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wargreymon2023 , in Is there a temperature so hot that relativistic effects are noticeable?

Yes, time dilated when I am simping over OF girls so hotšŸ„µ.

mechoman444 , in Is there a temperature so hot that relativistic effects are noticeable?

There are places in the universe that are so hot that weird things start to happen. Like the core of Jupiter could be a giant hard hydrogen crystal or in the center of suns where lighter chemicals fuse into heavier ones. Or my favorite, the temperature of the early universe which may have contributed to hyper inflation which would constitute what you refer to as ā€œrelativistic effectsā€.

In terms of noticing them we have detected the cosmic microwave background radiation.

Everythingispenguins , in Can you get a sunburn from light reflected by a window pane?

It really depends on the type of glass some glass transmits UV light and some types reflect UV light. And that is not taking into account the pile of other factors that will affect it.

DarkNightoftheSoul , (edited ) in How do we know the Hubble Parameter is constant in space?
@DarkNightoftheSoul@mander.xyz avatar

Weā€™d see that in the redshift: one direction would be more redshifted than another. Instead, we see all points in space moving away from all other points (except points mutually within gravitationally bound systems), and the rate of expansion between two points (recessional velocity) is directly proportional to the distance between them: the more distance, the faster they expand.

Edit: To answer the question in the title: Strictly, we donā€™t. We know, as you pointed out, that our measurements donā€™t agree. We also have good evidence that the rate of expansion was different in the past (much, much faster) in the early universe.

Gork OP ,

That makes sense, but how would we then be able to distinguish how much of the redshift is due to the metric expansion of space and how much is due to their velocity vector component in that direction?

DarkNightoftheSoul ,
@DarkNightoftheSoul@mander.xyz avatar

Inflation is supposed to explain this: It could provide the initial impulse to kickstart the velocities. I think the general idea is that the fact that everything is moving away from each other to begin with is explained by inflation, and the fact that this expansion is accelerating is explained by dark energy. Take all this with a grain of salt, here we approach the limits of my tenuous understanding, but what I do understand is that none of this is experimentally verified: No ā€œinflatonā€ has been found, or any other mechanism to otherwise explain inflation theory has ever been produced such that we could test it, and no working model of dark energy has ever been produced (to my limited knowledge) that we could test or detect.

Tl;dr: Iā€™m pretty sure itā€™s untestable anyway, we basically will never know during our lifetime short of some breakthrough in physics.

Gork OP ,

Right, but the velocity component would still be present in some form due to the gravitational attraction between bodies. I donā€™t know how significant this would be compared to the redshift value from the initial kick from inflation, or if it is possible to separate the two components somehow.

DarkNightoftheSoul ,
@DarkNightoftheSoul@mander.xyz avatar

Gravitational attraction is not a relevant factor on the largest scales where dark energy takes over. To be more precise, itā€™s possible to measure the effects, and to describe a specific distance limit between two bodies where they can no longer become gravitationally bound and are doomed to eventually expand out of each othersā€™ event horizons. That limit is the precise boundary between gravitational dominance and DE dominance.

To be specific, literally everything outside of the Virgo Supercluster (home to Andromeda and Milky Way among others) is outside of this limit, and will eventually become impossible to detect because the light between us and them isnā€™t moving as fast as the rate of expansion between us and them. Everything within the supercluster is gravitationally bound, and will eventually (iirc, grain of salt on this one) form a supergalaxy.

Gork OP ,

Wow. So itā€™s like that adage. However big you think space is, itā€™s much bigger than that.

Itā€™s hard to fathom scales at which being gravitationally bound is insignificant relative to those type of effects.

DarkNightoftheSoul ,
@DarkNightoftheSoul@mander.xyz avatar
PhlubbaDubba , in How do some animals (or at least humans) manage to generate more force than their own muscles are rated to handle?

Momentum is determined by more than just the strength the muscles put into the movement

Doesnā€™t take a lot of force to step off a ledge, but youā€™re still gonna hit the ground pretty dang hard

FlowVoid , in Given a writing speed of one logical symbol per planck time, would the amount of time it takes to write Rayo's Number exceed Rayo's Number?

No. The amount of time it takes to write Rayoā€™s number is 1, in units of Rayotime.

trolololol ,

Correct but not the answer weā€™re looking for.

FlowVoid ,

Ok, then it takes two Planck times if you write it in base Rayo.

orb360 ,

I love you

trolololol ,

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Raffster , in How do different body parts (specifically shape) emerge from our genes?

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  • remotelove OP ,

    I found this video today that seems similar to what you are talking about: youtu.be/M_vRgMBL0yA?si=5OsRiVnKt9A2Q4_u

    Ok, I knew those genes were called something! Thinking about homeotic gene mutations has sufficiently jumbled my brain again though. (Hopefully, if I can code a simple analog to represent them, natural evolution can sort out any mess homeosis creates.)

    lemming ,

    I would just add that itā€™s a gradient of transcription factor(s), proteins that regulate production of other proteins. Some of the regulated proteins are other thranscription factors that create finer gradients, like repeated stripes of gradients. along the initial, single gradient. This can be repeated on multiple levels so that pretty much every point of the body has unique combination of transcription factors. This combination triggers all the other proteins, including structural that create the form of the body. and of course, all this doesnā€™t just happen in 3D, but also changes with time. Itā€™s complicated.

