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But the 19 century scientists didn't just accept or reject an aether. They calculated consequences according to their best Science and then proposed tests, which they carried out to the best of their ability. A real shining example of progress via the scientific method. Furthermore they knew the limits of their abiltiy. They knew that the experiments of Fizeau were against calculations carried out by neglecting higher order terms in series and so were first order. They were only able to measure the effects of higher order terms at the very end of the century. It was these later experiments that confirmed the lack of aether and lead to a search for other explanations. By the way, siecle is the French word for century.

There was an initial assumption that if there were waves, there must be some sort of physical medium for those waves. That assumption turned out to be false. Another example of science winning over "common sense". Basically, we have detected something that we can describe using wave equations. Does that mean that mean the waves are real or just a useful description? "Physically exists" is a difficult concept that belongs in the philosophy forum. You could spend months arguing about the meaning of "physical" and then months more arguing about the meaning of "exists". When you have a 5 definitions of each, you then spend years arguing about which of those apply to the electromagnetic waves. And, if you take the quantum view, there are no waves at all. Just quanta of the underlying field. Does that field exist? Yes, because we measure its effects. No, because it is just a mathematical abstraction. It is impossible to say which of these is "true". We have new models that work. The ether model did not work. Ditto phlogiston, caloric, "plum pudding" atom, steady state universe, etc. As these models are not consistent with the evidence, they have been replaced with new models that do. I cannot understand why so many people want to go back to models that have failed. Some of them seem to have a weird romantic attraction; a sort of "steam punk science" aesthetic. Fine. But this is a science forum, not an "aesthetics of dead theories" forum. I'm not really sure how that relates to the concept of a luminiferous ether as a substance that pervades space. Obviously, many people have later used the word "ether" to describe other things: Einstein famously described spacetime as being an "ether" (because it is everywhere) much to the delight of the steam-punk pseudoscientists. They ignore the bit where he went on to point out that it could not be a material substance (ie. is not the luminiferous ether they were looking for). Others have used to word to describe one or more of the quantum fields that pervade space, etc. This is not a science discussion. It is a history of science discussion. Maybe you should go and cast a vote in the "should there be history forum" thread. I knew someone (or two people) would pick up on that. But it is important to note that the leeches are used for very different things. Which is a good analogy for the fact that wave equations can be used to describe the movement of material substances (eg. sound waves in air) but can also describe things that are have no material existence (eg. light or electrons, etc). Just because we use the same tool, doesn't mean we are clinging on to the old, discredited ideas of how things work. Let's turn this around. What reasons do you have for considering the ether? If there are reasons to accept this ether, I would also like to see that. What properties are you claiming for the ether? How is the experimental evidence consistent with those properties? What other experiments do you need?

Yes, what then? In my opinion they are intimately related. Let's take an example. Imagine a very weak photon source, emitting about one photon every minute. All around it, but at a distance of one light second (=300,000 km) we have photon detectors. Now according to Maxwell (no photons, just waves) every minute a circular wave front expands into space. According to QM however, we only have a 'probability wave', and the photon is detected at only one detector. At the moment of detection, I know immediately that none of the others will detect a photon. So the event 'measuring a photon' and 'not measuring a photon' are entangled. If behind every detector would stand a human observer, one could send a message to all the others when measuring a photon and tell them that at timepoint 5:09h she knew that nobody else had measured a photon, based on the fact that she already had measured it. So the entanglement follows directly from the wave character of the probability distribution. The power of real entanglement experiments (also known as EPR, or Bell experiments) is that we have positive measurements on both sides, not just a lack of a measurement. But they are expressions of the same phenomenon. So, what then? No. We do not need realtime measurements. If two detectors at a great distance of each other are in the same inertial frame they just can make their measurements, notice the exact time of measurement, and then later compare their measurements. There is no faster-than-light communication. See here. The mathematical theory of QM is unambiguous: entanglement must exist. Do not forget, it was theoretically derived before it also was measured. So there is no problem to solve. The only problem is that we, humans, cannot picture this based on our daily concepts.

