exchemist

1 hour ago, Moontanman said:

Such photos avoid the blanket idea that they are all photoshopped but a huge number of modern photos exist and the number grows by leaps and bounds everyday but are easily dismissed by simply saying it could have been photoshopped. This idea of photoshop has pretty much destroyed the idea of photos being evidence of anything not just UFOs. If you want a more modern approach then feel free to watch this video in your spare time.  This is an interview of Garry Nolan where he talks about his research into the physical effects of UFOs on humans. It's long but very interesting and based in science not some redneck talking about anal probes. 

https://youtu.be/ShX-WM5TiXc

 

OK the crack about anal probes was a bit below the belt -  as it were - I admit.

But look, photographs have been faked long before Photoshop was born or thought of, and I don't really want to watch a long video on a subject I am highly sceptical about. Bigfoot, ghosts, the Loch Ness Monster and similar stories show that people dream up all sorts of weird explanations for things they think they have observed. Nobody has yet produced any coherent, corroborated evidence for any of this, in spite of stories having been around for decades, let alone any kind of explanatory hypothesis that can be tested.  

In the case of the 1950s flying saucer craze, what is known is that there was widespread worry - hysteria even - about communism at the time, in the US. There were lots of movies about aliens landing and taking over, as a metaphor for fear of the communists. I ask myself why did these stories almost exclusively relate to the USA? Why not other countries? It seems to me the most credible explanations for those UFO stories are in the realm of social psychology, rather than hard science.   

16 minutes ago, Moontanman said:

So you assume a conclusion before seeing the evidence? 

No we don't assume a conclusion, we accept one. That's what we all do, all the time, when we don't have ready access to the data in question. We rely on the findings of others who have looked at it, ideally people with some relevant expertise in the field.

The basic problem with these claims is the lack of reproducible evidence. Thy are just aerial Bigfoot stories, basically: anecdotes from individuals that have not been corroborated by anyone with a record of competence or objectivity, mixed up with photography that may well be bogus and can't be verified. When you also take into account the lack of a credible hypothesis for why any of this stuff might be what its proponents claim, (e.g. why would aliens visit some obscure place in the US Midwest, carry out a couple of anal probes and then bugger off, without attempting to communicate or leave a forwarding address?), one is entitled to be sceptical. 

These photos you have produced are famous old flying saucer pics from the 1950s. That's very disappointing. Is that really the best you have? 

17 hours ago, joigus said:

Thanks! I used 2KBT/m−−−−−−−−√ with Boltzmann's constant. The ballpark of it certainly checks with me. Your argument seems convincing, and very informative. +1

We sometimes forget the cosmic time scales. We see Saturn in the sky with its beautiful rings and it isn't a static situation. Probably the aftermath of a catastrophe as compared to Solar-system lifetime. Similarly, it's very likely that this giant got sucked into the inner region from a recent event --in terms of the age of that star system.

I sometimes fantasize with the possibilities they offer. I don't think it's too far-fetched that a select group of them can seed other systems with life.

Actually, on further reflection, if @Janus were here he'd probably be telling me I'm going about this all wrong and that the real mechanism of depletion is the stripping action of the solar wind on the outer atmosphere (ionosphere?), like the way a diffusion pump works. 

11 hours ago, swansont said:

I remembered reading about a tip to do this with beer, if you want to release some more of the carbonation, which allegedly affects the flavor. From back when a bowl of peanuts was commonplace at a bar.

(moved to plain old chemistry)

Of course, the cognoscenti among us drink real ale, which has not been artificially carbonated in the first place....

Which is just as well, as I dislike roasted peanuts (though I do like the fresh ones.)

13 hours ago, kenny1999 said:

If, to put it simply, avoiding sugars, how about salt? Is it another thing that should be avoided in order to achieve better health?

Too much salt can give you high blood pressure so yes. But no need to avoid it completely: if you do that everything will taste horribly bland.

