41
Just Chat! / Re: Freudian Word Link
« on: 18/05/2009 13:53:31 »
intricate
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43
That CAN'T be true! / Fir tree in lung
« on: 17/05/2009 22:18:57 »Is there anyone on the firum from Aldershot?close - Nr Petersfield.
45
That CAN'T be true! / Fir tree in lung
« on: 17/05/2009 08:59:28 »
How one lungs for a decent thread to be aired
50
Just Chat! / Freudian Word Link
« on: 15/05/2009 21:26:35 »
THe rules: only ONE word per post, read the word then post your immedate thought!
First word:-
GUMBALL
First word:-
GUMBALL
51
That CAN'T be true! / when we shut off the light in a room, what is the "speed" of darkness?
« on: 15/05/2009 21:18:28 »thus the speed of silence is the same as the speed of sound... [No, it took you a whole 2 hours for you to shut up! lol!]
52
Guest Book / new to all this.
« on: 15/05/2009 21:16:26 »You're all male aren't you?I just checked and sure enough you are correct, now where was I - ah yes coronal mass ejections...
53
That CAN'T be true! / Is cold water better than ice water for cooling down?
« on: 15/05/2009 20:04:33 »
You are all assuming that the regulatory temperature function somehow overcompensates, it does not. If you want to keep cool, drink cool. Think about it, suffering from Hypothermia, do you give them Iced water or a nice hot cuppa joe?
Drink hot tea on a hot day you will sweat more than than if you drink cold, but your body will attempt to regulate whichever way you push it. I also understand that drinking Ice water after hot heavy exercise can cause vomiting, thus warmer fluids are used.
Drink hot tea on a hot day you will sweat more than than if you drink cold, but your body will attempt to regulate whichever way you push it. I also understand that drinking Ice water after hot heavy exercise can cause vomiting, thus warmer fluids are used.
54
That CAN'T be true! / Have I been duped?
« on: 15/05/2009 19:53:33 »
Another myth down the plughole...
55
Physics, Astronomy & Cosmology / Could the Hubble telescope see astronaut footprints?
« on: 15/05/2009 18:43:59 »Hello all, great replies so far for the resolution question,I'd be very surprised if there were no filters, shutters built in, even a system to close the telescope hen being maintained or possibly redirected past the sun.
especially the NASA link puts things into perspective.
But what about the brightness aspect?
I'm pretty convinced Hubble's CCD would burn up if the telescope
would be pointed directly at the Sun, but what about the Moon (or the Earth)?
Would it suffer any damage?
Would the CCD be overloaded and produce a completely white picture?
Roger
As for the moon no, my understanding is that that there is almost no heat reflected just visible light so although the CCD may be saturated it is unlikely to be damaged.
Not sure how much light hits us from the moon but I'll bet it's less than 1 watt/square metre.
THats from the whole moon, now consider how much light hits the earth from a a tiny square of that
probably only a few nanowatts, (to lazy to do the sums) THe moon only looks bright beacuse of the dark background,during the day it's no brighter than sunlit cloud.
EDIT: Moonlight at earth's surface approx 1mW/M2 (1 thousandth of a watt per square meter).
THus the total light from the moon entering Hubble would be around 4.5mW (enough power to
light a low power LED. (Hubble Mirror 2.4 Metres Radius. Nothing like enough to harm even the most sensitive CCD camera.
56
Technology / Re: Which small loudspeaker is best for this application?
« on: 15/05/2009 18:33:44 »
Any speaker will do. the problem is finding a language where "Peekaboo" translates to "Click"
57
Physics, Astronomy & Cosmology / How far back in time can we see with powerful telescopes?
« on: 15/05/2009 18:31:10 »
So just how fast has our galaxy been travelling away from these other galaxies to be able to look back and see a time when our galaxy would have been there not here?
58
That CAN'T be true! / Fir tree in lung
« on: 15/05/2009 18:16:30 »
Fir god's sake will you please stop now!
59
That CAN'T be true! / when we shut off the light in a room, what is the "speed" of darkness?
« on: 15/05/2009 18:15:16 »
Ok time to put you all out of your misery, the speed of 'dark is the same as the speed of light. If the sun instantly dissappeared it would take some 8 min 20 secs before the last (direct) light (from the sun) hit the earth
60
Physics, Astronomy & Cosmology / Re: What is the temperature in space?
« on: 15/05/2009 18:11:52 »Actually, the original quote isn't too bad. It says they "experience a temperature change," which is different from "the temperature of space is..." They're talking about the temperatures experienced by the suit, or by the astronauts if they fell out of their suits, which are certainly well-defined.
uh?
If the astronaut 'fell out of his suit' he would not suddenly experience temperatures of minus 200C - think about a vacuum flask, no air, no light, a vacuum, yet the hot drink inside remains warm, (yes I know why) same in space the astronaut would slowly lose heat as it was radiated, he would not feel a sensation of cold until a certain amount of heat had been radiated away.