what if the moon hit the earth

thugfella · Mar 19, 2005

im not sayin its possible jus askin what do you guys think will happen and would there be any sign of life after the impact?

kmarinas86 · Mar 19, 2005

People would start living off of the new lunar materials =P

thugfella · Mar 19, 2005

i was thinkin the only thing that would be left is roaches and small bacteria

bryanharley · Mar 19, 2005

I doubt the earth or even the solar system would survive. It'd through everything out of whack. Luckily this can't happen.

yevaud · Mar 19, 2005

Hmm. Yes, sure, it's not precluded from happening. It's extraordinarily unlikely, that's all. Would life survive? Doubtful, except for perhaps some of the simplest organisms (bacteria, etc.). The impact would likely strip a huge amount of the atmosphere clean off of the planet. However. This would *not* destroy the planet itself. There's something called the "binding energy," of which I won't get into, except to say it would take a mass equivalent to the Earth (or larger) to smash the planet into fragments. And, yes, the Solar System would indeed survive. <div class="Discussion_UserSignature"> Differential Diagnosis: "I am both amused and annoyed that you think I should be less stubborn than you are." </div>

Saiph · Mar 20, 2005

A planet as big as earth...or bigger? I think you could do it with a moon sized object...if it was moving very fast (a good fraction of C fast). though I'll admit, any standard gravity induced collision will really mess up earth, but it'll mess up the impactor as well, and you'd still end up with a planet sized chunk of stuff (churned and stirred for sure). So a planet would still be where earth is (even if it's so messed up you may as well give it a different name). <div class="Discussion_UserSignature"> --------------------SaiphMOD@gmail.com -------------------"This is my Timey Wimey Detector. Goes "bing" when there's stuff. It also fries eggs at 30 paces, wether you want it to or not actually. I've learned to stay away from hens: It's not pretty when they blow" -- The Tenth Doctor, "Blink" </div>

dark_energy · Mar 20, 2005

The moon hitting the Earth would cause a shockwave and impact so big it would burn the entire planet. Only the most persistent of organisms would survive. We'd definitely die out. It would make most of the Earth and most of the moon into one planet through gravitational attraction, some pieces would fly off though. This won't happen since the moon is gradually getting farther from us. <div class="Discussion_UserSignature"> </div>

yevaud · Mar 20, 2005

Well, ok, velocity counts for a lot. Kinetic energy and all. But the standard model on that, unless there are very high collision velocities, is that the body has to be at least the size of what it impacts to exceed the binding energy. Or, so I recollect in one of those nasty "term projects" I had to do... I might add, I hope I never see something the size of the moon moving at a significant fraction of "C"... <div class="Discussion_UserSignature"> Differential Diagnosis: "I am both amused and annoyed that you think I should be less stubborn than you are." </div>

meteo · Mar 20, 2005

http://www.lpl.arizona.edu/impacteffects/ Depending on the impact velocity you melt 10-25% of the earth but there is negligable change in mass. The entire surface of the earth would be molten but there should be rocks shot off containing intact microbes. The radius of the moon you can find and density is 3300kg/m^3. I don't know what the range of impact velocities from two impacting protoplanets would be, I guess it would depend on the situation. The only time an impact like this could occur is at the begining of the solar system. Unless say a moon/planet ejected from another star hits the Earth but the odds of that happening have to be VERY astronomical.

newtonian · Mar 20, 2005

Thugfella - It is not possible - just so you know. Again, this is another way earth is protected. While some planetary moons are in decaying orbits, our moon is not. In fact, due to the special nature of tidal interactions and rotational speeds, etc., our moon is actually receeding from earth. The question should be, will we lose our moon? That would also cause a problem, since the moon stabilizes the tilt of earth's axis and produces beneficial tides which support very important wetland ecologies. However, we need not worry about moon's orbit decaying and impacting earth. Of course, the posters are noting how much harm we are actually protected from!

Saiph · Mar 20, 2005

yeah, the longer I spent writing that post, the longer I realized that, excluding obscene velocities (obscene depends on the binding energy) that you'll still have something there. A huge chunk will be ejected, but a huge chunk will be added by the impactor. so I'll buy it. <div class="Discussion_UserSignature"> --------------------SaiphMOD@gmail.com -------------------"This is my Timey Wimey Detector. Goes "bing" when there's stuff. It also fries eggs at 30 paces, wether you want it to or not actually. I've learned to stay away from hens: It's not pretty when they blow" -- The Tenth Doctor, "Blink" </div>

dark_energy · Mar 20, 2005

Funny how that the moon is exactly the apparant size of the sun from the earth's ground. Coincidence or something....more?

