Answer: Consider the alternative?

 Most animals have a left- and a right-side...  

P/C. OpenAI [create a grid of diverse animal noses including human, dog, cat, gorilla, etc. ]

... nose... that is, we're (mostly) bilaterally symmetric, even to the level of the nasal passages.  I have two kidneys, two eyes, two nostrils, etc.  (Yes, I know--one heart, one stomach, one intestine... those are special cases.  But even your brain comes in two halves.)    

But when I noticed that I seem to switch from my left to my right nostrils, it caused me to wonder a bit about this bilaterality.  If I really DO switch nostrils during the day, what else might I switch from left to right?  Do my kidneys work differently at different times of the day?    

Let's turn this into a SearchResearch Challenge for this week: 

1. Is my nose just weird, or do people really have a slow change in breathing from side-to-side over the course of the day?  

I was really unsure about where to start, so I did the first search I thought of: 

     [ switch nostrils breathing during the day ] 

which led me to an article in Live Science ("Why don't we breathe equally out of both nostrils?")  that told me "..The dominant nostril switches throughout the day. This is called the nasal cycle.." 

That's an interesting phrase, nasal cycle.  Live Science tells us that people tend to breathe out of one side, then switch to the other.  That article points to a paper in PLOS One (a respected journal), "Measuring and Characterizing the Human Nasal Cycle."  That paper in turn tells us that "Nasal airflow is greater in one nostril than in the other because of transient asymmetric nasal passage obstruction by erectile tissue. The extent of obstruction alternates across nostrils with periodicity referred to as the nasal cycle."  

Fascinating.  Who knew that we have small patches of erectile tissue in our noses that alternate the side of breathing.  

A quick search in Google Scholar for [ nasal cycling ] leads to a bunch of papers, including this one in the journal Rhinology ("The nasal cycle: a comprehensive review") In that paper, we read "... It is based on the dilation/constriction of the venous cavernous tissue in the submucosa of the turbinates and septum, but also of the ethmoid sinuses. It is accepted that almost 70-80% of adults experience a regular

nasal cycle, but a true periodicity/reciprocity exists only in 21-39% of the population."  

Even more details--most people have nasal cycling, but a strong nasal cycling seems to be present in around a quarter of all people, although it's a little unclear why this happens.  It's a complicated mechanism--what's the evolutionary advantage?  My friend Rehan Khan sent me an article that he co-authored in Nature (1999).  That paper, "The world smells different to each nostril" suggests that the reason for switching the sides of your nose is that each nostril has a somewhat different set of receptors--so switching gives a better, higher-quality perception of what's going on in the environment. "..we show that this difference in airflow between the nostrils causes each nostril to be optimally sensitized to different odorants, so that each nostril conveys a slightly different olfactory image to the brain."  

In any case, this look like a real effect.  And now we picked up some terminology for the alternation--this should help us with the next Challenge.    

2. What other kinds of behaviors might happen for a while on one side of the body, and then switch to the other side of the body?  (Think outside the body: What about non-humans?  Do they have these odd behaviors?) 

I started with this query: 

     [ alternating cycles in humans  ] 

I didn't know if I'd find anything or if I'd just get some ideas to pursue.  

The results mostly did the latter, and suggested a couple of bilaterally symmetric systems to check--e.g., ovaries, kidneys, brain hemispheres, eyes, ears, etc.  But the results weren't incredibly specific.  So, I had to try each system in turn: 

     [ ovaries alternating cycles ] [ kidney alternating cycles ] etc... 

The first query (about ovaries) led me into a rabbit hole where search led to some results that indicated that humans DO ovulate alternatively on the left one month, and then on the right the next month.  This was apparently believed for quite a while (largely because it seems like common sense, and detecting the side of ovulation takes some pretty high resolution ultrasounds.  But once that visualization technology became available, it wasn't long until a decent sample size was reached, and it was discovered that NO.. in fact women ovulate or more less randomly (wrt left vs. right)!  I found this paper through my searches: "Side of ovulation and cycle characteristics in normally fertile women" published in the journal, Human Reproduction in April, 2000.  

On the other hand, searching for alternating phases of kidneys, testes, eyes, and ears all led nowhere.  I wasn't able to find ANYTHING to suggest that there are interesting alternations of perception or production.  

BUT, when I searched for :

     [ brain hemisphere alternating cycles ] 

I found (way down on page 2) a mention of hemispheres alternating in sleep patterns for marine mammals and certain birds!  

