Wikipedia:Reference desk/Archives/Science/2024 August 12

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August 12

Moffat and ozone

Who was "Dr Moffat of Hawarden", who wrote papers about ozone, invented an ozonometer (see for example [1]), and after whom "Moffat's Ozone papers" ([2]) appear to be named? What more can we know about him? Was he Thomas Moffat MD FRAS ([3])?

How do the papers work? Andy Mabbett (Pigsonthewing); Talk to Andy; Andy's edits 14:44, 12 August 2024 (UTC)

Seems very likely it was Thomas Moffat, since the PMC2439974 article mentions ozone 13 times and was written in 1856, soon after ozone had been characterised for the first time by Christian Friedrich Schönbein in 1840. The Google books reference was also written in 1856, by David T. Ansted. Mike Turnbull (talk) 15:31, 12 August 2024 (UTC)

The full name is given as Thomas Barbour Moffat ([4], p.17), an obituary is here, and genealogical data here. --Wrongfilter (talk) 15:41, 12 August 2024 (UTC)

Thank you, both. I have compiled data from the above sources into Thomas Barbour Moffat (Q128923496). There is also an obituary in the BMJ, which describes him as "the author of many papers on geology, meteorology, sanitation etc."; though I can only find one other (On Medical Meteorology (Q58709971)).

Thomas Barbour Moffatt, of the distinguished Moffatt clan of Sundaywell, Dumfriesshire. What's the origin of the name "Sundaywell", sometimes written "Sunday Well"? 91.234.214.10 (talk) 17:41, 12 August 2024 (UTC)

According to the Dumfriesshire OS Name Books, 1848-1858 "Sundaywell - [Situation] At E. [East] end of Sundaywell Moor. A good Spring, the water of which is deepened by a Stone dam round it, seemingly very old, There is a tradition, that, at Some remote time, there were great numbers of people Baptised here, The farm takes the name from the well." and "Sundaywell - A large Farm House with extensive outbuildings and garden the property of trustees of the late Alexander Moffatt Occupied by John Edgar". Mikenorton (talk) 21:27, 12 August 2024 (UTC)

How did Carl Linnaeus know about the species he described?

I was reading about the Pied kingfisher, whose article states that it was first described by Linnaeus in 1758. I assumed he must have visited "Persia and Egypt" in order to catalogue the species, as that's where he says it lives—but I don't see reference to any such expedition on the catalogue's article. Were their earlier catalogues that Linnaeus drew from? How did he know about this bird? ꧁Zanahary꧂ 16:19, 12 August 2024 (UTC)

To quote from this webpage from Berkeley, "Linnaeus continued to revise his Systema Naturae, which grew from a slim pamphlet to a multivolume work, as his concepts were modified and as more and more plant and animal specimens were sent to him from every corner of the globe". Mikenorton (talk) 20:51, 12 August 2024 (UTC)

He was apparently quite happy to accept specimens, but very stingy in giving credit or sending some back (according to a German bio podcast I recently listened to). --Stephan Schulz (talk) 14:30, 14 August 2024 (UTC)

photons

Suppose the Sun were part of a binary: identical twins, separation several million miles. When the stars were 'side-by-side' in our line of sight, the radiation received on earth would be twice its present value. But what would happen when one star was eclipsing the other? Would photons from the distant star pass unscathed through the nearer one? If not what would the received intensity be? What spectral changes if any would be observed compared to the familiar G2 spectrum? Renshaw 2 (talk) 16:37, 12 August 2024 (UTC)

Subjecting our planet to double the usual solar radiation is likely to leave no one alive to make the interesting observation of whether a star is transparent. Philvoids (talk) 17:11, 12 August 2024 (UTC)

I heard that the average photon generated in the sun's core bounces around in there for hundreds of thousands of years before accidentally escaping to the surface. So I'm pretty certain that the sun isn't transparent. Abductive (reasoning) 23:10, 12 August 2024 (UTC)

"When this random walk process is applied to the interior of the sun, and an accurate model of the solar interior is used, most answers for the age of sunlight come out to be between 10,000 and 170,000 years."^[5]  --Lambiam 23:17, 12 August 2024 (UTC)

If the expected number of steps of a random walk process for getting a distance d away from the starting point equals n, the expected number of steps needed to traverse twice that distance, 2d, equals n². I don't know the average time between two hops of a photon, but I bet it is less than 3 seconds. This means that a randomly hopping photon takes more than 10⁷ hops in a year, and more than 10¹¹ hops in 10,000 years. To get all the way through the Sun instead of getting out from the core would then take more than 10²² hops or 10¹⁵ years, several orders of magnitude longer than the estimated age of the universe.. Of course, many incident photons would find their way out earlier, but in a very different direction than where they came from.  --Lambiam 23:42, 12 August 2024 (UTC)

Subjecting our planet to double the usual solar radiation is likely to leave no one alive

What about a hypothetical planetary environment with an unusually strong magnetosphere? Same result? Viriditas (talk) 23:42, 18 August 2024 (UTC)

Among the countless binary star systems there are probably such star systems elsewhere, two yellow dwarfs, each of approximately one solar mass. Photons reaching the surface of a hot star are almost immediately absorbed by the ions of it outer layer.  --Lambiam 23:12, 12 August 2024 (UTC)

Stars are pretty dense and full of free electrons, so they're very good at scattering light. The light from the other star will loose its identity in the photosphere (i.e., it will be scattered and frequency shifted to match the temperature of the gas).

