Wikipedia:Reference desk/Archives/Science/2023 February 15

= February 15 =

Butterflies of Maine
Is the Eastern tiger swallowtail (Papilio glaucus) native to Maine, or not? According to greennature.com and butterflyidentification.org, it is found in Maine, but a county-by-county search on factsaboutbutterflies.net did not find it even in York County, Maine (the southernmost county in the state). So which is it? (No pictures please -- I am not searching because I want to find it, I am searching because I do not want to find it, this being the only butterfly species in the Northeast region which causes a phobic reaction on my part, so I don't want to see it until I've desensitized myself through multiple close encounters with P. canadensis!) 69.181.91.208 (talk) 07:45, 15 February 2023 (UTC)


 * That sounds like a very specific phobia if exposure with canadensis is acceptable (from the article Papilio canadensis [it] was once classified as a subspecies of Papilio glaucus, and the pictures are strikingly similar). Assuming you are not a troll, you need a therapist, not an entomologist. Tigraan Click here for my talk page ("private" contact) 10:49, 15 February 2023 (UTC)
 * He's probably not a troll, he's asked similar questions before. The problem is one of defining "range". In birds you have the resident range, the breeding range, and the non-breeding range. The breeding range, in the case of butterflies would be where their caterpillars are found, and usually this range is demarcated rather conservatively; only where the species is successfully breeding every year. Individual adults may fly or get blown far from their breeding range, and even if they managed to mate and lay eggs, their offspring might be too far north and be doomed to die in the winter. So I would say that one would have to know if the websites above require caterpillars to be observed to list the species as being "from" York County. Alternately, maybe York County is the furthest north an Eastern tiger swallowtail adult has ever been observed. Abductive  (reasoning) 11:16, 15 February 2023 (UTC)


 * The Maine Species List from the Maine Butterfly Survey, conducted between 2006 and 2015, via this page which calls it Pterourus glaucus glaucus says it is RC (Rare temporary colonist)/ST (stray). So apparently not native and you are unlikely to see it. MinorProphet (talk) 01:34, 16 February 2023 (UTC)


 * Thanks! And yes, I know that P. canadensis and P. glaucus are very similar in appearance (as, indeed, are all of the tiger swallowtails except P. eurymedon), except in terms of size -- and that is why P. glaucus scares me but P. canadensis doesn't, because it's quite a bit smaller (its maximum size is about 3 1/4 inches, and that's just below my threshold for phobic response (for butterflies with vertical stripes only --those that lack such stripes, such as P. troilus, don't scare me even at 4 inches of wingspan) -- as I've established for myself through my own original research!) 2601:646:8A81:6070:75FB:9B75:3F50:7236 (talk) 02:39, 16 February 2023 (UTC)