The paper "Unihemispheric sleep and asymmetrical sleep: behavioral, neurophysiological, and functional perspectives"  (in the journal, Nature and Science of Sleep) tells us that "... certain marine mammals and species of birds show a different sleep behavior, in which one cerebral hemisphere sleeps while the other is awake. In dolphins, eared seals, and manatees, unihemispheric sleep allows them to have the benefits of sleep, breathing, thermoregulation, and vigilance. In birds, antipredation vigilance is the main function of unihemispheric sleep.."  

Even more details:  ".... In some aquatic mammals, sleep and wakefulness periods alternate between the hemispheres, and it is the only way of sleeping. In other animals (seals and birds), unihemispheric sleep is a transitory sleep event intermingled with bilateral sleep." 

I checked multiple sources (naturally), and found lots of corroboration--those marine mammals listed DO sleep just one side at a time.  Remarkable.  I hope to see a semi-sleeping dolphin one day while out diving in the sea.  

SearchResearch Lessons 

1. Count on your friends.  Shortly after I wrote my SRS Challenge, Rehan wrote to say that he just happened to have published a paper on this topic.  It's a wonderful paper, well worth the read.  And it both confirmed that smelling alternates sides AND that there's a reason for the effect.  

2. Search for leads, not just answers.  It's often the case that when searching you'll learn something along the way that's useful in your later searching.  That's what happened when I did a search for [ alternating cycles in humans ] and found some suggestions that I was able to follow up and find gold.  Sometimes the path to an answer is another step away... and you need to find the terminological bridge to get there.  

3. Sometimes you just have to check each category.  When I did my search for alternating cycles of ovaries, kidneys, etc., I did so because I couldn't come up with a single search term what would capture the idea of "bilateral pairs of organs in human bodies."  It would have simplified my search if I had, but I couldn't find one.  So... I had to check each by hand, hoping that would work.  And it did!  

Hope you had as much fun as I did in searching for the answers.

Keep searching! 

 

SearchResearch Challenge (4/17/24): Consider the alternative?

"Strange."  I thought... 

P/C. OpenAI [create a grid of diverse animal noses including human, dog, cat, gorilla, etc. ]

... early this morning, I noticed that my left nostril was slightly congested.  Now, a couple of hours later, I noticed that my right nostril is slightly congested.  

Is this just a peculiarity of people who do SearchResearch?  Or is it a real phenomenon?  Is this all just in my head?  

Let's turn this into a SearchResearch Challenge for this week: 

1. Is my nose just weird, or do people really have a slow change in breathing from side-to-side over the course of the day?  

2. What other kinds of behaviors might happen for a while on one side of the body, and then switch to the other side of the body?  (Think outside the body: What about non-humans?  Do they have these odd behaviors?) 

Of course, the real question is how on Earth do you search for something like this?    Any good ideas?  Of course, you'll fact-check what you find... 

Let us know what you find out.. and how you discovered it! 

Keep searching! 

 

Gemini has serious hallucinations (at least when you ask about composers!)

 Asking an LLM for facts isn't great... 

P/C Midjourney. Prompt: Bach, Beethoven, Brahms and Chopin sitting at a
coffee table with a musical score in the background.

Remember our Challenge from March 28...when we looked for names of composers that had associated movements, societies, or foundations?  

The easy example is Richard Wagner.  Immensely famous in his lifetime, his legacy gave rise to the adjective Wagnerian, to describe fans who are enthralled with his work.  Gustav Mahler, for instance, has been called a Wagnerian for the kind of music he composed.  

There are also many Wagner societies and clubs.  There's a Wagner society in Northern California, another in London, etc etc.  

In that Challenge, I was curious how we might use Google search AND the power of LLMs to help answer this question.  

After I wrote up the SRS Answer for that Challenge, I had a sudden brainwave.  Why not make a big spreadsheet of all the composers I could find, and then ask an LLM to tell me, for each of these composers, is there a society, club, or foundation associated with their name?  

After an easy search on Wikipedia, I found a long list (4962 composers!) of musicians and composers.  It was simple to pull that into a spreadsheet.  Here are the first few rows... 

And then, I looked for a Google Sheets extension that would connect me to ChatGPT.  (That's an obvious search, and was straightforward to install the extension. I used GPT for Sheets and Docs.) Just for completeness, I did the same thing to find a sheets extension for Gemini (AI Assist for Gemini).

Then, for both sheets, I wrote a prompt in Column B like this: 

=GPT("does this " & A26 & " have a society or foundation to promote their music? Please give a short answer that includes the name of the society or foundation and give a URL to the website if possible")

 That's a pretty straightforward way to ask ChatGPT a bunch of similar questions.  Here are the top few rows of results: 

Note that the first ChatGPT reply is a bit odd ("Michel van der Aa is not a composer.  He is a Dutch composer..."  -- so which is it?)  

Column B is ChatGPT's reply to the prompt.  

