Hammer and Feather

[freon]

What was the temperature at the Apollo 15 site during this experiment? I've read anywhere from 190 to 275( in direct sunlight) degrees F. What affect did the heat of the sun or the radiation reflected from the surface have on this real falcon feather? Did it quickly disintigrate on the surface?

[JayUtah]

The temperature of what?

[hplasm]

Blam!

5 point throw!

(ooh!- harsh...)

[freon]

Mostly was interested in the affects of the ground temperature on it and the pressure change on it, if there was any.

[scooter]

...here we go...again...



edit...no atmosphere, vaccuum, thus no "pressure change". The surface temp has no effect on the feather falling in a vaccuum. It will fall as fast as any other object, i.e. a hammer.

[hplasm]

Hmm- can you expand on what you mean by pressure change- on the ground, when the hammer hit it, or the solar wind on the feather -or other...?

[nomuse]

So here's a hint.....what happens to a falcon feather if you go outside on a sunny day and hold it up?

[freon]

Did they coat it with alluminum like the cameras?

[BertL]

Well, I think I can see what freon means.

That feather was exposed to direct sunlight, and it touched a lunar morning surface. Right?

Well, what were the consequences of the feather (other than the "obviously nothing, as seen in the video")?

Mmm, I remember the times when I debated the hammer and feather. Only two months ago.

[echnaton]

The tools were designed to have reflective properties so they wouldn’t heat up excessively while in the sun. I doubt the feather had a special coating.

[freon]

Going from a pressurized cabin out into the elements.

[nomuse]

I wonder a bit about long exposure by the feather. Not to sunlight or radiation per se...but combination of vacuum and UV is not going to be good for organic materials, even the filamentary keratinous outgrowths of an avian epidermis.

[sts60]

Think about what happens when you put an ordinary "solid" object in a vacuum chamber. Say, a wrench, or a piece of paper, or for that matter a feather.

What happens? You get a feather which dries out after a while.

Now think of leaving a feather on your dashboard in the summer sun. The air temperature inside a parked car on a hot summer day can easily reach 180 degrees F. I imagine the dashboard can get just as hot or hotter.

What happens? You get a hot feather.

Now put a feather on the lunar dayside surface.

What happens? You get a hot feather which dries out eventually.

[scooter]

The "morning" surface temperature on the Moon is relatively cool, certainly not the 250F that we hear so much. So the feather would not suddenly go to ashes or disintegrate. Now, after many years exposed to the lunar environment, there may be little left (as with some other items up there, the flags etc...)

Going from 3.5psi to vaccuum wouldn't do much either...even to an "untreated" feather.

[echnaton]

On the moon, like here on earth, objects receiving sunlight heat up as the day goes on then begin to cool in the afternoon as the angle of the sunlight changes. They don’t rapidly go from being cold to very hot just because they are in the sun. The feather was exposed to the sun for only a few minutes, so would not have made a significant change in temperature. The surface of the moon get much hotter than the earth for a variety of reasons. One of which is that the lunar day is +- 28 earth days, meaning that the sun is shining for more than 300 straight hours rather than the average of 12 here on earth.

The lunar surface cools substantially during the long night period and then gradually heats up as the sun gets higher above the horizon. The Apollo missions all landed early in the lunar day when temperatures were relatively cool.