    For illustration and possible direction for some particular interesting cases wrapped in a very entertaining package, I recommend this: www.youtube.com/watch?v=ydqReeTV_vk

    surewhynotlem , in What's the equivalent of physics constants for social studies?

    Look, Mr Hari Seldon, youā€™re going to need to work these out on your own.

    souperk OP ,
    @souperk@reddthat.com avatar

    TIL en.m.wikipedia.org/wiki/Hari_Seldon

    Seldon develops psychohistory, an algorithmic science that allows him to predict the future in probabilistic terms. On the basis of his psychohistory he is able to predict the eventual fall of the Galactic Empire and to develop a means to shorten the millennia of chaos to follow. The significance of his discoveries lies behind his nickname ā€œRavenā€ Seldon.

    surewhynotlem ,

    TIL??

    Oh man, you are lucky. You have the chance to read the Foundation series for the first time. Iā€™m kinda jealous and highly recommend it.

    BreadstickNinja , in Do we know of a means by which artificial nuclear fusion could be used to mimic stellar carbon-12 production?

    Youā€™d be talking about replicating the triple-alpha process in a fusion reactor, and itā€™s a process that takes places at much higher temperatures and pressures than other stellar nucleosynthetic reactions. Assuming you could get the conditions right it may be theoretically possible, but itā€™s probably much further off than even viable deuterium-tritium fusion.

    CanadaPlus , (edited ) in Is the "Tromatz" bioelectric wave toothbrush legit, or snake oil?

    Based just on the name even, snake oil. WTF is a ā€œbioelectric waveā€?

    Chobbes , in [Mycology] Are yeasts analogous to each other, to the point they can be used in food interchangeably?

    Okay, ewā€¦ but for what itā€™s worth brewers yeasts are very specific strains of yeast that have been bred for the purpose. One of the most important aspects of these brewers yeasts versus regular bakers yeasts or wild yeasts (like a sourdough starter) is that they can thrive in higher alcohol environments, allowing them to convert more sugar into alcohol (e.g., I think champagne yeasts can give you a higher ABV). Brewers yeast will also likely be more efficient and convert sugar to alcohol faster than wild strains (sourdough is also a much slower process than using bakers yeasts), which might have implications for food safety if the yeast cannot outcompete other nastier microbes. You can make alcohol with wild yeasts but itā€™s not as controlled of a process.

    Tar_alcaran ,

    You can make alcohol with wild yeasts but itā€™s not as controlled of a process.

    Several drinks have ā€œstore barrel in cave/shed in specific regionā€ as a manufacturing step, specifically because of the wild yeast in the area.

    But only a small number, because making people violently sick is a poor business strategy.

    Telorand OP ,

    One of the most important aspects of these brewers yeasts versus regular bakers yeasts or wild yeasts (like a sourdough starter) is that they can thrive in higher alcohol environments, allowing them to convert more sugar into alcoholā€¦

    And it was this aspect that I learned about just a few days prior that led me to question the whole thing. For the purposes of making what average people would consider beer, it seemed like you couldnā€™t just swap in whatever you wanted.

    Chobbes ,

    You definitely can use wild yeasts to make alcohol. It probably wonā€™t work as well or as consistently, but Iā€™m sure you can make some good stuff just by letting things ferment naturally. I bake a lot of sourdough and itā€™s very fiddly compared to commercial yeasts. You also technically can use bakers yeast for brewing, but I think itā€™s not ideal for various reasons, like the flavour can be different and I think it doesnā€™t clump together as much so itā€™s harder to remove.

    eyes ,

    Also not all yeast strains convert sugar into alcohol, the strain in question in this case will only produce lactic acid.

    Chobbes ,

    I was wondering about that! I wasnā€™t sure what strain it was and didnā€™t really want to look it up, haha. Very good point, though!

    eyes ,

    Just to add technically Iā€™m wrong, theyā€™re using a Lactobacillus not a yeast.

    eyes , in [Mycology] Are yeasts analogous to each other, to the point they can be used in food interchangeably?

    Without any additional research beyond my homebrewing experience, itā€™s possible but very unlikely - almost everything would be against you. Brewing is a pretty fragile process and whilst homebrewing with wild yeast is possible, its a struggle to keep it alive long enough for it to reproduce to sufficient quantities to do itā€™s thing. And thatā€™s if it can even get the alcohol content high enough and you donā€™t get any bacterial or mold contamination.