Of the 4962 composers/musicians, ChatGPT responded affirmatively for 1214 of them.  I wrote a little function to extract the URL from each of the responses that had a link to the composers website, and I found that about half of them were actually valid sites--632 of them worked.  That's not great, but it was a lot better than what I could do by hand.  

HOWEVER... 

I did exactly the same thing with Gemini (using the Gemini Sheets extension), but got a VERY different answer.  Here's the top of that spreadsheet.  Notice anything different? 

Gemini's replies

Yeah.  Gemini thinks everyone has a foundation and a website. 

What's strange is that it's like that for most of the rest of the spreadsheet.  Gemini found that 75% of the composers listed in the sheet had a society or foundation to promote their music.  I checked around 150 of them--they're all bogus.  

After spending a bunch of time checking the results, I decided to try and just vet the URLs that Gemini suggested.  

Instead of testing every one of these URLs by hand, I wrote a function to extract them, and then did a simple WHOIS (to check and see if they were actually valid domains).  No surprise, virtually none of them were valid. 

But look at the very first result:  It turns out that Michel van der Aa DOES have a foundation, but it's called DoubleA Foundation, and its URL is https://doublea.net/  The URL that Gemini gives above (Michelvanderaafoundation.org) is not a valid website.  This is purely hallucinated.   

This is true for the next several thousand URLs that Gemini "found" for us.  The URLs look convincing, but they're just plausible looking junk.  

Ugh. 

Results 

It's interesting that ChatGPT missed the DoubleA Foundation of Michel van der Aa, AND it hallucinated about 50% of the positive hits.  Still... I was able to learn some useful things.  

But ChatGPT is very picky about the prompt.  In an earlier version of the spreadsheet I asked with the prompt 

"Is there a musical society for the music of <musician>?"  

In the case of musician Gamal Abdel-Rahim, ChatGPT said "No, there's no such society."  

But when I asked with a slightly different prompt: 

"does <musician> have a society or foundation to promote their music? Please give a short answer that includes the name of the society or foundation and give a URL to the website if possible"

The answer completely flipped to "Yes, Gamal Abdel-Rahim does have a society dedicated to promoting his music..."  

That's no especially handy but it does show how sensitive these things are.  

On the other hand, Gemini hallucinated thousands of results and just made-up thousands of URLs, nearly all of which have invalid domain names.  (And it ALSO missed the DoubleA Foundation!)  

Looking on the bright side, ChatGPT at least found a few hundred valid composer/musician societies AND legit links to websites describing them.  I actually found the GPT results to be useful, if slightly buried.  

But after wading through a few hundred totally bogus results from Gemini, I got discouraged.  So much nonsense made up so fast.  

Recommendation

Don't trust ANY LLM for accurate answers to prompts that involve actual people. You really can't trust the results.  

And in particular, don't count on Gemini until they really improve their game.  If accuracy counts, think of another way to do this.  

Keep searching.  

Answer: Solar eclipses and shadows?

The eclipse of April 8, 2024... 

... was seen by millions.  And if you were lucky enough to see it, you almost certainly know the answers to this week's Challenge.    

The shadows we see every day are round things.  The Challenge was why, and now we have some clues.    

1. Why ARE the dapples of sunlight round in shape?  Why isn't the shape of the sunlight exactly like the shape of the hole in the tree canopy?  Related: Why are only the small patches of light round while the bigger ones are other shapes?  Super related: Will the round sun patches change shape during the eclipse? 

I started with a statement of the Challenge: 

     [ why are dapples of sunlight round ] 

which led me to a blog post about dappled light effects (Gurney Journey) about the effects of dappling light in artwork, which led me to Edward Tufte's article about visualization, which led me to M. G. J. Minnaert's brilliant book Light and Color in the Outdoors.  In there, we find this page: 

The text goes on to say that at a large enough distance, the gaps in the tree foliage act as pinhole cameras, creating images of the disk of the sun on the ground.  THAT's why most of the dapples we see are round--they're little suns projected onto the surface of the earth.  (Keep reading to learn why some of the dapples are other shapes.)  

To pursue the second question about the changes in shapes of the dapples during the eclipse, SRS Regular Reader Ramón searched for this:   

     [tree canopy eclipse light shape]

which led him to this article about the Mystery of the Crescent Shadows, with a nice explanation of why eclipses will produce crescent-shaped shadows.  

Regular Reader remmij contributed this wonderful YT video about why solar eclipses make those crescent (with some nice animation in the middle). https://www.youtube.com/watch?v=wGeKWOD468k 

This change becomes clear when you see photos of the dapples taken during the eclipse: 

25% covered. Pacman-like.