STEPHEN C. MEYER
HELLO. I REVIEWED A WIKIPEDIA ARTICLE ON STEPEN C. MEYER. IN THE ARTICLE IT STATES THAT PROFESSOR MEYER IS A PROPONENT OF THE PSEUDOSCIENCE OF INTELLIGENT DESIGN. QUESTION: IF THE SCIENTIFIC EVIDENCE SUGGESTS INTELLIGENT DESIGN WHY IS THAT CONSIDERED PSEUDOSCIENCE? THANKS FOR CHECKING. BRYON GORTON OFALLON,ILLINOIS. 99.177.221.45 (talk) 18:27, 15 February 2023 (UTC)
 * Hello Bryon. Just a quick note: Please don't write in ALL CAPITALS.  In written communication, all capitals reads like your screaming, so please don't do so.  It can be read as rude.  Secondly, the consensus is that intelligent design is pseudoscientific, which means that while it presents itself as a scientific theory, using the language of, and some of the superficial trappings that actual science does, that it has never stood up to rigorous scientific analysis.  As noted at pseudoscience, "Pseudoscience is often characterized by contradictory, exaggerated or unfalsifiable claims; reliance on confirmation bias rather than rigorous attempts at refutation; lack of openness to evaluation by other experts; absence of systematic practices when developing hypotheses; and continued adherence long after the pseudoscientific hypotheses have been experimentally discredited."  That describes the status of intelligent design.  -- Jayron 32 18:38, 15 February 2023 (UTC)
 * To put it more directly (reduce Brandolini's law impact), the statement "the scientific evidence suggests intelligent design" is not scientifically correct, therefore nothing based on that premise has scientific validity. DMacks (talk) 18:52, 15 February 2023 (UTC)
 * Supposed "evidence" for intelligent design generally is not actually evidence, but rather fallacies or absence of evidence. For example, the argument of "irreducible complexity" usually designates things as irreducible when, in fact, they are reducible. The eye is the classical example; while separate components that make up the eye do need to all be there for the eye to function precisely as it currently does, that doesn't mean that those components have zero function separately. For example, the light receptor protein (rhodopsin) has many uses outside of the function of the eye and, in fact, we have found this protein in these uses throughout nature. In the example of the rhodopsin, we have things like Channelrhodopsin proteins which are light sensitive. They may not function as an eye per se, but they do have a function and work quite well for it, and then can be adapted to form a primitive eye (such as an eyespot). Another form of "evidence" for intelligent design is the fallacious "gaps" (or God of the gaps) argument. This is the absence of evidence form of "evidence." Basically, it can be described as "we don't know how this evolution step or formation of life step happened, so therefore an intelligent designer (God) did it." Our lack of knowledge or understanding of something is not scientific evidence for an intelligent designer or a god. It's literally just "we don't know this," and that's it. Maybe, in the future, we will find actual evidence that step was done by an intelligent designer (or God), and maybe we will find the natural explanation that doesn't involve an intelligent designer (or God). To date, the pattern of discovery has gone towards the natural explanation 100% of the time, and there is little reason to expect that to change (though that pattern is also not evidence that something we don't yet know wasn't an intelligent designer or God, just that it isn't likely the answer, when discovered, will be intelligent design or God). --OuroborosCobra (talk) 19:22, 15 February 2023 (UTC)
 * Irreducible complexity is fancy speak for 90% "I'm not personally smart enough to understand this" and 10% "Not every single thing is entirely known now, so the entire thing must be fake". -- Jayron 32 12:02, 16 February 2023 (UTC)
 * All too true and Stephen C. Meyer even has a Ph.D. in the philosophy of science from the University of Cambridge. Hmm. Intelligent design is religion so it makes sense the guy studied and embraced it, not a fruitful endeavor IMHO. Modocc (talk) 14:01, 16 February 2023 (UTC)
 * As an old math teacher once said to our class, "If you start with incorrect assumptions, you're likely to get 'interesting' results." ←Baseball Bugs What's up, Doc? carrots→ 17:15, 16 February 2023 (UTC)
 * To some extent, sure, but in science, that initial assumption should itself be falsifiable and tested. This might be more difficult to do in mathematics, but in science, it is usually easily (relatively speaking) done. For example, the assumption that the human eye is too complex to arise through evolutionary processes and that its components cannot function independently of each other is testable (see my earlier comment about rhodopsins, channelrhodopsins, and eyespots, for example). Testing that hypothesis shows it to be false. --OuroborosCobra (talk) 17:22, 16 February 2023 (UTC)
 * Every slipped disc, fallen arch, and pot belly is proof that any putative designer could not have been very intelligent. Those problems exist because a basic mammalian quadrupedal anatomy has been rather awkwardly repurposed into a bipedal form and has not been properly modified for it. Such biological "spit and baling wire" solutions make sense in an evolutionary context but not an ID one.--User:Khajidha (talk) (contributions) 12:47, 17 February 2023 (UTC)
 * The ID proponents would likely say that's because of Adam and Eve's original sin, fall from grace, etc. ←Baseball Bugs What's up, Doc? carrots→ 20:26, 17 February 2023 (UTC)
 * To make this into a scientific argument (which this thread is about), we need a little scientific experiment. Recreate the heaven and the earth, but this time with a minor twist: we muzzle the serpent so that it cannot tempt the woman to eat the forbidden fruit. Wait another 60 centuries or so, and test the hypothesis that there are significantly fewer slipped discs than on the current earth. --Lambiam 11:25, 18 February 2023 (UTC)
 * Reminds me of something Carl Sagan said on Cosmos: "If you wish to make an apple pie from scratch, you must first invent the universe." ←Baseball Bugs What's up, Doc? carrots→ 18:16, 18 February 2023 (UTC)
 * A stronger argument against intelligent design than potbellies is the blind spot in the vertebrate eye, caused by the wiring (nerve fibres) from the retina to the brain running on the inner side of the eye. This is not by some engineering necessity, since the wiring runs along the outer side in the cephalopod eye. Given how natural evolution leads to optimal designs, this can be seen as an argument for creation by stupid design: the universe was apparently created as homework by an inept demiurge apprentice. --Lambiam 11:36, 18 February 2023 (UTC)
 * The evidence... doesn't suggest... intelligent design... BITRATE Bitrate6789 (talk) 23:16, 21 February 2023 (UTC)

Relativity and everything's moving
Sorry if this is all answered somewhere; it's so far above me that I don't know where to look.

