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View Full Version : What would happen if the Earth cracked in Half...?



dashell
2010-Apr-22, 01:12 AM
For a possible story I'm writing....

what if the earth, or rather, parts of it broke off....? Like about 40% of it broke off?
would the parts stay in earth's orbit?
what would happen to the earth's climate?
would the oceans dry up at all?
could earth still hold life?
what would, if anything, happen to the moon?

any thoughts?

Swift
2010-Apr-22, 02:39 AM
I guess it depends on what caused part to break off. I think the most likely reason would be if it was struck by a very large object, probably the size of a large asteroid or moon. If that was the reason, there would be neither climate, oceans, nor life left; such a collision would probably turn the surface of the Earth to molten rock. It is theorized that such a collision, very early in the Earth's history, formed the moon.

01101001
2010-Apr-22, 04:03 AM
Yeah, what does the cracking?

Otherwise I'm picturing a lump of clay that is really two lumps of clay cracked apart, only not yet separated -- and therefore pretty much still one lump of clay, healed up immediately.

Why would 40% of Earth set off on its own?

novaderrik
2010-Apr-22, 04:10 AM
i think everything would die, and every bit of evidence that there was ever anything alive would get wiped out as the debris tried to coalesce back into a spherical body.

DrRocket
2010-Apr-22, 04:30 AM
I guess it depends on what caused part to break off. I think the most likely reason would be if it was struck by a very large object, probably the size of a large asteroid or moon. If that was the reason, there would be neither climate, oceans, nor life left; such a collision would probably turn the surface of the Earth to molten rock. It is theorized that such a collision, very early in the Earth's history, formed the moon.

No matter the cause, it would probably qualify as a bad day.

Canis Lupus
2010-Apr-22, 05:12 AM
Why would 40% of Earth set off on its own?

Fed up with the other 60% is my guess.

astromark
2010-Apr-22, 07:49 AM
Without going into why or how this is to happen., and yes it does mater a great deal. As to the how. Lets go with the collision idea.
What would happen if sufficant force as to break the globe ... Absolute chaos. Total inhalation of all life forms atmosphere and oceans...
As for the poor sods that were to witness such a catastrophic event...
I would imagine a few moments after impact where you would be aware that some horrible death is upon you...
The resultant parts and debris would by the force of gravity draw back into a sphere.. that process could take thousands of years and I would be certain that the resultant surface structure and atmosphere would have little in common with what we might require...

noncryptic
2010-Apr-22, 04:21 PM
If the cause for the breaking apart does not include a force that separates the two parts then they will rejoin and reform one planet (though it might look different than Earth does now).

If the cause for the breaking apart does include a force that separates the two parts then those will form as two separate (semi) spherical bodies.

Either way it would be much worse than the 2012 movie scenario and destroy all life on Earth. You'd end up with one or two primordial Earths were life would have to start all over again.

neilzero
2010-Apr-22, 08:09 PM
A small clay sphere can crack in half or 40%/60%, but Earth has too much gravity, so it would snap back together before the crack was a millimeter wide, unless the force continued to widen the crack. So much force is needed to widen the crack that both halves would crumble and get hot enough to melt. Even if cooling was applied to prevent melting, the halves would crumble into two separate spheres or spheroids. Even separated by a million kilometers, the halves would fall back together, in about one hour unless they also spun around each other at high speed. Orbital speed = 4000? kilometers per hour. Neil

Sticks
2010-Apr-22, 08:24 PM
Sorry but someone has already done this idea back in this 1965 film (http://www.imdb.com/title/tt0059065/)

See also here (http://en.wikipedia.org/wiki/Crack_in_the_World) (Wikipedia article about this film)

Swift
2010-Apr-22, 08:29 PM
No matter the cause, it would probably qualify as a bad day.

Dr. Peter Venkman: I'm fuzzy on the whole good/bad thing. What do you mean, "bad"?
Dr. Egon Spengler: Try to imagine all life as you know it stopping instantaneously and every molecule in your body exploding at the speed of light.
Dr Ray Stantz: Total protonic reversal.
Dr. Peter Venkman: Right. That's bad. Okay. All right. Important safety tip. Thanks, Egon.



