Wikipedia:Reference desk/Archives/Science/2025 May 14

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May 14

Origin of the Moon

What is stopping us from having a solid understanding of the origin of the Moon and resolving the unsolved problems? Is it just the fact that we really haven't been studying it all that long and it takes time? Could new tools help resolve the competing theories and definitely say one way or the other? Or will we never know without a fictional time machine or wormhole viewer to look back into the past? Could we (or have we) spotted a moon forming elsewhere in deep space? Viriditas (talk) 09:06, 14 May 2025 (UTC)[reply]

For a time machine to be helpful, it would need to be an actual time machine. A major issue is that current hypotheses fail to explain some known observations, so new ideas seem to be needed. Additionally, the predictive power of these hypotheses is limited, partly because they are incomplete theories giving rise to fuzzy predictions, and partly because some theoretical predictions cannot be tested with available means (similar to how we do not know how to experimentally test hypotheses about the composition of Earth's inner core).  ​‑‑Lambiam 10:34, 14 May 2025 (UTC)[reply]

Viriditas, I think it is worth noting that despite a number of competing theories and open questions about the precise planetary mechanics, the Theian Impact model remains the overwhelmingly dominant theory. A major factor contributing to stronger confirmation of any one model, in addition to those already noted by Lambiam, is the vast amount of time that elapsed since the formation of the Earth and Luna, and the resulting need to reverse-engineer the material arrangement of the solar system in the relevant far-distant epochs. As to the notion of new tools adding at least some degree of confidence to any scientific consensus, yes, that is always a possibility--to a point. In particular, quantum computing and AI can be expected to lead to some semi-near-term advancements in relevant modelling. But because we have many gaps in in requisite data to fix various of the variables relevant to the existing theories, a much stronger consensus than exists now will probably remain evasive for a long time. As to whether we have a confirmation of a moon in formation outside the solar system, the answer (I believe) is no. Remember that it is actually within just a couple of decades that we could even begin to validate the existence of exoplanets, and we continue to do so through indirect observation of stellar bodies. Being able to confirm fine details of the mechanics of the formation of an exomoon is well outside the scope of our current celestial observation capabilities--indeed, we're not even to the stage of a firm confirmation of a single exomoon's existence. SnowRise ^{let's rap} 03:20, 22 May 2025 (UTC)[reply]

Gerotranscendence

There used to be a wiki article on Gerotranscendence. Why was it deleted? Cerebrality (talk) 14:45, 14 May 2025 (UTC)[reply]

It was deleted in 2008 (!), with "was a very short article providing little or no context" [1] --Wrongfilter (talk) 14:55, 14 May 2025 (UTC)[reply]

(edit conflict) If like me you've never encountered the word see Harald Ofstad (note 4). 2A00:23C7:2B60:8401:74ED:7F23:A69C:1530 (talk) 15:03, 14 May 2025 (UTC)[reply]

Looking it up on Google, I would see it as a fancy-schmancy word for "getting nicer as you get older". Which does not always happen. Some folks get meaner as they get older. ←Baseball Bugs ^{What's up, Doc?} carrots→ 16:43, 14 May 2025 (UTC)[reply]

You misunderstand it. Not all elderly people experience gerotranscendence, just some. Cerebrality (talk) 19:38, 14 May 2025 (UTC)[reply]

Yes. Some do, and some don't. ←Baseball Bugs ^{What's up, Doc?} carrots→ 23:42, 14 May 2025 (UTC)[reply]

No the article was available until the past few years or so. Cerebrality (talk) 19:38, 14 May 2025 (UTC)[reply]

THe logs don't lie. Maybe there was nothing in it that wasn't already in the Harald Ofstad article? ←Baseball Bugs ^{What's up, Doc?} carrots→ 23:45, 14 May 2025 (UTC)[reply]

There was also Wikipedia talk:Articles for creation/Gerotranscendence which I assume was some sort of draft despite apparently living in AfC talk space, but I'm fairly sure that only ever lived there and was also deleted very long ago. Nil Einne (talk) 21:14, 25 May 2025 (UTC)[reply]

embryology

Apologies if this question has been addressed before, but if so I couldn't locate it.

How does the developing embryro distinguish its left from its right side?

For instance in humans how does it know to grow the liver (mostly) on the right side & the spleen (entirely) on the left? Obviously this isn't an infallible process since very ocasionally there can be revesals, which evidently still result in a viable individual - although in later life they might confuse a surgeon.

Do we know if there's any connection with this and differences at a molecular level (L-amino acids & D-sugars)? Renshaw 1 (talk) 18:25, 14 May 2025 (UTC)[reply]

See Situs solitus § Development. If indeed the unidirectional rotation of nodal cilia establishes the usual situs, the next question is why these cilia don't rotate clockwise. This can only be due to chirality of the axonemal dynein (the dynein motor protein animating the cilia). So this is, ultimately, a difference at the molecular level.  ​‑‑Lambiam 19:15, 14 May 2025 (UTC)[reply]

Aside: It looks like you're the same user as Paul Renshaw. You only need one ID here. ←Baseball Bugs ^{What's up, Doc?} carrots→ 19:19, 14 May 2025 (UTC)[reply]

No, we're different users: I am David Renshaw (but Paul and I have a lot in common). Renshaw 1 (talk) 10:31, 15 May 2025 (UTC)[reply]

What is the name of the manoeuvre when a bird performs an aileron roll in flight?

Because birds don't have ailerons. But they do perform aileron rolls if something comes at them from above. They strike with claws and beak when inverted and then attempt to spiral away. 146.200.107.90 (talk) 22:49, 14 May 2025 (UTC)[reply]

The Aileron article indicates that birds do, in fact, have ailerons. ←Baseball Bugs ^{What's up, Doc?} carrots→ 23:41, 14 May 2025 (UTC)[reply]

I see the term "barrel roll" used for a manoeuvre that, as described, is probably the avian equivalent of an aileron roll: [2], [3], [4], [5], [6].  ​‑‑Lambiam 08:40, 15 May 2025 (UTC)[reply]

Am guessing this is typically used only by raptors and not by these or these? Martinevans123 (talk) 08:46, 15 May 2025 (UTC)[reply]

As I understand it, an aileron roll is performed with the aircraft following a straight path. In the reference frame of the pilot, apparent gravity makes a full rotation in the plane perpendicular to the longitudinal axis of the aircraft. The pilot has to operate elevators and rudder to perform the trick. A barrel roll is performed at more or less constant angle of attack, sending the aircraft along a helical path, along the surface of a barrel, with the rudder centred and the elevator slightly up. In the pilot's reference frame, apparent gravity constantly points more or less down. Barrel rolls are relatively safe and easy in non-aerobatic aircraft; the largest type I know to have performed a barrel roll is the Boeing 707. PiusImpavidus (talk) 10:50, 15 May 2025 (UTC)[reply]

Birds use wing warping instead of ailerons. So did the Wright brothers. You can call the manoeuvre a roll. PiusImpavidus (talk) 10:33, 15 May 2025 (UTC)[reply]