exchemist

OK. I look forward to learning from you in due course what tests you would propose to show the validity of your ideas.

I’m not a physicist but I suspect the reception you will get will depend on: (1) what predictions your model makes that enable its validity to be tested and (2) whether it is compatible with the rest of physics. We get a lot of people who just dream stuff up with no attention to how their ideas could be validated experimentally, and a lot more who think their ideas can exist in a vacuum, when they are incompatible with everything else. Obviously no one is going to tear down the whole of physics, just because of a claim to account for a handful of phenomena in a different way. Good luck.

As a rank amateur in these matters, I must say Pigliucci and Peter Woit are 2 people I value highly as thoughtful but clear and well grounded, with functioning bullshit detectors. Degrasse Tyson and Krauss are slightly too glib for my taste.

What is meant by the dashed arrows a and b?

No.

My opinion of him went down considerably when I learned he has tried to rubbish philosophy: https://whyevolutionistrue.com/2014/05/20/pigliucci-pwns-neil-degrasse-tyson-smbc-teases-pigliucci/ He doesn't seem to understand that science is both rooted in philosophy and poses philosophical questions. So I suspect he's a bit shallow. I'm sure he knows his science but I would take anything he says about other matters with a pinch of salt.

Don't think the qualifier "standalone" would suggest the OP had neutrinos in mind.

Are you sure this is right? My understanding was neutrons are some of the secondary products produced when cosmic rays interact with atoms in the atmosphere.

A bullet most definitely does make a noise as it flies through the air. Whether you hear it as a whizz or as a crack depends on whether it is sub- or supersonic as it passes. But in the case of paper and tape, you also have something else: a resonator. The surface of the paper or the tape will be made to move when the breaks take place and this will make a larger volume of air move.

If you think being 13.8 billion years old is "fresh and new", you have a curious conception of these terms.

Any sudden movement will disturb the adjacent air. In both the cases you mention there is a stretching action followed a break in quick succession. When the break occurs, the stored energy in the stretch is released suddenly, causing a very tiny but rapid movement of a portion of the paper or tape. This will create a sound wave. There does not have to be - and in this case there won't be - a vibration, just a single motion. This is shown in fact by the absence of any discernible pitch or tone to the sound. It's more or less white noise. If there were vibration, that would cause a sound at a particular pitch, or pitches.

I think I have read that spontaneous emission processes can be modelled as a special case of normal stimulated emission, but due to interaction with the virtual photons of vacuum fluctuations. We did not go any of that at university, as QED was out of scope for chemists (and my physicist girlfriend at the time preferred to talk about other things). Is it the case?

Indeed, QM interactions are inherently probablistic rather than exact no/no go processes. So the probability of interaction goes up progressively as the match gets more exact. I think uncertainty broadening is also still present for a single atom, if the excited state has a significant spontaneous emission probability, which for electronic transitions it will do, if I recall correctly that it depends on the cube of frequency. But I’m rusty on this and away from my books.

Probably, but you can still tackle it in manageable chunks by learning selectively those bits that interest you. For me spectroscopy was one of them, after a hairy first term at university reading and having stiff tutorials based on Gerhard Herzberg's little green book, which did me a lot of good.😀 Keeping asking questions: they are not daft.

No, spectral lines have finite width for a variety of perfectly good reasons. (Finite line width means there is a range of absorbing or emitting frequencies of course.) These include the Doppler effect, from motion of the emitters relative to absorbers, and uncertainty broadening, due to finite lifetime of the excited state leading to uncertainty in its energy, by Heisenberg's Uncertainty Relations. In gases, this can be a function of pressure, cf. "pressure broadening", since collisions may shorten lifetimes of excited states and also alter their energy, due to transient proximity of second atoms, thereby disturbing the potential experienced by the electrons. And for matter in condensed states, atomic lines tend to get broadened into bands anyway, due to the overlay of vibrational and/or rotational fine structure. If you read up a bit about spectroscopy, there is quite a bit to it besides simple line emission and absorption.

If the soil is poor I should think a solution providing missing important elements might be appropriate. Fertilisers normally focus on N, P and K, in various ratios. There are commercial liquid fertilisers available. Anything that alters the pH is very risky, which rules out most of the things you have listed. Bear in mind plants make their own carbohydrate by photosynthesis, so it’s pointless adding starch or sugars to the soil.

