Former chemistry teacher nitpicks and clarification:
This is true when you dissolve ionic compounds, not molecular compounds. Molecular compounds do not dissociate in water. (And ionic compounds do not actually contain distinct molecules.)
When you dissolve an ionic compound in water, it dissolves and dissociates into ions. The resulting solution conducts electricity (which you can easily demonstrate by experiment and which I frequently did in class). Such a substance that dissociates into ions is also called an electrolyte.
An example of a molecular compound that dissolves in water but does not dissociate into ions is table sugar (sucrose). Sugar is therefore a non-electrolyte and the resulting solution does not conduct electricity.
Do you know what the dates were during which this consensus existed?
I just tried a EBSCO Academic Search Complete using access I have to the San Francisco Public Library, and for better or worse, the first thing I came up with was not a journal article, but a Saturday Evening Post article dated Dec. 15, 1962, “Fatty Foods and Poly-Saturated Nonsense.” It says there was then “a cross-current of conflicting claims.” Also: “the Army said it had no intention of changing the GI diet. Reason: Evidence was inconclusive.” The article goes on to, in a mildly approving way, cite the American Heart Association recommending polyunsaturated fat, but also quotes the Heart Association saying there is “no final proof” of benefit.
I don’t mean to pick on you, as I could have picked a bunch of other claims in the thread that there once was a consensus concerning some medical advice now discarded. I am wondering if it is in the nature of medicine that true consensus is historically rare.
Good point. For every article or study showing light alcohol consumption is good, another says it is not. Currently the thought is that alcohol is not good for you, but I do not think it is a true consensus. The WHO thinks it is a consensus, but …
In a chilling, existential, bizarrely comic moment, the new movie “Oppenheimer” revives an old question: Did Manhattan Project scientists think there was even a minute possibility that detonating the first atomic bomb on the remote plains of New Mexico could destroy the world?
The long, strange history of what came to be known as the “atmospheric ignition” scenario has been distorted over the years, and the movie distorts it further.
The nightmarish idea was this: The tremendous fireball generated by the bomb is so great that it heats nitrogen atoms in the atmosphere to the point that their atomic cores, called nuclei, fuse. The energy released causes more nuclei to fuse, triggering a runaway reaction that sets the atmosphere ablaze.
And this is the way the world ends.
Except that it didn’t. And physicists knew it wouldn’t, long before the Trinity test on July 16, 1945, at the Alamogordo Bombing Range, about 210 miles south of the secret Los Alamos, N.M., laboratory.
“This thing has been blown out of proportion over the years,” said Richard Rhodes, author of the Pulitzer Prize-winning book “The Making of the Atomic Bomb.” The question on the scientists’ minds before the test, he said, “wasn’t, ‘Is it going to blow up the world?’ It was, ‘Is it going to work at all?’”
You’re splitting hairs. Scientists and physicians had a consensus as to the believed cause of ulcers (stress & lifestyle). Then, when it was shown what actually causes them, the consensus changed from a belief, to something much more concrete. Same thing with miasma theory of disease and the germ theory of disease.
You are right in that once there’s a scientific theory with evidence and experimental proof, they’re very rarely, if ever changed because there’s actual proof that it works. It’s the nature of the beast.
But there are often situations where something is imperfectly understood, and the consensus is one way, but upon further research, there is a better understanding and the consensus changes, like @Jeff_Lichtman’s trans fats example. We thought they worked one way, then upon further research, discovered that not only are they not healthy, they’re actively unhealthy. The consensus changed after we better understood something.
It was presented for decades that pupating butterflies’ bodies completely dissolve and are reconstructed from the soup. We know now that it doesn’t completely dissolve, although various larval body parts are used as fuel to help complete the metamorphosis. Looks like this thinking is only about 15 or so years old.
I don’t know that that’s the case for other pupae, as I’ve only seen this for butterflies. I’ll leave that to some other intrepid researcher.
It’s a documented fact (hence, in the movie Oppenheimer ) that Enrico Fermi offered a bet just before the test that the blast would trigger a world-wide chain reaction in the atmosphere. Since he was intimately involved in the project, and knew the numbers, it was more likely just dark humour rather than anything close to a serious worry, the risk was infinitesimal and would mean they missed something really big and obvious in the calculations - which they hadn’t. They knew what the numbers said, and the numbers also said the bomb would work as planned - but of course they still had to test it.
