I've been meaning to write a neutral thread, asking some questions that puzzle me. From the title it is obvious that two main questions that puzzle me
are the subject of space junk and the subject of Moon's gravity.
This "analysis" will be purely amateurish, and I could be misunderstanding some the space mechanics involved. That's why I have you guys to point me
in the right direction.
Let's throw in some numbers. So the Moon is 1/4 the size of Earth. Numbers say it's gravity is also far weaker, 83,3% weaker. So the Moon's gravity is
around 16% of that of the Earth's. This is rather logical to my mind. Since today's paradigm revolves around gravity being the product of mass (in
layman's terms). So more mass means stronger gravity. So far nothing out of the realm of unexpected.
Now, let sidetrack for a moment and check out what are tides:
Tides are the rise and fall of sea levels caused by the combined effects of the gravitational forces exerted by the Moon and the Sun and the rotation
of the Earth.
I'm sure this is nothing new to educated men/women, but let's sit with that for a while. So the Moon, with it's 1/4 size and 16 % gravity of that of
the earth's is influencing events on earth ? It would be safe to assume than that the earth's gravity is influencing the moon far more than vice
versa. 3/4 larger and having far stronger gravity...it's a safe bet.
So how come the moon's orbit around the earth is getting bigger ?
Is moon moving away?
It's getting 3.8 centimeters longer per year. What this means is that it takes a moon 3.8 centimeters per year longer to go around the earth. Due to
strong earth's gravity, should it really move away? I know there are many more orbital forces at work here, like "tidal friction", but those really
don't logically explain the moving away part. Actually, tidal friction is slowing the moon down, so if anything the effects of earth's gravity should
be even greater on the moon if it is slowing down. Please don't say the sun, 'cos there are no indications that it is moving towards the sun.
Eternally "hovering" space junk right above the strong gravitational pull
This is what I don't get. I'm sure you've all seen this pic:
And here is the excerpt from wiki junk page
The vast majority of the estimated tens of millions of pieces of space debris are small particles, less than 1 centimetre (0.39 in). These include
dust from solid rocket motors, surface degradation products such as paint flakes, and coolant released by RORSAT nuclear powered satellites. Impacts
of these particles cause erosive damage, similar to sandblasting. This damage can be partly mitigated through the use of the "meteor bumper", which is
widely used on spacecraft such as the International Space Station. However, not all parts of a spacecraft may be protected in this manner, e.g. solar
panels and optical devices (such as telescopes, or star trackers), and these components are subject to constant wear by debris (and to a much lesser
Continuing from the earlier supposition that earth exerts far stronger gravity than the moon...it still does not manage to attract all of the junk
that circles around it on an altitude from 1-2 thousand miles. Yet moon is influencing objects pinned to the earth from a distance of around 356,400
km to 406,700, depending on the time of the year. What's keeping it up there for so long (besides the initial orbital velocity, which can not explain
the long periods of junk staying up there) ? I red somewhere that the junk "life" cycle is around 50 years or something like that. 50 years of
circling around the earth, as if...there is no attracting force. Or a very weak one.
Seeing how the moon is able to exert gravitational pull on Earth's water masses, how come the earth has space junk problems and our junk remains
there...and it's even getting bigger.
We know that large orbital bodies, such as Sun, Saturn and Jupiter attract many asteroids that pass through our solar system, and thus saving the
earth from them. The moon's face is bombarded with craters, compared to earth's relatively small number of craters. It is apparently known that the
earth and the moon are almost of the same age. Shouldn't Earth attract far more space collisions than the moon ?
What my layman mind is seeing here, is that something is off here. Either the moon has far stronger gravity than we were told, or the Earth has a far
weaker gravity than we think (but since we can measure it...it's not likely)....ooooor I understand very little about space and space objects.
In conclusion, It will probably be apparent from this post that I'm a not even an apprentice when it comes to space science, and there is probably
info I'm missing about these things. Perhaps this junk busyness is not all that strange...but something is off with our current knowledge of the
moon's gravity. So much that I feel it's kicking me in the forehead with a baseball bat.
Anyway...knock yourselves out.
edit on 1-10-2012 by MarioOnTheFly because: (no reason given)
edit on 1-10-2012 by MarioOnTheFly
because: (no reason given)