The best advice I can give you is to avoid ready meals of any sort, and especially highly processed ones with a long list of incomprehensible ingredients. Manufacturers tend to use various tricks to make their stuff seem appetising, which may involve various sugars (including high fructose corn syrup, which can make people put on weight at frightening speed), too much salt and various hydrogenated fats, plus other doubtful ingredients. Almost everyone I know who who subsists on ready meals is horribly fat and/or unhealthy seeming. Cook - properly - for yourself: it's good for you, improves your quality of life and the modest time you spend doing it is a good way to unwind.  

13 minutes ago, Erina said:

Wow, cool experiment !

In the interests of speed what edible chemical could be used to decarbonise a drink in place of a straw with a lot of time on its hands ?

Sucrose, as I mentioned previously. Or NaCl but that would spoil your drink.

2 hours ago, Erina said:

@exchemist: So then, two glasses side by side, if one had a straw inside of it then the drink would lose more CO2 faster ?

Very likely yes. The straw would provide more nuclei to initiate bubbles.

In the lab, we used to put "boiling sticks" into flasks of solvent that we wanted to boil, to make sure there were plenty of nuclei for bubbles to form evenly. The worst thing was to have glassware that was perfectly smooth and clean, because then you could get superheating and "bumping" when the superheated liquid finally found something to initiate a bubble and everything boiled over at once.

1 hour ago, Erina said:

Assuming that carbon is the element of which makes something like Fanta or Coca Cola fizzy, is there a way to remove that is a short period of time ?

Such beverages go "flat" after being exposed to oxygen, could I therefore introduce that to achieve the same aim ?

It's not the element carbon but dissolved carbon dioxide, CO2, that makes drinks fizzy. And it's not exposure to oxygen that makes them go flat, but the reduction of pressure on exposure to the atmosphere.

When you open a bottle of fizzy drink, the pressure above the liquid drops. Since the amount of gas the water can dissolve depends on the pressure of CO2 above it, you then have a supersaturated solution, which is why it fizzes. Any nucleus for bubbles to form on will accelerate the rate at which the CO2 comes out of solution. A classic way is to put in a sugar lump. This has a large surface area with many sharp edges, which promotes the initiation of bubbles. Sand would also do the job, but not so good if you want to drink it later.

The reason why you need a nucleus to start the bubbles off is because of the energy needed to pull apart the water molecules. The excess pressure inside a bubble is 2T/r where T is the surface tension of the liquid - a measure of the strength of the intermolecular forces - and r is the radius of the bubble. From this you can see that the smaller the radius, the higher the pressure, so in the limiting case this formula predicts an infinite pressure is needed to blow up  a bubble of zero radius i.e. at the start. While this formula is not accurate at very small radii, it gives an idea of the problem. Sharp edges reduce the intermolecular forces in their vicinity, as the water molecules are not entirely surrounded by other water molecules, making it easier for gas molecules to push them apart and start off a bubble. 

19 hours ago, joigus said:

That makes sense. It's intriguing... I've read about exoplanets that are in a similar situation to what you suggest, and in some cases a trail has been identified as due to their atmosphere being lost from the exposure to the star's heat.

I've just found this on Wikipedia, concerning another planet (51 Pegasi b) that's in a similar situation --tidally-locked gas giant very close to its star--,

Why are experts so excited about SO₂? --even more than by the presence of water or CO₂.

Doing some back of the envelope calculations, the rms velocity of water molecules at 900C will be about 1.26km/sec, if I've got my arithmetic right.  (v[rms] = √(3RT/m) m being in kg. ) The escape velocity of Saturn, which has about the same mass as this planet, would be 36km/sec. I have not worked out how to do the velocity distribution curve, to see what fraction of the "tail" of the velocity curve will represent molecules with a velocity greater than this, but one can see it could easily be 0.1-1% or so. So one might expect the water to escape over time.

Regarding SO2 I'm not sure I follow this, except that one might expect reducing conditions, in which case the presence of SO2 rather than H2S presumably indicates photochemical reactions. They propose photolysis of water, apparently.   

4 hours ago, kenny1999 said:

Someone in an outdoor open area dissembles and repairs an old Television, cars and traffic around, full of dust and dirt and polluted air. Are most circuit boards, electronic components of any kind, manufactured in any generation able to tolerate dust and dirt to some extent by design?

