate tectonics movement?? the plates are known to float, but i dont know if its known why they move...if the underlying magma rock is experiencing tidal currents frequently...2x per day like the oceans, this could help explain the 2 inches per year the plates move...
Thoughts please??
Well for one thing I imagine everybody on it would be really afraid of whoever had the big weapon.
you know, come to think of it, I HAVE heard of a relation between volcanic eruptions and the position of the moon. Guess it makes sense.
As for the orbits, they might CHANGE, but orbits are not unstable...that is, if you destabilize an orbit, it will simply reform a more elliptical orbit, instead of everything crashing into each other. The moon doesn't weigh that much, so the orbits wouldn't be that much more elliptical, but I'd bet that would be one effect. It's the TILT of the earth that causes seasons, not wobble, so seasons would still exist.
The 'center of gravity' between the earth and the moon would shift. Since this center of gravity forms something of a sine wave as it goes around the sun the net effect on our orbit would be very small. Also since planetary inhabitants of earth would move the same as the earth itself we would probably not notice.
Now on the other hand:
The entire earth is pulled into a bit of an egg shape by the moon. Yes, the oceans are pulled more into this shape causing tides, but the ground itself also moves. This egg shape slowly grinds around to pull a different direction over the course of 24 hours. If you removed the moon, the earth would snap back into a more spherical shape instantly. What you could expect: earthquakes. Lots of earthquakes. You probably see volcanic eruptions almost immediately in a circle around the earth where the the moon is at the horizon. You would see volcanic eruptions shortly thereafter in all the usual places at the edge of tectonic plates. More earthquakes. Tidal waves. Really bad atmospheric storms. After things settled down a bit you would see weather patterns forever altered.
The moon exerts a lot of force on the earth. Things now have reached a nice equilibrium with inertia. If you suddenly take away one of the two opposing forces you will have a LOT of energy that is going to have to go somewhere. Heck the earth may just fart another moon out it's opposite side.
edit:
I don't think you would see a mass extinction event but it would certainly knock us back to the early metal ages.
Now on the other hand:
The entire earth is pulled into a bit of an egg shape by the moon. Yes, the oceans are pulled more into this shape causing tides, but the ground itself also moves. This egg shape slowly grinds around to pull a different direction over the course of 24 hours. If you removed the moon, the earth would snap back into a more spherical shape instantly. What you could expect: earthquakes. Lots of earthquakes. You probably see volcanic eruptions almost immediately in a circle around the earth where the the moon is at the horizon. You would see volcanic eruptions shortly thereafter in all the usual places at the edge of tectonic plates. More earthquakes. Tidal waves. Really bad atmospheric storms. After things settled down a bit you would see weather patterns forever altered.
The moon exerts a lot of force on the earth. Things now have reached a nice equilibrium with inertia. If you suddenly take away one of the two opposing forces you will have a LOT of energy that is going to have to go somewhere. Heck the earth may just fart another moon out it's opposite side.
edit:
I don't think you would see a mass extinction event but it would certainly knock us back to the early metal ages.
DrPizza
Administrator Elite Member Goat Whisperer
I disagree with your proposition of volcanic eruptions, earthquakes, tidal waves, etc.
As far as tidal waves, I suppose you may notice some effect... nothing massive though. I can't logically see how you would expect a tide to come in higher than high tide normally would be. Mental image for you. Imagine a swimming pool that you move back and forth, left to right, and back again. As you move it, the water would become deeper on the side opposite the direction of movement, and shallower on the side in the direction of movement. Basically, the water would slowly slosh back and forth. Now, suddenly stop moving the pool... you're expecting the water to get even deeper than it did before??
Earthquakes, the pull of the moon isn't a huge factor (as far as I know) in normal earthquakes. i.e. It's pulling on faults in opposite directions all the time. Now, when the moon is in a position to exert the greatest possible force along a fault, yet, it doesn't cause an earthquake, can you explain how suddenly eliminating what would for most faults be a lower force is going to trigger an earthquake? That'd be like suggesting that if I push against a brick wall, I can't knock it over, but if I remove the force I'm exerting rapidly (or even instantaneously), the wall will collapse.
Volcanic eruptions???
However, lets not let your ideas go to waste. Allow me to suggest the following: Terrorists kidnap some great scientists. Somehow the ultimate superweapon is created. As a demonstration of their power, the terrorists eliminate the moon. They keep the weapon from being detected by cleverly disquising it as a concert tour bus for some rock group. The terrorists demand xxx billions of dollars as well as demand most of the governments of the world step down in favor of certain individuals chosen by the terrorist group. Since it's not an all at once catastrophe, you can tie some romance story into the plotline, not to mention gratuitous sex and lots of special effects as tidal waves devastate all the coastal cities, Mt Olympia destroys Seattle (or whichever mountain it is...) Oh, and Las Angeles and San Fran get a double whammy as they're hit by tidal waves during the earthquakes.
