Why Can't We See Mountains on the Moon from Certain Places on Earth?

[Smartoad]

I may be wrong, and I will feel pretty stupid if i am, but i think that we can see Earth's shadown on the moon, that's why it has cycles right? if so, then why can't we see mountains and stuff from certain places on the earth. Is it because the moon is so far away?

 

[russ_watters]

The moon's phases are not due to Earth's shadow, they are due to the fact that only half of the moon can be illuminated at a time and that half may not be facing us. See: http://www.moonphases.info/images/moon-phases-diagram.gif

And I'm not sure what you mean about seeing mountains: you can see mountans on the moon from anywhere on earth. They just don't look very big because we're far away.

 

[Smartoad]

oh my gosh, I feel dumb now, see, I thought that the reason the moon had its phases was because the sun was on the other side, and the Earth was blocking the light from the sun to the moon, but that only happens during lunar eclipses. It makes sense that the phases come from the moon being halfway illuminated at a time. Well then, During lunar eclipses, where the moon and son are opposite and Earth in the middle, could you look at Earth's shadow on the moon and see Earth's mountains? Sorry if my questions are dumb or my grammar is bad, I'm only a sophomore in high school

 

[russ_watters]

It's ok - everything is new the first time you think about it.

 

[cesiumfrog]

Smartoad, how large are Earth's mountains compared to Earth's radius? Also, are you interested in whether you can see, in the shadow, Earth's sunsets?

 

[Janus]

oh my gosh, I feel dumb now, see, I thought that the reason the moon had its phases was because the sun was on the other side, and the Earth was blocking the light from the sun to the moon, but that only happens during lunar eclipses. It makes sense that the phases come from the moon being halfway illuminated at a time. Well then, During lunar eclipses, where the moon and son are opposite and Earth in the middle, could you look at Earth's shadow on the moon and see Earth's mountains? Sorry if my questions are dumb or my grammar is bad, I'm only a sophomore in high school

Here's an old example that might help answer your question. If you were to scale the Earth down to the size of a billiard ball, the Earth would be smoother than a billiard ball, mountains and all.

 

[willem2]

Here's an old example that might help answer your question. If you were to scale the Earth down to the size of a billiard ball, the Earth would be smoother than a billiard ball, mountains and all.

Actually Everest is higher than 1/1300 of the diameter
I don't think billiard balls with 0.04 mm irregularities on them would play well.

Of course you would be able to see the shadow of the mountains on the moon during a lunar eclipse (with a telescope) if the sun was a point light source.

 

[Janus]

Actually Everest is higher than 1/1300 of the diameter
I don't think billiard balls with 0.04 mm irregularities on them would play well.

The tolerance for irregularities on a billiard ball is 0.127 mm. This falls in the range of the thickness of a black hair (blond hair is finer).

 

[jostpuur]

I have a friend who had this precisely the same misunderstanding.

We took same classes in the high school, and both got good grades on courses of natural science. Later, our paths separated when we graduated from the high school. I went to one university and began my studies in physics, and my friend went to another university and began studies in biology.

We did keep in touch occasionally however, and at one night we were driving a car. I had almost gotten my masters degree, and my friend was doing pretty well with his biology studies too. We saw the moon, and talked about something. During the discussion it became clear that my friend didn't know what caused the phases of the moon, and believed that we were looking at the "shadow of the earth". It was surprising from my point of view.

Sorry if my questions are dumb or my grammar is bad, I'm only a sophomore in high school

You learned it faster than my friend then

 

[davenn]

I may be wrong, and I will feel pretty stupid if i am, but i think that we can see Earth's shadown on the moon, that's why it has cycles right? if so, then why can't we see mountains and stuff from certain places on the earth. Is it because the moon is so far away?

As mentioned by one other that's not the Earth's shadow BUT not mentioned is that
when you see an eclipse of the moon then that is the moon in the Earth's shadow :)

just like when we get an eclipse of the sun its a narrow strip of the Earth's surface inside the shadow of the moon.

Dave

 

[gttjohn]

i am so happy to have found this thread i also thought the Earth caused the moons diff phases now it all makes sense its the position that the moon is in relation to the sun that give it its dif phases that's brilliant

 

[Dr Lots-o'watts]

You can watch the same phases by watching a tennis ball (moon) by your living room light (Sun), and taking your own head to be "Earth".

Anyone can understand this easily, they just often don't take the time do these simple experiments.

 

[Redbelly98]

Also, the dark part of the moon has a different shape than the shadow cast by a round Earth:

[PLAIN]http://www.astroimages.org/astrophotos/mn-3-10.jpg[/CENTER]

http://www.astroimages.org/astrophotos/mn-3-10.jpg

(EDIT: link appears to be broken/gone)​