Is it just considered and designed to have some protection so that surrounding pollutants cannot make too much damage or is it not particularly designed but it has to be a lot of dust and dirt ( e.g. which are done by accidents or with intention ) before any damage can occur?

I think you mean disassemble. To dissemble means to lie.

I should think the main risk from ingress of dust will be dirty contacts and hence poor electrical connections at points where subassemblies are joined together. 

20 minutes ago, Alfred001 said:

Jesus, guys, OBVIOUSLY the argument isn't that unlikely things are impossible. It's that, along with the ASTRONOMICALLY unlikely explanation of the origin of the virus, there is also a perfectly ordinary explanation that doesn't involve any kind of astronomical unlikelihood - the virus leaked from the lab - follow?

If you have two explanations of an event and one involves an improbability that is so extreme it's hard even to intuitively conceptualize and the other doesn't, OBVIOUSLY the right explanation is the one that doesn't involve astronomical improbabilities.

Which part?

But the zoonotic explanation of the origin of the virus is not "astronomically unlikely". We've seen it before on several occasions. Do you really think most of the world's virologists are fools, while you are the genius to spot the flaw in their thinking? Get real. 

Just finished Heinrich Böll's "What's to Become of the Boy", a reminiscence of his time growing up in Cologne at the time of the Nazis. I found a copy when reorganising some books after redecorating. My wife must have bought it.

I also found a 1938 French translation of Three Men in a Boat, with original illustrations, which was the book she read in her teens that first made her an Anglophile - so she once told me. So I've started reading that.... a lot of passé simple, which is quite unfamiliar to me, and vocabulary I don't know but am trying to guess, to avoid stopping to get out the dictionary. We'll see how far I get. So far I've learnt that the French for Housemaid's Knee is épanchement de synovie.  That should come in handy......... It's just the sort of useless thing I find I tend to remember, just as I remember the French for combine harvester and the Dutch for horseradish.

19 hours ago, joigus said:

This certainly sounds like a big deal:

https://www.nature.com/articles/d41586-022-03820-3

5 papers published so far on it:

References

Rustamkulov, Z. et al. Preprint at arXiv https://doi.org/10.48550/arXiv.2211.10487 (2022).

Alderson, L. et al. Preprint at arXiv https://doi.org/10.48550/arXiv.2211.10488 (2022).

Ahrer, E.-M. et al. Preprint at arXiv https://doi.org/10.48550/arXiv.2211.10489 (2022).

Tsai, S.-M. et al. Preprint at arXiv https://doi.org/10.48550/arXiv.2211.10490 (2022).

Feinstein, A. D. et al. Preprint at arXiv https://doi.org/10.48550/arXiv.2211.10493 (2022).

But I would like to sample opinions from local experts.

Some kind of photochemistry seems to be going on in the atmosphere of exoplanet GASP-39b

The bulk of the information I've been able to gather so far is the presence of some mighty-selective absorption lines detected during the transient, and significant amounts of CO₂ and SO₂.

Interesting that there is so much water, considering the high temperatures - 900C- on the sunward side (it's tidally locked, apparently). One would think water would be lost into space at such temperatures, as the fraction of light molecules with velocity > escape velocity must be significant, I'd have thought. But then if, as they suggest, it started out in an orbit of similar radius to that of Jupiter, and was later kicked inward, we are probably not looking at an equilibrium state.

14 minutes ago, sologuitar said:

Young, strong, energetic people dropping like flies. This is happening all over the world not just in the United States but people refuse to believe the fact that COVID-19 vaccines are dangerous. This has to be the most wet behind the ears generation of people in the history of mankind. The democrats are counting on us to get dumber and dumber by the minute. It's very easy to brainwash and control people who are not well-informed. You say? 

I say: malevolent, mad ballocks.

1 hour ago, paulsutton said:

Just a quick question about this,  I downloaded the attached from Openclipart.  I am a little confused as to why

Uracil and Thymine appear identical,  other than the numbers.  I am not too sure what the numerical values around Uracil represent.  Could someone clarity what these are please.  If the molecule is wrong then I will just have a look for a better resource for this.