Also, Stephen Segal happens to be a roadie for the band...
p.s. if there are any movie-writers reading this, lets talk numbers
As far as tidal waves, I suppose you may notice some effect... nothing massive though. I can't logically see how you would expect a tide to come in higher than high tide normally would be. Mental image for you. Imagine a swimming pool that you move back and forth, left to right, and back again. As you move it, the water would become deeper on the side opposite the direction of movement, and shallower on the side in the direction of movement. Basically, the water would slowly slosh back and forth. Now, suddenly stop moving the pool... you're expecting the water to get even deeper than it did before??
Earthquakes, the pull of the moon isn't a huge factor (as far as I know) in normal earthquakes. i.e. It's pulling on faults in opposite directions all the time. Now, when the moon is in a position to exert the greatest possible force along a fault, yet, it doesn't cause an earthquake, can you explain how suddenly eliminating what would for most faults be a lower force is going to trigger an earthquake? That'd be like suggesting that if I push against a brick wall, I can't knock it over, but if I remove the force I'm exerting rapidly (or even instantaneously), the wall will collapse.
Volcanic eruptions???
However, lets not let your ideas go to waste. Allow me to suggest the following: Terrorists kidnap some great scientists. Somehow the ultimate superweapon is created. As a demonstration of their power, the terrorists eliminate the moon. They keep the weapon from being detected by cleverly disquising it as a concert tour bus for some rock group. The terrorists demand xxx billions of dollars as well as demand most of the governments of the world step down in favor of certain individuals chosen by the terrorist group. Since it's not an all at once catastrophe, you can tie some romance story into the plotline, not to mention gratuitous sex and lots of special effects as tidal waves devastate all the coastal cities, Mt Olympia destroys Seattle (or whichever mountain it is...) Oh, and Las Angeles and San Fran get a double whammy as they're hit by tidal waves during the earthquakes.
Also, Stephen Segal happens to be a roadie for the band...
p.s. if there are any movie-writers reading this, lets talk numbers
Allow me to modify your swimming pool analogy for a moment.
Imagine a swimming pool held a foot off the ground by chains. Over the course of 24 hours you slowly lower and raise each chain so that each end of the swimming pool touches the ground once ever 24 hours. If viewed from within the pool, yes you will see the water level rise and fall on each end but it would take a 24 time lapse view to actually see it happening.
Now cut one of the chains while the opposite end of the pool is resting on the ground.
Tidal waves. See?
The same sort of effect would happen to the solid earth in addition to the oceans. Not only would water rise on the dropped end it would likely slosh out of the pool.
I don't believe your brick wall analogy applies in this situation. Unlike a brick wall, the Earth is elastic and can change shape. If you dug your finger into a big sphere of jello and pulled until the whole sphere became egg shaped you would get an idea of what the moons force of gravity does to the earth. If you
suddenly let go, shock waves will travel through the jello as it snaps back to a spherical shape.
Imagine a swimming pool held a foot off the ground by chains. Over the course of 24 hours you slowly lower and raise each chain so that each end of the swimming pool touches the ground once ever 24 hours. If viewed from within the pool, yes you will see the water level rise and fall on each end but it would take a 24 time lapse view to actually see it happening.
Now cut one of the chains while the opposite end of the pool is resting on the ground.
Tidal waves. See?
The same sort of effect would happen to the solid earth in addition to the oceans. Not only would water rise on the dropped end it would likely slosh out of the pool.
I don't believe your brick wall analogy applies in this situation. Unlike a brick wall, the Earth is elastic and can change shape. If you dug your finger into a big sphere of jello and pulled until the whole sphere became egg shaped you would get an idea of what the moons force of gravity does to the earth. If you
suddenly let go, shock waves will travel through the jello as it snaps back to a spherical shape.
It could. Resonant frequency.
And the Earth is not like a brick wall, it is very flexible on a large scale. Closer to a stack of bricks with no mortar.
This is somewhat innaccurate. The tidal bulge caused by the difference in moon's gravitational pull (due to the size of the earth) being swept across the face of the earth with the earth's rotation. When the moon is overhead the whole earth is pulled towards the moon slightly because the ground below is closer to the moon than the ground on the other side of the earth. (Since we're in HT, I should correct myself and say that the bulge is slightly forward of the moon-earth line.) Nevertheless, this bulge is currently being swept across the face of the earth. Remove this difference in the moon's gravitational pull and that bulge doesn't become larger -- it instead settles down to a sun sized bulge -- approximately 30% the size of the current bulge.
For the earth to instantly "snap" back into the shape of a moon-less earth would require the addition of a force in the opposite direction to the moon's gravitational pull. Put your hand in that pool and create a bulge in the water by moving your hand. When you take your hand out of the water it doesn't suddenly snap to a flat surface. Nor will that bulge ever get larger. It just continues onwards until it runs out of momentum.
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