Sorry but someone has already done this idea back in this 1965 film (http://www.imdb.com/title/tt0059065/)

I remember that movie. It is one of those it is so bad it is almost good. I remember even as kid going "that doesn't make sense" for large chunks of it.

JohnD
2010-Apr-22, 08:35 PM
In another forum on this site, I proposed that there should be a special SciFi forum, where authors could pitch their ideas and get fed back from the assembled gurus. I think that this is one that is especially suitable, and I shall use it as a potent example of the pressing need for such a forum.

John

Ilya
2010-Apr-22, 08:39 PM
Any conceivable process that could rip 40% of Earth's mass away from other 60% would also heat up both pieces to melting. All oceans and atmosphere would boil away.

A small clay sphere can crack in half or 40%/60%, but Earth has too much gravity, so it would snap back together before the crack was a millimeter wide, unless the force continued to widen the crack.
If "crack a millimeter wide" is all you want, one tool that could do it is a cosmic string (http://en.wikipedia.org/wiki/Cosmic_string). "Tides of Light" by Greg Benford (SF writer and astrophysicist) has a dramatic description of what happens when a loop of cosmic string cuts through a planet. (Not much. Planet just seals up behind it, so unless the string passes almost on top of you the only lasting effect are some earthquakes.)

captain swoop
2010-Apr-22, 09:31 PM
In another forum on this site, I proposed that there should be a special SciFi forum, where authors could pitch their ideas and get fed back from the assembled gurus. I think that this is one that is especially suitable, and I shall use it as a potent example of the pressing need for such a forum.

John

Not in this thread. It is for answwering questions. If you want to raise things like this do it in the Feedback Forum

dashell
2010-Apr-22, 10:24 PM
Thank you all for very insightful ideas....
some questions....
If this actually occured...what would become of the molten core?
Ilya mentioned that both pieces would heat up and boil away....why is that?

thanks again very much for your time

TrAI
2010-Apr-23, 01:32 AM
Hmmm... Well, it is seriously difficult to take any significant mass of a planet. The Moon is thought to have formed from the Earth being impacted by a Mars size planet, so I would think that something like that would be needed, and an impact like that would wipe out all life on the planet, as the entire planet would be one huge ball of molten rock due to the energy released.

I am not sure that this really fits the bill though, as I would think the earth is now more massive than before it absorbed Theia, so it was an overall gain of mass and a moon too...

Swift
2010-Apr-23, 02:00 AM
Thank you all for very insightful ideas....
some questions....
If this actually occured...what would become of the molten core?
Ilya mentioned that both pieces would heat up and boil away....why is that?

thanks again very much for your time
What would boil away is the water from the oceans and the atmosphere, but even that might stick around as a "cloud" in orbit. What exactly would happen depends on the dynamics of the event, but it is quite likely that most of the pieces would eventually coalesce back into a planet. It would probably be mostly molten to start but would cool down (we're talking thousands of years probably). But it might never big more than a rocky ball with maybe a little water and atmosphere.

Van Rijn
2010-Apr-23, 02:22 AM
Ilya mentioned that both pieces would heat up and boil away....why is that?


The only obvious way that 40% of the Earth could be broken off would require an impact of even greater force than what likely formed the moon. That means a lot of energy. Much of the planet would be vaporized.

Now, if 40% of the Earth was magically sliced off and disappeared, a great deal of energy would be released as the rest of the planet collapsed into a smaller sphere (and this would happen very quickly). It would be somewhat less impressive than an impact, but still wouldn't leave any people behind.

dtilque
2010-Apr-26, 11:08 AM
I am not sure that this really fits the bill though, as I would think the earth is now more massive than before it absorbed Theia, so it was an overall gain of mass and a moon too...

Mars has only about 10% of Earth's mass, so the pre-impact Earth was about 90% its current mass.

TrAI
2010-May-01, 05:37 PM
Mars has only about 10% of Earth's mass, so the pre-impact Earth was about 90% its current mass.

But the point of the thread was that a large part of the earth would be broken of, so it wouldn't fit very well if the mass of the impactor was added to the resulting object.