If I correctly understand little bits of special relativity: for an object at rest, time passes at such-and-such a speed and the object has such-and-such a mass, but when the same object is moving, time gets slower and mass increases in proportion to the speed. But of course, an object at rest on Earth isn't quite at rest; it's rotating Earth's axis, orbiting the Sun, orbiting the galactic centre, and probably other things too. Is it possible to account for all motion (and thus calculate the mass and speed-of-time-passing for the same object if it weren't moving at all), and if it's not, how can special-relativity-based calculations function? I suppose you could pretend that Earth is stable, and calculate everything relative to terrestrial motion, but such an assumption wouldn't work for space travel, and while I know that special relativity has no naked-eye-observable effects, I don't suppose that physicists prefer to rely on "that's too small to care about". When an object's speed is X percent of the speed of light, and this percentage is critical to certain aspects of its behaviour and nature (e.g. mass and speed-of-time-passing), I don't see how you can calculate anything without roughly knowing the actual ratio of the object's speed and the speed of light. Nyttend (talk) 20:12, 15 February 2023 (UTC)


 * "if it weren't moving at all" is where you come unstuck. There is no absolute stationary frame of reference. Provided you are not accelerating or rotating, you yourself define a frame of reference that can be considered as "not moving at all". Other objects are in movement relative to your frame of reference, and the relativistic changes can be calculated on that basis. But you yourself are moving relative to their frame of reference, so from their point of view you will be experiencing shortening, increased mass, and time dilation. You can't escape.
 * The 'gotcha' is that the speed of light is apparently the same in all frames of reference; it is from this observation that the 'distortions' suffered by objects moving relative to yourself can be calculated. -- Verbarson talkedits 20:43, 15 February 2023 (UTC)
 * The speed that is relevant is not a property of the moving object. It is its speed relative to an observer. Observers are always at rest relative to themselves. If two observers pass each other at a very high constant speed in identical vehicles with visible clocks, each will observe the other's vehicle as being shorter and its clock as moving more slowly than their own. --Lambiam 21:25, 15 February 2023 (UTC)
 * "if it weren't moving at all" Even weirder. But that's much easier to understand, at least.  apparently the same in all frames of reference So if a spaceship going 1% of the speed of light emits beams of light directly ahead of itself and directly behind itself, the spaceship will see the beams going the same speed as each other, rather than one appearing to go 99% the actual speed of light and the other 101% the actual speed?  Nyttend (talk) 22:34, 15 February 2023 (UTC)
 * In theory, according to relativity, yes, the light is said to always travel at the same speed c in every inertial reference frame and there is an enormous amount of literature regarding SR covered in the relevant articles and SR's relativistic Doppler effect holds for all inertial reference frames as well. But clocks can and do interact at different rates. For example, the atomic clocks flown westward in the Hafele–Keating experiment gained time relative to the "stationary" terrestrial clocks such that the planes' and terrestrial's clocks interacted at very different rates. Of course, the westward flown clocks that ticked faster traveled slower than the Earth's rotation relative to the Milky Way. This interesting fact even holds, as it should, if the curvature k of their trajectory tends to zero. Modocc (talk) 23:19, 15 February 2023 (UTC)
 * Thank you; this really helps. I knew that one can never reach the speed of light, but I figured it was an effect of go-faster-mass-increases (you'd end up with infinite mess, so you'd need infinite energy) and had no idea that light always goes away from you at the same speed, no matter how fast you're going.  Nyttend (talk) 00:46, 16 February 2023 (UTC)
 * The 99% and 101% numbers you give seem to suppose that velocities combine via simple addition. You may be interested to learn that according to Special Relativity, this is not the case. If you are traveling at speed x relative to an observer, and you throw a ball forward at speed y relative to yourself, the observer does not see the ball traveling at speed $$x+y$$, but rather at $$\frac{x+y}{g}$$, where $$g = 1+\frac{xy}{c^2}$$. When velocities x and y are small compared to c as they usually are in everyday life, $$g$$ is close to 1, and the difference between $$x+y$$ and $$\frac{x+y}{g}$$ is small, so the naive velocity addition formula ($$x+y$$) seems to work, although it's wrong.This formula predicts that the combination of c with any velocity x will be simply c, since $$\frac{x+c}{g} = \frac{x+c}{1+\frac{xc}{c^2}} = \frac{x+c}{1+\frac{x}{c}} = \frac{x+c}{\frac{x+c}{c}} = c$$, so light travels at c relative to any observer. CodeTalker (talk) 06:30, 16 February 2023 (UTC)
 * The OP, Nyttend, understood. He said "...the spaceship will see the beams going the same speed as each other, rather than..." their example of a Galilean invariance and thanked me for clarifying that is precisely what SR claims.  Modocc (talk) 11:41, 16 February 2023 (UTC)
 * I however don't understand how a spaceship can be expected to "see" a difference in one-way velocities of light beams that it emits in different directions. Can a traveller on the spaceship devise a way to test that? It's no use asking Messrs. Michelson and Morley whose oft repeated and refined experiment hasn't found a difference since 1887. Philvoids (talk) 19:03, 16 February 2023 (UTC)
 * Michelson and Morley are dead, so we can't ask them, but when they built their interferometer on spaceship Earth, they expected to see a difference. --Lambiam 11:46, 17 February 2023 (UTC)