Very near totality

Note that the "pinhole" (or leafy equivalent) has to be far enough away from the surface to have a focusing effect.  If the non-circular "pinhole" is near enough to the focus plane, it will project the shape of the hole, and not have any focusing effect.  Example:  

Triangle aperture in my "pinhole" projection.
Distance from hole to surface, about 4" (10cm)

But when you move the triangular "pinhole" farther away from the surface, the dapple becomes circular. 

 

The projection throw is about 2 meters.

As it turns out, I was in Austin, TX with some friends to see the eclipse.  The weather was cloudy, but everything worked out, more-or-less, with clouds sometimes parting enough for us to see the eclipse happening.  I did't have any fancy photo gear, but I got  a couple of okay shots with my iPhone 17--here's my best from the day.

Totality, with some cloud cover (and Texas telephone wires)

2. What other solar light phenomena should I be looking for?  Are there any other extraordinary shadow and light things I should be looking for?  

My query was: 

     [ other phenomena associated with eclipse ] 

which easily led to a bunch of other effects, some of which I expected (the temperature drops), and several of which I did NOT expect.  One of the ones I didn't expect was the 360-degree sunset, brighter towards the north and south, which are outside the path of totality. Apparently, darkening happens first to the west and as the eclipse progresses, the darkening moves to the east as the Moon's shadow rushes over you.  

Regular Readers provided some additional ideas:  Almaden Mike pointed out that "There are optical phenomena such as Bailey's Beads, the Diamond Ring and shadow bands, which are described here [on Space.com]."

Shadow bands!  What are those?  I haven't heard about them before either.  

RR Mark said that shadow bands are "are kind of a cherry on the top of the whole eclipse dessert experience" explaining that "When the first tiny bit of sunlight appears at the end of the eclipse, all the photons from the sun are aligned. This provides something of a free 'Schlieren Optics' setup, that makes the pressure of the wind visible. So the bands are letting you see the 'wavelength', of the speed of wind in the air. Very cool to see the invisible, made visible."  

Remmij pointed to an article at Shore & Islands, with a nice pic of the shadow bands.  

My quick search for [ shadow bands ] led to this really nice article on Space.com  (Shadow bands are a solar eclipse mystery), including a great video by Destin ("Smarter Every Day") about how to photograph the bands.    (Update: Here's a excited video of shadow bands from the April 8th eclipse. Worth the 1 minute watch time.)  

What a marvelous physical phenomenon!  Moar eclipses, please!   

SearchResearch Lessons

There was SO MUCH written about the eclipse that this wasn't a difficult Challenge.  (It's good to have them every so often as well.)  But I did want to point out: 

1.  Notice the things you don't know about. Good searching involves reading and understanding... and picking up on the things that are new to you.  In this case, there was SO MUCH written about the eclipse, that there was a hyper-abundance of content.  As I scanned the material, every so often I'd notice something that I didn't know about (like, Shadow Bands, or the 360-degree sunset).  

Keep searching!  

SearchResearch Challenge (4/3/24): Solar eclipses and shadows?

 I'm sure you've noticed... 

... that when you're walking through a group of trees, they cast shadows on the ground, dappling the surface with a lovely pattern of light and shadow.  

When I look up into the trees, I can see where the sunlight is coming from, and I'm struck by something: Why are some of the spots of light round when what I see in the trees is not round?  

Here's another view of light through trees: 

See those gaps?  The patches of light projected onto the forest floor are shaped like the openings in the tree canopy... mostly.  

But when the holes are small, the projected light is always circular.  In the image above, you can see that the large patches of light are soft rectangles, irregular blobs, and triangles with fuzzy edges.  When I look up into the tree, I see those rectangles, triangles, and irregular gaps in the tree cover.  

But when the hole is small, it always creates a small circular pool of light.  

Why? 

That's our Challenge for this week.  Since there's a solar eclipse that's passing over the center of North America on Monday, April 8, I thought I should understand why the shadows are like that. 

Path of eclipse on April 8, 2024. P/C NASA.
I will be standing at the tip of the red arrow on April 8. 
Hope there are clear skies!

To prepare for the eclipse and the avalanche of shadows, I have a couple of Challenges: 

1. Why ARE the dapples of sunlight round in shape?  Why isn't the shape of the sunlight exactly like the shape of the hole in the tree canopy?  Related: Why are only the small patches of light round while the bigger ones are other shapes?  Super related: Will the round sun patches change shape during the eclipse? 

2. What other solar light phenomena should I be looking for?  Are there any other extraordinary shadow and light things I should be looking for?  

Of course, all this will happen next Monday--so I hope you post your answers to the blog before then so I'll know what to look for!  Tell us how you found your answers.  

Keep searching!  

(And wear eye protection if you're going to watch the eclipse.)