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Megan
Skeptic Friend
USA
163 Posts |
 Posted - 04/29/2002 : 17:47:57
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What happens to light when you are standing on the moon? Like, if Lisa and I were on the moon and we both had flashlights, and we shined them at each other, what would happen? Would we be able to see the light like we do here on Earth? Or, because of no air, would the light just scatter? And if so, then what would it look like?
~Megan~
BTW, I'm a 15 year old that never stops asking questions(=P).
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filthy
SFN Die Hard
USA
14408 Posts |
Posted - 04/29/2002 : 18:20:05 [Permalink]
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This is a little out of my field of expertise (this is WAY out of my field of expertise!), but light, being photons, wound travel at it's normal speed in the direction the reflector in the flashlight pointed it. In short, yes, you would see each other's light, probably better than on earth. Fewer (none?) dust particals to defuse it.
luck,
f
"He who joyfully marches in rank and file has already earned my contempt. He has been given a large brain by mistake, since for him the spinal cord would suffice."
- Albert Einstein
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Donnie B.
Skeptic Friend
417 Posts |
Posted - 04/29/2002 : 18:45:03 [Permalink]
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Actually, the Earth's atmosphere has surprisingly little effect on visible light. A small percentage of the incoming sunlight is scattered by nitrogen molecules (which makes the sky look blue). Dust and clouds can block and/or scatter light, too. But on a clear day with little wind, you can see for fifty miles or more (from a high enough spot). And at night, you can see things hundreds of light-years away.
Just as filthy says, your flashlight experiment would work fine on the Moon, and it would look very much the way it would in a clean, dust-free environment on Earth.
If it was night, or you were in a shadow (of a crater wall, say), you would see the bright spot of light at the reflector of your friend's flashlight, and an illuminated area on the ground (or wherever you were aiming your lights). What you would *not* see would be a "beam" from the flashlight, since there is no atmosphere to keep dust particles suspended in the air. So, you'd see the light sources, and whatever they were lighting up, but no little "sparklies" in the beams -- unless you kicked up some dust, but that would fall back to the surface promptly.
Another answer to your question is, go look at any of the Apollo photographs. After all, what is a picture? It's a record of the light that entered the camera's lens. Whether the source is sunlight or a flashlight is only a matter of degree.
-- Donnie B.
Brian: "No, no! You have to think for yourselves!" Crowd: "Yes! We have to think for ourselves!" |
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Stygma
New Member
36 Posts |
Posted - 04/29/2002 : 19:09:17 [Permalink]
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On the topic of the moons' atmospheric effects, how hot can its surface become when staring the sun in the face?
Knowledge is power. Arm yourself. |
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Donnie B.
Skeptic Friend
417 Posts |
Posted - 04/29/2002 : 21:28:24 [Permalink]
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quote:
On the topic of the moons' atmospheric effects, how hot can its surface become when staring the sun in the face?
The number I've seen most often is around 250 C, in full noontime exposure. Of course, that's the surface temperature, not the "air" temperature; the latter is meaningless since there's no air to speak of.
-- Donnie B.
Brian: "No, no! You have to think for yourselves!" Crowd: "Yes! We have to think for ourselves!" |
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Wiley
Skeptic Friend
68 Posts |
Posted - 04/30/2002 : 16:52:46 [Permalink]
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Ostensively, this is in my field of expertise, so I felt I should comment.
Donnie B. is right on the money. Air does not scatter visible light very much, so it's hard to notice any scattering from a weak source like a flashlight. A flashlight beam appears scattered, but this is not caused by scattering from the air. The flashlight bulb is omnidirectional and the reflectors behind the bulb give it a crude beam shape. The effect looks like scattering; well, it is scattering from the reflectors not the air.
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Megan
Skeptic Friend
USA
163 Posts |
Posted - 05/01/2002 : 10:49:14 [Permalink]
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Omnidirectional?? What does that mean?
But anyway, thanks, that makes sense.
~Megan~
BTW, I'm a 15 year old that never stops asking questions(=P). |
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Lisa
SFN Regular
USA
1223 Posts |
Posted - 05/01/2002 : 11:56:49 [Permalink]
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Omnidirectional - all directions.
Sometime when we have nothing better to do, I'll tell you about the difference between directional and omnidirectional radio antenna. Pretty technical and boring, so have a back-up subject ready.
Lisa
If you're not living on the edge, you're taking up too much room. |
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Physiofly
Skeptic Friend
USA
90 Posts |
Posted - 05/01/2002 : 18:05:04 [Permalink]
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quote:
Omnidirectional - all directions.
Sometime when we have nothing better to do, I'll tell you about the difference between directional and omnidirectional radio antenna. Pretty technical and boring, so have a back-up subject ready.
Sounds fascinating. 
How about a discussion on the differences between omnipotence and impotence?
"Men are so simple and so much inclined to obey immediate needs that a
deceiver will never lack victims for his deceptions." - Niccolo Machiavelli
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James
SFN Regular
USA
754 Posts |
Posted - 05/02/2002 : 05:26:21 [Permalink]
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quote:
quote:
Omnidirectional - all directions.
Sometime when we have nothing better to do, I'll tell you about the difference between directional and omnidirectional radio antenna. Pretty technical and boring, so have a back-up subject ready.
Sounds fascinating.
How about a discussion on the differences between omnipotence and impotence?
Ow.
________________________
Two more years...Two more years...Two more years...Two more years...Two more years...
*whine* |
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Megan
Skeptic Friend
USA
163 Posts |
Posted - 05/03/2002 : 19:26:44 [Permalink]
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Oh I get it. Actually, Lisa, it sounds like fun....
~Megan~
Questions: never leave home without them. |
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Wiley
Skeptic Friend
68 Posts |
Posted - 05/06/2002 : 16:46:08 [Permalink]
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quote:
Omnidirectional - all directions.
Sometime when we have nothing better to do, I'll tell you about the difference between directional and omnidirectional radio antenna. Pretty technical and boring, so have a back-up subject ready.
Lisa
Yeah! This is good stuff. This is what I do for a living.
[faux insulted]Boring, indeed![/faux insulted]
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Lisa
SFN Regular
USA
1223 Posts |
Posted - 05/06/2002 : 23:05:43 [Permalink]
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quote:
quote:
Omnidirectional - all directions.
Sometime when we have nothing better to do, I'll tell you about the difference between directional and omnidirectional radio antenna. Pretty technical and boring, so have a back-up subject ready.
Lisa
Yeah! This is good stuff. This is what I do for a living.
[faux insulted]Boring, indeed![/faux insulted]
Somewhat interesting in theory, very hazardous in practice. My dream: put up an antenna in nice clear sunny weather with other trained technicians.
reality: cold, rain, mud, and I know those operators are gonna drop that sucker on my head.
Lisa
If you're not living on the edge, you're taking up too much room. |
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Trish
SFN Addict
USA
2102 Posts |
Posted - 05/07/2002 : 12:02:19 [Permalink]
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quote:
Somewhat interesting in theory, very hazardous in practice. My dream: put up an antenna in nice clear sunny weather with other trained technicians.
reality: cold, rain, mud, and I know those operators are gonna drop that sucker on my head.
Lisa
A friend of mine, medically outed from the Army, very nearly had this thing happen to her. The antenna hit her shoulder tearing the muscles and rotator cuff. Wasn't pleasant for her. And she had 18 years in.
---
...no one has ever found a 4.5 billion year old stone artifact (at the right geological stratum) with the words "Made by God."
No Sense of Obligation by Matt Young |
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