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Pieces of Ancient Earth May Be Hidden On the Moon
Posted by
Soulskill
on Fri Jun 27, 2008 11:00 PM
from the what-you-leave-behind dept.
from the what-you-leave-behind dept.
swestcott brings us a story from Space.com about the possibility of finding evidence for ancient Earth life on the moon. A team of scientists has published work confirming that meteorites originating from Earth could have remained sufficiently intact while colliding with the moon to allow the survival of biological evidence for life. Quoting:
"Crawford and Baldwin's group simulated their meteors as cubes, and calculated pressures at 500 points on the surface of the cube as it impacted the lunar surface at a wide range of impact angles and velocities. In the most extreme case they tested (vertical impact at a speed of some 11,180 mph, or 5 kilometers per second), Crawford reports that 'some portions' of the simulated meteorite would have melted, but 'the bulk of the projectile, and especially the trailing half, was subjected to much lower pressures.'"
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That's no moon... (Score:5, Funny)
It's a... oh, right.
Re:That's no moon... (Score:5, Funny)
Parent
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I've never seen a square anything in space in my life.
Governor Tarkin?
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you mean like how meteorites are apparently square? Seriously, wtf was that.
A cube is probably the least likely structure to carry surviving life. A sphere is the strongest, and therefore the most likely. A cube was probably therefore the best simple structure to simulate.
Re: (Score:2)
Four letters:
NaCl
Earth is full of it. And so are you.
Do you want to engage in some kind of debate about this, or just resort to name calling? What about my statement do you think is wrong, and why?
Re: (Score:2)
http://users.bigpond.net.au/dax/cube_FC.jpg [bigpond.net.au]
(and yes, whole earth are part of space.)
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It's more difficult to build something spherical than something cubic with nice right angles. Hence, the Borg ship is a cube, but, they still get the structural efficiency/stability of a sphere by circumscribing the ship in an imaginary sphere, then assimilating all the unfilled space in the sphere.
Seriously, though: since the Universe is only 6,000 years old, we know that any Earth "debris" on the Moon was just put there as a test of faith. ;)
Let's start with the obvious (Score:5, Insightful)
Why the hell would you model an asteroid with some improbable shape like a cube?
Re:Let's start with the obvious (Score:5, Funny)
A group of wealthy investors wanted to be able to predict the outcome of a horse race. So they hired a group of biologists, a group of statisticians, and a group of physicists. Each group was given a year to research the issue. After one year, the groups all reported to the investors. The biologists said that they could genetically engineer an unbeatable racehorse, but it would take 200 years and $100 billion. The statisticians reported next. They said that they could predict the outcome of any race, at a cost of $100 million per race, and they would only be right 10% of the time. Finally, the physicists reported that they could also predict the outcome of any race, and that their process was cheap and simple. The investors listened eagerly to this proposal. The head physicist reported, "We have made several simplifying assumptions... first, let each horse be a perfect rolling sphere..."
Parent
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Re:Let's start with the obvious (Score:5, Interesting)
A cube is pretty much the worst shape possible when it comes to distributing the force of an impact evenly across the entire object. So simulations show that cubes can survive crashing into the moon, then its fairly safe to say that other shapes can survive too.
Parent
Krypton (Score:3, Funny)
A cube is pretty much the worst shape possible when it comes to distributing the force of an impact evenly across the entire object
Not true; What about those crystalline spacecraft that the Kryptonians use to send their infants to Earth in? They have all sorts of jutting and produding suraces.
Re:Krypton (Score:5, Funny)
A cube is pretty much the worst shape possible when it comes to distributing the force of an impact evenly across the entire object
Not true; What about those crystalline spacecraft that the Kryptonians use to send their infants to Earth in? They have all sorts of jutting and produding suraces.
Crumple zone, duh!
Parent
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Re:Let's start with the obvious (Score:4, Funny)
Why the hell would you model an asteroid with some improbable shape like a cube?
Tetris killed the dinos!
Parent
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http://meteos.nintendods.com/ [nintendods.com]
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Because you have to model it as *something*.