 * So, Philvoids tangent at the bottom is actually rather important point; enough to bear dealing with in some detail. His sentence "I however don't understand how a spaceship can be expected to "see" a difference in one-way velocities of light beams that it emits in different directions", this brings up the excellent point that there is no way to measure the One-way speed of light, which is to say, the speed of light moving away from the observer OR the speed of light moving towards the observer.  One can only measure the "round-trip speed of light".  Lets say you are on a spaceship traveling from Earth to Mars, and are oriented such that Earth is directly behind you and Mars is directly in front of you.  If you shine a light out of the back of the ship and shine a light out of the front of the ship, the only way to measure the speed of those light beams is to wait for them to bounce off of a target, and return to the ship.  If light was moving faster going backwards, and slower going forwards, you'd never know, because on the return trip, the beam is moving in the opposite direction, so that difference in speed perfectly cancels every single time, no matter how you do the experiment.  Veritasium, a few months back, did an excellent video on the problem..  If there was some fundamental property of the universe that gave light a greater velocity in some absolute direction, and a lower velocity in opposite direction, like some kind of "ethereal wind" that only affected the speed of light, you'd never be able to know, because any trip that light takes to get back to the observer so its speed can be measured would always have vectors that exactly cancel in a way to make any such putative effect obscured.  It's a real problem that we always gloss over; the Occam's razor explanation is that there is no such difference, however, Occam's razor is not a scientific proof, just a "rule of thumb", and science depends on more than such things.  -- Jayron 32 19:22, 16 February 2023 (UTC)
 * Philvoids tangent is fair enough. Indeed, all observers can take selfies, which wouldn't be any different than current measurements of c. -Modocc (talk) 21:35, 16 February 2023 (UTC)
 * You have to have rather strange laws about how clocks change when moved slowly in one direction compared to another. There's no need to go on about one way measurement of the speed of light here, it's supposed to be about trying to answer the OP, and if Einstein was happy with his way of doing it then it is good enough for the OP. NadVolum (talk) 21:58, 16 February 2023 (UTC)
 * The laws aren't all that strange. Lorentz transformations have been well known, understood, and confirmed by measurement for more than a century.  Also, Einstein was well aware of the problems with the one-way speed of light.  Einstein synchronisation was an arbitrary convention he established, he was well aware it could never be proven to be true, merely acceptable.  -- Jayron 32 23:06, 16 February 2023 (UTC)
 * The laws do change considerably, for instance you have to consider time dilation even when moving slowly. Einstein was just being sensible doing what he did. It is worthwhile trying to see if there might be holes in a theory - but something that's more complicated and does nothing for insight is no good here. This is all just irrelevant to the OP's question. NadVolum (talk) 14:19, 17 February 2023 (UTC)
 * I know that the speed of light was measured centuries ago, but I don't understand how it was done, let alone how it's done with current equipment or could be done with equipment that's invented by the time that 0.01c spaceships would be invented. Interesting to know that you can't measure its one-way speed.  Nyttend (talk) 00:27, 18 February 2023 (UTC)
 * @Jayron32
 * "If you shine a light out of the back of the ship and shine a light out of the front of the ship, the only way to measure the speed of those light beams is to wait for them to bounce off of a target, and return to the ship."
 * You could of course measure the light from inside the spacecraft if you wanted.
 * "If light was moving faster going backwards, and slower going forwards, you'd never know."
 * Light travels at the same speed in both directions. It's the frequency of the light that changes. Earl of Arundel (talk) 02:08, 19 February 2023 (UTC)
 * For whom does the frequency change? Doppler effect does not happen for an observer inside the spacecraft who is moving with the light source. Philvoids (talk) 21:01, 19 February 2023 (UTC)
