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Hi,

I found this scientific paper that I believe is very well supported and is for me the most satisfying new cosmological development I ever read.

Cosmological Particle Production: A Review (2021 December 7 // @ arXiv...) https://arxiv.org/pdf/2112.02444.pdf

... the way I read it, it provides an alternative explanation for the cosmological microwave background (CMB) and an alternative for the Big Bang.

I am simply on a quest to find an effective non-distillation method for purifying isopropyl alcohol used for rinsing resin 3D prints.

I have seen some elaborate systems for curing and then filtering resin that is suspended in the isopropyl by running it through standard carbon water filters. That just seems a bit over-complex and does a poor job of removing dyes. In some cases, the filters are not fine enough and the isopropyl will eventually get "sticky".

It seems to me that a finer filtration system would work much better. Carbon and celite should catch most of the monomers and oligomers, but I am not sure about the photoinitiators and other additives.

Distillation is obviously the best method for purity, but there may be a worse cleanup and a higher fire hazard risk.

Are there better materials that I could use for filtering besides celite and carbon? IPA is tiny compared to the rest of the molecules I am dealing with so filtration seems viable.

(I should note that I would bulk develop the used IPA in clear plastic containers in the sun for a day or two first.)

I'm referring to the human race evolving in the African continent and then migrating to the rest of the world.

Evolving in Europe made people light skinned to account for the reduction in sunlight exposure, are there any other traits which other ethnicities developed to adapt to their new environment? Or are the diifferent traits in different ethnicities just stuff that developed by chance and got somehow reinforced because of the isolation between populations?

This question came to my mind first thinking about "Asian eyes", do they serve any "purpose"?

There are many other bee species that can sting Humans and survive, but the European honeybee has a barbed stinger, so it cannot remove the stinger once it's stung. In attempting to remove the stinger the bee will rupture its lower abdomen and then die.

Why? What is the evolutionary advantage to that?

We often talk about the climate impact based on greenhouse gases, but extracting fuel from the ground and using it in exothermal processes of course also releases energy as heat.

This is mostly¹ in contrast with renewables, which make use of energy that's not long-term contained to begin with, so would end up as heat in our atmosphere anyways.

So, my question is: Does the amount of energy released by non-renewables have any notable impact on our global temperature? Or would it easily radiate into space, if we solved the greenhouse gas problem?

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¹) In the case of solar, putting up black surfaces does mean that less sunlight gets reflected, so more heat ultimately gets trapped in our atmosphere. There's probably other such cases, too.

Say a dissolvable spring is compressed with a bolt and nut that do not melt in a sulfuric acid solution. The spring has quite a bit of potential energy at this point since it is compressed. Assuming the spring dissolves perfectly (no breakage, just complete disintegration), what happens to the potential energy of the spring?

Famously, Oppenheimer and co worked out how close a nuclear bomb test would be to causing a chain reaction of nitrogen fusion in the atmosphere. They made a lot of worst-case-scenario assumptions and still came to the conclusion that no, a nuclear bomb test wouldn’t scour the surface of the world.

But let’s say the atmosphere was twice as dense as it is. Or ten times as dense. At what point would that calculation turn very, very scary?

Obligatory xkcd

Edit: man, seriously, most of the people ‘answering’ this question didn’t even read it.

Okay, so I know this might be a bit hyperspecific, but I don't know where else to ask it. I'm working through a microbiology lecture, and the professor says the the B strain of E. coli has a tRNA suppressor that allows it to transcribe phage genes that have any nonsense mutation. That seemed a bit vague, so I decided to look it up. But the only thing I can find that's even remotely similar is that that strain doesn't express T7 RNA polymerase, which doesn't seem terribly helpful. Is there anything like this in that particular strain? It seems like a load of bs to me that a bacterium should just be able to ignore any stop codon.

Edit: My prof might have been referring specifically to an amber mutation. So, just one stop codon. Seems my resources are just poorly worded.

Asking because while I see that paint hardeners exist in the USA, there doesn't seem to be anything similar in my country (Brazil)

What could I use as a substitute to harden paints? Are there any catalysts or powders that would work?

Google and DDG always show sites/articles about epoxy resins whenever I search for "acrylic hardener", is it safe to assume that catalysts for epoxy, like polyamide, will work with acrylics?

Now that late spring/early summer is upon us, there's increasingly more headlines about less rain in various places (recent floods notwithstanding). I'm assuming that's because water is evaporating and not returning to those places, but where is it going?

Is it arriving, now, in these bursty flash floods? Is it staying longer in the atmosphere and moving to new locations? Is more of it just staying in the atmosphere period?

I assume it would break into smaller particles similar to the formation of microplastics. I hear about the effects of microplastics all the time. Are the effects of disposed rubber on the environment studied as extensively?

I know evolution is governed by chance and it is random but does it make sense to "ruin" sleep if there's light? I mean normally, outside, you never have pure darkness, there are the moon and stars even at night. In certain zones of the Earth we also have long periods of no sunshine and long periods of only sunshine.

I don't know if my question is clear enough but I hope so.

Bonus question: are animals subject to the same contribution of light or lack of it to the quality of sleep?

