reply to post by OrionHunterX
First, where's that 'Mars sized' object that hit Earth?
You're standing on part of it. Some of it is up in the sky, roughly 250,000 miles away. We call this the "Moon".
Anything that was leftover?? Depends on the various trajectories, if they escaped Earth's gravity well, some would have simply hung around in Solar
orbit, eventually to impact either/both the Earth/Moon as meteors. Some bits may have very eccentric orbits, especially long ellipses, and impacted
Mars, Venus, Mercury...or fallen into Jupiter's gravitational influence.
There are a vast number of possible combinations, and a vast number of various-sized objects back when the early Solar System was still forming, and
stabilizing. This took a BILLION years, probably...give or take a few hundred million...for most of the various debris to eventually be "swept up".
(Of course, there are still plenty of left-overs still....in the Inner Solar System. Not to mention, the Oort Cloud, etc...we live in a very
To call that video crap seems to indicate a certain lack of intellectual fortitude and understanding of the concepts presented. With the 40+ years
of study, and especially after Apollo and the physical samples to examine, the age of the Moon is well-established...and its composition, and density,
indicate (to those expert scientists who make it their business to understand such things) that the materials "up there" are not too dissimilar from
Working it backwards, then: Since the ages are pretty close to the same, the formation is assumed to have occurred concurrently with Earth's.
BUT.....all that matter would normally have just accrued into ONE glob, and formed a sphere (Earth). The presence of this separate
mass, that has been imparted with a certain amount of energy of motion, to cause its orbit, implies a GREAT force of some kind acting from without.
Think about it like this: The Earth/Moon system is very nearly...well, COULD be considered a "double planet". Because of the relative sizes. How
like that do you see, in our Solar System? The other three rocky planets didn't form "doubles" as part of their normal
evolution, as the debris accumulated.
Therefore, it's logical to surmise that something HAPPENED, here. Different that Mercury, Venus or Mars. In other words, the original glob or
"cloud" of debris that pulled together to make the Earth did NOT also, off in the distance of a few hundred thousand miles, form a separate globe,
to later become the Moon. It just defies the laws of motion and gravitation. So, we are left with TWO possibilities: The "capture" hypothesis, or
the "impact" hypothesis.
"Capture" is generally ruled out, again because of mass, physics and motion...because of the orbit of the Moon is not a very eccentric ellipse. It
is massive enough that IF it had simply "passed by" and been attracted to the Earth's gravity well, on its way in, as it accelerated, it would not
have resolved into the orbit we see today. It would likely have a very wide difference between apogee and perigee. (A comet's orbit is an extreme
So, the "impact" hypothesis is the best fit, form what's observed. It's a bit like detective work, and ALL the facts are not yet fully
known....but circumstantially, there is a strong case.
To sum up: Before
any "hit", the "proto-Earth" was less massive than it is now. The other celestial body (another
"proto-planet") is estimated to be "Mars sized"...but that comes only from working the math backwards to calculate the energies required to result
in what we observe today. Maybe "Mars mass" is more apt...doesn't mean it was the exact
same diameter or anything. So, the combined mass
of Earth/Moon, today, equals the original masses of the "proto-Earth" and the "proto-planet" --- -minus any debris that was flung violently out
far enough to not join the mix.
Good question, though, is WHERE did the "proto-planet" form? And what sort of Solar orbit was it following? Who knows, if the two objects had not
hit, they may have still met up later, since there was proximity obviously....and ended up as a "double" planet, orbiting each other eccentrically,
but in a very different configuration than we have now.
We may very well see some examples of this, someday, when we can visit other star systems....