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Comment Re:surprisingly stable? (Score 1) 67

Read Ignition!, an excellent and entertaining history of the development of liquid rocket fuel by John D. Clark (one of the main protagonists of the field), with the truly excellent forward by Isaac Asimov that includes the following excerpt:

Now it is clear that anyone working with rocket fuels is outstand-
ingly mad. I don't mean garden-variety crazy or a merely raving luna-
tic. I mean a record-shattering exponent of far-out insanity.

      There are, after all, some chemicals that explode shatteringly, some
that flame ravenously, some that corrode hellishly, some that poison
sneakily, and some that stink stenchily. As far as I know, though, only
liquid rocket fuels have all these delightful properties combined into
one delectable whole.

Search for a PDF, and you'll find it. I've had the fortune to meet a number of scientists cut from the same cloth as Dr. Clark, and they are among my favorite people. I'm sorry I never had a chance to meet him.

Comment Re:Really cool, application to rockets not so much (Score 2) 67

But would it really be non-polluting?

In fracturing its atomic bonds, N6 will likely release most of its energy as heat and we all know that if you heat N2 and O2 enough you end up with all types of oxides including a nasty pollutant called Nitric Oxide (NO). I can't see N6 simply disassembling itself neatly into 3(N2) in an oxidative environment such as the earth's atmosphere.

Any sort of combustion-level heat in the presence of nitrogen and oxygen creates lots of messy NOx byproducts (that are all atmospheric pollutants), so, yeah, unlikely to be a pure N6 -> 3(N2) reaction without at least restricting its decomposition environment to exclude O2.

My father designed instruments to measure atmospheric concentrations of NOx (and I wrote much of the software for them) for one of the biggest manufacturers of things like that. He explained the chemistry to me years ago, and NOx pollutants are nearly unavoidable in the presence of O2.

Comment Re:Salmon (Score 1) 47

The C code itself isn't obfuscated. The problem is that your text editor isn't showing you the code.

If you look at the C code in a plain ASCII text editor, you'll see everything. But a text editor that interprets UTF-8 hides a bunch of stuff from you.

If you happen to be viewing the entry in VIM, use ":set encoding=latin1" to see what's really going on.

Comment Re:Reverse logic? (Score 2) 49

Thinking of the void as an analogy to a gas is misleading, that's why your supposition doesn't work.

The universe is expanding, everywhere, as far as we can tell. Without any evidence to the contrary (and a fair bit of evidence supporting it), the expansion is constant, everywhere, and is described by a value called, you guessed it, the Hubble Constant. Most recently, however, a handful of different measurements have suggested two disparate values for the Hubble Constant, resulting in what's known as the Hubble Tension ("tension" because the two values appear to be being measured correctly, but are not the same).

The idea in this paper, as far as I understand it, is that there are large-scale fluctuations in mass distribution, and we happen to be in a local minimum compared to the average across the universe, thus a local void. Since the Universe isn't filled with a gas under pressure (at least to first approximation), there isn't a grand rushing-in to fill that void. Rather the opposite: the relatively higher density elsewhere is pulling harder by its larger gravity than the mass in our local neighborhood, creating a local anomaly in the large-scale gravitational field, pulling us outward. This local anomaly appears as a local increase to the Hubble constant, adding on to the underlying Hubble expansion. We are, locally, expanding slightly faster than the Universal average.

This local effect might explain the two measurements for the Hubble Constant, one in our region of the Universe which is affected by the local paucity of mass, and one across greater expanses of the Universe where the lumpy distribution of mass is evened out by the law of large numbers.

Comment International law applies. (Score 1) 2

Like ships and aircraft, spacecraft fly a country's flag. Where those countries fail to assert sufficient control over spacecraft operations, they are subject to their neighbors' displeasure. But first, someone has to do something sufficiently displeasurable and escape their own country's legal ire.

Comment Why black holes? (Score 1) 45

I read the article to see why black holes in particular would be a useful way of determining position in space, rather than, say, a handful of stars.

The answer is that they aren't just using any black holes, but the ultra-massive black holes at the center of galaxies which spew lots of radiation from their accretion discs, so are bright in radio frequencies, and are far away and have limited self-motion since they are at the center of their galaxies, so are stable from our vantage point.

Someone correct me if I got that wrong.

Comment Re:Grandstanding (Score 1) 20

I don't get excited by SWA saying 'derp we are not going to use AI for pricing or revenue managment' either.

He's lying through his teeth. Revenue management has used ML for a loooong time to set things like price of different fare buckets, number of seats released to different fare buckets, exactly when seats are released to specific fare buckets, how many seats to hold back, how many instrument-supported upgrades to allow (e.g., upgrade certificates), how many complementary upgrades to allow, etc., forget things like schedule and route planning, and so forth. All three of the big US airlines are already using dynamic pricing on reward tickets such that you get a different price if you're logged in to their web site versus doing it anonymously.

So, again, lying through his teeth.

Comment Re:The climate changes have been obvious (Score 1) 186

There's no Maui water rationing "due to a drought." If there's water rationing, it's because the natives have obstructed the construction of sufficient aqueduct capacity to match the increase in population. Plenty of fresh water falls in the rain forest and uselessly empties into the sea. You just have to pipe it to where the people live.

Comment Re:"inventor"?! (Score 4, Insightful) 110

Inventor?!

Is there absolutely any evidence to back this technique up as successful? Injecting something hazardous to kill cancer isn't new; but you actually need real studies to see if it succeeds.

Succeeds, or causes a different morbidity to the patient, or worse.

I mean, you can inject tuberculin toxin into a tumor too, or radioactive thallium, or any of the vast suite of toxic concoctions, but it might not work out so well for the rest of the patient. Especially if you call yourself an inventor, instead of a medical scientist, with the level of training and knowledge expected for each.

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