Or maybe not. From https://en.wikipedia.org/wiki/Hirudo_medicinalis#Today

You live in the forest so your immune system is probably strong enough

Hi, Is it possible to increase the density of a solid? Such as metal

or an unmotivated universe with at least a few billion motivated, directional, conscious beings who've been aware of each other since prehistoric times.

The evidence against the ether now is largely the same as it was in the 19th century. All attempts to have measure the effects of any ether model have failed. We have developed alternative models, such as the invariance of the speed of light, which are consistent with the evidence. Some, if not all ether models, imply Lorentz violation. Noether's theorem tells us that if there were Lorentz violation then we would see different effects if the same measurements were made at different places. Many other types of experiments have been developed to test this, again they are all consistent with the view there is no ether. So, on the one side we have zero evidence for the ether (and no need for it, apart from "common sense" which is equivalent to no reason at all) and large quantities against it. It is a reasonably good example of how evidence and science can show that common sense is wrong. But I think there are many better examples of how science progresses. For example, phlogiston was a good theory that matched the evidence available. So it was, for a while, a scientific theory (unlike ether). But then, as more evidence became available, it was clear a new model was required and it was replaced. However, these are both examples of ideas (one unsupported and one a good theory) that were completely overturned. That is actually fairly unusual in science. Most theories are just incrementally adjusted and improved as more information becomes available. And often, even when there is a better model, the old one continues to be useful (eg. Newtonian gravity). Which is partly why modern science is not considered to be about discovering "truth" or "reality".

They don't produce the same effect. Case A produces an electric field at some distance away, while case B does not.

The Richard Nixon defence. I might have to report myself...

In the bad old days leeches were used very unscientifically for letting choleric or stagnant blood etc, with Robin Hood allegedly the most famous victim of this quack treatment. Nowadays they're used to scientifically exsanguinate people because it's better than alternative treatments. https://en.wikipedia.org/wiki/Hirudo_medicinalis#Today It's perhaps significant that the only recipe, for a stye treatment, in the 10th century Bald’s Leechbook that has been tested and found as effective as modern treatments had nothing to do with leeches. From https://www.nottingham.ac.uk/news/pressreleases/2015/march/ancientbiotics---a-medieval-remedy-for-modern-day-superbugs.aspx "It's not off topic if a mod introduces it."

Nor is anyone else. First of all, as already discussed, the luminiferous ether as per the concept as we know it is inconsistent with our measurements. We know it doesn't work. I think an argument for considering "something" is that we have come to agree on a physical model where a photon leaving the Sun arrives some 8 minutes later, the exact time varying in an exact way, very accurately and consistent with our model. So what is it about this distance that doesn't allow the photon to arrive in 6 minutes? Or 6 years? We don't know what it is about the photon that does the accounting for this consistency, or anything about the space between the Sun and the Earth that would allow for such consistency either. We really don't know if there is something actually needed to do this accounting or not, we just know if there is it is not the type of mechanism we have yet imagined.

Ok, quiet. Fair enough. A reason to keep it, or rather resurrect it in a modified form, could be facilitated by extra dimensions. Credible attempts have been made earlier by Kaluza-Klein and others, and later string theorists, but nothing come up with yet has fully made sense.

I was. Thanks for the correction. +1. I need to keep better track of my science history. OTOH, did you know that leeches have been back in use for some time? http://sciencenetlinks.com/science-news/science-updates/modern-leeching/ OT: The luminiferous ether was assumed to be fixed to some preferred frame, but measurements of the speed of light, and in electricity and magnetism, indicated otherwise. Edit: I see Carrock was much quicker

Or are you thinking of caloric, another out of favour idea? While we are at it, maybe we should start s thread one why leeches and blood letting are no longer in use

There is a book devoted to this A history of theories of the Aether and electricity E T Whittaker There were two volumes of thos Vol 1 from Descartes to the end of the 19th century Vol 2 (written later) Modern theories (to about 1930). You could also look at the firat 30 pages of The Theory of Relativity Professor C Moller Oxford University Press. This develops the theory of light as known in Maxwellian times, as classical wave theory and sets the requirements for ethers of various natures, developing them from Hugens onwards to determine the difference between phase and ray velocities, showing their importance and invariances. He then goes on to analyse in detail early (fizeau and foucalt) experiments ans demonstrate what these were capable of and equally importantly what they were not. After then analysing Hoek and Fizeau's experiments He turns to discuss Lorenz / Fitzgerald and Finally to Michelson whose experiments were the first capable of detecting an ether. The mathis in this early part of the book is not difficult. However the whole of Chapter 1 is rather too long to post as an extract.

