Wikipedia:Reference desk/Archives/Science/2024 March 1

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March 1

Neanderthal speech

Could Neanderthals and other premodern humans been handicapped by being tongue tied? How could we find out or rule it out if it isn't preserved by fossils? Maybe by DNA?Rich (talk) 06:57, 1 March 2024 (UTC)

The Neanderthal Throat - Did Neanderthals Speak?. Alansplodge (talk) 10:50, 1 March 2024 (UTC)

Neanderthal genomic DNA has successfully been sequenced and analyzed. To use this for testing hypotheses regarding ankyloglossia impacting Neanderthal speech capability, researchers need to identify the genes involved in the development of a human untethered tongue. I do not know whether this has been achieved, but I doubt it has even been attempted. Mutations (possibly epigenetic) connected to ankyloglossia are reported for the MTHFR gene and the TBX22 gene, but these have much more general roles than the development of a normal tongue. (According to sources, most cases of the anomaly (in humans) are sporadic, so I do not understand why the infobox in our article has "Specialty    Medical genetics".) Finally, the handicap impedes the production of coronal consonants, but not of vowels and the labial, dorsal and laryngeal consonants, leaving enough phonemic space for a rich vocabulary.  --Lambiam 10:53, 1 March 2024 (UTC)

Manually igniting a star

In theory, if you were to go to the center of a cloud of hydrogen/helium gas in the middle of space, an area of gas that hasn't undergone nuclear fission, would it be possible to light the gas and start burning it? Assuming you have the oxygen required to actually light the initial flame, could you, in theory, start the process of fission through a simple handheld lighter? Or would the gas not ignite and simply remain how it is until it's compressed and undergoes fission that way? 71.38.197.194 (talk) 23:08, 1 March 2024 (UTC)

You mean fusion, which (like fission, its opposite) is a nuclear reaction. A chemical reaction, such as oxidation, has too little energy density to start fusion; else life would be very different. —Tamfang (talk) 00:31, 2 March 2024 (UTC)

Stars run on fusion which is multiple times more powerful per gram than fission. The scales of either are absolutely insane compared to fire (https://xkcd.com/1162/). By the time fusion starts the star would average about 4 times the density of osmium (the densest material), have a center of 5,400,000 Fahrenheit, 1,000,000 times sea level pressure and thousands and thousands of times the pressure a human could survive & 1,000 times denser than water (522 pounds per 8 fluid ounces), 44 times denser than osmium, 52 times denser than gold, 11,600 times denser than unboiled hydrogen, 816,000 times denser than air and 12,000,000 times denser than the boiled hydrogen in a party balloon. With tens of thousands of Earth masses of hydrogen crushing down with a human-fatal surface gravity 165 times Earth. Only then does the least massive protostar ignite (it's very hard to crush hydrogen to 0.01% the size of mundane maximally compressed hydrogen cause matter takes up space/void-free liquids+solids are hard to compress/electron degeneracy pressure). It's amazing science is even able to fuse thin gas density hydrogen in a medium-size building though that's cause fusion increases exponentially with temperature they just heat the easiest fuel to hundreds of millions of Fahrenheits. There's fusion reactions where if the temperature doubles the burn rate rises 68,719,476,736 times. Whatever the x is watts rise x times x times x times x times x times x times x times x times x times x times x times x times x times x times x times x times x times x times x times x times x times x times x times x times x times x times x times x times x times x times x times x times x times x times x times x times (x times itself 35 times). So the lowest mass 0.06-0.07 Sun mass stars won't "use up their fuel" for 380,000,000,000,000 years while the biggest stars are thousands of times more massive but die 190,000,000 times sooner with core temperatures only about a hundred times hotter. When the core of an 8 to 30 Sun mass star "runs out of fuel" the starstuff falls almost as fast as freefall, fusion accelerates exponentially till 11 to 18 billion Fahrenheit which is when large fractions of the energy it'll ever fuse in its life (few million years) fuse in like 2 seconds and even the 100,000,000,000 to 1,000,000,000,000 Earth surface gravity 1.4 to 3 Sun mass center that remains is powerless to stop the core bounce and runway fusion explosion from escaping the gravity forever. With the light of billions of Suns despite 99% of the explosion energy "wasted" not on light but ghost particles that'd average 6,000,000,000,000 miles of solid lead before the slightest interaction. Sagittarian Milky Way (talk) 00:42, 2 March 2024 (UTC)

It is too difficult as the gas is not dense enough. Perhaps a cold fusion technique will work, like Muon-catalyzed fusion. Graeme Bartlett (talk) 09:32, 2 March 2024 (UTC)

To the 3 questions in short: No, No, agreeing No. Less respectfully, I ask the OP to review the wrong assumptions in their question. It's reasonable to suppose that given a handheld lighter, the OP can ignite the gas from a gas cooker. The gas goes on burning with a flame that emits light and heat, and you can assume that the atmosphere supplies sufficient oxygen under pressure to maintain the required stoichiometric ratio of fuel/oxygen. Each of the underlined terms that are relevant to a cooker in your kitchen are irrelevant and as assumptions misleading to understanding the fusion process in stars. That is a subject of intense research, both because it may become a practical power source if researchers solve difficult challenges of initiating fusion (needs high pressure and energy to start) and containing the subsequent reaction, and because science predicts that we can find the origins of chemical elements in star fusion. For that we are indebted to a landmark 1957 paper called B2FH after the initials of its authors. The best use for your hand lighter at this point would be to heat cups of tea for the hard-working fusion researchers. Philvoids (talk) 11:14, 2 March 2024 (UTC)

ITER/DEMO being possibly the most famous horse in the race to the first power plant though if we're lucky one of the others is sooner. Sagittarian Milky Way (talk) 15:04, 2 March 2024 (UTC)