Saiph · Mar 20, 2005

well, considering a few facts: 1) It used to closer, and bigger. 2) It's getting further, and smaller 3) Even now it isn't always the same size, due to the slightly eccentric orbit. So, I vote coincidence. <div class="Discussion_UserSignature"> --------------------SaiphMOD@gmail.com -------------------"This is my Timey Wimey Detector. Goes "bing" when there's stuff. It also fries eggs at 30 paces, wether you want it to or not actually. I've learned to stay away from hens: It's not pretty when they blow" -- The Tenth Doctor, "Blink" </div>

dark_energy · Mar 20, 2005

Yes, I know that the moon was much closer than it is now, but it seems strange, or maybe I'm paranoid, that the moon is the apparant size of the sun during the human reign. I vote paranoia. <div class="Discussion_UserSignature"> </div>

newtonian · Mar 20, 2005

dark_energy - There comes a point when one realizes there are too many coincidences to be merely coincidence. And it does involve math and probability, btw. The list of fine tuned properties and laws which make life possible on earth and in the universe is very long indeed - and some are far more fine tuned than our moon's orbit! Of course, like beautiful sunsets, beautiful flowers (and fragrant) and beautiful nebulae, etc., awesome solar ecclipses are not necessary for survival. But they sure make life more enjoyable for us humans - to me it is an indication that God loves us and wants us to be happy - and to enjoy science, among a plethora of other things. It is good you are noting some of the seeming coincidences - there are many more.

dark_energy · Mar 20, 2005

Tell me about some other "coincidences". <div class="Discussion_UserSignature"> </div>

newtonian · Mar 20, 2005

dark_energy - Here are a few. A number are explained in "The Symbiotic Universe," by George Greenstein - available in some public libraries. The last one on the list is my own personal theory. Estimates on powers of 10 do vary, depending on various models and factors. Btw 10^10 means 1 followed by 10 zeros, i.e. 10 to the power of 10, aka 10 billion. 1. Our expansion rate is fine tuned to 10^59. Slower and our universe would have already collapsed. 2. Expansion by that fraction faster and the universe would already have ?heat death.? NOTE: Recent evidence adds to this mystery of life's origin, there are other forces involved with expansion, all of which have been fine-tuned to get us so close to omega=1 and yet continue expanding. E.g. dark energy, inflation models, etc. 3. Fine tuning of weak nuclear force allowing supernovae allowing elements heavier than H & He. 4. Fine tuning of electromagnetic force. If significantly weaker, electrons would not be held around atomic nuclei, so no atoms or molecules could exist. 5. If electromagnetic force was much stronger, electrons would be trapped on atomic nuclei so no chemical reactions could occur. 6. The charge of the electron exactly equals the proton. If it was greater by a fraction 100 billion billionth no stars could stay together - they would all explode - Actually never form. 7. If the charge of the proton was that fraction larger, the same repulsive spontaneous explosions would occur. Fine tuning #8. This is a series of 3 fine tuned factors which allow red giants to synthesize carbon. The random collision of 3 Helium atoms in a red giant to produce carbon is exceedingly unlikely: roadblock #`1- too unlikely to allow synthesis of carbon. It therefore normally occurs in two steps: 1. Two heliums combine (with 2 protons and 2 neurons each) to produce a very unstable isotope of Beryllium with 4 p

Saiph · Mar 20, 2005

also: Peanut butter tastes like peanut butter. Change any of the molecular structure and it doesn't taste like peanut butter! Of course, then we've got something else. Just because the universe is the way we see it, doesn't mean it was made that way so we can exist. My view: We evolved in this universe, so we are idealy suited to it, not the other way around. If the universe was different, then we'd be different (or not here), and we could make the exact same arguement you are newtonian. Because we could make your claim, if we existed, in any universe we existed it, I don't buy it. My claim on the other hand, invokes the same thing over and over. We are the way we are, because we wouldn't fit into the universe otherwise. Your claim says this is the only way it would work, however if we existed under a different set of rules (and there are lots of sets! heck, the physical laws could be different, let alone the parameters), we could say the universe was made for us...and be referring to an entirely different set of values and laws. anyway, I'm done sidetracking for now. <div class="Discussion_UserSignature"> --------------------SaiphMOD@gmail.com -------------------"This is my Timey Wimey Detector. Goes "bing" when there's stuff. It also fries eggs at 30 paces, wether you want it to or not actually. I've learned to stay away from hens: It's not pretty when they blow" -- The Tenth Doctor, "Blink" </div>

vogon13 · Mar 20, 2005

in resonse to: "Change any of the molecular structure and it doesn't taste like peanut butter!" This is correct. Then it would taste like chicken. <img src="/images/icons/laugh.gif" /><img src="/images/icons/laugh.gif" /><img src="/images/icons/laugh.gif" /> <div class="Discussion_UserSignature"> TPTB went to Dallas and all I got was Plucked !!So many people, so few recipes !!Let's clean up this stinkhole !! </div>

yevaud · Mar 20, 2005

Or Cat! "Mmmm....cat: the other white meat." <img src="/images/icons/tongue.gif" /> <div class="Discussion_UserSignature"> Differential Diagnosis: "I am both amused and annoyed that you think I should be less stubborn than you are." </div>

