Flag on the moon

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tlb467

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I have a question. I don't want to get into discussions about how does it wave or if the landing was real.
My question is.... How did they get the flag to stick into the moon? The moon is solid rock isn't it?
 
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tlb467

Guest
But would a fine powder hold up a flag when there is no gravity?
 
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a_lost_packet_

Guest
tlb467":31h70x83 said:
But would a fine powder hold up a flag when there is no gravity?

There is gravity on the Moon. Otherwise, the Apollo astronauts wouldn't have been walking around on it much. :) The Moon's gravity is about 17% that of Earth's. So, one can jump pretty high on the Moon.

As to the surface the flag is actually planted in, I can't vouch for its composition. But, consider that the flag only weighs about 17% of what it does on Earth and you can see it wouldn't need much to keep it in place. Also, there's no atmosphere on the Moon. Its gravity isn't strong enough to hold an atmosphere. So, there's no wind to come along and knock down our flag.

However, interestingly enough, it appears there are "moon quakes" as a result of tidal forces and the interaction of the Moon's gravity and Earth's. So, while wind won't knock our flag down, I suppose it's remotely possible that a moonquake might, one day. :)
 
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SpaceTas

Guest
The moon's surface (at the landing sites) a layer of regolith. This is well settled pulverized rock (dust to boulder size), so not quite solid rock. It was often hard to plant the flag with the astronauts pushing and twisting the flag into regolith.
 
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kelvinzero

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SpaceTas":2xkulmn6 said:
The moon's surface (at the landing sites) a layer of regolith. This is well settled pulverized rock (dust to boulder size), so not quite solid rock. It was often hard to plant the flag with the astronauts pushing and twisting the flag into regolith.

The regolith grains also tend to be horrid jagged abrasive stuff. not rounded eg like beach sand. At one point the apollo astronauts had to drill into the regolith, and they couldn't get it out at all (until the next day I think)

http://en.wikipedia.org/wiki/Apollo_15,_Lunar_surface
http://history.nasa.gov/alsj/a15/a15carrier.html

I remember an old science fiction that speculated that the dust would be so fine the lander would sink straight into it. It didnt turn out that way at all.
 
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crazyeddie

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kelvinzero":2b38e8dy said:
I remember an old science fiction that speculated that the dust would be so fine the lander would sink straight into it. It didnt turn out that way at all.

It was also the basis of Arthur C. Clarke's excellent novel, A Fall of Moondust. Prior to the Surveyor lander missions, there was some worry that the lunar maria had surfaces of dust so fine that it exhibited the properties of a liquid.

Of course, moondust is extremely abrasive stuff, almost like crushed glass, and it will be a problem for future colonists. They will have to vacuum the stuff off of any equipment they bring indoors.
 
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amshak

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Probebly they dug a hole placed it and put some cement . Digging hole in rock is possible . Or there may be smoother surface in the moon . :cool:
 
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MeteorWayne

Guest
That's just silly. I watched them every time, and they just pushed to pole into the regolith as best they could.
 
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OleNewt

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Do you think they tested the plant before they left, or did they just go "ok, it's up, nobody touch it!"?
 
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halcyondays

Guest
I am sure I have read over the years that one at least of the flags, maybe several, blew over from the blast effects of the launch of the LEM's ascent stage. True ?
 
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MeteorWayne

Guest
Most likely it has happened. From watching the events live, I never recall them going back to check...they had higher priorities for their limited time.
 
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Woggles

Guest
Here’s a question. We all heard the flag can’t wave because there is no atmosphere on the moon but what about solar winds or a cme?
 
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MeteorWayne

Guest
FARRRRRRRR to small an effect to wave any flag. Please look at the actual physics involved.
 
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amshak

Guest
I think its just animation that they show on T.V . To make it more atractive . And what do the asronuts say about the waving of flag?
 
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MeteorWayne

Guest
You think what is an animation? The live pictures of the flags being planted on the moon from 1969 to 1972?
 
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amshak

Guest
Sorry about that , But I got the Answer -
The flag in those pictures of Buzz Aldrin and Neil Armstrong is rippling in the wind; everyone knows that there is no atmosphere on the moon. And no atmosphere means no breeze.

Well, as you can imagine, the folks who came up with the idea of taking an American flag to the moon were aware that unless they rigged something up, the flag would just hang there. So they built a special flagpole expressly for the purpose of making the flag appear to fly. Its not a trivial problem.

The astronauts would be wearing bulky space suits, so they needed a flagpole that was easy to assemble and to plant in the ground. Plus, the pole had to be portable, and not use up a lot of precious cargo space. So scientists rigged a telescoping pole with a telescoping horizontal crossbar that was supposed to make the flag look as if it were blowing in the wind.

