Wikipedia:Reference desk/Archives/Science/2025 July 30

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July 30

Mosquitoes and other flies in northern North America

could the extremely dense prevalence of mosquitoes and black flies in North America be due to the human-caused extinction of a vital predator of flying bugs? Either by Europeans in the last few hundred years or even thousands of years earlier by First Peoples?Rich (talk) 08:34, 30 July 2025 (UTC)[reply]

Doesn't have to be black-and-white like that. Bats and dragonflies and fish that feed on larvae have taken major hits to their populations. Also, not too long ago the area was covered by a kilometer of ice. Abductive (reasoning) 19:12, 30 July 2025 (UTC)[reply]

US and ICD

Does US still use the ICD (meaning ICD-10-CM), or it has declared that ICD is wholly obsolete in US medicine? tgeorgescu (talk) 13:28, 30 July 2025 (UTC)[reply]

According to ICD-10-CM, then yes. Their relevant link to officialdom is this one updated in June 2024. Mike Turnbull (talk) 13:34, 30 July 2025 (UTC)[reply]

I used the prompt "Does the U.S. still use ICD-10-CM" in the new Google search that has just been released in the UK and it gave an unequivocal "Yes", for what that's worth! The full answer was "Yes, the United States continues to use ICD-10-CM for diagnosis coding and ICD-10-PCS for procedure coding. These are the mandated standards for electronic health transactions in the U.S. The transition to these systems was finalized in 2015, replacing the older ICD-9-CM." Mike Turnbull (talk) 13:38, 30 July 2025 (UTC)[reply]

That is not a reference, it's a string of plausible noises output by a smooth-talking large language model.  Card Zero  (talk) 14:42, 30 July 2025 (UTC)[reply]

No-one said it was a reference. My first reply gave the relevant reference. I thought that the fact the LLM mentioned ICD-10-PCS was interesting, since my prompt made no suggestion I might be interested in that. Mike Turnbull (talk) 15:03, 30 July 2025 (UTC)[reply]

infinite universe

I've heard two things: 1) the presence of a singularity at the Big Bang or at the center of a black hole is considered unsatisfying from a theoretical perspective. They want better theories that keep the densities finite. 2) the universe (I mean the entire universe, not just the observable part) might be infinite in size.

But, is the infinite size not also a singularity of sorts? Especially if the infinite universe was supposed to have originated from the same big bang? The density of the universe is supposed to stay about the same throughout the infinite space, right? So that makes the mass infinite too. Do they have an explanation for where it came from? 2601:644:8581:75B0:979C:5F82:9ADC:661A (talk) 20:08, 30 July 2025 (UTC)[reply]

There are theories in which the universe did not come into existence because it has always existed; there has not been a "first moment". These theories include the so-called cyclic models and the eternal inflation model. It is debatable whether these are scientific theories, because (at least in their current versions) they are not falsifiable. They have no explanatory value as to how come there is something rather than nothing. None of the scientific theories in which the universe came into existence at some absolute time 0, together with time itself, offers an explanation for this cosmogony.

In this cosmological context, a "singularity" is a state in which the laws of physics as we understand them break down. Since many theoretical physicists are not happy with their theories breaking down, they spend a good deal of time trying to theorize the problems away, with limited success. An infinite universe is not a theoretical problem and does not entail the existence of a singularity in this sense.  ​‑‑Lambiam 20:44, 30 July 2025 (UTC)[reply]

Yet all of science's attempts to understand the creation of the universe fail in some way. The very existence of something that either (a) has always existed, or (b) started from literally nothing, is the greatest singularity possible, under the definition you provide. That would be true of a grain of sand just as much as a thing as monstrously large as the universe. To those scientists who say they understand the universe, I quote André Gide at them: "Trust those who seek the truth but doubt those who say they have found it." -- Jack of Oz ^{[pleasantries]} 22:24, 30 July 2025 (UTC)[reply]

It occurs to me that "In the beginning, God created the heaven and the earth" is about as falsifiable as the other hypotheses about the Big Bang, etc. ←Baseball Bugs ^{What's up, Doc?} carrots→ 02:37, 31 July 2025 (UTC)[reply]

Well, kind of. We did once take a picture of the one and not the other. But yes, your two options are equally questionable in terms of answering where "it" came from. Matt Deres (talk) 13:17, 31 July 2025 (UTC)[reply]

When did "we" take a picture of one of the two, and of which one was it a picture? Can we see it?  ​‑‑Lambiam 06:34, 2 August 2025 (UTC)[reply]