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Flags on the Moon


Guest liliangrn

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wierd. in another thread somebody said that the light from the moon would be so bright it would burn the hubble camras insides. (sorry i don't know camera anatomy) and now i see there are pictures! oh well, either way it's amazing to me.

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Guest liliangrn

Oh I see. Forgive my mistake.

 

I imagined if say a car (like the moons orbit) was driving around you clockwise, for example, you would always see the right side of the car. I did not consider this to be the car rotating because the head lights are always in line with it's orbit. But actualy the car is rotating once for everytime it orbits me.

 

If the car had not been rotating. I would see a 360 degree view of the car in orbit (or the moon). And,yes, you are right I haven't spent much time thinking about this obviously.

 

Eggs on my face!

 

Thanks Josephine

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With a quick google I found that Hubble's mirror diameter is 2.4 m which lays the optical limit on resolution as being just over 3 * 10^ -7 radians. Considering the tan of this angle (hardly more than the angle itself) and the moon's distance we may evince that an object would have to be at least 100 m across to be even a little spot in the image.

 

With a 24 m mirror Hubble could barely pick out a 10 m object on the moon, with a 240 m mirror it could see a 1 m object as a little spot.......

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The great wall of China cannot even be seen from orbit unless you look really, really hard...this was confirmed by the fist Chinese astronaut in 2003 (to the dismay of the Chinese), who was unable to see it.

 

As for what you can see from the moon - oceans, continents, polar caps, cloud formations...possibly Sahara and other large areas.

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It all depends on what sort of a mood the atmosphere is in, what kind of glasses you are using and... how well the Chinese astronaut knew the geography of his homeland!!! :)

 

When the first astronauts were orbiting nearly half a century ago, mission control thought they were being funny when they said some of the details they could pick out with binoculars. It turned out they weren't being funny. I don't trust my vague memories enough to say more.

 

After all, Tormod, orbit can be as low as 300 km, even lower if you don't need to stay up long. Most of the haze that can bump out detail is at the lower altidudes, so even comparing to what you can see between distant mountain peaks isn't so appropriate at all. Spy satellites are reading in details that you wouldn't believe, I've even heard car plates being mentioned.

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I heard that the great wall of china is the only man-made structure on the earth visible from moon.Is this true???Otherwise what are the general natural geological formations visible from moon.

Visible from space, not the moon. I think I read somewhere that the shuttle astronauts said they could see it.

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After all, Tormod, orbit can be as low as 300 km, even lower if you don't need to stay up long. Most of the haze that can bump out detail is at the lower altidudes, so even comparing to what you can see between distant mountain peaks isn't so appropriate at all. Spy satellites are reading in details that you wouldn't believe, I've even heard car plates being mentioned.

 

I assumed we were talking about what people can see, not what satellites can see. :)

 

I work at a space centre and yes, we get pictures of a quality you wouldn't believe - and we don't even get to see the really good stuff (ie the spy and military stuff).

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Guest liliangrn

I'm concerntrating on this black hole thing so hard that any information, relevant to another topic, gets pushed out of my brain.

 

:)

Jo

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That must be interesting Tormod, have you posted any of the pictures?

 

Of course, I was also talking about what astronauts were seeing and referring to mission control! :)

 

As far as I know, there is top secret even on info about how good the resolution of the spy & mil stuff is. True?

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