The Moon

Jehosefat said:
Didn't understand a word I said did you?

Its a closed system. By definition the "wobble" can't add any energy to the system because it is part of it. So no energy being added and the moon is moving further away. So while yes, eventually the moon will get closer to the earth, it has absolutely nothing to do with the reason that you gave in your earlier post.
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K I got schooled. Just did some reading and must say thanx for pointing me in the right direction.

When a object is in motion it needs "energy" to slow it down in space, this can come from friction or other sources. So the moon is already near escape velocity hence the moving away from the earth. If there was friction it would have slowed down like low orbiting satellites do, but its to far out for this to happen.

My bad.

Edit: oh and High orbit satellites have rockets to change its direction in order to avoid collisions, not "speed it up" like I thought.
 
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Just something interesting for those who don't know. Below is a picture of the earth and moon both with the correct size and distance. It is quite small and far away. Pictures normally show the moon much bigger and closer.

M3fM6ei.jpg
 
SaiyanZ said:
Just something interesting for those who don't know. Below is a picture of the earth and moon both with the correct size and distance. It is quite small and far away. Pictures normally show the moon much bigger and closer.

M3fM6ei.jpg
Click to expand...

That is amazing. It puts the moon landings in a whole new perspective.
 
When an object's in orbit the force exerted by its motion must match that of gravity for it to stay in orbit. If its momentum is slightly less it will gradually fall closer. The moon's momentum is slightly more so it is exerting a greater force against gravity and is moving away. Just to clarify here that while it may move closer in the future that has nothing to do with this interaction. There's no reason why it would cause it to move away and then fall back. When the sun becomes a red giant the atmospheric drag exerted on it will slow it down but both the earth and the moon will fall into the sun and be vaporised.
 
The moon is moving away from the earth because:

1. The earth rotates
2. The moon gravitational effects on the earth tides are causing the earth rotation speed to slow.
3. This is resulting in a transfer of energy from the earth to the moon, which is increasing the moons velocity
4. This increase in velocity is caused the moons orbit to expand.

The angular momentum of the earth-moon system must remain constant. Therefore the decrease in the earth's rotation is compensated by an increase in the moons speed.

To understand where the moon gets its energy from you need to know how the earth moon system formed. Current theory is that the moon was created by the collision of earth and another large body in the very early stages if the solar system. It was a glancing blow at just the right angle and velocity and the relative sizes where where the right numbers. Such a collision would impart a enormous amount of energy to the earth-moon system.

The collision theory is currently the best one. The reason the "capture" theory is not as accepted is because the moon is relatively large and the earth's gravitational field would not have been able to capture such a large object.

Also material from the Apollo missions show the composition the moon to be almost identical to the earth.
 
Joe_Soap said:
Apparently the moon slows down the spinning of the earth. So if there is not moon, earths rotation will increase in speed.
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yes its a "friction" created by gravity .... its the same reason you never see the dark side of the moon.

Although the moon does show that side to the earth its orbit and rotation has been formed in such a way that you never see that side of the lunar surface at night
 
Here's another scale image of the sun, planets and moon. The sun and the moon appear the same apparent size when seen from earth. Just a little difference in actual size though.

I have this picture as my desktop background:


TL1V8Fm.jpg
 
a bit bright for a background. I use a night shot of the earth from space
 
RiaX said:
a bit bright for a background. I use a night shot of the earth from space
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I hardly ever see my desktop though. It's more for that moment when someone sees it and says "Wow, I never knew the earth was that small compared to the sun and some of the other planets". I get that a lot. Education for the nation.
 
SaiyanZ said:
I hardly ever see my desktop though. It's more for that moment when someone sees it and says "Wow, I never knew the earth was that small compared to the sun and some of the other planets". I get that a lot. Education for the nation.
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yeah its shocking ... students are really stupid. Though its not the lack of knowledge thats the problem IMO. Giving a few lectures I realised they dont give a damn. Their mindset is degree = money.
 
RiaX said:
yeah its shocking ... students are really stupid. Though its not the lack of knowledge thats the problem IMO. Giving a few lectures I realised they dont give a damn. Their mindset is degree = money.
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Based on what I see around me and what's shown on tv (the stuff people watch) I doubt the majority of people actually want to learn and enlighten themselves. If you look at most training these days it's all about making more money.

If a massive EMP was to hit this planet today and wipe out all computers and digital archives I reckon that we would be stupider than 50yrs ago and society as we know it would crumble and people would die en mass.
 
ponder said:
Based on what I see around me and what's shown on tv (the stuff people watch) I doubt the majority of people actually want to learn and enlighten themselves. If you look at most training these days it's all about making more money.

If a massive EMP was to hit this planet today and wipe out all computers and digital archives I reckon that we would be stupider than 50yrs ago and society as we know it would crumble and people would die en mass.
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http://en.wikipedia.org/wiki/Idiocracy
 
I can't imagine that ending well for Earth. Aside from the points already mentioned (such as no more tides and the moon's effect on our rotation), wouldn't we also get hit by the debris?
 
samus said:
I can't imagine that ending well for Earth. Aside from the points already mentioned (such as no more tides and the moon's effect on our rotation), wouldn't we also get hit by the debris?
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We'll be roasted long before that.
 
RiaX said:
yes its a "friction" created by gravity .... its the same reason you never see the dark side of the moon.

Although the moon does show that side to the earth its orbit and rotation has been formed in such a way that you never see that side of the lunar surface at night
Click to expand...

No, you never see the far side of the moon ever, because it never faces the earth
Tidal_locking_of_the_Moon_with_the_Earth.gif
 
samus said:
You mean from the shock wave from the impact? Sorry if I'm being slow here.
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No from the gases from the sun. If it disintegrates it will be from the friction of the sun so by that time the atmosphere will be the same as the sun.
 
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