pfdietz

The application to EUV/XUV is important, as those wavelengths can be very useful for photolithography.

The Fermi paradox doesn't require we're good at observing aliens. It asks why didn't aliens colonize everything, including the Solar System, billions of years ago, in which case we wouldn't even exist.

An intermediate possibility is he got a wrong answer and, for subconscious reasons, didn't press himself to confirm it was correct.

I know nothing, nothing...

Japan had already lost 272 out of 665 sq. km of built up urban areas, with no sign of collapse.

It's convenient, yes, but it's also true. The deaths in Japan had an invasion and ground conquest been necessary would have dwarfed anything they had yet seen. Just their deaths from starvation would have been horrific.

There was one proposal to use dry ice as the moderator, in a low power experiment.

"Default teaming" really isn't viable due to the Fermi problem.

But if OoL is extremely unlikely, the cluster panspermia idea still allows extraterrestrial life to reasonably exist and be reachable, because that life didn't require a separate highly unlikely OoL event.

I think SETI should focus on stars that look like the Sun's siblings.

Yes indeed, I've thought panspermia in the Sun's natal cluster is an interesting idea. What could make it even more interesting is that small bodies in our Solar System (and likely its sister systems) were warm enough for liquid water to exist for some millions of years then, so there would be an enormous volume of material in which Origin of Life might have occurred (and, if it did, to then spread after the parent body froze and then fragmented.)

It would make a fine science fictional scenario that could get around the Fermi problem: those 10,000 or so systems could have life, but the rest of the universe not have life.

Maybe you can be salty and bitter, as if you too were trapped in potassium chloride for millions of years...

There's a yttrium-containing variety of LFP that's supposed to work better at lower temperature (down to -45 C). But yttrium itself is quite expensive ($35/kg).

So these bots are going to get the Aaron Swartz treatment, right?

RIGHT?

So, two negative effects make a positive??

Even that looks abandoned. The last post on the Popehat website is from June of this year.

That link goes to a nonexistent message. Didn't Popehat leave X a while ago, if he's even still a thing?

So this means it's a new dawn for Common Lisp, right? :)

What matters is the state of the gas as it starts traveling down though the nozzle. All that comes before that doesn't matter.

Well, you didn't even present any evidence for your negative claim, so I had to guess what you were thinking.

What should I call the excess self-regard of some of these mathematicians?

The problem is the temperature limit on the heating elements. You could use arc heating, but that's not very efficient and also causes erosion of surfaces (and demands high instantaneous power; this scheme stores energy as chemistry).

The temperature of gas in a conventional rocket engine is high enough to melt or vaporize the thrust chamber; only cooling and limits on heat transfer to the walls keeps that from happening. In the SpaceX Raptor engine, for example, the gas reaches a temperature of at least 3500 C. In comparison, the boiling point of iron at 1 bar is 2870 C.

When AI can blast out major results that humans missed for decades, I think some appreciation for the limitations of human intellect is warranted.

I've noticed a cooling down of the human chauvinism arguments since the QRH results.

> I think hydrogen it a pretty poor coolant anyway.

Hydrogen is a pretty good coolant. For example, it's used as a coolant in large generators.

You are under the impression that beauty is some sort of objective thing, independent of what you were taught and what's in your culture. It's not. It's deeply embedded in culture, and is part of human power dynamics.

The article states they are electrolyzing water to make hydrogen and oxygen, then burning these gases in a rocket.

Normally, a rocket will have higher Isp if fuel is present in somewhat higher amounts than is needed to react with all the oxidizer. This is true in H2/O2 engines as well as hydrocarbon/O2 engines. This is because otherwise the combustion temperature is so high that some dissociation occurs, which robs some heat. Adding extra fuel makes it cooler so combustion is more complete, but also reduces the average molecular weight of the gas, for a net increase in Isp.

Here, I'd worry the combustion temperature would be too high. They might avoid problems by operating at very low chamber pressure, but that makes dissociation even more of a problem.

One might ask why not just heat the water directly. The problem there is that at reasonable temperature for a heater making steam, Isp is be very low. You'd be lucky to get much above 200 seconds, less than half the Isp of a H2/O2 rocket. Ammonia or methanol are better choices that that situation (they can decompose to hydrogen-rich gas, improving Isp at a given temperature).

Open that wallet wide.

I was pointing out a concern with that non-PFAs solution.

I also understand the silicone in current parchment paper isn't a PFAS, as it contains no fluorine.

The concern is twofold. First, chromium is an element and as such does not break down, it can only be secreted. Second, the higher oxidation state Cr(VI) is a known carcinogen. It's claimed the Cr(III) here will not oxidize to Cr(VI) under normal cooking conditions, however.

My understanding is the claim that Cr is a necessary micronutrient is disputed.

I'm rejecting the presumption that "collectively it's a disaster".

These frills aren't something that's objectively good. I view them as social signals, something to indicate you can afford it, and that you belong in an elevated social class. This sort of signalling is parasitic. We are worse off for it being there, and we are better off if we actively identify the tendency toward it and consciously reject it.

Once again, it's the market telling you something you don't want to hear.

Do I want to play this?

Nah.

Nah nah nah, nah nah, nah nah.