What scientists would say that? We are in the Holocene epoch, which is distinctly an inter-glacial period. CO2 levels tended to vary between 180 ppm at glacial maxima to about 280 ppm at the peaks of inter-glacials. Levels were at around 280 ppm – the typical inter-glacial level – for over 11,000 years prior to the industrial revolution, then started rising rapidly due to anthropogenic carbon emissions. Today they’re 427 ppm and still rising.
That quote doesn’t mean what you think it means. We are unquestionably, by any rational definition, in an inter-glacial in terms of the distinct ice age cycles of the last million years or so.
What that confusing quote means is that the fact that there’s still ice cover present means we’re not in the totally ice-free greenhouse state that earth was in for millions of years prior to the first glaciation 34 million years ago before the Late Cenozoic. It concerns a vastly greater timescale than what we normally refer to when we speak of ice ages. It has nothing to do with the relatively recent semi-regular ice age cycles of roughly 100,000 year duration. If indeed we ever lost all ice cover we’d have runaway climate change, enormous sea level rise, and likely an extinction event.
Isn’t it more correct to say the universe appears to be expanding more rapidly and we don’t know why so we’ve called that driving pressure dark energy?
There are solutions proposed by some scientists that dark energy doesn’t exist.
Confusion and worse can come from a difference between the lay definition of a term and the strict scientific definition. The lay definition of ‘Theory’ is scientifically ‘Hypotheses’. That one has led to no end of misinformation. The lay definition of ‘Ice Age’ is scientifically a glacial period as opposed to an inter-glacial.
The old articles talking of a coming ice age were actually referring to the question of whether the next glacial period could be only a few thousand years away as opposed to tens of thousands. Climate change deniers are constantly slipping a few zeroes on the time scales.
Thanks. I thought that was the case, but couldn’t find the details.
Fair.
There was some evidence during Covid that beards did filter out the droplets that carried the disease.
That’s all anyone can do - he conceived of a theory that fit all the known facts (including facts he had worked to uncover). It’s a cliche’ but it’s true - science doesn’t deal with proofs - it deals with explanatory theories that made disprovable predictions but haven’t been disproved yet. That’s what the consensus is.
Yeah, pretty much. Dark matter is pretty conclusively proven, and honestly it’d be kind of weird if it didn’t exist. All the folks who claim to have models that don’t need dark matter are crackpots. But dark energy is just the currently-popular label for a phenomenon that nobody has any understanding of at all. We know the phenomenon is occurring, but to say that we’re clueless as to why is to overestimate the amount of clue that we have: If anything, we’re negatively clueful.
Great point on The lay definition of ‘Theory’ is scientifically ‘Hypotheses’, absolutely true. Sometimes people disagree- not over the actual fact- like here- but over the definition of a few terms. “Ice age” is not easily definable. We can be in an an inter-glacial period- which we are- and TECHICALLY still be in a “Ice age”.
Again, good point. The glaciers will not be coming back in our lifetimes, or a our childrens lifetimes. Climate change and overall warming is a fact. Of course, that does not mean that after we- somehow- “fix” the excess CO2, that maybe in a few millennia- it may be time for the glaciers to start creeping back . Or not. We simply do not know as Humans have really fucked the normal climate and cycles. But even if we had not- the glaciers would STILL not be coming any time that would even bother out grandkids.
So the glaciers are not coming- the climate change denialists are wrong. Technical definitions can confuse the lay people.
The key thing that Newton did (besides being one of the two who invented calculus) was to prove that the heavens behaved in a manner that meant they behaves the same as things on Earth. The orbits of the planets and moons had been mapped out, but nobody explained why. Newtorn showed that the same gravity as measured by falling objects (apples?) on Earth could also explain orbits. Inertia was universal, friction was a separate force. Calculus was used to prove the gravity from all the mass in a big sphere was the same as the equivalent mass as a single point at the center. So essentially there was nothing magically different about the rest of the universe outside the earth - the same rules applied.
There is, in fact, one example of such a cabal that hasn’t been brought up in this thread. The subject is New World Paleoanthropology and the theory they supported was called Clovis First. That theory claims that the first humans to enter the Americas was the Clovis culture dating to around 13,000 years ago. Whenever some researcher reported a site that apparently pre-dated that period, the major experts would come up with reasons that the date was wrong. No matter how carefully the researcher collected his data, the cabal would find something to claim it was mistaken.
I’m not sure there was any one thing that disproved Clovis First, although the Monte Verde site in Chile was influential. There were several other sites, but perhaps the funeral thing was the most important.
