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comment by kleinbl00
kleinbl00  ·  103 days ago  ·  link  ·    ·  parent  ·  post: Pubski: June 5, 2024

So I've seen the math on what an 'Oumuamua flyby looks like. It's gnarly. I wholeheartedly invite you to run shit down yourself but when I glimpsed it here's the following:

Rate of closure: 17km/s

Target size: 0.1km

New horizon's LORRI imager had an angular resolution of 5 microrad/pixel or around 1 arcsec. If you were able to build a 1 gigapixel camera, which clears frames at 10 frames/second, you will get 100 pixels for 20 minutes, 1000 pixels for 2, and 120 frames at 10,000 pixels.

You're also out there at 207AU. New Horizons passed Pluto at 34 AU so you've got 1/6 the light.

Now here's the thing. I've worked with some weird fuckin' metals in my day. For attaching spark plugs to hearts we used an 80/20 platinum/iridium alloy cooked up special just for us. You don't alloy platinum for anything but jewelry and catalysts, that I know of. And yet ole Avi Loeb did some trawling out Australia way and turned up an 8mm curl of platinum-manganese wire.

I have spent some time trying to find a manufacturer of platinum manganese wire. Closest I've gotten is an outfit that will make it for you if you order it. I don't know what you'd use it for. It's probably a lot like steel but more corrosion-resistant. And when Dr. Loeb went "so we found this thing" everyone went "it's obviously natural, you crank."

Even though nobody else has ever found platinum-manganese wire in nature before.

You should read his book. His argument is basically "look, space garbage is far and away the easiest explanation for the data" and then he decided to dredge up some space garbage. Further, his argument is "in an infinite universe it makes sense to get the delta V of anything you jettison at cosmic rest so no one can track you down" and that's exactly what 'Oumuamua was at. Really, he's at "space garbage is probably boring AF but it's also the most likely sign we'll ever find that there are other intelligent species out there, so why not look" and I gotta say, he makes a compelling argument.

But 8mm hairs of platinum manganese aren't likely to slaughter cows so it's boring.





am_Unition  ·  102 days ago  ·  link  ·  

Oh no, I should have been more clear, sorry.

When I say "Oumuamua chaser", I don't mean "something to chase Oumuamua", I mean "something to chase the next one". I'd have to work extended launch readiness scenarios into the proposal. You probably have to launch while the thing is somewhere between Jupiter and Saturn and headed in for another similar close approach to the sun (within maybe a few tens of solar radii?) on a hyperbolic (non)orbit. And like I said, it's doubtful you can rely on the hyperbola being within the plane of the ecliptic, which complicates launch and/or a good trajectory. Need a superlight craft and something like a Starship, ideally.

I'll be back

Devac  ·  102 days ago  ·  link  ·  

    You don't alloy platinum for anything but jewelry and catalysts, that I know of.

It's not common, but notable in chemistry. You sometimes burn/melt stuff for analysis in Pt/Au bowls because it's known that ceramics could introduce (soluble) contaminants (leeching sodium from glaze, metals and glass 'fluxing' around alumina dust - that level of analytic pedantism). For 'chemically inert' reason, gas-phase synthesis may necessitate piping and vessels made of platinum or Pt/Rh or Pt/Ir alloys, but I can't give you a reaction example off-hand. I also got to use Pt/Nb anode and Pt/Ir 'combustion mantle' (that fine mesh around a flame, like on old-timey gas lamps) in organic synthesis, but the latter was hella niche even by the "Pt alloys in lab" category. And it wasn't used for catalyst either; I needed to cleanly keep the water away with flame, with this somehow being the least stupid setup.

kleinbl00  ·  102 days ago  ·  link  ·  

That makes sense. I once asked "so what happens when I put gold foil on silver for enameling" and was told "you increase the gold content in your silver alloy" and silver is relatively benign as alloyants go.

The Edwardian Era/Belle Epoque is noteworthy for platinum because it allowed haute joilerrie houses to make light, lacy constructions that would be impossible in gold or silver. Of course it also wants to be worked in an oxygen-free environment so it was mostly cold-formed stuff pinned together rather than castings or soldered components.

So. Ever seen Pt/Mn? Any guesses what it would behave like? "manganese alloys" aren't really where I live. Only thing I know about alloying manganese with steel is it gets impressive and the only comparison I can draw between platinum and steel is neither likes oxygen and both can be made magnetic (which freaked me out when I first learned that).

Devac  ·  102 days ago  ·  link  ·  

    Ever seen Pt/Mn?

Not really, but maybe it's more notable industrially, considering what you wrote about its mechanical properties. I recall someone from Czechia working on MnPt nanocomposites, but I couldn't see the significance of their work, to put it euphemistically. I guess it could be used as a catalyst, since both manganese and platinum are stupidly robust in that role? Maybe for alcohol oxidation or more generally as a replacement of sorts for metal-carbonyl complex catalysts. I can search more thoroughly if you want, but nothing pops up in my immediate wheelhouse.

kleinbl00  ·  102 days ago  ·  link  ·  

I wanna say no because I WANT TO BELIEVE but I'm going to say yes because if there's a legit use case for platinum-manganese wire I'm really curious as to what it is.

You'll be much more successful at your search than I was because you are not a golden retriever in goggles in this field.

Devac  ·  102 days ago  ·  link  ·  

Hah, no worries, I'm Team Mulder too. And science is probably always a blast, so it looks like an interesting thing to check out for myself. For instance, I looked into chemical, but completely neglected (the applications of) magnetic properties it could have, which is much more my day-job area of interest. I'm just lukewarm on the whole controversy, because Avi "chair of physics at Harvard" Loeb crying foul at the 'physics establishment' is a tad hilarious. If nobodies like am_U or I seriously postulated anything like he did, we'd be keelhauled under the liquid nitrogen cystern, not published. ;)

kleinbl00  ·  102 days ago  ·  link  ·  

Yeah it's all Eugene Levy in Splash until someone finds a mermaid, and then it's suddenly the Sackler Chair of the Department of Astroarchaeology at Columbia.

Devac  ·  101 days ago  ·  link  ·  

I'm not saying 'the system' doesn't suck, but it's undeniable that anyone else would have been strongarmed into removing the part even implying/suggesting ET intelligence as a possible explanation for the possibility of the object being a 'pancake' sail rather than rotated oblong.

Would it be awesome to be true? Absolutely. Do we need more data? Yes. Does it require more research? Ditto. Do I want to believe? Hell yeah! But because of the implications of this work, skepticism has to be on the all-time high.

Back when the topic was fresh, I was being dismissive of quite a few rebuttals to Loeb, saying how "adding these 15 parameters gives a better explanation" is a worthless statement on par with "my gf is homeomorphic with a torus, so is Liv Tyler, therefore I'm screwing Arven on the daily, therefore I'm Aragorn." Now? I want to believe, but don't want to be reckless or show any less scrutiny than I'd give to my research, neither on the record nor off. Which I suppose is exactly what you want in a scientist. I just became far more wary of Loeb('s persona) with time.

am_Unition  ·  102 days ago  ·  link  ·  

    fluxing around ______

fun fact, this is how one of the Cassini instruments (CAPS) died, I think?. It starting growing tin whiskers fluxing around soldering lead from the current in some of the high voltage circuits and shorted itself out. Little guy lived a full life, though, only missed the last few years in a nearly two-decade lifespan.