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Last 10 Posts [ In reverse order ]
Robittybob1 Posted on Today at 4:40 AM
  looking up Google to see if anyone has dared to estimate the speed of the Early Moon.
QUOTE
The newly formed moon circled just 14,000 miles above Earth, racing around the planet every two hours. It orbited so close to Earth it filled much of the sky

from http://books.google.co.nz/books?id=EIrwxgp...20earth&f=false

That seems even more ridiculous?
Doesn't seem to be easily found.

Also look in here please http://www.fas.harvard.edu/~planets/sstewart/Moon.html
"A New Model for the Origin of the Moon"
Robittybob1 Posted on Today at 4:05 AM
 
QUOTE (Robittybob1 @ May 21 2013, 08:17 PM)
What with a Moon at 40,000 km above the Earth! The tidally induced friction in the Earth's crust would continue to knock life back.  How does it go, the Earth was completely molten after the collision.  So when did it start to cool, when was it cool enough for water and where did the organic precursors come from once the Sun was intense enough to blow all the protoplanetary dust away?

OK the Yo-yo Moon capture theory brings the Moon close in too, how close I haven't calculated yet, but in my scenario there is vast oceans of water to evaporate before the Earth ever became a molten cauldron.
You calculate the stresses on the Earth's crust of a Moon at 40,000 km with the Earth whipping around at 4-5 revolutions per day. To remain at that minimal distance the Moon would be orbiting at a phenomenal rate too.
My first attempt at calculating that gave a result of 22 hours, can you live with that?
Period of the Lunar month 22 hours and the day length 5 hours?  How long before you get things cool enough for life?

T = 2 * PI * SQRT ( A^3 / ( G * ( M1 + M2 )  T in seconds. = 7.91E+04
7.91E+04 / 3600 = 2.20E+01 hours.

Can anyone confirm they read that the newly formed Moon immediately after the Giant Impact was orbiting the Earth once every 22 hours or thereabouts?

So what speed would the material initially have in order to able to have an average speed enabling an orbit at 40,000 km?
Just the speed relative to the Earth will do. OK so would any material after impact and blasted backward be included in the Moon?
Well if it was it would be lowering the net orbital momentum/energy.
Mass goes from zero to "V" at a height of 40,000 km.
Putting in the figures the velocity at that height, on first calculation, came out to an incredible 1.82E+06 m/sec or 6/1,000th the speed of light. Can that really be true??? 1,821 kms/sec???
Must have made a mistake somewhere! Either that or the GI theory has flaws.

If Theia comes in at 20 km/sec how does the scatter have an average velocity of 1,821 km/sec even after climbing to 40,000 km against the Earth's gravity?
I going to have to check the math but it doesn't add up.

OK let's work that backward if it hits the Earth at 20 km/sec and the ejected material is able to maintain that velocity, how high up will it be able to go into orbit around the Earth?
Strangely enough it comes out to 40,000,000 meters or 40,000 km, but it has to climb to that height under the Earth gravitational attraction so the speed will decline and it won't reach that height! (look at the ballistic equations) There's a problem Houston!

The Maths of the Giant impact theory seems a bit suspect to me.
Something starting off at 25,000 m/sec how high will it go under the Earth's gravitational field?
And then you would have to factor in air resistance as well.
And wasn't it supposed to be hitting a relatively slowly spinning Earth, imparting momentum to the Earth in the process? That must cut back the speed as well.
And the fact that all the particles will be going in different directions their net velocity is cut back even further.

I'll look at the calculations later - maybe.
Robittybob1 Posted on Today at 1:02 AM
 
QUOTE (Robittybob1 @ May 21 2013, 09:43 PM)
I think there are problems with the Giant Impact theory. What do you think?

WOULDN'T THIS BE ANOTHER NAIL IN THE COFFIN OF THE GIANT IMPACT THEORY?

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.

If the there was a massive impact these points would have collected dust wouldn't they?
https://en.wikipedia.org/wiki/Lagrangian_po..._point_missions

In the yo-yo Moon Capture theory these points would have been swept clean every 16,000 years.
Robittybob1 Posted on Yesterday at 9:43 PM
 
QUOTE (Robittybob1 @ May 21 2013, 08:17 PM)
What with a Moon at 40,000 km above the Earth! The tidally induced friction in the Earth's crust would continue to knock life back. How does it go, the Earth was completely molten after the collision. So when did it start to cool, when was it cool enough for water and where did the organic precursors come from once the Sun was intense enough to blow all the protoplanetary dust away?