As far as I am aware Uracil is not one of the main 4 actual nucleobase.  However would be good to have a little more understanding of what I am looking at here, as I am planning an activity to build these molecules from molymods as part of a STEM Group activity.  

 

Thanks

 

Paul

Thymine has a methyl substituent in the 5 position, which uracil does not have.

The numbering is just a way to denote the ring substituents. With heterocycles it is normal to pick one of the hetero atoms as position 1 and the others then follow round the ring. 

1 hour ago, Innocent Muggle said:

Thank you for replying [exchemist]

 

I thought it can be depend on capacity cause engines are usually heavy in high performance. 

 

Thank you so much I really appreciated it!! I hope you have a good day👍

It will certainly depend on battery capacity, just as a big engine will be usually more powerful than a small one. However it will also depend on the battery technology and design as well. 

15 hours ago, Lorentz Jr said:

Or maybe let go the idea that they're entities. They could be mere phenomena.

I think they have to be entities, because something continues to exist in between interactions. If that were not the case, we would be unable to predict the properties of the entity in the next interaction, which is what QM enables us to do with great success.  

25 minutes ago, Innocent Muggle said:

Thank you for replying! Then What I need more?

The weight of a battery pack depends on how it is designed. It is not something you can work out from electrical performance data.

You would not expect to be able to work out the weight of a petrol engine from its power output, would you?  Because, again, It depends on the design.  

6 hours ago, Lorentz Jr said:

Why are all the theories of quantum mechanics formulated in terms of particles? I don't see any conclusive evidence for their existence. They seem like an artifact of classical thinking. Tiny little "objects" that no one can see.

Even quantum field theory is based on a similar idea, that fields are inherently quantized, that quanta are "entities" of some kind, which requires "probability waves", with not even an attempt to explain more deeply what they might be based on.

Max Planck started the quantum revolution with his theory of black-body radiation, and the whole physics community took that to mean that electromagnetic waves are quantized. But black-body radiation isn't just electromagnetic waves, it's the generation of electromagnetic waves. An interaction between the electron field (or whatever the system is made of) and the electromagnetic field. Why can't that be the source of quantization? Choosing the target field as the reason for quantization seems arbitrary when the quantization is always associated with an interaction.

If matter and energy are continuous fields with quantized interactions, there's no need for mysteries like the "wave-particle duality", and maybe there would be a way to eliminate the infinities in the calculations of quantum field theory. Fields would still be effectively quantized, sort of, but only indirectly, through their interactions.

The only complication I can think of is that I'm not sure how direct interactions could be quantized, since each interaction would have to involve two quantization coefficients. So there would probably have to be something like a form of energy that mediates interactions. Not a field, exactly. Something localized. What we call "particle detections" would be localized interactions with the field(s) of detectors, and what we call "virtual particles" would be failed interactions, where the energy goes back to the field it came from.

A particle traveling through space would be an ordinary wave packet in its field. A particle making a track through a bubble chamber would be a wave packet that keeps getting localized repeatedly through interactions with the fluid.

Is there any evidence for particles independent of their interactions? Any data that requires fields to be quantized when they're not being measured?

I must say it has always seemed to me that the notion of "particles" is a fairly preposterous construct, when one thinks about it: the idea of an entity with no physical dimensions but nevertheless finite properties such as mass, charge, intrinsic angular momentum etc. Just as artificial as "waves", really. Originally, in classical physics, the concept of particles was merely used to simply physics problems to their essentials, for ease of modelling. 

Like you, it has often seemed to me that QM entities only behave like particles when they interact. Reading Rovelli's Helgoland last year, I was quite impressed by his idea that QM entities only have defined properties at all when they interact, so we should perhaps let go our idea that they possess them in a continuous sense in between. 

2 hours ago, Gian said:

 

If you have time, can people give me their response to this video on artificial gravity please?

The coriolis effect is discussed from 13.31

I've no science beyond GCSE so I can't evaluate all the technicalities.

GIAN xxx

 

Yes, I think the point is that "r dot" signifies velocity in the direction of r, which means radially. That's what I and others have been saying.