 * Assuming the spacecraft is moving in the opposite direction as the "stationary" observer, both will detect a red-shift from any light originating from the other. Heading toward the stationary observer, the gets blue-shifted. And of course there are more complication situations, as described in the article describing relativistic Doppler effects. Earl of Arundel (talk) 19:35, 21 February 2023 (UTC)
 * 1) How do you measure the speed of light inside the spacecraft? Like, give me a procedure.  2) How do you know light goes the same speed in both directions?  Can you point to an experiment which has verified that?  -- Jayron 32 13:28, 20 February 2023 (UTC)
 * I think that the nearest we have is the Wu experiment. Many scientists would invoke symmetry (physics) and not seek experimental verification. Mike Turnbull (talk) 13:49, 20 February 2023 (UTC)
 * The Wu experiment was not a measure of the speed of light. Yes, everyone is well aware that you can just invoke a principle.  I mentioned Occam's razor above, however, no experiment has ever been done which established the one-way speed of light.  -- Jayron 32 13:55, 20 February 2023 (UTC)
 * It almost sounds as if you feel that the one-way speed of light somehow needs to be "proven". I don't think there is any serious consensus for that kind of doubt. AFAICT, measuring the one-way speed is just a synchronization problem. At any rate, the two-way speed can be done with any beam of light, regardless of origin. All electromagnetic waves move at the same speed. Earl of Arundel (talk) 19:43, 21 February 2023 (UTC)
 * Take a look at the diagram at Michelson–Morley experiment. The effects of an "aether wind" would not exactly cancel out in a round trip.  If there was a "wind" the light would spend longer going into it (at c - v) then going with it (at c + v).  If the light was traveling perpendicular to the "wind" a round trip would be two sides of a triangle and light would travel farther than if there was no wind.  The two effects are not the same.  If the there was an aether that we are moving through, a difference in the two directions would be measured.  The Michelson–Morley experiment found no difference. Alien878 (talk) 09:47, 21 February 2023 (UTC)
 * How would a difference in the two directions be measured? -- Jayron 32 13:40, 21 February 2023 (UTC)
 * Measurement 1: Back and forth East/West. Measurement 2: Back and forth North/South. If there was an “aether wind”, they should be different.  See the diagram I linked above.  The Michelson–Morley experiment is really quite brilliant. Alien878 (talk) 19:36, 21 February 2023 (UTC)
 * "If the speed of light were different in different directions, not necessarily. You're still measuring the round-trip speed of light.  Any effect that would privilege one direction over the other would cancel out on the return trip in any measurement.  I'm quite aware of the Michelson-Morley experiment.  It still does not measure light speed in one direction.  No one has yet proposed an experiment that can.  I don't mean like, in this thread, I mean like in history.  Experiments that attempt to directly probe the one-way speed of light independent of synchronization have been proposed, but none have succeeded in doing so. -- Jayron 32</b> 19:46, 21 February 2023 (UTC)
 * Your right that no experiment has directly measured the one directional speed of light and ruled out a preferred direction. The Michelson-Morley experiment ruled out an aether wind with a preferred frame of reference, which is what the OP seems to be asking about.  The “object’s speed” doesn’t change the measured value of c. Alien878 (talk) 20:45, 21 February 2023 (UTC)
 * "If the speed of light were different in different directions, not necessarily. You're still measuring the round-trip speed of light.  Any effect that would privilege one direction over the other would cancel out on the return trip in any measurement.  I'm quite aware of the Michelson-Morley experiment.  It still does not measure light speed in one direction.  No one has yet proposed an experiment that can.  I don't mean like, in this thread, I mean like in history.  Experiments that attempt to directly probe the one-way speed of light independent of synchronization have been proposed, but none have succeeded in doing so. -- Jayron <b style="color:#090">32</b> 19:46, 21 February 2023 (UTC)
 * Your right that no experiment has directly measured the one directional speed of light and ruled out a preferred direction. The Michelson-Morley experiment ruled out an aether wind with a preferred frame of reference, which is what the OP seems to be asking about.  The “object’s speed” doesn’t change the measured value of c. Alien878 (talk) 20:45, 21 February 2023 (UTC)