There isn’t a link in your post, but it looks like you’re referring to this preprint. The article has been published in a peer reviewed journal paywall warning.
This is a review article, so it isn’t proposing anything new and is instead giving a summary of the current state of the field. These sorts of articles are typically written by someone who is deeply familiar with the subject. They’re also super useful if you’re learning about a new area - think of them as a short, relatively up-to-date textbook.
I’m not sure how you’re interpreting this review as an alternative to the standard model of cosmology and the Big Bang. Everything is pretty standard quantum field theory. The only mention of the CMB is in regards to the possibility that gravitons in the early universe would leave detectable signatures (anisotropies and polarization). They aren’t proposing an alternative production mechanism for the CMB.
Haha it’s in the title: “Cosmological Particle Production: A Review”. Also the journal it was published in is for review articles: Reports on Progress in Physics. Mostly though the abstract promises to give a review of the subject.
Another indication is its lengthy (28 pages) with tons of citations throughout. If someone is doing new work, citations will mostly be in the introduction and discussion sections.
i cannot understand everything (far from it) but here is the part where I believe is an alternative explanation for the CMB :
Equations (2.38), (2.39), (2.40), and (2.53) all illustrate that the creation rate of particles with energies larger than the inverse expansion time, ρ, is exponentially suppressed. Parker [11] has noted that these exponential factor are similar to those which appear in thermal spectrum at finite temperature.
So unfortunately the article they reference by Parker is paywalled. I have access but can’t share it easily. The article is essentially the foundation of quantum field theory in curved space time - in other words the genesis of the standard cosmological model. Cosmological particle production in an expanding universe isn’t an alternative to the Big Bang, it’s an essential part of it.
May I take another route and ask you what you know about the history of science … about paradigm shifts … and about how people very knowledgeable on the current paradigm cannot see (most of times historicaly) that a paradigm shift is about to happen ?
how people very knowledgeable on the current paradigm cannot see (most of times historicaly) that a paradigm shift is about to happen ?
I’m not sure I’d agree with that assessment. Generally a new model or understanding of physics arises because of known shortcomings in the current model. Quantum physics is the classic example that resolved a number of open problems at the time: the ultraviolet catastrophe in black body radiation, the photoelectric effect, and the interference pattern of the double slit experiment, among others. In the years leading up to the development of quantum theory, it was clear to everyone active in physics that something was missing from the current understanding of Newtonian/classical physics. Obviously it wasn’t clear what the solution was until it came about, but it was obvious that a shift was coming.
The same thing happened again with electroweak unification%20and%20the%20weak%20interaction.) and the standard model of particle physics. There were known problems with the previous standard model Lagrangian, but it took a unique mathematical approach to resolve many of them.
Generally research focuses on things that are unknown or can’t be explained by our current understanding of physics. The review article you linked, for example, details open questions and contradictory observations/predictions in the state of the art.
We are discussing here in a community dedicated to science and clearly I have to acknowledge that your arguments here are much better than mine 😆 and that you are very knowledgeable in the current paradigm of science.
Unfortunately for me, there is no community at Lemmy dedicated to the history of science where “very knowledgeable on the current paradigm” would be so telling for historians knowledgeable in this field.
Unfortunately for me, there is no community at Lemmy dedicated to the history of science
I agree! The history of science is often even more interesting since you get both the science and the personalities of all the people involved, plus the occasional world war in the mix. It’s a shame there isn’t an “askhistorians” type community here.
I have a stock of 99% IPA already that I use for cleaning the bed of my regular 3D printer, electronics cleaning and for drying things coming out of my ultrasonic cleaner. (I can use salt to drop any water out of IPA, actually.)
With resin 3D printing, my washer uses about a gallon of IPA and it will get super dirty after a while. For that particular case, it’s just going to be more efficient to clean the IPA and reuse it until it needs to be distilled. (Wishing the parts in stages will help reduce IPA use, actually. Water washable resin is an option, but I would rather not dump that water down the drain or hassle with hazmat disposal, when applicable.)
Maybe an actual chemist will chime in, but I couldn’t find any sources about purifying or recycling IPA, at least none that you could do at home. At a guess, maybe a reverse osmosis system without the finest membrane? Like you said, the water and IPA molecules should be smaller than the dyes and resins.