By ether, do you mean the old idea of the luminiferous ether? if so: 1. There is no evidence for it 2. There is no need for it 3. Why resurrect a dead theory? In our next episode: “phlogiston: why has it fallen out of favour?”

If you meant "how to separate chemical compounds?", you should start from reading this article and its links: https://en.wikipedia.org/wiki/Separation_process It should give you brief idea which procedures are available.

Is it meant to be a powder? Sometimes you just have to work with what you’ve got. It shouldn’t matter too much that it’s a sticky solid, unless the fact that it’s sticky is because it contains impurities.

Change can still occur by mutations or infection resulting in endosymbiosis (mitochondria, chloroplasts etc), even if isolated.

You probably shouldn't be using it for that long. "Use of intranasal decongestants (such as oxymetazoline) for more than three days leads to tachyphylaxis of response and rebound congestion" from https://en.wikipedia.org/wiki/Tachyphylaxis#Other_examples I suggest you check with your doctor. Good point.

For starters it looks like xylometazoline is a vasoconstrictor, which is the opposite MOA that you indicate in your post. Am not a doctor, but it sounds like a symptom relief type of drug and I find it odd that you've been using it for 6 months. https://www.drugbank.ca/drugs/DB06694

An eggshell is 'designed' to protect from considerable steady crushing pressure, which that outer light light blue casing is not and will not do. However that light blue outer casing is designed to protect from a British Standard drop height onto a hard (concrete) floor. Such a drop would certainly break the egg. Are you suggesting that the time to complete the impact with and without the light blue casing would be the same? Deformation of that light blue casing extends the impact time over a longer period, which is another way of saying it reduces the deceleration of the protected item. This is the same principle as crumple zones and energy absorbing bumpers in vehicles to protect occupants from excessive deceleration forces.

You are new here and you obviously haven't read the rules like so many other don't. So I will help you by posting the abstract of your thesis and commenting upon it. But I will ask the moderators to explain the rules. 1) Not all methods of root extraction require an initial 'guess'. There is a perfectly satisfactory rote method a bit like long division, though admittedly it is multi step as is long division. You would probably need to look up some algebra texts from 1890 to 1920 to find it though. 2) Your methods claim a single step, but appear to require an inexhaustible supply of more advanced functions such as trigonometric ones to achieve this. How many steps does the computer or calculator execute to obtain these, and what would do without them? What about the accuracy obtainable for these? For instance the tangent changes very rapidly indeed near its singularities. Suppose you wanted the square root of the difference of two similar numbers with one known to a large number of decimal digits, so the difference looses many decimals? How would your formulae be successful then? 3) Suppose the real number you wish to extract the root from is a surd. How do you handle those?

I have waited to weigh in on NDT's behaviour to see which direction this thread would go. Other than the case involving alleged drugging, which would be criminal IF PROVEN IN COURT, the others are simply cases of bad behavior. And going on about it, and making assumptions about thoughts/circumstances/actions for six pages is simply spreading gossip. Is that proper behavior on a science forum ? The fact that NDT is an excellent populariser of science does not mean that he has to be a proper, or even good, person. We've had some people who I thought were excellent scientists on this very forum. But that didn't translate into people skills, and some had really bad attitudes. Fortunately I can separate the two qualities, as no-one is a 'total package'. I might listen to a NDT lecture, but maybe I won't go on a date with him ( also I like women ). I suggest we all do the same. Other than Raider, who is still at that wonderful age, we are all old enough to know what is socially acceptable behavior. And I'm sure some of us ( myself included ) have chosen to act inappropriately ( never criminally ) at some point before reaching our old age.

https://www.dailymail.co.uk/news/article-6269297/Islamists-rally-Pakistan-death-sentence-Christian.html