OK the Yo-yo Moon capture theory brings the Moon close in too, how close I haven't calculated yet, but in my scenario there is vast oceans of water to evaporate before the Earth ever became a molten cauldron.
You calculate the stresses on the Earth's crust of a Moon at 40,000 km with the Earth whipping around at 4-5 revolutions per day. To remain at that minimal distance the Moon would be orbiting at a phenomenal rate too.
My first attempt at calculating that gave a result of 22 hours, can you live with that?
Period of the Lunar month 22 hours and the day length 5 hours? How long before you get things cool enough for life?

T = 2 * PI * SQRT ( A^3 / ( G * ( M1 + M2 ) T in seconds. = 7.91E+04
7.91E+04 / 3600 = 2.20E+01 hours.

I think there are problems with the Giant Impact theory. What do you think?
Robittybob1 Posted on Yesterday at 8:17 PM
 
QUOTE (Capracus @ May 21 2013, 07:33 AM)
How does a Theia collision alter the history of life on Earth? It wold be another 800 million years before the appearance of life on Earth, still ample time for development.

What with a Moon at 40,000 km above the Earth! The tidally induced friction in the Earth's crust would continue to knock life back. How does it go, the Earth was completely molten after the collision. So when did it start to cool, when was it cool enough for water and where did the organic precursors come from once the Sun was intense enough to blow all the protoplanetary dust away?

OK the Yo-yo Moon capture theory brings the Moon close in too, how close I haven't calculated yet, but in my scenario there is vast oceans of water to evaporate before the Earth ever became a molten cauldron.
You calculate the stresses on the Earth's crust of a Moon at 40,000 km with the Earth whipping around at 4-5 revolutions per day. To remain at that minimal distance the Moon would be orbiting at a phenomenal rate too.
My first attempt at calculating that gave a result of 22 hours, can you live with that?
Period of the Lunar month 22 hours and the day length 5 hours? How long before you get things cool enough for life?

T = 2 * PI * SQRT ( A^3 / ( G * ( M1 + M2 ) T in seconds. = 7.91E+04
7.91E+04 / 3600 = 2.20E+01 hours.




Robittybob1 Posted on Yesterday at 6:33 PM
  Tornado in Oklahoma - 2 miles wide! Total devastation. I found I couldn't focus my mind on the Moon while the news of this disaster was on the TV.
Robittybob1 Posted on Yesterday at 8:28 AM
 
QUOTE (Robittybob1 @ May 20 2013, 11:11 PM)
It is one thing to say the Earth captures the planet Luna and throws it over itself!  I have to really figure out if that is possible.
It must have been possible for other planets as plenty of the planets have captured moons, but is it possible for Earth to capture Luna?
I like the way the tidal deceleration has worked to synchronize the two bodies (bringing them into nearly the same orbital period).
I recall seeing a diagram (Trippy's?)of the Moon's wavy passage around the Sun.  The Moon orbits the Earth but this is more or less created from periods of dropping toward the Sun and then being flung out again.  The Moon never goes backwards when viewed from the Sun.

This image gives the idea correctly, whereas most YouTube animations have the scales out so much it looks like the Moon goes periodically backwards when viewed from the Sun's perspective.
http://en.wikipedia.org/wiki/File:Moon_trajectory1.svg

From the diagram, looking from the lower left hand corner, follow the arc up to the right and see how the Moon takes quarter revolutions around the Earth. So that is the way the Earth "throws the Moon up and over itself" but it is not just the Moon orbiting the Earth but the Moon is coming and going from the Sun as well and this will affect its kinetic energy to potential energy balance. So I guess it is really difficult to take the eccentricity out of the Moon-Earth system, even though with the Yo-yo Moon Capture theory when they were tidally locked, I'd like to know whether all this eccentricity was present then or not? If my reasoning is correct the eccentricity is inherent, but with the larger orbit, as the Moon is making now compared to then, I would hazard a guess that the eccentricity is getting worse because the radius is getting larger (the Earth is adding energy all the time), but on the other hand it could be lessening because the orbital period is getting longer. So which effect dominates?
Any comments on what the answer maybe please?

The study below has picked up an increase in the eccentricity of the Moon. So maybe the action of throwing the Moon into a higher orbit, which implies the Moon gets both closer to the Sun and further away depending on which side of the Earth it is on, has an intensifying effect on the Moon's eccentricity. Well that is my rough and ready guess.

