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Collision With Earth's "Little Sister" Created the Moon
astroengine writes The primordial planet believed to have smashed into baby Earth, creating a cloud of debris that eventually formed into the moon, was chemically a near-match to Earth, a new study shows. The finding, reported in this week's Nature, helps resolve a long-standing puzzle about why Earth and the moon are nearly twins in terms of composition. Computer models show that most of the material that formed the moon would have come from the shattered impactor, a planetary body referred to as Theia, which should have a slightly different isotopic makeup than Earth.
It was only a matter of time before Earth-Two was discovered!
....if both planetary bodies formed in the same area of the accretion disk.
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What about this explanation: a planetoid smashed into early Earth and split Earth into two. The two halves eventually smashed back together, but created the moon in the process. One "half" may have mixed more with the collider than the other due to the angle of impact, creating the slightly different isotopes in the parts of it that became the moon.
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The huge bulk of Theia growing larger in the sky...
Wouldn't Earth and Theia have been both planetoids at that point? One of the new requirements for being a planet is clearing your orbital path. It's pretty clear neither body had done that yet before that point, given the fact they smashed into each other.
Collisions with someone's little sister -- a series of carefully controlled and mutually pleasurable collisions -- often produce new bodies. Why should planet-fuckers be any different?
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So Gaia banged her little sister and made the moon? I assume rule 34 has already been satisfied for this, right?
Serious? Seriousness is well above my pay grade.
Why should the material composition of Theia have differed all that much from the Proto-Earth? They formed from the same planetary nebula, and at relatively similar distances from the Sun; shouldn't they have been similar in composition? And how can anyone state with any certitude, 4+ billion years later, how much of the merged Earth's crust was from Theia, and how much from the proto-Earth, and whether the lunar material was one, the other, or mostly mixed? It was a long time ago, and the Early Heavy Bombardment period would have stirred things up further. In fact, it's not unlikely that the Early Heavy Bombardment material was long-period debris from the original collision.
If Theia had formed substantially closer, or substantially farther away from the Sun, then the debris from the collision could hardly have remained close enough that the shards would coalesce to form the Moon. The differing orbital velocities would have seen to that.
not really new news
this was a hypothesis pre Apollo
and confirmed from the sample returns
then reconfirmed using computer models of a highly tangential impact
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Our substantial magnetic field may be due to the merging of the iron cores of the Proto-Earth and Theia. Earth is the most dense planet in the solar system, and from what we know of Mars and Venus, we suspect that our iron core is far larger than the other terrestrial planets.
Venus has a super-thick poisonous atmosphere; it's at least possible that our large Moon has, over a period of 4+ billion years, "skimmed away" enough of our atmosphere to have protected the Earth from a similar fate.
Of course, we only think that our atmosphere is right because we evolved here, in this atmosphere; if the atmosphere had been different, we would have evolved differently, and (had intelligent life developed at all) we'd think that THAT was the right sort of atmosphere.
Little sister wouldn't do that anyway, she's too busy out in the back yard, playing like this
Of course, we only think that our atmosphere is right because we evolved here, in this atmosphere; if the atmosphere had been different, we would have evolved differently, and (had intelligent life developed at all) we'd think that THAT was the right sort of atmosphere.
IIRC earth's atmosphere was different. Our current atmosphere the result of life polluting that environment with oxygen. Causing an environmental catastrophe at the time.
Like Jupiter breaking up an earlier Super Earth, and then the remnants of that larger world becoming the Earth and Moon
Or perhaps Earth and Theia.
There was also the theory that explained the Moon's density by proposing it was like honeycomb inside, only a handful of people thought either of those theories made any sense.
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Venus and Mars both have no usable atmosphere because of the lack of a strong magnetic field. Venus has a dense (and poisonous) atmosphere because all the lighter gasses are forced to the top, and whisked away by the solar wind, leaving only the heaviest behind. If the planet had a magnetic field, the wind effect stripping away the atmosphere wouldn't have been as strong, and an equilibrium could have been achieved. Mars has the same effect, but not as much concentration of "heavy" because the lighter gravity. There's simply less to begin with. But what's there is CO2, heavier than O2 or N2, though some N2 is present. The elemental gasses were stripped away as well.
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Or maybe the Moon was here first, and Earth crashed into it. So we're actually on the Moon, and the thing in the sky at night is actually Earth!
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The same could apply to evolution, to most of cosmology, to archaeology, to Egyptology, how the pyramids were made, to how cells formed, to just about every aspect of science.
It's just sheer ignorance to suggest that it's not worth pursuing.
Science is about looking what's ALREADY out there. Formulating a theory that ties some parts of it together and maybe how it originated.
Then testing your theory on other, sometimes unrelated parts of the universe. If they work, great, we have a certain amount of knowledge and ability to predict what might happen next. If they don't, great, we know that we have the wrong idea / made an incorrect correlation somewhere. Both are knowledge you can use to improve your next hypothesis and so get closer to a probable answer.
Without simple bases like these, you can't answer the bigger questions. And suggesting the knowledge is useless because "we'll never know exactly what happened" is like saying that studying an air-crash into the Alps is pointless because "we'll never know exactly what happened"... there's still things to deduce, lessons to learn, knowledge that you can use going forward to improve people's lives.
You're an idiot. And a not particularly forward-thinking one either. Proving that, even only to a certain probability, the Earth, Moon and this object were of the same composition suggests where all of them might have come from. It suggests what to look for. It suggests how planets themselves might form. That suggests how we might find places where planets might be likely to form. That suggests how we look for those places. That suggests what might be interesting areas of the universe.
In the same way that some dickhead can claim that the world just popped into existence 6000 years ago and consider themselves "just as correct" as hundreds of years of scientific study by hundreds of thousands of scholars, you're just as much an idiot to suggest that this knowledge is as worthless as you claim.
And the reason you see so many earth-moon-creation theories (actually hypotheses until they are proven) and papers every month? Because it matters. And because each one - by its disproval - gets us closer to an answer, and builds on the knowledge of the previous, and is an area of intense study by respected scientists. And all that stuff in the news you see about how we've located thousands of planets around foreign stars that we didn't even know were there before, how we've managed to detect Earth-like ones in that, how we might choose candidates to mine in the future? That's all possible because of those papers.
And, even simpler than that, just simple geology here on Earth is improved by that knowledge.
If you don't get that science is merely a way to predict the future using the evidence of the past, you're a fucking moron.
little sister, don't you.... little sister, don't you.... little sister, don't you me kiss once or twice and then you run.... little sister, don't you do what your big sister done...
So the theory is that there were 2...they collided...and are still 2. They are made of similar stuff too, before and after. I'm sorry, how do we know they impacted again? Oh right...they are slightly different ages...we've mastered that whole dating thing back to 14 billion years. Wait, that doesn't mean they collided...hmmm I'm stumped.
OK, am I the only one to read that summary and thin "shattered impactor" would be an awesome name for a band?
Lost at C:>. Found at C.