Thanks for the non bio take. Heard that Bio is applied Chem which is applied Physics (least on the smallish scale).

Was overall curious if we would ever replicate bioluminescence proteins to make something multi color.

There are chromatophore cells (especially for Cephalopods) that can do a variety of colors as well.

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Not quite correct in your explanation of biliary obstruction. If biliary outflow is obstructed, more soluble conjugated bilirubin is excreted into the urine (because it cannot go into the GI tract due to biliary obstruction), causing dark urine. The obstruction prevents excretion of conjugated bilirubin into the GI tract, so less urobilinogen (and later stercobilin) is formed and you get pale stool.

Edit: also, gallbladder obstruction would give you cholecystitis but would not give you symptoms of obstructive jaundice like dark urine or acholic stool

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Off topic but kinda adjacent, why when you mix a bunch of colors the corresponding mix always goes toward the colored brown?

23 × 1.2 tonnes is 27.6 tonnes of debris. To convert to tons, multiply by 1.1, giving about 30.4 tons. (Remember, a tonne is 1000 kg, and a ton is 2000 lbs. Don't mix those numbers up.) So, it's more like a 65% increase daily, which may be no laughing matter, depending on what those compounds are. But first, make sure your facts are correct.

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Yep, also people aren't factoring in that the initial approval is best effort. Maybe they applied for 42k and claim they have a 5 year lifespan, but the reality is they want them to last longer and would be much happier doing it with fewer satellites. 5 years is under certain conditions and likely lowballed, if they don't need to do collision avoidance maneuvers could be longer, if there's a lull in space weather could be longer, if there's a lot of that could be shorter.

The gen 2s require starship, which is much MUCH larger than falcon, meaning fewer launches to expand the network and more users per satellite, more fuel per satellite which extends the lifespan, etc.

>[...]silicate minerals have tons of aluminum in them.

That might be on Earth, because the lightness of aluminium drove its concentration in the crust.

> A quick check shows that most types of low-iron meteorites appear to still be very roughly 5-10% aluminum by mass.

According to https://periodictable.com/Properties/A/MeteoriteAbundance.html aluminium is ony 0.9 % of general meteorites mass.

You might have misread, at that rate it won't reach limits for 2500 years

I am not a biologist, so take my answer with a grain of salt. I wouldn't respond except that your post is getting stale and I don't see anyone addressing the core question. Mods feel free to Dunning-Krueger my comment into oblivion if somebody else gives a more cogent answer to OP.

The question of "can" is easy to answer: Given funding, we can find some biological molecule that fluoresces at any wavelength you want between about 350nm and a few thousand nm. (human sight is about 400 - 700nm) Below about 350 is hard because it takes a lot of energy to generate.

The question of evolutionary fitness is more interesting. Evolutionary adaptation does not "seek new solutions". Rather, some random adaptation is evolved, and if it is advantageous it has a chance to become widespread. The advantage of bioluminescence is beyond my training, but I assume (perhaps wrongly) that it provides some competitive advantage in hunting/attracting mates/whatever.

Two factors are worth considering now:

1. How likely is it that an organism mutate to produce a bioluminescent protein at wavelength "X".

2. How advantageous / disadvantageous is that mutation?

To point (1) it is likely that some luminescent proteins are just one or two mutations away from some other protein that is common. These mutations are likely to occur more frequently than others, and are therefore more likely to catch hold if there is some competitive advantage to bioluminescence.

To point (2) if a luminescent protein is easy to achieve by mutation but is very energy intensive or poisonous or whatever, it is less likely to produce a net competitive advantage.

In some population, if two different mutations can occur, one being a low-cost protein at wavelength "X" and the other being a high-cost protein at wavelength "Y" I would expect the former to take hold in the population. And once the capability to luminesce at wavelength "X" is evolved, it becomes much less likely that a capability to luminesce at wavelength "Y" subsequently evolve. The organism already has a means of luring food/attracting mates/whatever. A mutation that produces another (more costly) method is a competitive disadvantage in most scenarios, unless there's a "Red Queen" situation where the organism is under a lot of pressure to evolve new capabilities due to competing evolution of a predator or similar.

Why blue-green for aquatic and red-yellow for terrestrial? The attenuation of light in sea water is wavelength dependent. Blue-Green propagates better than red or blue. That color is called "Aqua" for a reason. UV is rapidly attenuated. Presumably, then, a mutation for bioluminescence in the UV or IR provides little or no benefit. For terrestrial, red and infrared propagate just fine through air and are less energy-costly than blue or green. I have no idea if there's a lot of infrared bioluminescence, but I wouldn't be surprised.

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Oh so that’s why the urine in the toilet turns more yellow the longer I pee.

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