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Re:Let's start with the obvious (Score:5, Insightful)
some improbable shape like a cube?
why is cube improbable? That's like saying, an asteroid looks more like a baseball than a lego brick. I would say, sphere is more improbable than cube.
To find a perfect model for an irregular shaped object, cube is as good as any. Sphere would be the least likely and desirable shape to model after.
Parent
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Planets and moons are only round because their gravity is strong enough to form them into spheres. Many asteroids aren't spheres because they are too small.
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since when is a cube a more likely shape for a stellar object?
Since perfect sphere is even less likely shape for a stellar object than cube.
A shape with no gravity usually has, as you say, an irregular shape but 9 times out of 10 it's more "roundish" than "cubic".
Would you be more agreeable if the model was a potato shape? Idaho or Dakota potato? Personally I like Idaho.
Imagine if you are trying to find trajectory of two objects on a pool table after a collision. They, both are on a collision path.
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maybe secret fans of the borgs?
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Why the hell would you model an asteroid with some improbable shape like a cube?
Borg.
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Looking for a reason... (Score:5, Interesting)
Here's a good reason to go back to the moon if there ever was one. Or at the very least a better excuse than we've had so far.
Though the survival of the species is always a good reason...
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It's just such a shame that kids in school are considered "uncool" if they show this wonderful trait.
The next planetary scandal (Score:4, Interesting)
Can just see the reaction to this. Life can't survive elsewhere in the solar system. It's all pieces of Earth that got blown out.
Re:The next planetary scandal (Score:5, Interesting)
Can just see the reaction to this. Life can't survive elsewhere in the solar system. It's all pieces of Earth that got blown out.
That's why a study of the DNA etc. is important if life is found on another body. If the basic "alphabet" of the newly-discovered life matches that of Earth's, then most likely its a form of contamination from a central source.
We wouldn't necessarily be able to tell where the original source is if such was the case. Other bodies in the solar system were stable while Earth was still smoldering such that perhaps life formed on a different body that cooled faster and then spread to Earth after it cooled. Identifying the original "seed body" may be tricky.
Parent
Re:The next planetary scandal (Score:5, Interesting)
(The cell itself probably post-dates the first 'true' life by a few hundred million years - long enough for any Earth fragments to be blasted onto nearby worlds - and the cell is only one way of building structured life. Assuming you have structured life. Pre-cellular life might be fine for some worlds, and mono-cellular life could potentially do much better than multi-cellular life in the atmosphere of a gas giant. You don't want complexity under harsh conditions.)
However, this leads to a major problem. Given that the bases that exist on Earth probably are the bases that would be used elsewhere, anything that is too simple cannot be distinguished from a parallel line of evolution. Given the level of sophistication you can pack onto a tiny space probe, the level of sophistication you can distinguish at in practical terms is far greater than the level that you could distinguish at in textbook theory.
Parent
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I had thought that the moon is mostly composed of material from the earth anyway? I know it's just a hypothesis but it seems pretty sensible. It could have been before any forms of life had started developing though, I don't know my time periods for when life is projected to have begun.
(Source: http://en.wikipedia.org/wiki/Moon [wikipedia.org] )
Giant Impact hypothesis
The prevailing hypothesis today is that the Earthâ"Moon system formed as a result of a giant impact. A Mars-sized body (labelled "Theia") is believed to have hit the proto-Earth, blasting sufficient material into orbit around the proto-Earth to form the Moon through accretion.[6] As accretion is the process by which all planetary bodies are believed to have formed, giant impacts are thought to have affected most if not all planets. Computer simulations modelling a giant impact are consistent with measurements of the angular momentum of the Earth-Moon system, as well as the small size of the lunar core.[41] Unresolved questions regarding this theory concern the determination of the relative sizes of the proto-Earth and Theia and of how much material from these two bodies formed the Moon.
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The Giant Impact studies done a few years back by Robin Canup (SWRI, Colorado) and others (whose names escape me ; I'm at work) showed that most of the core of a likely impactor ended up in the (proto-)Earth's core, while the debris ring consisted of similar amounts of the impactor ("Theia" in your cite) and the (proto-)Earth. The debris ring then segregated to form orbiter(s) and to re-impact.