What is misleading, it seems to me, is that the film accompanies this by showing a film of someone jogging round the circumference, i.e. not moving radially. I suppose there is a little bit of radial motion, in that the jogger is moving up and down a little as he runs. Whether that is enough to cause a sensation of his head moving sideways to left and the right, as it goes up and down, I am not sure. It will depend on the radius of the circular tube he is running inside. It's a very small diameter tube in the film. Whereas If you think of 2001, for instance, the space station is hundreds of metres across. (The effect of r dot will be much less because ω will be much less: you need a lower rotation rate to simulate 1g of gravity in a larger ring.)   

The two guys trying to throw a ball to one another, across the centre of the circle as they rotate, is a much better example of what happens, I feel. That is radial motion, so that is the scenario in which the Coriolis effect arises. 

52 minutes ago, Gian said:

As a means of creating artificial gravity sci-fi authors and movies have often suggested using a centrifugal force in a rotating space station or spacecraft, as in 2001 A Space Odyssey

However the idea apparrently fails to take note of the "Coriolis effect" which would cause immediate nausea and loss of balance, like motion sickness, unless the rotating radius were very large eg 1 mile+

Yet even Lord Nelson was seasick for several days after putting to sea, but would then gain his sea legs and be unaffected.

Is it possible that the bodies of individuals like the crew of 2001's spacecraft Discovery One may adapt after a few days and get their "space legs" leaving them unaffected by the Coriolis effect?

Thanks

GIAN🙂

I'm not sure the Coriolis effect would have that dramatic an impact. In most uses of rotation to produce artificial gravity that I have read about, the spacecraft would take the form of a tubular wheel. According to my understanding , the Coriolis effect would chiefly affect objects moving radially, rather than circumferentially.

Or am I missing something?   

16 hours ago, raphaelh42 said:

Any genre welcomed

Thank you very much, I saw Terminator, Alien, MIB and BTTF series, preferred Alien > Terminator

Did you watch Prey (2022) ? And Prometheus ?

I just re-watched Taken 1 before creating this topic it's great IMO

The Ipcress File and Get Carter. 

14 hours ago, Peterkin said:

Yes, I understand that. I meant, only the [microfibre] cloth itself; it is not treated or infused with any chemical cleaning agent.

Before microfibre, for 3000 years, people were cleaning items made of glass (but not coated with anti-scratch or anti-glare film) with ordinary cloth and some chemical cleaning agent, mostly commonly soap and vinegar. So people used to glass surfaces might be forgiven for mistakenly using the same method they employed with old-fashioned television screens on their non-glass computer screens, as the first reviewer did. He was comparing the Apple microfibre facecloth thingie to the very similar microfibre product amazon sells as a pack of 24 for the same price as a single two-layer one from Apple.  I did not link review, because of the alcohol. 

OK fair enough, you mean there is no cleaning chemical impregnating the cloth. Yes, one is just as well off using a regular spectacle-cleaning cloth, from the optician or wherever. 

19 minutes ago, Peterkin said:

Apparently the Apple cloth is just a cloth: in use, people apply some kind of cleaning fluid. So, how clean and streak-free your screen is depends more on the fluid than the fabric it's applied with. In one test I read about, they used 70% alcohol, which may have been a mistake. Alcohol, vinegar and glass cleaner work fine on my eyeglasses (with either silk or cotton cloth), but I've been advised by my computer repair guy not use any solvents on the screen; he recommends distilled water and a mild detergent, applied with a soft, lint-free cloth.

Here's a review https://www.pcmag.com/reviews/apple-polishing-cloth

It is, as I suspected, a microfibre cloth though, not "just a cloth".

5 hours ago, kenny1999 said:

From the scientific viewpoint, is it making a real difference? I think any cheap cloth would do the same job, if no debris is stuck when you wipe your delicate screen with your cloth, if there is any, then a cheap one or expensive one would scratch your baby too.

Anyone who wears spectacles will know that you need a microfibre cloth to clean the lenses properly so that you don't get reflections, glare in sunlight etc. I don't know what an Apple cloth is but I suspect what you need is a cloth for cleaning lenses, not just any old piece of fabric. At any rate, that is what I use to clean the screen on my laptop.