OK as we all Know the moon is moving about 3.8 centimeters away from the earth per year . So my questions are... when the moon was formed around earth how close was it? Wouldnt the earths gravity of pulled it in since the moon would been so close... and what would would the moon look  if you were 2 billon years back?  Thanks For Reading

The current model for the Moon's origin holds that a planetary body about the size of Mars struck the Earth a glancing blow and the Moon coalesced from the bits of the impactor and Earth's crust that were thrown into orbit.

Some bits that were in low Earth orbit fell back to Earth once the Moon grew large enough for orbital resonances to disrupt the ring of material that had not yet coalesced. Other bits were thrown outward by those same resonances, depending on how close the Moon passed to them.

So, on the one hand you could say the Moon was practically in contact with the Earth (since it formed from Earth impact ejecta) and in the other you could say it was "much nearer" the Earth (without being able to specify a precise orbit). The move outward was quite likely nonlinear, being a much more rapid retreat early on. Models differ on the details, of course, depending on the density, mass, velocity, and trajectory of the impactor and the amount of material it ejected from the Earth.

This all happened something like 4 billion years ago (4,000 million years to perhaps 4,500 million years).

Analysis of lunar rocks returned by the Apollo missions shows some of them were of that same age (the highland samples ... the mare basalts tended to be much younger, about 3,180 million years), so the accretion of the Moon from the impact remnants occurred very rapidly, in geological terms.

Between 3,000 million and 3,500 million years ago, the Late Heavy Bombardment created most of the larger impact craters we see on the Moon today (and triggered the massive lava flows we see as the lunar maria).

Therefore, the appearance of the Moon 2,000 million years ago would have been pretty much as we see it today. Astronauts walking the surface of the Moon in that period, however, would have noticed a much less rounded appearance to the crater rims and impact ejecta blankets than is apparent today -- because "gardening" by micrometeorite bombardment (which continues today) would have had much less time to "weather" the lunar surface.

If the moon is moving away from the earth a minute amount each year, are the planets doing the same thing in moving away from the sun a small amount each year?

jodoak:

If the moon is moving away from the earth a minute amount each year, are the planets doing the same thing in moving away from the sun a small amount each year?

Yes, but the reason is different from that for the Moon.  As the Sun loses mass due to the solar wind and the conversion of matter into energy, its gravitational force lessens and the orbital semi-major axis (average distance) of each planet slowly increases. 

In the case of the Moon, that body's gravity creates an oceanic tidal bulge on the Earth which is dragged to a position slightly forward of the Moon due to friction.  The gravitational attraction on the Moon from that forward shifted tidal bulge accelerates the Moon into a wider orbit, which paradoxically slows it down.  The simplistic theoretical way of looking at it is to say that the tidal friction takes away angular momentum from the Earth’s rotation and “transfers” some of it to the Moon’s orbital angular momentum.

Now THAT's a good answer: short, sweet, covers all the bases!

Ok, so think of this scenario then. Currently astronomers think that Venus might be an early Earth, or something close to that. Mars, may or may not have some kind of life, but it has lost a lot of its atmosphere and water.

Could the planets have been closer to the sun long ago where Mars was more in line to our orbital path and Earth may have been closer like Venus is now. Maybe our orbital path is at an optimum distance fromt he Sun for life to flourish and now Mars is in an orbital path where it can't. In time Earth moves further away, or the Sun shrinks some, causing life to extingusih on this planet and Venus moves into a more optimal orbital path for life to begin.

Is this something ever thought of?

Good thinking.  But the amount by which the planets have been moving outward has not been great enough to suit your scenario.  At the same time the Sun has been slowly but continuously growing hotter.  The concern is that over the next billion years the increased heat from the Sun will extinguish all life on Earth, despite the Earth moving further from the Sun.  At that time Mars may be more hospitable to life than Earth.

I may not have the astronomical education but I have an active imagination for an older guy.

An additonal theory about the differences between Venus and earth that I've heard is:  Our moon stripped away part of our atmosphere allowing life to occur.  Venus doesn't have a moon and so that never happened.

I've also heard a theory that Venus could once have been like Earth, but it's closer proximity to the Sun caused it's oceans to evaporate into its atmosphere, and the lighter hydrogen escaped leaving carbon dioxide.

Oh, and one other consequence of the Earths motion being transferred to the moon: Our days will increase in length until one day is about 47 hours long

there was a really cool special on the history channel or discovery channel where they went into the various theories. i really enjoyed the 3d model that shows the mars impact idea. they think that after the initial impact the big mass broke off and then reinpacted the earth again. with the heavier materials going back onto earth and the lighter crust type material beign ejected again and forming  the moon. eventually gathering all the debri matieriali.

 check out the animation if you have a chance. surely its on the internet somewhere.

The moon is moving away from Earth 

I cannot find a reference at 21st Century Publishing House. I can find the publisher's Web site (link in previous sentence), but not a reference to the book mentioned.

Can you provide a link?

hi  chipdatajeffB :

www.sea3000.net/zhuyonghuan

This appears to be your own filesystem located on a webhost server. Is that correct?