    Telorand OP ,

    I understand that fungi can and do swap genes, so I wonder if theyā€™ll try to create a brewerā€™s and vaginal yeast hybrid.

    eyes ,

    They can, to an extent, if you had lots time and a staffed lab. Crossbreeding yeast strains is kind of tough as most of the ones used in industrial fermentation (ie the stable, commonly used ones) donā€™t breed well with others and when they do crossbreed, the resulting new strain is often infertile itself. Itā€™s possible, but difficult, unreliable and the resources required put it well beyond the scope of people who donā€™t own a brewing company.

    Telorand OP ,

    Thatā€™s fascinating!

    Amouranth just apparently dropped $17mil on some fruit farms, so money isnā€™t a problem for her, but who knows if she would go to the trouble, since it sounds pretty error-prone.

    eyes ,

    I told myself I wouldnā€™t do it but I did the research: turns out thereā€™s one company who claims to brew with ā€œdonorā€ yeast and thatā€™s the company sheā€™s talking about partnering with. As far as I can tell from everything Iā€™ve found reporting on them these claims are unverified so everything below should be taken with a large amount of skepticism.

    Their websites are pretty sparse with information (and unsurprisingly creepily neckbeardy) but looking at whatā€™s available and been reported Iā€™ve been able to piece together what I think is happening. They talk around it and try to couch it in scientific jargon, it sounds like theyā€™re using it to produce lactic acid only, so no alcohol, which is then sterilised and filtered to death before being used as an additive.

    All in all it seems that the steps they describe between ā€œdonorā€ and beer that would result in no actual yeasts from the ā€œdonorā€ in the beer at any point, or even any yeasts cultivated from the originals - Which would seem to be the ultimate intent, probably for food safety law complaince. And this all assumes that they arenā€™t just lieing about it.

    Telorand OP ,

    They talk around it and try to couch it in scientific jargon, it sounds like theyā€™re using it to produce lactic acid only, so no alcohol, which is then sterilised and filtered to death before being used as an additive.

    Seems like a lot of work to make sour beer, but I have no doubt these will sell out in no time regardless, due to the provenance.

    And this all assumes that they arenā€™t just lieing about it.

    And I had to ask, because it sounds a lot like a recipe for snake oil.

    eyes ,

    Also just to add I did more reading and technically theyā€™re using a Lactobacillus which is a bacteria and not a yeast. Which makes more sense as thatā€™s whatā€™s responsible for yeast infections, just to add to the yuck factor.

    Telorand OP ,

    I wonder, if someone were to explain the actual science behind it, if people would still want to buy it? Because this is not sounding any better.

    MagnusRobotFighter , in [Mycology] Are yeasts analogous to each other, to the point they can be used in food interchangeably?

    You can make beer with any kind of yeast. You can make good beer with only certain yeast.

    eyes , (edited )

    The kind of yeast in question canā€™t produce alcohol as far as I can tell, only lactic acid. Edit: Lactobacillus not yeast

    rowinxavier , in Does everyone learn the same gravity in school or is it different everywhere?

    People learned different values for g for a number of reasons, but as far as I understand local variability is not one of them. The primary root cause seems to be accuracy of the measurement over time and the age of textbooks/course material.

    Over time we have gotten better at measuring the true value of g through advances in technology and this has caused the taught value to shift a little. The value when initially measured had fairly large error margins, meaning that we were sure it was near a specific value but not sure of the exact value. As the tools improved we have reduced the uncertainty, getting to a more accurate and also more precise value, meaning more digits after the decimal as well as higher confidence in each digit. We have also changed what we mean by g over time, bringing it in line with the metric system and basing it on fundamental values and constants. From my understanding the most recent method relies on how much the repulsive force of an electromagnet with a specific number of culombs passing through is overcome by gravity at a specific distance from the center of the mass of Earth, so a little more removed from backyard science than measuring if things drop at the same speed at the top of a mountain and sea level.

    Part 2 is the differences in how recent your material is. In my primary school in a relatively affluent area of an affluent country we had textbooks from the last 10 years. My partner went to a school in the same country but a worse area about 5km away from mine. Their school had textbooks literally 20 years old. In that time the measurements had changed, understandings had changed, and they were therefore taught things that were untrue. These sorts of differences based on geography reproduce the impacts of racism and inequality from the past into the future.

    amio , in [Solved] Trees supposedly take 30 years *before* they absorb COā‚‚. Why?

    Could be sort of a "break-even" point? Assuming it's even true, which is a pretty big assumption. You could ask them for a source next time if you hear it often, because I've heard it precisely 0 times before.

    Knusper OP ,

    Yeah, last time I heard it, it was in this German video: piped.video/watch?v=ThqfNX8EMe4
    (I did not note down the timestamp, sorry.)

    As I understand, the guy has a PhD in forensics. Obviously, not quite his field of expertise, but Iā€™d expect a biologist to know how a tree works at a basic level.

    I have watched other, similar videos of the guy before and since people here seem to not have heard this number before, Iā€™m now consider that it was maybe always this guy who said it. Iā€™m sure, he has some source for it, but it was an offhand, somewhat cynical comment, so maybe he oversimplifiedā€¦

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