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Comment by yk | Hacker News Reader

Quite simply, x-ray diffraction tells you the distribution of electrons in the unit cell of the alloy. So you just put an sample into your spectrometer and it will print out the chemical elements and how they are assembled. And even if there is another island of stability of super heavy elements or something like that, it will still just tell you the charge of the nucleus. So this side of quite literally magic, as in all of chemistry of the last 150 or so years fails catastrophically, there is no possibility of having an alloy sitting in a warehouse and not knowing exactly what it is.

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What if there are no electrons, because there are no atoms?

The suggestion that all these alleged weird alien materials are “alloys” is just a placeholder for “looks and acts metallic, therefore made of metals.”

But if we happened to be dealing with real alien tech, that’s a naive and unscientific assumption. We already have people thinking about how to build programmable matter with variable properties, and it’s a fair bet we’ll have working examples within 50-100 years.

And there is no possibility that conventional x-ray diffraction will reveal how that kind of matter works.

Assume for a second this is real alien tech. No atoms, programmable matter, literal magic, whatever.

Why would this be in a warehouse of a $22 million (i.e. super small potatoes) government project? It would be the biggest budget and highest secrecy project on the books.

Also the NYTimes would not be allowed to print it, to the extent of the editor disappearing.

Also people posting on hacke

So you're saying that if the number were, say, $220 billion, you would believe that it's a real alien tech, but you don't believe it at $22 million? I don't understand.

If so, you're logically entangling an arbitrary funding number reported in the article, with the idea that perhaps some new material (or alternative particle physics) could exist.

If alien visitation were real (a huge IF), this wouldn’t have been the first project started to investigate it. Most likely there would be deeply secret and entrenched organizations around this in the government, which would also explain why this program was shut down without explanation despite “much progress”.

You're assuming "unit cell" is a meaningful concept for these materials. Can x-ray diffraction completely characterize, say, a quasicrystalline structure? Moreover, even if you can tell what it's made of, that doesn't necessarily tell you how it was made or how it works.

Well, there are other techniques for anything that is not a crystal, and they are similarly developed as x-ray diffraction, if nothing else, take an atomic force microscope and identify each individual atom directly.

> that doesn't necessarily tell you how it was made or how it works.

Absolutely, there may be materials were we don't have the slightest idea how they are made or how some property arises. But my point is, that the analysis techniques are at a level were it is pretty much guaranteed that an expression like "unknown alloy" is pretty much just clickbait, we know a great deal of anything that is made out of atoms a few days after a sample showed up in a laboratory.

"Identify each atom individually" won't scale very far for complex materials. In short, I think it's unwarrantedly optimistic to assume that our current lab techniques, optimized for natural and human-fabricated materials, will immediately figure out (hypothetically) alien technology. No assumption is completely safe; even "made of atoms" is not guaranteed. Probable, but not guaranteed.

>even "made of atoms" is not guaranteed. Probable, but not guaranteed.

How is that not guaranteed?

It is possible that there are other stable particles besides the ones we know now (like protons, neutrons, electrons, photons, neutrinos, etc). And maybe they can form stable arrangements which are not atoms, but which can still interact with ordinary matter. In that case you could have a material that was not made of atoms.

I don't think a lump of such material is in a warehouse in Nevada, but maybe it exists somewhere in the universe.

I would think those would just be made of different kinds of atoms but OK.

An atom is a particular type of arrangement of protons, neutrons, and electrons. If something is not made of protons, neutrons, and electrons in that particular arrangement, it's not made of atoms, by definition.

We already know for a fact that there are units of matter smaller than protons/neutrons/electrons. As such, x-ray diffraction is obviously not sufficient to analyze all matter.

We already know for a fact that there are units of matter smaller than protons/neutrons/electrons.

Yes, and everything we know about them suggests that they either:

Decay almost immediately when encountered in the wild

Immediately clump together with other particles to form larger units

Do not interact with normal matter

Etc.

IOW, there's little or no reason to think that any kind of stable material, anything that you could store in a warehouse as a clump of "stuff", is made without atoms.

If it is possible, as far as I know, that would be deep into "entirely new physics that violates a lot of central tenets of our current thinking". So yeah, that could happen, but you have to ask "is it likely"?

Of course it's unlikely. Being visited by an alien race is, in fact, highly unlikely.

That's not the point, though, is it? This article said "experts say that creating materials we don't understand is impossible." Not unlikely - impossible.

An alien race with the capability to visit earth would have a grasp of physics that we obviously do not, otherwise we would be visiting habitable planets right now. That's the whole point. The argument this article puts forth is just as silly as the young-earth creationist argument that "abiogenesis is incredibly unlikely, so it must be God". Or in this case "we don't understand it, so it must be impossible".

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