Saiph · Mar 20, 2005

:::sigh::: that, was awful yev. just awful. <div class="Discussion_UserSignature"> --------------------SaiphMOD@gmail.com -------------------"This is my Timey Wimey Detector. Goes "bing" when there's stuff. It also fries eggs at 30 paces, wether you want it to or not actually. I've learned to stay away from hens: It's not pretty when they blow" -- The Tenth Doctor, "Blink" </div>

yevaud · Mar 21, 2005

Er....*sorry* <div class="Discussion_UserSignature"> Differential Diagnosis: "I am both amused and annoyed that you think I should be less stubborn than you are." </div>

newtonian · Mar 21, 2005

Saiph - You need to study my posted examples more carefully, and then postulate how life as we know it could exist under different properties in a universe not so fine tuned. For example - how do you propose carbon coming to exist without that exact triple matching of the nuclear resonances of Helium, Berylliium 8 and carbon? And, of course, the unique properties of carbon which allow long aperiodic chains that can contain sufficient information to direct life's processes. And you need to post some model that would account for information somehow entering a statistical molecule, e.g. a statistical protein, etc. Your post, without such details, is actually science fiction - proposing life forms with no evidence for their existence and no scientific model postulating how they came to exist. And, of course, to believe what you posted requires a totally blind faith - with no scientific basis for it. Remember, again, that all life that scientists have observed require elements that would not exist in our universe if it was not fine tuned in a number of ways, only some of which I posted. And scientists cannot create life - we lack the wisdom and power to incorporate from scratch information into statistical molecules. In fact, we have difficulty even creating statististical proteins! Humans are creators incorporating intelligent design. Yet we have far better success when we use the intelligence already incorporated in life's informational molecules, with their fine tuned informational templates. And this is why genetic engineering is far easier than humans attempting to create life from entirely non-living sources. And when you respond, please include some detail in some model you consider tenable. For example, how did proteins assemble, or how can humans assemble proteins, with L-chiration (= left handed polarized), alpha-peptide bonding, and informational co

Saiph · Mar 21, 2005

First, I'm not going to post a model. Why? Several reasons: Most of the chemistry you just spouted is beyond me (valid or not). As such I can't come up with a viable model. Absence of evidence is not evidence of absence. I'd prefer to keep this in a realm where I can debate (not argue) the point with you, and that's on a logical and philosophical regime. If we can change the interactions of atoms by tweaking the fundamental constants why can't we change the laws? I have seen no evidence that the current setup of the universe is a unique, stable, solution to all the possible permutations of fundamental constants and laws. Without such evidence it is possible for another stable solution to exist. And using the current state of the universe for that evidence, doesn't cut it. We've only got one sample. So by that precedent I could look at me (a single sample), say I'm representative of the population, and say that in order for humans to live to 21, they must be 6'4" and have brown hair, brown eyes, ~200lbs, and size 14.5 shoes (U.S. male). As I have yet to see any evidence that this combination of laws and constants is the only stabe solution (scratch stable, it may not be stable, but it is life-supporting), it is not invalid to say there are other solutions. If there are, my view outlined in my last post is, imo, more consistent, less complicated, and a "more valid" point of view. The fundamental constants you say are fine tuned may be a consequence of the fundamental laws, and therefore not so fine tuned. Of course, then you go after the fundamental laws... The constants, especially the fine structure constant, may not be constant, but have changed over time (currently under investigation, so far it looks to be constant...). If they were different, but approached current values over time, that also suggests a sort of natural equilibrium that requires no more intelligent design than h <div class="Discussion_UserSignature"> --------------------SaiphMOD@gmail.com -------------------"This is my Timey Wimey Detector. Goes "bing" when there's stuff. It also fries eggs at 30 paces, wether you want it to or not actually. I've learned to stay away from hens: It's not pretty when they blow" -- The Tenth Doctor, "Blink" </div>

yevaud · Mar 21, 2005

I know I used this once before here to illustrate this, but I'll do it again. A noted British physicist was discussing modern physics and cosmology at a public event: how stars, planets form, etc. An elderly woman stood up. "Rubbish! Everyone knows that the Earth is balanced on top of a giant turtle." The physicist thought about it, then replied, "and what is the turtle standing on, Madam?" She replied, "you're very clever, young man, very clever indeed. But it's turtles all the way down..." <div class="Discussion_UserSignature"> Differential Diagnosis: "I am both amused and annoyed that you think I should be less stubborn than you are." </div>

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