I didn’t know this. Rather good. The reference to “Judenstrasse”, though fairly innocent in his time, has an eerie prescience. (I’ve just watched “Downfall”.) But he was wrong to say that dead nations don’t rise again, as it turned out. I’m reading, or rather re-reading, Martin Brasier’s “Darwin’s Lost World”, about Ediacaran and other Precambrian life. I’m enjoying it more second time round. Now that I have a son at St. Andrew’s, in the university mountaineering club, I feel I want to go to Loch Torridan with a geologist’s hammer and climb Quinaig.

Arf arf. To be fair I think all these techniques were already in existence by Bach's time, but he was the apotheosis of them all in combination. So much so that everyone wanted to go back to a simpler texture after he died and almost nobody played him for a century. There were even people of my grandparents' generation who referred to JSB as "Bach's father". I believe we have principally Mendelssohn to thank for bringing him back to the concert hall. When we were rehearsing the B Minor Mass, our director spent some time in one number on getting the tenors and altos to be aware of the interplay between their parts, so he got the accompanist to play just those two lines on the piano, for us to listen. We were mesmerised. I remember thinking people would pay good money to hear that played in a piano recital. And it was just 2 parts - and the inner parts at that! So the full 4 part harmony was pretty rich, dense stuff. One can see why people wanted a change. But Bach is an inexhaustible pleasure to sing. There's always something you hadn't spotted. He seems to write from the bass up, so the bass parts are always terrific and somehow very virile - provided you can do octave jumps easily and have three lungs. (Unlike Handel, he takes no prisoners where voices are concerned and you have to follow a line that could have been written for a string instrument or the keyboard.)

It's simply that velocity always has to be stated relative to something in order to have any meaning. 2 cars in adjoining lanes on a motorway may be travelling at 5mph relative to each other but at 75 and 80mph relative to a policeman by the side of a road with a speed camera, and at 20 and 25mph relative to a truck which it itself travelling at 55mph relative to said policeman. The problem is we unthinkingly assume "the ground" is our reference frame in daily speech, treating it a bit as if it were an absolute frame of reference, when in reality there is no such thing. (This should however be a bit more obvious in space.) So you can't say you have a spacecraft "travelling at 0.999% of c" without saying with respect to what. Hence I proposed a space station to provide a reference, so that these speeds have a meaning.

Yes Bach seems to be a great inflexion point in the evolution of Western music. All the pros play Bach, even rock musicians. I remember once talking to a Thai pianist, playing jazzy hotel stuff in a hotel bar in Bangkok. My colleague asked him what music he played for pleasure at home and he replied "Bach". I tried to persuade him to play some for me, as he was taking requests, but he said the hotel management wouldn't like it (!) and I could not convince him. I also recall once listening to an organ performance of the Art of Fugue in my room in Oxford, when a fellow chemist came in who was a jazz clarinettist (He had been a member of the Kent Youth Orchestra before coming up). One of the weirder fugues was playing and he couldn't make it what it was. He thought it sounded so edgy it must be some c.20th composer - Messiaen or something. He was amazed when I told him. But if you liked what I posted, this (opening chorus, 1st 7 mins) is another of my all time favourites as a choral singer, from Part V of the Christmas Oratorio (apologies if I've posted this one before at some point): You have to click the "watch on YouTube" link to see it. This is also in 3/4. My impression is Bach does not often use that time signature and when he does, he often thinks it's time for some gaiety. In the video you can actually see the musicians enjoying it. They are making eye contact with each other and smiling.

Just come across this Flashmob video from Lausanne, in the course of revising the bass line in my favourite chorus from Bach's St. John Passion: The cellist plays part of one of Bach's Cello Suites and ends on a (baroque pitch) G, from which the basses can get the C they need to start the fugue. The conductor pretends to be a waiter delivering beer to the next table, until the moment arrives. They sing it very well, especially given the acoustics of a busy restaurant. Pretty cool, I thought. This chorus is in 3/4, with real JSB swing, syncopation and drive. Fantastic music.

No, you've got it, that's the point. You obviously don't add the velocities, as you would in classical dynamics.

OK I give up.

You can only define a speed relative to some other object. So far the only objects you have mentioned are the two spacecraft. Is 99.999% of c measured relative to the other spacecraft or to something else? If the former, you have already stated the answer. If the latter you need to say what that something is. You could for example say each space craft approaches the same space station, from diametrically opposite directions, at 99.999% of c relative to the space station.

99.999% of c relative to what, though?