If a planetary collision made the moon..?, page 1

reply to post by Totalstranger

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The Giant Impact theory says that the impact occurred when the Earth was still semi fluid. When the smaller planet hit Earth the impact was so great that it essentially remelted both planets. Most of the core and heavier material of the smaller planet merged with Earth. The remaining, mostly lighter, debris formed a disk around the Earth. The disk coalesced and formed the Moon.

In a nutshell, much of the small planet became part of Earth. The moon is composed of parts of both.

reply to post by Jim Scott

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The oldest samples from the Moon are dated at 4.46 billion years. This is about 100 million years younger than the oldest meteorites which formed at the same time the Solar System did.
www.psrd.hawaii.edu...

Here is a astronomical definition that may be handy to those who dispute or simply do not understand the process...

Accretion



[edit on 9/29/2009 by jkrog08]

reply to post by ThaLoccster

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Yes, that is the 'bulge' created on the Earth by the tidal force created by the Moon. It is all basic celestial mechanics.

[edit on 9/29/2009 by jkrog08]

Originally posted by Phage
reply to post by Totalstranger

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The Giant Impact theory says that the impact occurred when the Earth was still semi fluid. When the smaller planet hit Earth the impact was so great that it essentially remelted both planets. Most of the core and heavier material of the smaller planet merged with Earth. The remaining, mostly lighter, debris formed a disk around the Earth. The disk coalesced and formed the Moon.

In a nutshell, much of the small planet became part of Earth. The moon is composed of parts of both.

(Love this BTW) so....is Saturn going to 'coalesce' someday? Why has it not? Surely it can't be that much younger than the earth and moon, right? Would the increased forces acting on the earth make the moon and earth coalesce faster?

Does the moon have an metal core? Does the presence or lack of a metal core allude to it's origins?

I always love your answers phage, their so sterile. That's not an insult. (nothing but the facts, m'am.)

reply to post by KSPigpen

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The rings of Saturn are within what is known as the Roche Limit so they will never form a moon. In fact it could be that they once were a moon. The Roche limit is the distance from a planet at which another body will disintegrate due to the tidal forces applied to it. According to the Giant Impact theory there was enough material thrown outside the Roche limit to form the Moon.

There is evidence that the Moon may have a small iron core. As it formed, the heavier material would settle to the center.

No facts (except for the Roche Limit), just theory. But theory that has a lot of evidence to support it.

Discovery Channel did a whole documentary on this... here is the DVD link.

Moon

Following is the DVD Description, if you don't want to go to the link
__________________________________________
What would life on earth be like without the moon? Well, chances are, there wouldn't be any life on earth without the moon. Life – if it had started at all – would still be in the earliest stages of evolution.

Scientists use the latest computer simulations to show how an ancient rogue planet – Orpheus – collided with the earth millions of years ago, producing a sizable chunk of debris that eventually became our moon. If that collision had never occurred, we would live in a very different place. Imagine a moon-less weather report – blizzards over the Sahara, floodwaters swallowing the Pyramids, 90-degree temperatures in Antarctica. As the earth wobbles on its axis – unsecured by the moon's gravitational pull – the polar caps would grow and recede at frightening rates. And without the moon, our planet would spin much faster – meaning four-hour days and searing temperatures.

Worse yet, evidence reveals that we are in fact losing our grip on our lunar friend thanks to the ebb and flow of the oceans' tides. Experts reveal theories for salvaging the moon – including hijacking Europa from Jupiter – and demonstrate how we can prepare ourselves for our eventual life without it.

Originally posted by Jim Scott
The Moon is much older than the Earth or the Sun, by at least one billion years. The material from the Moon was tested in labs on Earth. Surface rocks dated around 4.5 billion years, but the soil deeper tested over a billion years older. The Moon is not from the Earth or from our own solar system. It is foreign to our solar system.

That's not true at all. Why are you making stuff up? The moon rocks range in age from about 3.16 billion years old for the basaltic samples derived from the lunar maria, up to about 4.5 billion years old for rocks derived from the highlands.

James Papike, Grahm Ryder, and Charles Shearer (1998). "Lunar Samples". Reviews in Mineralogy and Geochemistry 36: 5.1–5.234.

US Geological Survey
pubs.usgs.gov...

The oldest dated moon rocks, however, have ages between 4.4 and 4.5 billion years and provide a minimum age for the formation of our nearest planetary neighbor.

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