There is no theoretical reason that a room-temperature superconductor cannot exist.

Room-temperature superconductors would be really cool. It's not clear that electromagnetic propulsion gets you to orbit, though. Once there, sure it works.

Multiple-Tesla fields that are changing their orientation rapidly in time aren't particularly healthy to be around. Induced currents in your nerves, heating, etc. That MRI field is acceptable because it's DC. That is, if you don't have any ferromagnetic objects on you.

No, the superconductors are not simple magnets.

What's on the tele then?

Rockets being the only solution does not automatically mean rockets are a viable solution. Please quit ignoring the real challenges presented.

Unfortunately, this can't be approached as an engineering problem and get the result you would like. It needs to be approached as a problem in fundamental research of the physics underlying our world.

There were lots of efforts to miniaturize the vacuum tube. They only resulted in smaller tubes. It took new insights in fundamental physics before people could understand how to make a transistor. There were many experiments with germanium (a natural semiconductor) that could have led to the transistor before 1947 if anyone had understood what was happening.

Some steel. Not all of them. That's why the refrigerator magnet doesn't stick to that silver door.

A field strong enough to work on water would kill you first.

Look at the amount of money made on oscillococcinum, and you might agree it's a successful hack to make money from the stupidity of others.

This would be cool if it was more than a stage trick. The superconductor needed to do this used to be mail-ordered from Edmund Scientific. So lots of hackers were doing levitation demonstrations in the 90's. People think it's cool because they've not lived through that, or have forgotten it.

It works on the principle of superconductors excluding a magnetic field. When they are cooled to liquid nitrogen temperatures. Steel is low in ferromagnetism and isn't as good a conductor as copper so it's not as good for making electromagnets.

Well, I did that once with a bottle of liquid nitrogen from Airco and a superconductor I bought from Edmund Scientific. This was before there was a Slashdot. So, no, not impressive.

Before someone makes a working hoverboard, we will first hear about the principle that makes it possible. Because one that's practical is almost guaranteed to get someone a Nobel Prize. And certainly Lexus would go for that if they could.

No new principles lately. There is an existing principle of magnetic repulsion that would work only in an extreme condition. One requiring really special stuff buried in the street, and probably including liquid nitrogen to keep it working for even a short time and a few feet.

So, it's a gimmick.

But probably not the reason you think. :D They cost that much so that some CIO can cover his arse when something goes terribly wrong with the corporate database... "we are waiting for Oracle support to tend to our ticket."

It's actually the best kind; there are two types of code, code that's almost certain to work and code that's almost certain not to work...

I will assume your question is serious. Posix never isolated processes. One process can see other processes' files, ports, and even the processes themselves. That is what containers are about: your web browser cannot see your email client's files and vice-versa (so a vulnerability in one process cannot give you access to the content of the other).

Hey, I hang out with a lot of creative people. Not Elon Musk, but Steve Jobs for more than a decade, and lots of people at least as smart that you don't know. They can be really brilliant, and successful, and they can still make really stupid mistakes and sell them to the rest of us pretty well because they believe in themselves completely and they have a track record. I've done that too.

That's the hyperloop. Something Elon never meant to stand behind (and still really isn't), just put out there to torpedo a worthy project that he didn't believe in.

Anyone who looks at the hyperloop design can see it's not a no-brainer. It has safety issues up the wazoo :-) It's going to take a long time to get right.

Meanwhile, little Switzerland can have incredible trains everywhere and the United States can't get it together, and unlike with rockets and cars Elon's not helping this time. And I am not sure that the "lease" part of his solar business is a great thing for the world either.

Although the hyperloop is possible and might even be practical someday, let's please be honest about the reason it was created. Elon Musk just wanted to kill the California high-speed rail.

That might have been OK if there was a hope that we could actually replace it practically with a hyperloop. But given the history of bleeding-edge rail - ride any maglevs lately? We haven't even had much success with monorails outside of theme parks and Las Vegas - we don't really have any working system to replace high-speed rail. Hyperloop should really be called "Pipes that carry People" and we need decades of work on it before considering intercity lines.