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Posted on 11/21/2007 1:12:51 PM PST by Aristotelian
Moons like the Earth's - which are formed in catastrophic collisions - are extremely rare in the Universe, a study by US astronomers suggests.
The Moon was created when an object as big as the planet Mars smacked into the Earth billions of years ago.
The impact hurled debris into orbit, some of which eventually consolidated to form our Moon.
The Astrophysical Journal reports that just 5-10% of planetary systems in the Universe have moons created this way.
(Excerpt) Read more at news.bbc.co.uk ...
Lots of paths to the same ends...
This was claimed by Zecharia Sitchin in his Book The 12th Planet published in 1976.
I’m the same way. I look to science and astronomy as all the evidence of God that I need.
... and where did that Mars-sized object come from, and where did it go? Answer that, Sagan!!!
Mars appears to have had a planet of its own at some time. That is, Mars would have been the moon of that system. What happened to its planet is not clear although it is possible some of it is in the Asteroid Belt and a piece of it could have been the body that nearly hit earth creating the moon.
It couldn’t have happened billions of years ago. The earth is only 6,000 years old.
Indeed the moon could have been wondering around the universe for billions of years, and when G*d created the earth, the gravitational pull of the new planet snagged the moon into place.
Carl is unusually silent today.
Perhaps as rare as it having the same angular dimensions as the Sun at Earth’s surface, thus providing a “perfect” solar eclipse to us mere mortals at this time in history...
A momentary circumstance, an instant on the cosmic timescale. The moon is already gone, escape velocity achieved.
When the Days Were Shorter
Alaska Science Forum (Article #742) | November 11, 1985 | Larry Gedney
Posted on 10/04/2004 1:31:59 PM EDT by SunkenCiv
http://www.freerepublic.com/focus/f-chat/1234919/posts
New evidence for the Moon’s soft middle
New Scientist | 14 February 2002 | Will Knight
Posted on 12/27/2004 5:29:35 PM EST by SunkenCiv
http://www.freerepublic.com/focus/f-chat/1309193/posts
In the shadow of the Moon
New Scientist | 30 January 1999 | editors
Posted on 08/31/2004 11:42:25 AM EDT by SunkenCiv
http://www.freerepublic.com/focus/f-chat/1203912/posts
Did an ancient impact bowl Pluto over?
New Scientist | October 5, 2007 | Maggie McKee
Posted on 10/30/2007 10:29:02 PM EDT by SunkenCiv
http://www.freerepublic.com/focus/f-chat/1918724/posts
Red Planet’s Ancient Equator Located
Scientific American (online) | April 20, 2005 | Sarah Graham
Posted on 04/24/2005 11:18:25 PM EDT by SunkenCiv
http://www.freerepublic.com/focus/f-chat/1390424/posts
The Moon produces slightly more than half of the tides — the rest are produced by the Sun. So, no, the Moon isn’t necessary for the Earth to have tides.
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The South Pole-Aitken basin (circled) is the largest impact crater in the solar system. One edge lies on the Moon's south pole, while its centre lies about 30° away (Image: Clementine Project/LPI)
Did the new moon lose its iron heart?The current theory says that the material that now forms our moon was ejected when Earth was struck by another planet-sized body. But Peter Noerdlinger at Saint Mary's University in Halifax, Canada, says this theory has problems. "The collision has to be implausibly gentle. You practically need someone to hold a Mars-sized object just above Earth and drop it, to avoid messing up Earth's orbit."
New Scientist
January 23, 2007
The simpler idea that Earth and the moon were both created from the same gas cloud had been rejected because it could not explain why Earth formed an iron core and the moon did not. Now, Noerdlinger has an answer for that.
He suggests that the proto-moon did have an iron core, but that the satellite was ripped apart in a close encounter with Earth. His calculations show that iron from the core would be pulled towards Earth, while the remains of its rocky outer shell reassembled into our iron-free moon.
This fits with evidence that the Earth acquired a veneer of iron after it formed, Noerdlinger says. He presented the work at the American Astronomical Society meeting in Seattle, Washington, last week.
From issue 2587 of New Scientist magazine, 23 January 2007, page 16
The primary reason that I say that is because we only recently discovered that there are literally a billion other galaxies, and at this point we have only surveyed a few dozen or so with telescopes of different varieties and only a couple of those are close enough to determine that some of the systems have one or more planets.
We are not close enough to any of those to determine how many or what kind of moons they may have, and certainly not how they were formed. We can only prove that some sort of planet exists because of orbital anomalies in their suns. We cannot actually see any planets at all, much less moons.
