Lunar questions

Lustrum

I've just watched a programme about the moon that was on BBC last year and have 2 questions.

We know the moon causes high and low tides, but why is it only sea water that it affects? Why not fresh water, or soil or anything else for that matter?

They talked about the dark side of the moon aswell, and how we always see the same side of the moon as it turns so slowly. When spaceships go into space, do they orbit the moon aswell, or has anyone been around to the dark side of the moon?

Just reading back over these makes me seem like a 12 year old, but these are actual questions that came into my head! As you can gather, I'm not too well up on my lunar knowledge

AlmightyCushion

The moon does affect smaller bodies of water, even if you filled a glass with water it would have an effect on it. The effect is so small that you won't notice it though. On very large lakes the effect is noticeable e.g. Lake Superior. As for your second question, we don't really send many rockets/ships to the moon but when we did they sometime were in the dark side.

Doom

The sun shines on all sides of the moon, think about the phases of the moon, like when its a crescent shape, the moon travels around the earth but does not rotate , the earth travels around the sun and rotates , the sun is stationary.

Rubecula

You will find that a lot of the features on the Dark side are given Russian names as the first space mission there was in fact Russian back in the 1960's.

Most lunar missions since then have orbited the moon.

And yes as stated the moon affects all bodies of water. in fact it affects just about everything on Earth but as stated small bodies are not affected as noticeably as the oceans. But even the land mass rises and falls with the tidal forces.

Captain Chaos

Doom wrote: »

The sun shines on all sides of the moon, think about the phases of the moon, like when its a crescent shape, the moon travels around the earth but does not rotate , the earth travels around the sun and rotates , the sun is stationary.

The Moon does rotate but it rotates at the same rate that it orbits the Earth so to us it looks like it never does. It's tidally locked to the Earth. The sun ain't stationary either. It's orbiting the center of our galaxy and we are moving with it.

Lustrum

Trust you guys to all be up at night time!

Thanks for the replies, at least I can claim to know something about it now

AlmightyCushion

Lustrum wrote: »

Trust you guys to all be up at night time!

Thanks for the replies, at least I can claim to know something about it now

It seems somewhat fitting that questions about the moon are answered at night.

Cú Giobach

Lustrum wrote: »

We know the moon causes high and low tides, but why is it only sea water that it affects? Why not fresh water, or soil or anything else for that matter?

The moon does affect fresh water, soil and everything else.
It actually pulls on and raises the very ground beneath your feet just like it does to the oceans, it's just that the effect on rock is much much less due to it being harder to move than water, and this movement is not noticeable by you. It is measurable though.

The term "dark side" is also inaccurate and misleading, the better term is "far side", because the Moon, just like the Earth, has day and night, a full lunar day/night cycle is just over 27 Earth days long.

Zubeneschamali

Rubecula wrote: »

small bodies are not affected as noticeably as the oceans.

The tides in the Mediterranean are small compared to the Atlantic, because the water is not free to move about as much.

Cú Giobach

Zubeneschamali wrote: »

The tides in the Mediterranean are small compared to the Atlantic, because the water is not free to move about as much.

Tides are more a consequence of the difference in the gravitational forces exerted in different places around the Earth, than just say the Moon pulling the water up in one spot, remember there is a bulge on the opposite side to the Moon also and these bulges then create a dearth of water between them.
As the Earth rotates this "unevenness" moves around the Earth giving us our high and low tides.
Now a smaller body of water doesn't have such a large gravitational difference from one spot to another so has less "unevenness" and so has no large tides.

Lustrum

So with the moon having an effect on all these other bodies of water and soil etc, are any of them as note worthy (so to speak) as the effect on the tides? Do any of them have as big an impact in day to day life as the tides do for shipping, fishing etc?

Cú Giobach

Lustrum wrote: »

So with the moon having an effect on all these other bodies of water and soil etc, are any of them as note worthy (so to speak) as the effect on the tides? Do any of them have as big an impact in day to day life as the tides do for shipping, fishing etc?

Not really, the moon affects the atmosphere itself but only in a small way that is drowned out by the much greater effects of the Sun's warming and the Earth's spin, though forecasters do take the Moon into consideration because the ocean tides themselves affect weather so it would have an indirect effect there.

Scientists are looking into the effect the Moon could have on earthquakes and volcanoes, because of the nature of earthquakes often the "tipping point" can be reached with only a very slight "nudge", and it could well be possible for the Moon in certain circumstances to provide this.

The biggest effect the Moon really has on us is stabilising the Earth's position in space, without it the planet's tilt would vary considerably and consequently give us wildly varying seasons over time and make the Earth a very different place indeed.

Lustrum

Thanks guys for the info, much obliged