Most heat resistant light density material-- asbestos???

Dear Archimedes Plutonium:

It probably just vaporizes (sublimes). It is just metal oxides, for the most part. That is why it is important here on Earth. It cannot oxidize further. On the Sun, you'd be better of with an ablative coating, something you could sacrifice, that didn't transmit heat well. Diamond perhaps...

Assuming you couldn't just wait and go at night. ;>}

David A. Smith

Dear Ian Gay:

I was thinking more along the lines of what frequency of light it could emit, but you are right. Heat conduction is not in its camp as an "ablative coating that doesn't transmit heat". Only if the transmission is strictly radiative.

David A. Smith

Look up the thermal conductivity of diamond!

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No, it decomposes, losing water of crystallisation. That destroys the crystal structure. The melting point of the anhydrous product depends on the type of asbestos.

Terry Harper wrote: (snipped)

Any temperature at which this begins to take place. And I wonder if the Twin Towers had been made of asbestos (hypothetically of course) that they still would be standing. And I wonder if the Space Shuttle were made of asbestos tiles? Which maybe better for the Shuttle as a loose tile would damage other neighboring tile whereas asbestos would simply sublimate.

Archimedes Plutonium, a snipped-for-privacy@hotmail.com whole entire Universe is just one big atom where dots of the electron-dot-cloud are galaxies

Dear Archimedes Plutonium:

The steel girders of the twin towers *were* coated with asbestos. Asbestos is a lousy conductor of heat, but it still conducts. The steel lost its strength.

The space shuttle could not fly with asbestos tiles. The weight of the "envirowhiners" woudl be too much for the engines.

David A. Smith

The fire retardant about the trusses in the twin towers were in a state of disrepair. Ironically, they were in the process of repairing them in the year up to the towers being attacked - they had reached the floor below where the plane hit the second tower (or so that TV program on how the towers fell told us).

As for the shuttle, I thought that it was a couple of minutes after take off that the foam caused the damage. It was only on reentry that the damage became fatal, so sublimation of the asbestos would have made no difference. Maybe future shuttles should take along a free-form fabrication device to enable running repairs to be made in space.

Brendan Hall

Dear Brendan Hall:

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I was surprised to find out that a bomber had crashed into the Empire State Building... and stuck there, back in the 40s.

difference.

They are (supposedly) going to the ISS for every future mission, so the concept of a "waystation" has been reborn. Can you imagine what it woud be like to be on a ship with six other people and know that you are already dead? They didn't, by all accounts, but what a deal... perhaps like all the submariners sitting in the dark and cold.

David A. Smith

The twin towers' girders were sprayed with a "new high-tec" foam, or at least high-tec for the '70s. This was blown off of the metal by the impacts, and ended up serving no function. A more rigid material like rockwool or, god forbid, asbestos, might have done better.

Marc

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Aerogel might have done better. Improving the insulation would have allowed more people to exit the building before it collapsed. But would not have stopped the collapse.

Personally, I don't think we should locate and build a building we cannot bring down *intentionally*. They do "wear out".

David A. Smith

You don't get it I'm afraid. The foam was blown away by the impact and explosion of a jet aircraft. Aerogel would be blown away by a sneeze!

Marc

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I was referring to the experiments in the 70s and 80s where they altered jet fuel to make it less flammable in case of crashes. I was pretty sure thay called it aerogel then too, but perhaps not.

Seems like anti-misting agents had the best result. Seems to me, if there was little fire, more people could have gotten out. Maybe long distance flights could be fueled this way. Then only the collision would kill... the "bomb effect" they sought to use by choosing cross-country non-stop flights, would be defused.

Sorry I wasn't more clear.

David A. Smith

I understand you now, but that's not what aerogel is. Aerogel is a substance that's 99.8% air. It's an incredible thermal insulator. It has no physical strength to speak of.

The anti-misting agent didn't work too well in the practical test, crashing a plane. Don't know if it would have helped with the Twin Towers. Couldn't have hurt.

Marc