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Last 10 Posts [ In reverse order ]
Robittybob1 Posted on Today at 6:29 PM
 
QUOTE (Robittybob1 @ May 23 2013, 09:47 AM)
....  I had proposed that at 3.5 Billion years the whole Earth and Moon tidally locked together, so that is a definite thermal minimum. .....

I see there needed to be a correction here. On the timeline revision I did last night I see the Snowball Earth happened at about 3 billion years ago rather than 3.5 billion.
That doesn't change the Yo-yo theory, and may even make it easier to explain for the time of deceleration is lengthened.
Robittybob1 Posted on Today at 9:47 AM
  Can the Yo-yo Moon Capture Theory allow for the Moon to become molten sometime in the past that is sufficient to account for the paucity of water in the Moon rocks?

When would this have happened? Obviously it wasn't when the Moon was captured and it wasn't when they were tidally locked, but what about as the Moon tidally decelerated in toward a really massive Earth. Imagine if the Earth still had 3-4 times its current mass at that stage, the Moon had by now been reduced from the 42 at the time of capture down to just 1 Moon mass at the 4.4 billion years ago.

The tidal energy in the Moon flexing the Moon substance to the point of melting the surface. Is there a thermal maximum at sometime during the capture process. I had proposed that at 3.5 Billion years the whole Earth and Moon tidally locked together, so that is a definite thermal minimum. Maybe the Thermal maximum was at 4.4 billion years ago.
What causes this heating? Io one of Jupiter's moons is molten due to gravitational flexing.
https://en.wikipedia.org/wiki/Io_(moon)
QUOTE
With over 400 active volcanoes, Io is the most geologically active object in the Solar System.[7][8] This extreme geologic activity is the result of tidal heating from friction generated within Io's interior as it is pulled between Jupiter and the other Galilean satellites—Europa, Ganymede and Callisto. Several volcanoes produce plumes of sulfur and sulfur dioxide that climb as high as 500 km (300 mi) above the surface. Io's surface is also dotted with more than 100 mountains that have been uplifted by extensive compression at the base of the moon's silicate crust. Some of these peaks are taller than Earth's Mount Everest.[9] Unlike most satellites in the outer Solar System, which are mostly composed of water ice, Io is primarily composed of silicate rock surrounding a molten iron or iron sulfide core. Most of Io's surface is characterized by extensive plains coated with sulfur and sulfur dioxide frost.

If the Moon still had rotational energy and excessive kinetic energy left over from the capture maybe this was enough. Momentum is being transferred to the Earth as rotational energy so the Moon has to lose the huge amounts of orbital energy as result of being captured by a massive primordial Earth.
But since mass is being lost by the Moon and the Earth it is very difficult to put figures to the situation, but it may be possible to make some estimates if we say the maximum heating occurred at 4.4 bys.
Robittybob1 Posted on Today at 8:27 AM
  must be the full Moon.
http://answers.yahoo.com/question/index?qi...11214623AAxBnmT
Why are the oldest moon rocks older than the oldest Earth rocks?
QUOTE
The Moon doesn't have plate tectonics. Earth's surface still has some zircon crystals dating to 4.4 billion years old, just 100 million years after the Moon was created. However, nearly all of Earth's surface is millions of years old rather than billions. Rock cycles through and get melted or transformed by pressure and heat. This process never took place on the Moon. The rock froze solid and most of it stayed solid.


Was it really the oldest Moon rock? No it may just be the oldest of the few rocks brought back from the Moon. But on Earth they have really searched for the oldest rock and nothing comes real close.
http://www.nhm.ac.uk/nature-online/space/p...m/moon/samples/
QUOTE
The lunar rocks were also much older than expected, the oldest being 4.4 billion years old. This is much older than the oldest Earth rocks, which are around 3.8 billion years old. This is because the Moon's volcanoes have stopped spewing new lava to the surface and there is no wind or water to erode the surface, whereas the Earth's surface is continually changing. Little has changed on the Moon's surface for billions of years.
Robittybob1 Posted on Today at 4:17 AM
  The Moon forming first explains why the Moon orbits the Sun close to the ecliptic. (The ecliptic is the plane of the Solar system.)

I'm not saying it did form first but in the Yo-yo Moon Capture theory there is nothing saying it couldn't do this.
I tend to think it may have been at the same time, but that is just as unlikely really.
Robittybob1 Posted on Today at 4:05 AM
 
QUOTE (Robittybob1 @ May 23 2013, 01:11 AM)
How are these times established anyhow? I think we need to refresh on the timing of the events, and how they can be established. How accurate are these estimates?

Well there are extensive writings on this topic in Wikipedia "History of the Earth"
http://en.wikipedia.org/wiki/History_of_the_Earth

It ends up that the rocks on the Moon are older than any discovered on the Earth!