Maybe also consider washing with the dirty IPA, and just giving a rinse at the end with the clean IPA in order to conserve. Ultimately it sounds like everything I’ve found is material you’re already familiar with, unfortunately.
Thanks for looking around! I already have a good selection of chemistry glass and am no stranger to doing home experiments. (I could probably use a good vacuum filter anyways and maybe I am just searching for an excuse to get one.) Distillation is an option for me, but it’ll be last resort. Still, having a few proper distillation pieces would go nice with my collection…
Some filter rigs I have seen are using small RO systems, but that seems like a pain to clean and those people probably need to filter a ton of IPA for it to be cost effective. Regardless, it is absolutely worth exploring more as setting up a filter loop would be awesome until it gets gummed up.
This looked promising as it is dealing with ethanol and plant extracts: youtu.be/VjxZVpGv_aM?si=5VFLYQkObCzUawbb … (This video specifically got me thinking about what could/couldn’t be filtered and is the root of this post.)
And absolutely, a multi-stage rinsing system is going to be needed if I scale up, which may be in the near future. Full context: I am studying and planning for a reverse engineering/prototyping business, so there could be a considerable amount of printing in my future and this is particular problem is part of the cost analysis.
I’m no expert but I think it’s a mutation that still isn’t universal i.e. there is still a very large lactose-intolerant population in east-asia, which is also reflected in their cuisine.
One more is that some people in the Himalayas (Nepalese, Tibetans, etc.) have some pretty recent adaptations for living at extremely high altitudes where there’s less oxygen. This Wikipedia article has more examples of recent adaptations: en.m.wikipedia.org/wiki/Recent_human_evolution
Another interesting factoid is that Africa has more genetic diversity than the rest of the world. So, don’t sleep on the fact that that Homo sapiens spent more time radiating throughout Africa than radiating out of Africa.
I read the question as a difference of traits rather than whole new traits, if that makes any sense.
So my suggestion was that the strength of sexual dimorphism varies. That is, some ethnicities may have a very significant difference in appearance between sexes, but in other ethnicities the difference would be lessened.
There’s also sickle cell anemia: IIRC it protects against something like the tse-tse fly or mosquito borne illnesses native to parts of the African continent
I believe that it offers a degree of protection against malaria. Or, enough protection that you live long enough to reproduce before dying a terrible, agonizing death.
What was the process of ancient Sumerian experimenting and realizing the potential of this new tool they had on their hands?
“Maybe I can use writing to do such-and-such thing…” and proceeded to do the first ever written snail-mail message, or the first medical or mathematical instructions/textbook, the first poem or essay, etc.
I can almost picture the academic analysis…
“The first character syllable can be read as kah or kuh, while the second character is read as unt, together they make the sound kawnt…”
…and then to register astronomical observations! The birth of science, no less.
And all because every year like clockwork, the Eufrates and Tigris blanketed an area of hundreds of square kilometers with a fresh coat of silt (from the Taurus mountains in modern-day Turkey) that was perfect as a rudimentary but cheap, easy and quick writing medium, pushing the point of a stick into a pancake of soft clay, then leaving it to dry and harden in the sun.
Given a radiative forcing coefficient of ln(new ppm/old ppm)/ln(2)*3.7 W/m**2 I have previously calculated that for every 1kWh of electricity generated from natural gas, an additional 2.2 kWh of heat is dumped into the atmosphere due to greenhouse effect in every year thereafter (for at least 1000 years that the resulting carbon dioxide remains in the air). So while the initial numbers are similar, you have to remember that the heat you generate is a one-time release (that dissipates into space as infrared radiation), but the greenhouse effect remains around in perpetuity, accumulating from year to year. If you are consuming 1kW of fossil electricity on average, after 100 years you are still only generating 1.67kW of heat (1kW from your devices and .67kW from 60% efficient power plant), but you also get an extra 220kW of heat from accumulated greenhouse gas.
I have wondered this question myself, and it does appear that the heat from the fossil/nuclear power itself is negligible over long term compared to the greenhouse effect. At least until you reach a Kardashev type I civilization level and have so many nuclear/fusion reactors that they noticeably raise the global temperature and necessitate special radiators.
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