Wikipedia:Reference desk/Archives/Science/2022 June 11

= June 11 =

Have atoms with g orbitals been experimentally created?
It is my understanding that no currently known chemical elements have electrons on g orbitals in the ground state, and it is theorized that the 8th period will contain such elements. I'm curious, however: has anyone created excited atoms with electrons on g orbitals? As a layperson, I imagine no, since it would require pushing electrons up at least two energy levels from the highest ground state for currently discovered elements (from 7p to 8s to 5g), and I'm not even sure if current superheavy elements were synthesized as complete atoms or bare nuclei. - Linneris (talk) 09:18, 11 June 2022 (UTC)
 * When someone takes a bell and knocks it with a hammer, the bell will get into an excited state and start ringing. It is a bit unusual to describe this by saying they created an excited bell. Electron excitation is a common process, but if the excitation energy is too high, the electron flies off and the atom becomes ionized. Otherwise, with lower energy, the electron settles (usually for a brief instant) into a higher orbital, which can be the g-orbital. This happens all the time. Since this is a quantum system, more properly speaking this is a superposition of eigenstates, somewhat like the ringing of an excited bell is a superposition of the fundamental and overtones. When superheavy elements are synthesized, this happens in a highly energetic environment by bombarding already heavy nuclei with a beam of nuclei, brought to a very high speed in a particle accelerator. It is all very messy; the most meaningful statement one can make about whether the new element was formed as complete atoms or bare nuclei is that neither is the case (and no atomic physicist cares). The new nucleus as originally formed by fusion will emit some neutrons before it is stable long enough (still very short) that it can be identified as having a specific atomic weight. --Lambiam 10:33, 11 June 2022 (UTC)
 * To answer the final part of your question,, the conventional chemistry of superheavy elements is normally accessible despite their short half-lives: see nobelium for an example. Its solution chemistry in the +2 or +3 oxidation states (but otherwise with the expected set of electrons) is relatively well-known. Chemists do care.... Mike Turnbull (talk) 12:07, 11 June 2022 (UTC)


 * Exciting electrons to 'high' energy levels is surprisingly easy. Electrons that are still in orbitals - that is, still in a bound state - are by definition at lower energy than free electrons. If you have enough energy available to ionize an atom, then you need less energy than that to kick an electron up to an arbitrarily high-energy orbital. (The 'difficult' bit is often setting up your experiment to only supply enough energy for the appropriate excitation, rather than full ionization.)
 * There's a whole field of study devoted to Rydberg atoms: atoms with one or more of their electrons in highly-excited states, with very large principal quantum numbers (n). You can get delightfully weird behavior, where you start blurring the distinction between an 'orbital' and an 'orbit'. TenOfAllTrades(talk) 13:33, 11 June 2022 (UTC)
 * Actually the 8-th period begins with the element 119, which has not been created yet. So, the answer is no. Ruslik_ Zero 15:00, 11 June 2022 (UTC)
 * As others (inluding the OP) have mentioned, creating an electron configuration with an electron higher than the atom's neutral ground state (where the Aufbau principle predicts the electrons would be) is not intrinsically difficult. Excited states, by promotion of an electron to a higher orbital, are common. Where things get more interesting is actual reduction—forcing extra electrons in, to make anions—that crosses into the next principal energy level. That the H2– ion (no, that's not a superscript/subscript transposition!) can be made is interesting several ways.10.1126/science.191.4226.463. DMacks (talk) 17:05, 11 June 2022 (UTC)

Why is there comparatively so much junk DNA?
Why do so many living beings seem to have such a comparatively large amount of DNA that can mutate, for example, without this leading to functional impairments? What evolutionary advantage does this have?--2A02:908:422:9760:0:0:0:82C8 (talk) 14:17, 11 June 2022 (UTC)


 * Non-coding DNA will get you started. (See also selfish genetic element.) TenOfAllTrades(talk) 14:29, 11 June 2022 (UTC)

Neat roads in Japan
Why do roads in Japan, the roads themselves and the markings, always look so neat? Do they use different materials, do they repair them regularly, are they in a temperature sweet-spot (neither snow nor heatwaves, that implies neither salt in winter and less tyre attrition)? Do lighter vehicles contribute to this? Or is it just my Western impression based on typical images? --Bumptump (talk) 16:02, 11 June 2022 (UTC)
 * Search the web for "japan road quality" and you'll see a lot of answers. It's a combination of material selection, construction methodology, and standards. --jpgordon&#x1d122;&#x1d106;&#x1D110;&#x1d107; 16:39, 11 June 2022 (UTC)


 * Yep, but the problem is more what Finlay says: "to find a reference that's worthwhile"--Bumptump (talk) 16:58, 11 June 2022 (UTC)


 * It's my understanding (but I've failed to find a reference that's worthwhile) that Japan generally doesn't use road salt much. Instead, as with places like Norway, when the roads get cold and snowy enough, people in affected areas change to winter or studded tires. This was, apparently, an issue when Japanese car makers began to export cars to the UK. They figured this would be straightforward, as the climate in northern Honshu is fairly similar to the UK's, and both countries drive on the left. But British weather is very changeable (there isn't a consistent "ice season"), so winter or snow tires are very rare the UK (you'd fit them and then a week later it would be 8C and raining). So the UK uses a lot of road salt (applied as the weather forecast demands). The mostly Japanese-spec cars didn't have the additional undersealing that winter salt demands, and so initially had a bad reputation for rusting. -- Finlay McWalter··–·Talk 16:41, 11 June 2022 (UTC)


 * It is also notable that studded tires also cause road damage. When they were first introduced in Ontario, where I live, this became obvious when the lane markings rapidly disappeared from many roads, and studded tires were banned in response. (They were later allowed in Northern Ontario only.) If Japan avoids salt damage but their roads somehow stand up to studded tires, this is also notable. --174.95.83.56 (talk) 22:27, 11 June 2022 (UTC)
 * Per Snow tire, Japan has banned studded tires on paved roads and vehicles either use winter tires or snow chains.  Pinguinn     🐧   09:33, 13 June 2022 (UTC)
 * No snow in Japan? The macaques are very disappointed in you. Fgf10 (talk) 08:32, 12 June 2022 (UTC)
 * Japan has also hosted a couple of Winter Olympics. --←Baseball Bugs What's up, Doc? carrots→ 13:25, 12 June 2022 (UTC)
 * So has subtropical Sochi. Hardly a good measuring stick. Fgf10 (talk) 16:10, 12 June 2022 (UTC)


 * See also POROUS ELASTIC ROAD SURFACE AS URBAN HIGHWAY NOISE MEASURE in Japan, but use seems limited. Alansplodge (talk) 13:51, 12 June 2022 (UTC)


 * Road wear and tear is exponential with weight. Maybe cab-behind-engine-not-over-miniRV-behind-that 18-wheelers with the American sized 53 foot trailer aren't as popular there? Japanese car tax laws are so F-450 discouraging that kei cars became very popular. Tokyo is not mild in summer, it's hot and humid. Sagittarian Milky Way (talk) 02:54, 14 June 2022 (UTC)


 * According to this, the max trailer length in Japan is 12 metres (40 ft) and max gross weight is 20 tonnes (25 t on designated roads). Alansplodge (talk) 13:36, 14 June 2022 (UTC)
 * In the US max gross weight is at least 36.29 tonnes in all states (15.42 tonnes per tandem axle plus 5.44 on steering axle). Some states much more. Sagittarian Milky Way (talk) 06:00, 15 June 2022 (UTC)