The following study could be read:
"On the anomalous secular increase of the eccentricity of the orbit of the Moon"
http://arxiv.org/pdf/1102.0212.pdf
QUOTE
ABSTRACT
A recent analysis of a Lunar Laser Ranging (LLR) data record spanning 38.7 yr revealed an anomalous increase of the eccentricity e of the lunar orbit amounting to e˙meas = (9 ± 3) × 10−12 yr−1. The present-day models of the dissipative phenomena occurring in the interiors of both the Earth and the Moon are not able to explain it.
In this paper, we examine several dynamical effects, not modeled in the data analysis, in the framework of long-range modified models of gravity and of the standard Newtonian/Einsteinian paradigm. It turns out that none of them can accommodate ˙emeas. Many of them do not even induce long-term changes in e; other models do, instead, yield such an effect, but the resulting magnitudes are in disagreement with ˙emeas. In particular, the general relativistic gravitomagnetic acceleration of the Moon due to the Earth’s angular momentum has the right order of magnitude, but the resulting Lense-Thirring secular effect for the eccentricity vanishes. A potentially viable Newtonian candidate would be a trans-Plutonian massive object (Planet X/Nemesis/Tyche) since it, actually, would affect e with a non-vanishing long-term variation. On the other hand, the values for the physical and orbital parameters of such a hypothetical body required to obtain at least the right order of magnitude for ˙e are completely unrealistic: suffices it to say that an Earth-sized planet would be at 30 au, while a jovian mass would be at 200 au. Thus, the issue of finding a satisfactorily explanation for the anomalous behavior of the Moon’s eccentricity remains open.


I thought it a bit odd they didn't have an explanation for the increase in eccentricity yet I had proposed a reason even before I had known about this scientific study!
Capracus Posted on Yesterday at 7:33 AM
 
QUOTE (Robittybob1 @ May 17 2013, 08:05 PM)
There would be no prospect of life on Earth after that.

How does a Theia collision alter the history of life on Earth? It wold be another 800 million years before the appearance of life on Earth, still ample time for development.
Robittybob1 Posted on Yesterday at 3:36 AM
 
QUOTE (Robittybob1 @ May 20 2013, 07:52 PM)
So to recap some of the features of the Yo-yo capture theory in the last page:
1. There was a slow to non-spinning Earth prior to Moon capture.

2. The Earth catches up to the Moon via the natural orbital velocity difference.

3. At each pass of the planets Earth and Luna, the relative motion between the planet Luna (Moon) is slowed by speeding the Moon up (lower Lunar -Sun orbit)
(This must mean the period between conjunctions increase with time, as the orbital periods become synchronized. This bit is a logical consequence of #3.)

4. Earth Moon interact captures planet Luna (Moon) and throws it into an elliptical orbit over the top of the Earth from the Sun's perspective.

I want to clear up one thing, for there seems to be a contradiction in what I have said in the last several posts:
1. "3. At each pass of the planets Earth and Luna, the relative motion between the planet Luna (Moon) is slowed by speeding the Moon up (lower Lunar -Sun orbit)
(This must mean the period between conjunctions increase with time, as the orbital periods become synchronized. This bit is a logical consequence of #3.)"

And prior to that:
2. "The Moon gains speed on one leg, the Moon and the Earth move toward each other relatively (as well as orbiting the Sun, so I'm not suggesting anything goes backwards). The Moon would then slow on the going-away half of the orbit. I think that means the two halves are dynamically balanced."

So I will agree that these two statements are partially true but also a little contradictory too, for I would say that if there was angular momentum transferred the two halves of the orbit will not be fully dynamically balanced as a consequence. The transfer of the momentum dampens the balance.
This transfer of momentum would tend to make the Earth and Lunar spin anticlockwise looking down on the system. [I will try to use the term Luna for the planet Luna prior to its capture as the Moon.]
Robittybob1 Posted on May 20 2013, 11:11 PM
  It is one thing to say the Earth captures the planet Luna and throws it over itself! I have to really figure out if that is possible.
It must have been possible for other planets as plenty of the planets have captured moons, but is it possible for Earth to capture Luna?
I like the way the tidal deceleration has worked to synchronize the two bodies (bringing them into nearly the same orbital period).
I recall seeing a diagram (Trippy's?)of the Moon's wavy passage around the Sun. The Moon orbits the Earth but this is more or less created from periods of dropping toward the Sun and then being flung out again. The Moon never goes backwards when viewed from the Sun.

This image gives the idea correctly, whereas most YouTube animations have the scales out so much it looks like the Moon goes periodically backwards when viewed from the Sun's perspective.
http://en.wikipedia.org/wiki/File:Moon_trajectory1.svg
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