There was an old commenter on Slashdot that like to point out that "Mach 6 at 60,000 ft altitude is only 6% of the way to orbit". The math is just approximate, but tells you something about the (poor) viability of air-launching to orbit. See this detailed video from Everyday Astronaut.

Except that the trailer only has a single electrified axle. It has no steering capability (it doesn't even front wheels to support its weight!), no sensors to be aware of its surroundings, no compute power to make sense of the world and navigate to its destination.

It's highly likely that we'll end up with "animated death prisms", given enough time, but it's a giant leap from what this article is talking about to that. Any well-resourced engineer could stick a battery and motor onto a trailer. What you're talking about is Level 5 autonomous vehicles, which only barely exist after a few hundred billion dollars of development.

It's an awesome achievement - a really challenging problem, of depth and complexity beyond the ken of most armchair engineers, executed successfully.

That said: what they have achieved is basically the same as the DC-X from 30+ years ago! Let us sincerely hope this effort has a longer life ahead of it than that one did!

I don't think it's too rabidly nationalistic or ideological of me to say that I'd prefer such discoveries and technologies be developed in my own country, rather than importing them from China. From a scientific standpoint, I agree that the knowledge benefits everyone, no matter where the discoveries are made. But from the standpoint of economics and national security, every key technology that we have to import from a strategic rival is a potential liability.

Bummer, too, because his work on metal organic frameworks would have been perfect for extracting electrolytes. It's what plants crave.

I'll quote myself from a different comment:

The detector works by looking for neutron spallation off the fissile material. You can't tweak the design to get rid of the fissile material. So to avoid detection you either need to 1) prevent the Van Allen or cosmic ray protons from getting in and causing the spallation, or 2) prevent the neutrons from getting out. Both involve a fair bit of shielding, which may simply be impractical.

The detector works by looking for neutron spallation off the fissile material. You can't tweak the design to get rid of the fissile material. So to avoid detection you either need to 1) prevent the Van Allen or cosmic ray protons from getting in and causing the spallation, or 2) prevent the neutrons from getting out. Both involve a fair bit of shielding, which may simply be impractical.

Plutonium-based nuclear weapons usually contain uranium, too, as a tamper to aid in the original implosion, and/or as additional fissile material to boost yield. Here's a cross section of a US W87 warhead. Soviet designs weren't too different, because of espionage and physics.

I couldn't quickly find any sources that specifically discuss proton-induced neutron spallation in plutonium, but it is reasonable to expect that the effect would happen in fissile plutonium just like fissile uranium. Spallation from plutonium probably would have a different enough signature (i.e., a spectrum of neutron energies) that might even allow you to learn something about the bomb's internals.

I don't usually comment on AC posts. But this one beat me to the punch:

1) If the countermeasure is to jam the nuke's communications, then the obvious response is to rig the bomb to detonate automatically if it loses contact with command and control for too long.
2) But this approach only works as an effective deterrent if the other side - the one doing the jamming - knows that that will be the result.

In other words: it's very much like the ending of Dr. Strangelove.

The purpose of the itemized labels wasn't just to let consumers know how much their actual bill would be, rather than the advertised price. The itemized labels also made it harder for ISPs to hide their bullshit nonsense fees. What the heck even if a "broadband recovery fee" or a "convenience fee", and how does the ISP defend that being part of the bill? Now, it's just a "and here's all the extra stuff we're going to charge, justifiable or not, and we'll hide it in this one line item."

It's an informational asymmetry: the ISPs definitely know and have all the information - otherwise they couldn't generate a bill. But now the FCC is letting them obfuscate it. Properly functioning markets (which the GOP used to claim they cared about) rely on open and transparent pricing. This ain't it.

I am confused by this company's claims. It sounds very much like a magnatorquer - a device that can change a spacecraft's orientation - that just happens to use superconducting magnets instead of, say, copper wire. That's cool, and will certainly have useful applications.

But then they start talking about using it for propulsion, which I'm confused by. To get propulsion pretty much always requires reaction mass - something you're throwing behind the spacecraft. This doesn't do that, so how is it supposed to produce thrust?

do programming languages count?

That's neat, and I'm glad that it's out there. From the looks of it, it's a CAD program where you are using their scripting language to generate primitive solids and doing simple boolean operations on them (add, subtract, etc.). That could work for some things, but it sure seems tedious compared to CAD that offers a GUI. I also can't see that it allows for real parametric modeling, where this feature references this other feature (e.g., place a hole 4 mm from either edge of a corner; if the corner moves in space, the hole moves, too). It looks like you need to keep track of all that yourself in the scripting. I'm not sure how well it'll work with more complicated features, like defining rounds that follow edges, draft angles, and so on.