atomic_fungus (atomic_fungus) wrote,
atomic_fungus
atomic_fungus

#3753: Laser cooling

One of the biggest problems I face with my SF is how to cool massive starships.

The Laws of Thermodynamics are pretty clear on the subject: every system generates waste heat and you have a bitch of a time getting rid of it, especially when the system in question is surrounded by vacuum.

This isn't really a big problem for a civilian spacecraft; you can hang any number of radiators off the damned thing and let 'em glow away as bright as you like. But military vessels--the radiators are the weakest spots, and all you have to do to disable the ship is to take out its ability to shed waste heat. Once you've done that, past a certain limit the people running the ship must either shut down or broil.

So how do you cool a military ship in a non-vulnerable way?

My answer has basically been, "Hyperspace heat sinks, edge effects, and LOOK HALLEY'S COMET!" because the physics of hyperspace in my SF universe is tricky; objects in hyperspace have an imaginary rest mass (like tachyons purporedly do) which precludes hanging a simple radiator through a hyperspace wormhole. My solution involves using lasers, and a lot of handwaving and distraction.

What I want is for the waste heat to be beamed into hyperspace, carried by a stream of coherent photons (laser light). This lets you put your heat sinks inside the ship, well away from attack and much closer to the big heat sources, such as your main power reactor. The problem I have is that there's no way to do that according to modern science.

The Laws of Thermodynamics are pretty strict. Dumping your waste heat in hyperspace doesn't violate them; it only makes the system a bit bigger. It takes a lot of power to make the wormhole and it takes a certain smaller, continuous amount of power to maintain it, so the system is nowhere near 100% efficient. Hyperspace is an alternate space that's part of the universe, so it's effectively the same as hanging a big radiator off the side of your ship in normal space--just less vulnerable to attack. (And no, you can't sneak up on someone in hyperspace and blow up their radiators; the physics preclude that for a variety of reasons.)

Well, it's not a problem I'm going to solve today. But this may help me a bit.

* * *

JWF: "...[T]his is how the union thugs roll in Obama’s America." I'd argue that this is how union thugs roll, period.

NYC school bus drivers are on strike, and they're vandalizing school buses by stabbing the tires in the sidewalls.

Gee, vandalism from union goons. Who could have predicted that?

* * *

A jet-fuel fire can't melt steel.

But it doesn't have to in order for the WTC buildings to collapse due to one.

We've known how to smelt and shape iron for thousands of years and we still don't know everything there is to know about it...bue one thing is certain: a hot fire can soften metal without melting it.

When the WTC buildings were first designed and built, they were constructed such that the structural steel components of the buildings were sheathed in asbestos insulaltion so that--in the event of a fire--the structural integrity of the building would be maintained.

Then they discovered that asbestos causes cancer.

...removed the insulation from the beams, leaving them bare. Yeah. And when you've got jet fuel burning in a building constructed the way the Twin Towers were, it burns hot...and if you get steel under load hot enough, it bends without having to melt.

And that's without considering the chemistry of the fire itself, as mentioned in the second link.

In the AoSHQ link, Ace talks about the various properties of metals but doesn't touch on a property of certain alloys known as "eutectic compounds". Solder is a eutectic compound: it does not soften before it melts, but instead it changes from solid to liquid upon being heated to its eutectic point. This is useful because you want solder to solidify as quickly as possible once the heat source is removed.

Water is eutectic; you can't heat up ice and bend it into a new shape because ice turns directly to water once it passes 32°.

But steel is not a eutectic compound. When heated, as it gets closer to its melting point, it gradually begins to soften. You don't need to heat it to its melting point to change its shape; you need merely heat it enough to soften it.

So, yes: you can't melt steel with burning jet fuel; it doesn't get hot enough. But the steel girders forming the frame of the WTC didn't have to melt to cause the collapse; they only needed to soften--and if I can get a wood fire going in my fireplace that's hot enough to make the fireplace grate bend in the middle, then I'm sure twenty thousand gallons of jet fuel on fire in a high-rise can accomplish the same.

* * *

Gun control!

Shooting themselves in the foot. Big show organizer on the east coast says, "No eeevil black rifles at the gun show we're running!" And so a whole slew of participants simply pull right out of the show, leaving them with tons of empty space--enough that they had to "postpone" the show.

Borepatch discusses such a decision by Gutntag, which means I'm going to have to buy something from Gutntag pretty soon.

*

Democrats have to face the fact that many of their constituents do not like the idea of having their civil rights trampled by overweening government. And Democrats are the most vulnerable on this point.

* * *

Borepatch asks if the wheels are coming off the global warming bandwagon. I think they already have; the warmistas are desperately trying to stick 'em back on with hot glue and zip ties but the damage has been done.

* * *

80% chance of snow here in the Fungal Vale. Mrs. Fungus has gone to work, as usual, and faces driving home in snow...but she's driving home on the tollways, and those are usually kept reasonably clear.

I drove 294 to and from work for seven years, and in that time I had to drive in snow only 3 times. Of those 3 times, only once was it really bad; that was in 1993 and I was driving the Thunderbird. There were perhaps four inches of slushy snow on the road, and I was driving a car that was horrible in snow. I recall being passed by a moron driving on the shoulder.

It's a shame: I may have one or two photos of that car, but that's all. It was a nice, comfortable car. It had the 3.8 liter V6, climate control, power locks and windows; it's the most expensive car I ever bought new and it was perfect for my job as an on-site computer technician. It was comfortable, with a nice ride, and had a voluminous trunk.

I also wrecked the damned thing three times. I say "damned" advisedly; that car was cursed. I traded it in--three years after I bought it--with 92,000 miles on the odometer, and I paid extra to get new license plates for the new car (my green 1995 Escort) because I didn't want any bad luck transferring to the new car.

But I still have a soft spot in my heart for the old T-bird. I wish I had more pictures and/or some video of the thing.
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