The professional/managerial class is actually the most vulnerable to automation. It's far easier to automate nebulous paperwork than it is to automate real world work. Even the mighty Tesla had to backtrack on how many robots they used on assembly lines. We've only just begun to see how much of the "thinking" can be done by AI.

If you wear a suit and tie to work somewhere, chatGP and especially its successors should be scaring the pants off you.

A great argument about why not just unions, but strong unions are necessary. If that's not on the cards then government needs to step in and break up these behemoths. Actually, both needs to happen.

Cars are expensive because 'chip shortages'. Intel tanking because 'chip glut'.

Hmmm.

Both! Aluminum is extremely common and it's readily recycled!

The reason that we recycle so much of it is because it's actually cheaper and easier that making the new stuff.

If everything was like aluminum, it would go a long way to solving sustainably issues.

If you got a fat/grease buildup in a kitchen sink boiling water works. A plunger won't move a fatburg, but given enough time the continued addition of piping hot water will heat the PVC enough to both expand the diameter and melt the fat glued the walls of the pipe.

Of course... Don't dump grease down your sink.

As others have pointed out, you use materials in the container that have a higher melting point than the steel you want to melt.

A more interesting question is how do rocket nozzles not melt because they need to deal with both temps and pressures that will melt the materials they're made of in a matter of only seconds... And they need to do it in an environment that has no air to conduct away the heat...

Part of that answer is to use the cryogenic fuel as coolant before combusting it.

The problem is not 'burning' hydrogen. That's been done for ages. The problem with hydrogen powering aircraft is figuring out where to store the hydrogen. Hydrogen has an incredibly low energy density by volume. Because of this (and other) basic physics problem(s), hydrogen will not work to power planes on long duration flights. The most likely solution to decarbonizing intercontinental aircraft travel will be some form of liquid bio-fuel or even synthetic liquid fuel.

Because of the expense of hydrogen, medium and short haul flights will most efficiently be covered by some combination of an expansion of high speed rail and battery electric aircraft.

Unfortunately, people have missed the boat here. The problem is not burning hydrogen to make things go, the problem is finding places to store the hydrogen on the plane. Hydrogen has an incredibly LOW energy density by VOLUME.

The risk of fire is very low with the engine running or not. Slightly higher with the engine running, but not much.

I would imagine that the biggest reason is that it's simply bad practice to leave any machine on when you're away from the controls. A kid could knock the gear shift. A crook could jump in. Let your imagination run wild. Any manner of remote but real possibilities can be avoided by simply turning the thing off. Kind of like wearing a seatbelt. Most people never need it, but that one time they do makes all the difference...

Ah yes. Looks like fusion is only 20 years away... And always will be.