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Post by sts60 on Nov 18, 2005 10:08:19 GMT -4
The discrepencies on NASA's site that I've point out thus far, from my READING, have been ignored by everyone but Jay.
Speaking as a space systems engineer with roughly a decade and a half on the job, I'd be shocked if there were no discrepancies anywhere. It's in the nature of large projects.
There were plenty of discrepancies in the logs kept by various Allied ships and Allied and German land forces on D-Day, as to who was where and what happened when. There are discrepancies in the map books I use responding to fire/rescue calls. I found discrepancies in the mass data for a particular standard piece of flight hardware (over 100 of them have flown) that's been around for a quarter century. No hoaxes, just the imperfections you get when human beings get involved.
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lonewulf
Earth
Humanistic Cyborg
Posts: 244
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Post by lonewulf on Nov 18, 2005 16:29:22 GMT -4
Quoting Bazbear: The personal attacks come from posters who's frustration levels over your apparent willful ignorance have reached the boiling point. I try to avoid that myself, but I do understand their frustration with you.
Yeah, hence why we've been called trolls. :/
I'm not saying you said that; I don't keep track of who said what really. Just that it hurt a bit.
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Post by nomuse on Nov 18, 2005 17:53:49 GMT -4
Hey, I was making coffee yesterday and I think I suddenly understood the whole "flash freezing" of the urine dumps (and by analogy the glass-of-water-on-the-Moon question.) First off, at that pressure (lack of pressure), room temperature is boiling. So the water vaporizes. However, you still got heat of vaporization, and that comes from the water. So the vapor chills and crystallizes out. Then of course sunlight gets into the act, and the tiny tiny ice crystals sublimate again. Probably takes fractions of a second for the first effect, and up to a minute for the second.
Am I in the ballpark, guys? I've got no formal thermodynamic training.
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Post by PhantomWolf on Nov 18, 2005 21:17:01 GMT -4
I'd say that almost hit it out of the ball park.
I quite like the bucket of water analogy I sometimes use.
Imagine that the molecules from the outside of the water to the center are like a line of people with buckets. The water in their bucket is the amount of internal energy (not counting internal bonds here) that each molecule has. If they have less than 1/4 of a bucket of water then they would be a solid, if they have 3/4 bucket then they are able to leave the chain to be a gas. By adding the rules that each person must have the same amount of water in their bucket as their neighbour does then allows you to model how thermodynmics work. If the person on the "Outside" is considered to be in a heat sink, they simply empty their bucket at each stage, then the persn next to them halves their bucket so they have the same amount, then the next persn tops that one up so they are equal and so on till you get to the "center". Likewise if they are standing in a "heat source" then they get water added, and so have to them share that with therir neighbour and so on do the line. As you can see, the person in the "center" both heat and cool slower then the one of the edge.
To apply the model to boiling, you need to add on extra rule, that to leave the line, the person with the full bucket must first grab half a bucket of water from the person next in line to overcome the bonding energies. This means that what we'll see is that as each person gets their bucket full of water, they remove that, plus extra from the rest of the chain, thus cooling the entire chain towards the 1/4 of a bucket "freezing point."
We can see this with water being boilded at sea level. It will reach 100°C and stay to boil, but then this extra energy need will drop the temperature to about 98°C. In space, what we see is that the boiling point and freezing point are so close, that as the surface molecules boil off, the extra energy they remove while breaking the inter-molecular bonds drops the energy of the rest of the liquid to such a point that it will then freeze. Thus the liqud will both boil and freeze simultaneously.
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Post by neanderthal on Nov 19, 2005 17:52:47 GMT -4
And, to repeat the already stated conclusion, this effect has nothing to do with the "temperature" of space.
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