Collisions must be common during the formation of galaxies and their planetary systems because everything starts out as a compact cluster of gas and building block materials. Collisions are a part of that formation and not only do they occur, they must occur.
Nope.....the moon is not all that special to anyone but us. Sure it is important to Earth and it's ability to grow so much life, but their certainly could be billions of other Earths in the universe.....Billions (in my most humble opinion)
alas...
Earth’s Moon is Rare Oddball
Space.com on Yahoo | 11/20/07 | Dave Mosher
Posted on 11/20/2007 10:40:12 PM EST by NormsRevenge
http://www.freerepublic.com/focus/f-chat/1928673/posts
Yes, his "bill-yuns and bill-yuns" of molecules have been appropriated by worms.
Re: planets observed in other galaxies
While you’re right that there ars billions of other galaxies and rach of those have billions of stars, I don’t think we are capable of resolving images, visible or radio frequencies, of stars in other galaxies sufficient to discern the tell-tale wobble of even a binary star much less the wobble of a planet. Our extra-solar planetary discoveries are pretty much limited to the local area in our own galaxy and that is a pretty small volume... as astronomic volumes go. We actually are working with a very small dataset.
I agree with the article’s premise that our moon is a rarity. But I think the postulated 5-10% is way too high. That percentage would almost guarantee that every star system with a planetary population of ten or more planets would have a similar dual planet created from a similar hypothetical ancient collision. I find that hard to believe.
Such collisions would require large numbers of planetary bodies having formed by accretion with wildly differing orbital shapes... Something that the stellar accretion ring to planet theory does not support. Any planet formed from such an accretion ring around the same star would orbit in essentially the same plane and in the same direction in orbits mimicking the circular orbits of their accretion ring.
The forces necessary to change the orbit of any planet accreted in the same stellar system from its original near circular orbit to a potential collision prone parabolic orbit are, well, astronomic. Gravity alone cannot account for it... Tidal forces will have already been automatically adjusted during the billions of years of accretion (otherwise the planets could not have formed).
The odds that numerous planet/moon combinations like ours were caused by collisions with cosmic interlopers, planets from outside the stellar system, are also beyond astronomic. First we would have to postulate a free roaming planet that had somehow escaped its own birth star. Then we would have to have sufficient time for this hypothetical impacting planetoid to cross interstellar distances while only moving at non-relatavistic speeds. And then it would have to either pass by the target planet at just the right velocity to be captured or be vectored just exactly right to impact another planet of similar size (too large and no material is blasted off to form a moon; too small and the interloper is not even captured by the star). Space is huge... A miss is far more likely than a hit.
Neither of these scenarios is likely to have occurred often enough for there to be that high of a percentage... I think one in a million would be too high.
Or perhaps planets are not formed as we think and some other mechanism than gravity is at work in their formation.
Current estimate is 100 billion galaxies inside the Hubble volume. Odds are no other earth. Some may be close eough in the major parameters that they could be made livable, but we as a species of engineering creature are not equipped to do anything of the sort. About all we can do is pass a law against Global Warming.
Hoagland now claims that the three degree microwave background radiation is a local phenomenon and is the residue of the explosion of Planet V 65 million years ago.
What was in #24? :’D
Double post
An accidental double of the previous post...
Whoever penned the piece didn’t think it as rare as the headline writer either. I wouldn’t call 5 to 10 percent of planetary systems with similar features extremely rare. Extremely rare is more like White Sox world championships.
:’) Okay, but was it a double post? ;’)
One of those rare double posts caused by an internet collision...
Maybe it was just a lensing phenomenon...
Maybe it was just a lensing phenomenon...
Nuts, I was hoping it would be online.
December 2007
Features
Why is the solar system cosmically aligned?
The solar system seems to line up with the largest cosmic features. Is this mere coincidence or a signpost to deeperinsights?
DRAGAN HUTERER
http://www.astronomy.com/asy/default.aspx?c=ci&id=24
http://huterer.physics.lsa.umich.edu/~huterer/publications.html
http://astro.uchicago.edu/people/dragan-huterer.shtml
http://front.math.ucdavis.edu/author/D.Huterer
I see some discussion online but one article that seems appropriate is by subscription only. This COBE multipole study has been around for a while but only now is it getting some attention from the common people. This could change everything in cosmology.
Rumor has it that the DRAGAN HUTERER article can be found at http://huterer.physics.lsa.umich.edu/~huterer/PLOTS/CMB_Huterer.pdf
Very interesting and informative.
Earth’s Moon is Rare Oddball
Space.com on Yahoo | 11/20/07 | Dave Mosher
Posted on 11/20/2007 7:40:12 PM PST by NormsRevenge
http://www.freerepublic.com/focus/chat/1928673/posts
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