The flag itself was standard issue, although the top was hemmed so that the astronauts would be able to slide it over the crossbar. Plus the entire assembly weighed less than ten pounds. Even so, the astronauts reported having some trouble setting the flag up. They weren’t able to stick the pole far enough into the ground, and they weren’t able to fully extend the horizontal crossbar. That explains the rippling effect.

It takes the air out of your conspiracy theory. :cool:
 
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MeteorWayne

Guest
I'm not the one with a conspiracy theory. You are the one that said it was an animation for TV.

I watched the broacasts live from the moon as they happened.

Nothing you said was news to me, I've been following the space program intensely since Sputnik launched.
 
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Woggles

Guest
MeteorWayne":8ec26hsb said:
FARRRRRRRR to small an effect to wave any flag. Please look at the actual physics involved.

Hi MW. Well my search took me many places to see if I could find info regarding my question. One place was ScienceDirect. I decide to see if there was any info about the effect of CME on spacecraft. In particle is there was any or enough force to push the spacecraft out of its orbit. Even if it was a little. However I could not find any info regarding that effect. So I bow to your wisdom on the matter! Lol. However thank you! Your comment spurred me on to great knowledge about CME, solar wind and their dynamics’ in out solar system.
 
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MeteorWayne

Guest
Well, a number of things affect meteoroids and asteroids, so would also by extension do the same to spacecraft, though most operate on time scales longer than a typical spacecraft's. :) Still, some fun reading:

I've read all these articles, and they are accurate as far as my knowledge goes.

Solar Wind:

http://en.wikipedia.org/wiki/Solar_wind

Radiation Pressure:

http://en.wikipedia.org/wiki/Radiation_pressure
http://en.wikipedia.org/wiki/Solar_radiation_pressure

Poynting Robertson Effect:

http://en.wikipedia.org/wiki/Poynting%E ... son_effect

Yarkofsky Effect:

http://en.wikipedia.org/wiki/Yarkovsky_effect

YORP Effect (which mostly affects rotation rate):

http://en.wikipedia.org/wiki/Yarkovsky% ... ack_effect

Wayne
 
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Woggles

Guest
Thanks MW! Your right, all great reads! Ok back to my original question. Does the flag move on the moon because of solar winds and or CME
I see from the first link that I think it is possible but so very small of a movement it would not be visible to the human eye. I base this basically on the second paragraph listed below

From http://en.wikipedia.org/wiki/Solar_wind


“The Earth's Moon has no atmosphere or intrinsic magnetic field, and consequently its surface is bombarded with the full solar wind.

The solar wind "blows a bubble" in the interstellar medium (the rarefied hydrogen and helium gas that permeates the galaxy).”

I see from the second link, that there could be another pressure applied to the flag, however so small as to not cause any moverment

From http://en.wikipedia.org/wiki/Solar_wind

The fact that electromagnetic radiation exerts a pressure upon any surface exposed to it was deduced theoretically by James Clerk Maxwell in 1871 and Adolfo Bartoli in 1876, and proven experimentally by Lebedev in 1900[1] and by Ernest Fox Nichols and Gordon Ferrie Hull in 1901.[2] The pressure is very feeble, but can be detected by allowing the radiation to fall upon a delicately poised vane of reflective metal in a Nichols radiometer (this should not be confused with the Crookes radiometer, whose characteristic motion is not caused by radiation pressure).
I find this link interesting because of the part “consigned to oblivion” I wonder how many great discoveries have happen but only to be “consigned to oblivion” with no savior to be forward the discovery!!
From http://en.wikipedia.org/wiki/Yarkovsky_effect


Yarkovsky's remarkable insight would have been consigned to oblivion had it not been for the Estonian astronomer Ernst J. Öpik (1893–1985), who read Yarkovsky's pamphlet sometime around 1909. Decades later, Öpik, recalling the pamphlet from memory, discussed the possible importance of the Yarkovsky effect for moving meteoroids about the solar system.[1]

Thanks MW for helping in my understanding!!
 
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MeteorWayne

Guest
No, any flag movement was caused by vibrations from the original insertion into the surface or if they brushed up against it. Remember, these are springy metal rods holding it up and upright.
 
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Woggles

Guest
MeteorWayne":350ez707 said:
No, any flag movement was caused by vibrations from the original insertion into the surface or if they brushed up against it. Remember, these are springy metal rods holding it up and upright.

Yes I know that MW. I was talking about today. If it was possible for the flag to wave (move) because of solar winds and or CME.
 
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MeteorWayne

Guest
Oh, no not at all. The forces are way too small, except for possible a meteoroid impact. And that's for those that are still standing. It's quite possible some were knocked over by the exhaust outflow from the LEM taking off.
 
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Woggles

Guest
MeteorWayne":1pnfwq8w said:
And that's for those that are still standing. It's quite possible some were knocked over by the exhaust outflow from the LEM taking off.

Thanks MW. yes that is true. I heard a quote once. "We can land a man on the moon but we can't place the flag far enough to prevent the exhaust from blowing it over"
 
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