Irradiating a star with light from a nearby star may raise the temperature a bit on the sides where they face each other. On the other hand, two stars close together will deform each other by tidal forces and the tidal bulges get a bit cooler than the lower parts. I don't know what effect will be dominant in the case of two G stars in a very tight orbit, but I expect the tidal deformation. Such an unequal temperature distribution can be seen in the spectrum. The absorption lines in the spectrum will deform as the binary spins and the hotter and colder parts alternate redshift and blueshift. PiusImpavidus (talk) 08:30, 13 August 2024 (UTC)

The OP's proposed reconfiguration of our solar system cannot be carried out as a practical test before reaching a political consensus on the work that it will involve. The project to split the Sun into a Binary star pair will lie beyond the resources of a space agency such as NASA unless significant new funding can be raised. In the present political climate this funding must wait while Environmental impact assessment statements are properly considered. The OP's proposal implies that the binary stars' orbit is in the Ecliptic plane of the Earth's present orbit so that solar-solar eclipses are periodically observed but a full calculation of the Orbital mechanics of the revised solar system will be needed. Shall we have an assessment of how Gravitational waves from a local binary star will affect life on Earth? An international body might be formed to collect, review and eventually override statements from affected stakeholders that will include publishers of tidal predictions, representatives of the Sunscreen manufacturers, weather forecasters whose computer models will need updating, Sun worshippers, astrologers and others. As an interim and less radical test of the Sun's opacity I suggest allocating more resources to Solar observation where one may try to detect prominent Sunspots as they rotate out of direct view to the far side of the Sun. Philvoids (talk) 20:45, 14 August 2024 (UTC)

Dear Pius,

Thanks for your reply to my query about photons (13 Aug.). Apologies for the belated reaction.

‘Fearless’ or ‘intrepid’ you may be, but that’s no bad thing in science is it. Breakthroughs such as relativity & quantum theory, among others, would never have happened if their pioneers hadn’t been brave enough to violate the constraints of ‘common sense’ and envisage things that were “clearly impossible”.

Though admittedly, even Einstein’s nerve failed him when it came to contemplating black holes, or gravitational waves, or ‘spooky action at a distance’, or a universe that might not be static in extent. (and he regretted that last one didn’t he; I think he called it “meine größte esel” (‘ass’ or ‘donkey’) a few years later, after Edwin Hubble’s findings.

Anyway, thanks for your useful comments. You possibly guessed that I was asking the question in the context of the prospects for a habitable zone in a binary star system. We have a tendency to immediately dismiss binaries as not worth investigation. But it seems to me that there’s considerable scope for them to incubate life.

One possibility is a closely coupled binary, if viewed in terms of the Solar System, say both stars within the orbit of Mercury (although Mercury itself probably wouldn’t survive!), and this is why I asked about the combined radiation from two stars that sometimes eclipsed. This would obviously be a very disruptive environment for emerging life. It seems to me that a planet at 1AU wouldn’t be viable, but that a habitable zone could exist at the distance of Mars or possibly the asteroid belt. (I’m not taking into account the various other properties such a planet would also need to have, merely surface temperature & tolerable variation.)

Another scenario would be a widely-spaced binary system (viewed in solar-system terms, the second Sun orbiting at about the distance of Neptune). The resulting environment might not be entirely to our liking but it should be quite habitable. A rough calculation suggests that the inner planets of each star would continue in stable –albeit slightly more elliptical– orbits around their own star & would not be at risk of being captured into an orbit round both stars. This seems a reasonably benign environment, and that such a binary would be certainly worth investigating.

Of course some configurations might not have a HZ at any distance. If the stars happened to be Sun-like and about 1AU apart, I’d guess there might be no stable planetary orbit – except maybe ones that were far too distant– and hence no HZ.

Thanks for your help. Renshaw 2 (talk) 11:56, 19 August 2024 (UTC)

"It is estimated that 50–60% of binary stars are capable of supporting habitable terrestrial planets within stable orbital ranges." from our article Habitability of binary star systems. Modocc (talk) 13:00, 19 August 2024 (UTC)