The impact process would have li
Pieces of Ancient Moon May Be Hidden On the Earth (Score:2)
Another theory is that Moon was tugged into place to stabilize Earth.
Did you actually read it? (Score:2)
Directly from the page you apparantly googled (since you don't seem to have read it):
A detailed comparison of the properties of Lunar and Earth rock samples has placed very strong constraints on the possible validity of these hypotheses. For example, if the Moon came from material that once made up the Earth, then Lunar and Terrestrial rocks should be much more similar in composition than if the Moon was formed somewhere else and only later was captured by the Earth.
These analyses indicate that the abundanc
Groening has the argument against (Score:4, Funny)
We're whalers on the Moon
We carry a harpoon
But there ain't no whales
So we tell tall tales
And sing our whaling tune
Good (Score:3, Funny)
Tax the little buggers up there!
Fossils from the moon. (Score:2, Funny)
Pieces of Ancient Earth May Be Hidden On the Moon (Score:2, Funny)
But what about how they got up there? (Score:4, Insightful)
Presumably the collision needed to splash a bit of rock off the Earth, through its atmosphere, up its gravity well to the moon would be at least 6 times as forceful as the collision with the moon.
They'd have to show that bits of organic material would survive both collisions to make it plausible.
Then explain how you would go looking for the few unlikely surviving chunks on something the size of the moon. Which by the way keeps getting hit all over with rocks from everywhere else, hence all the dust and craters.
Good luck with that.
Or is this just one of those things like string theory where you get to make up a hypothesis that you can't possibly actually falsify?
Take off? (Score:3, Interesting)
The article doesn't mention how these earth-originated asteroids become space-borne, except a brief mention of the "Late Heavy Bombardment." I would think that pieces of earth that are sent into space by other asteroids hitting earth, would be subject to *far* more stress, heat, and general voilence in being struck hard enough to reach escape velocity, than they would on a simple re-entry.
Surely the impact event and associated energy required to eject the matter from Earth's stronger gravity and much thicker atmosphere, would be far worse when compared to the landing on the moon, no? (I know it's not a direct comparison, but consider how much fuel the Apollo missions in the massive boosters used to get out of Earth's gravity, versus how little they used to decelerate down to the moon's surface, carried on board the relatively small lander.)
Real Estate Agent's Perspective (Score:2)
Quiet, secluded location. Clear skies. Perfect for the adventurous. Ideal for your country estate or getaway. Some restrictive covenents; but they aren't being enforced. Possibility of well water on site. Bring all reasonable offers.
Re:First (Score:4, Funny)
Don't be too hard on yourself.
At least you got halfway there.
Parent
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Did you know DNA is what makes a lot of the choices in your brain? Right, in every neuron, every time it fires, messages go into the nucleus (that's the dna's housing and equipment) and get translated by RNA and DNA... the resulting parts of the neuron that fire are due to the response from the DNA!
Erm... not really, no. Most "firing" of neurons (generation of action potential) happens on a purely electrical basis. There is chemical modulation of this based on quantities of neurotransmitters that are prod
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Come on now... isn't this stretching things a bit. Science is supposed to be what about what we KNOW.
I used to think like that about evolution 10 years ago but now I think there is enough evidence to support it. I was a fairly fundamental Christian up until the last couple of years too, now I'm not sure what to believe, but what you are suggesting is just the "God of the Gaps" idea where you have to use God to explain everything you think is too amazing. I still believe there could be some greater intelligence/power than our own though, if only because another race could have evolved before ours in our own
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You can't post from the cache. When you clicked the 'submit' button, your request went to slashdot rather than the cache, and therefore was associated with your normal login details.
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IMO expecting to stumble on them by accident on a return trip to the moon, as it says, is way too optimistic.
It's a small world.. err.. moon, after all. It's amazing what you can bump into when you're not expecting it :p Send a few 'nauts up on holiday and they'll be sure to run into some pre-historic neighbours.
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It's a song/phrase. "It's a small world after all". I was basically just joking, but also pointing out that random meetings of people who know each other and end up meeting each other on holiday in a different country or an obscure part of their own country (even though they didn't know the other family was going there) do happen. Whenever that happens people tend to say "It's a small world" despite the fact that the world is not physically very small.