QUOTE
During the Apollo program, rocks from the Moon's surface were brought to Earth. Radiometric dating of these rocks has shown the Moon to be 4.53 ± .01 billion years old,[29] at least 30 million years after the solar system was formed.[30] New evidence suggests the Moon formed even later, 4.48 ± 0.02 Ga, or 70–110 million years after the start of the Solar System.[31]


OK this is probably explained by weathering of the Earth rocks, and no weathering on the Moon.
The earliest Earth rocks formed in oceans yet the Heavy to Late Bombardment had not yet occurred.
QUOTE
From crater counts on other celestial bodies it is inferred that a period of intense meteorite impacts, called the Late Heavy Bombardment, began about 4.1 Ga, and concluded around 3.8 Ga, at the end of the Hadean.[23] In addition, volcanism was severe due to the large heat flow and geothermal gradient.[24] Nevertheless, detrital zircon crystals dated to 4.4 Ga show evidence of having undergone contact with liquid water, suggesting that the planet already had oceans or seas at that time.[17]



QUOTE
The oldest rocks found on Earth date to about 4.0 Ga, and the oldest detrital zircon crystals in rocks to about 4.4 Ga,[17][18][19] soon after the formation of the Earth's crust and the Earth itself. The giant impact hypothesis for the Moon's formation states that shortly after formation of an initial crust, the proto-Earth was impacted by a smaller protoplanet, which ejected part of the mantle and crust into space and created the Moon.[20][21][22]


So even I can see the possibility that the Moon formed before planet Earth did
Could it have formed at L3 Lagrangian point and remained there till the Earth formed? If things were symmetrical it could of worked for a while?

There is very little to go on but this is what has been written up in Wikipedia.
Based on the raw data you have to have the Moon forming first.
Robittybob1 Posted on Today at 1:11 AM
 
QUOTE (Capracus @ May 22 2013, 11:26 AM)
At the time of the Giant Impact the Earth was only midway through its 100 million year accretion period. The volatiles and organics necessary for life still had hundreds of millions of years to be delivered by asteroids and comets before life would arise some 700 million years after the end of accretion.....

How are these times established anyhow? I think we need to refresh on the timing of the events, and how they can be established. How accurate are these estimates?
Robittybob1 Posted on Yesterday at 8:21 PM
 
QUOTE (Capracus @ May 22 2013, 11:26 AM)
At the time of the Giant Impact the Earth was only midway through its 100 million year accretion period. The volatiles and organics necessary for life still had hundreds of millions of years to be delivered by asteroids and comets before life would arise some 700 million years after the end of accretion.

How Life Arose On Earth: Researchers Brew Up Organics On Ice
http://www.sciencedaily.com/releases/2012/...20918162220.htm

Interesting related article as well:
"Organics Probably Formed Easily in Early Solar System"
http://www.sciencedaily.com/releases/2012/...20330205815.htm

You seem to think comets will bring enough chemicals to a planet to kick start the life forming process. I tend to the view it was the planet building process that brings the chemicals to the planet. So you might think we are saying the same thing but I tend to disagree. To me a planet is the condensation of a torus that formed in the protoplanetary dust disc. Comets are formed later from the off-pouring of the primordial oceans that formed on the planets. They go out and then a few return; with simply quite insufficient amounts to do the job.
Robittybob1 Posted on Yesterday at 8:03 PM
  So to recap some general discussion and the features of the Giant Impact theory that are not conducive to life, covered in the previous page:
1. The predominant motion of the Moon is an orbit around the Sun and secondarily it orbits the Earth.
2. Because of the mass differences the Earth and planet Luna orbited the Sun as co-planet but at different speeds, so from time to time they would pass each other.
3. The two orbits have an inherent instability and the eccentricity of the Moon gets larger as time passes.
4. Life would need temperatures under 100 degrees Celsius, so how does the Earth cool after the Giant Impact – unexplained.
5. The Hiten Mission (Japanese Space Agency) which flew through the Earth–Moon L4 and L5 Lagrangian points in 1992; found no increase in dust levels. – Does not support the Giant Impact theory (GI).
6. The physics of forming a Moon after the GI is suspect
7. I still feel all these major impacts would sterilize the Earth. No Chemical left to become the building blocks for life.
Capracus Posted on Yesterday at 11:26 AM
  At the time of the Giant Impact the Earth was only midway through its 100 million year accretion period. The volatiles and organics necessary for life still had hundreds of millions of years to be delivered by asteroids and comets before life would arise some 700 million years after the end of accretion.

How Life Arose On Earth: Researchers Brew Up Organics On Ice
http://www.sciencedaily.com/releases/2012/...20918162220.htm
Robittybob1 Posted on Yesterday at 10:48 AM
 
QUOTE (Capracus @ May 22 2013, 09:52 AM)
This article addresses some of the impact and water issues.
http://www.earthmagazine.org/article/moon-...t-impact-theory

To resolve the issue of the commonality of interior water shared by the Earth and Moon, I’m beginning to think that there may have been some asteroid debris sent in by the Jovians  that may have been present during the final stages of accretion of the Earth/Moon system.

I still feel all these major impacts would sterilize the Earth, all the preformed organic molecules so essential for life are going to be totally lost in a major impact. Without these chemicals life would just not be able to commence.
That is my fear, so how do you explain the source of the building blocks for DNA and proteins? Sensitive molecules that seem unlikely to survive a melting of the Earth.
Non-volatile also, so you can't just make them float in the clouds to rain down at a later stage.
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