Dangerous electrical/electronic 'toys'

[huitzilopochtli]

Some notes on monumentum.

If there are no outside forces influence a system its monumentum cannot ba changed. That is the basis of mechanics.

So, if we look at Moon and Earth as a system which is floating in space it's not too hard to conclude that there are no outside forces influencing it. Therfore, monumentum can only be transferred between the two.

To be honest, I lied up there. Due to the micro-meteors and all the other stuff caught by the Earth's gravity and pulled in, Earth is gaining on mass so its monumentum is in fact slowly decreasing.

But that all is so irelevant for when, in some 5 billion years, Sun's time is up we shall all be evaporated in nothingness. So have a good day!

[Sho]

Eh. . . I think you mean "momentum" there. But anyway, an increase in Earth's mass would not cause its momentum to decrease. Momentum is mass*velocity, and any incoming objects would have their own momenta, so they might cause the Earth's momentum to grow or to decrease. In addition, there's the gravitational effects of the Sun, all the other planets, and (to a negligible extent) the other stars, dark matter and whatnot. Just to make things even more fun, there are also effects caused by gravitational waves. It is probably relevant because, for example, if the Andromeda Galaxy collides with the Milky Way (which apparently will happen before the end of the solar system), a passing star might mess up our orbit.

[Meh]

It is monumental momentum hence monumentum.

[Sho]

5.9742×10^24kg×2×pi AU/year = 177946902174000000000000000000 kg-m/sec is indeed a lot of momentum.

EDIT: Well, taking into account the eccentricity of the Earth's orbit, angular momentum and relativistic effects. . . *gets dizzy and falls over*

[The Industriallist]

You see the word 'toys' in the topic? See it? Now, do you really consider the moon to be a toy?

But on the moon thing, anyway...

If the high tide runs ahead of the moon, then its distortion of the earth's gravitational pull would accelerate the moon along its orbit, and the earth's spin would be slowed to compensate by friction.
If the moon runs ahead of the tide, which seems more likely, it would be slowed down, effectively by the friction of the tide with the earth, and speed the earth up.

Just my 2-minute analysis

[Cheshierekat]

Wow...it seems that we got a little off topic..eh?

[west]

The world is my biscuit, the moon is my toy.

[kroner]

In terms of linear momentum, the Earth/moon system is not closed at all. both have tremendous interaction with the sun. The momentum of the Earth is alwaya drastically changing because it's constantly undergoing centripital acceleration. It's the rotational momentum of the Earth/moon system that has any bearing on the earth's rotation. Rotational momentum is measured in kg m^2/s (moment of inertia x angular velocity). Rotational momentum can be transferred between the Earth and moon as Sho and Meh were saying. The rotational momentum of the Earth/moon system can be changed by particles and photons that strike the Earth and moon and also by the moment of inertia of the Earth changing due to the use of hydroelectric power as Meh was saying originally. But I don't know how much of an effect that could be having.

[Sho]

Of course, there's also the issue of momentum transfer through actual exchange of mass. The National Geographic I got in the mail today says the Earth gets 40000 tons of micrometeoroids a year. There must also be some slowing effect from the interplanetary gases, solar wind and whatnot. Mass leaves the Earth through gases escaping the atmosphere. Finally, there's the small but growing effect of human activity, with rockets going out and junk coming in. All of these might affect linear as well as angular momentum.

[David]

Don't forget huge steel and concrete blemishes.

[David]

We call them cities.

[kroner]

But the cities don't effect the net mass.

But what does slightly effect the net mass is the use of nonrenewable sources of energy (fossil feuls, nuclear energy, etc). Atomic and chemical potential energy is released which means that more energy ends up radiating out from the Earth than is radiating in. It's nolonger in equilibrium. Each Joule of energy in whatever form contributes about 1.11x10^-17 kg to the Earth's net mass. So for each Joule of energy that is released through nonrenewable energy souces, the Earth loses a very small amount of mass.

[Sho]

Does it matter whether the energy source is renewable? Any energy radiated from the Earth leads to mass loss. The existence of a related mass gain in the past doesn't change that.

[kroner]

The energy from renewable sources originates from the sun's radiation. Taking advantage of that energy before allowing it to radiate off into space doesn't effect the net mass/energy of the Earth since it would radiate off as heat or reflected light if unharnessed anyway. Nonrenewable sources release potential energy from outside of that system. (On the other hand using enregy from renewable sources to do permanent work would increase the Earth's mass and using nonrenewable sources to do permanent work would cause no change in the Earth's mass, but this is rarely the case. Most of the energy we use is for light, heat or fighting friction.)

[grayjaket]

When each post hurts...it's time to move on. Let's just say, the moon is the big bright thing in the sky at night, and we all love it to deat alright?