Is it a stable/static effect no matter what, or is it a bit more stretchy/bouncy depending on how the object is behaving?

Thank you!

Say I am sitting in the shadow, but the sunlight gets reflected by some window pane onto me. Does this contain enough UV light to give me a sunburn?

If sociology's exclusive to humans, then what might be the field of other social animal research?

They say it's a picture of atoms, but what are the atoms: the glowing yellow balls or the entire meatball including the darker red? If it's the meatballs, then why do some have apparently two nuclei?

Here's the public press release: https://news.cornell.edu/stories/2021/05/cornell-researchers-see-atoms-record-resolution

Here's the actual scientific article: https://www.science.org/doi/10.1126/science.abg2533

So, let’s say there’s a species of bacteria that is known to dwell in Greek yogurt. How long would it take before that species of yogurt-dweller only has modern descendants different enough to qualify as one or more new species?

I'm thinking of switching fields within STEM and there are some mathsy modules which I missed out on during my undergrad (biology) that would come in really handy right now. Since I would like to avoid doing another bachelor's from scratch, I was hoping there might be a website that lets you pick and choose from a range of undergrad-level subjects that you would take online, and then possibly give you a certificate that you could put on your CV. Does anyone know if something like this exists?

I seem to remember as a young child being told that it is safe to touch a Van de Graff generator (for the hair demonstration), but that if you let go before it is safe you will get a nasty shock. I know a bit more about electricity now, and I'm a little skeptical now. Is it possible to get a shock from letting go of something?

Let's say you are dying of starvation. You pull one of your teeth out, causing blood to slowly seep into your mouth, which you swallow. The calories from the blood getting digested will delay the time you die of starvation, right? Or will losing blood while starving kill you faster?

How hot would it have to be?

I just watched the recent video from Stephen Milo on human life 1 million years ago. He mentions cannibalism evidence across multiple events. That has me thinking about morality in isolated groups and how it might have evolved or could evolve differently.

This is the paper reference for Atapuerca – human cannibalism 1 million years ago

• https://www.sciencedirect.com/science/article/abs/pii/S0047248412001406

This is Stephen Milo's upload to YT and relevant time stamp for the article:

• https://www.youtube.com/watch?v=MRnQrvi6N0M&t=1490
• https://piped.video/watch?v=MRnQrvi6N0M&t=1490

I'm curious about how human morality evolves in isolation before external influences cause an averaging effect. Do the rough edges get knocked off in a predictable fashion, taming the most eccentric behaviors over time until we reach peaceful cohabitation, or do we simply partition our animalistic stupidity and become far worse in the duality of civility and the barbarism of a primitive sub-sentient species with War?

I have a question I need to ask but I want to do it privately as the topic it correlates to is pretty taboo. Please comment or dm me, and I'll dm you back.

Mars influence on the Milankovitch cycles:

• https://www.nature.com/articles/s41467-024-46171-5

Anton Petrov's summary:

• https://piped.video/watch?v=DZnN2mPkoT8
• https://www.youtube.com/watch?v=DZnN2mPkoT8

I imagine there is a significant potential interaction over long time scales due to lunar position and orbital plane. If Mars has a measurable impact on Earth, the reverse must be true as well, and Luna is the primary anomaly IMO.

Since we know that it isn't constant with time, how can we be sure that it is constant with space? This might be a reason the variability in our measurements which seem to disagree.

Put another way, why couldn't the universe expand in one direction preferentially compared to another?

Was thinking about interstellar travel and the ability to provide artificial gravity by using a smooth acceleration and deceleration across the journey, changing from acceleration to deceleration at the halfway mark.

If we ignore relativistic effects, with smooth acceleration of 9.81 ms^-2, you'd be going 3.1e8 ms^-1 after the first year (3.2e7 s), if I'm not making a mathematical blunder. That's more than the speed of light at 3.0e8.

My main question, and the one that I initially came here to ask, is: if their ship continues applying the force that, under classical mechanics, was enough to accelerate them at 9.81 ms^-2, would the people inside still experience Earth-like artificial gravity, even though their velocity as measured by an observer is now increasing at less than that rate?

A second question that I thought of while trying to figure this out myself as I wrote it up, is... My understanding is that a trip taken at the speed of light would actually feel instantaneous to the traveller, while taking distance/speed of light to a stationary observer. In the above scenario, would the final time taken, as measured by the traveller, be the same as if they were to ignore the speed that they are travelling at according to an outside observer, and instead actually assume they are undergoing continuous acceleration?

For example, why did zinc, of all things, start getting utilized by brain and prostate tissue in humans?

Tectonic activity bends rocks all the time, even hard ones like granite. That takes a ton of heat, pressure and time. It also makes sense that in the right conditions, sheets of rock simply don't have the room to shatter so they must bend.

Have we been able to do the same in a lab and would it have any commercial use? Bending a random bit of hard rock would be an interesting novelty, for sure.

I've been learning some about rabies and learned about rabies causing hydrophobia. This is just a theory, I'm not saying I know anything about this topic to be knowledgeable, but if we could get someone with rabies to not fear water, could they survive?