October 25, 2021: A Blue Day in Sauk Centre

Looking across Ash Street South in Sauk Centre, Minnesota. Our front yard is green again, after the summer's drought. (October 25, 2021)

Autumn color in Sauk Centre, Minnesota. This isn't our best 'fall colors' year, but I've been enjoying what we do have. (October 25, 2021)

October’s weather isn’t necessarily “bright blue,” here in the Upper Midwest.

But today was a bright blue day. So I spent a little time this afternoon, sitting on the front stoop, enjoying sunshine and what autumn colors we have this year.

And remembering this poem:

October’s Bright Blue Weather
“O suns and skies and clouds of June,
And flowers of June together,
Ye cannot rival for one hour
October’s bright blue weather;
“When loud the bumblebee makes haste,
Belated, thriftless vagrant,
And goldenrod is dying fast,
And lanes with grapes are fragrant….”
(Helen Hunt Jackson (published 1893) via AllPoetry.com)

Looking west across Ash Street South, Sauk Centre; in mid-June. (June 14, 2021)This summer’s drought was a bad one. An ‘up’ side to the nearly-rainless weather is that I didn’t see a mosquito until August.

I’ve talked about that — the drought, not the mosquito — and other stuff:

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HD 63935: Two Sub-Neptunes and Maybe More

Designations like HD 63935 b and c don’t exactly roll of the tongue.

Although with a little work I might pronounce them “trippingly on the tongue,” as Hamlet put it.

Maybe saying “sixty five ninety three five bee and cee” would do the trick. Then again, maybe not. I thought, briefly, of calling HD 63935, HD 63935 b and HD 63935 c “Sam, Fred and Chuck;” but thought better of it.

At any rate, I’d been catching up on ‘exoplanet’ notes from the last year or so when I read about the HD 63935 planetary system.

HD 63935’s known planets there, sub-Neptunes, should help scientists learn more about how planets form. Or, rather, observing them and analyzing those observations should.

Defining and Detecting Planets

We’ve known about five planets since long before we started keeping written records.

Six, maybe, if you count Uranus.

Seven, including Earth, but we didn’t start thinking of our world as a “planet” until recently. Then there’s Earth’s moon and the sun, and that’s another topic. Topics.

How we define “planet” has shifted, most recently in 2006, when the International Astronomical Union issued a definition that’s still debatable. And debated.

Today’s telescopes let us see the Solar System’s planets, and about two dozen exoplanets: planets orbiting other stars.

The vast majority of exoplanets, however, aren’t directly visible. Not yet.

We know they’re there because they affect the stars they orbit.

Some are massive enough to move their stars toward and away from us as they orbit, or move the star back and forth across the sky.

Others pass between us and their star during each orbit. I’ll be talking about two of these transiting exoplanets.1

HD 63935’s Twin Sub-Neptunes

Scarsdale et al's Figure 4: transits of HD 63935 b and c. (2021)
(From Scarsdale et al., via Phys.org, used w/o permission,)
(“Phase-folded transits of HD 63935 b and c.”

Astronomers discover twin sub-Neptune exoplanets orbiting nearby star
Tomasz Nowakowski , Phys.org (October 20, 2021)

“By analyzing the data from the TESS-Keck Survey (TKS), an international team of astronomers reports the detection of two almost identically sized sub-Neptune exoplanets orbiting a nearby star. The newly found alien worlds, designated HD 63935 b and HD 63935 c, are about three times larger than the Earth. The finding is detailed in a paper published October 13 on the arXiv pre-print server.

“NASA’s Transiting Exoplanet Survey Satellite (TESS) is conducting a survey of about 200,000 of the brightest stars near the sun with the aim of searching for transiting exoplanets. So far, it has identified over 4,500 candidate exoplanets (TESS Objects of Interest, or TOI), of which 161 have been confirmed so far….”

HD 63935 is about 159 light-years out, in the general direction of Procyon. It’s a tad cooler than our star: 5,534 °K or maybe 5,560 °K, compared to Sol’s 5,772 °K.

The lower number for HD 63935 is from The Extrasolar Planet Encyclopaedia’s page, the arXiv paper’s number is 5,560 °K.

“K” temperatures are degrees Kelvin. The Kelvin temperature scale starts at absolute zero. Comfortable room temperature is 294 °K, eggs fry at 343 °K or thereabouts, and a nicely-burning hearth fire may be around 534 °K.

Getting back to HD 63935, that star is slightly cooler than ours, not quite a tenth as massive and chemically similar. It’s not a ‘Solar twin,’ but it’s close.2

Designations: A Digression

The Winter Triangle: Procyon, Betelgeuse and Sirius. From Akira Fujii; via Hubble Space Telescope, ESA, NASA; used w/o permission.As far as I know, neither HD 63935, HD 63935 b nor HD 63935 c have names yet.

But they’ve got other designations.

I talked about star names and designations last month.3

Basically, now that astronomers are studying far more than the 10,000 or so stars we can see without telescopes, catalog numbers and other designations are more convenient than names.

The planet HD 63935 b, for example, is also TOI 509.01; and the star is TIC 453211454.

The “HD” in their designations stands for Henry Draper Catalogue, which lists spectroscopic classifications for about a quarter-million stars.

HD 63935 is also known as HIP 38374 and TIC 453211454. “HIP” stands for the Hipparcos catalog: data from ESA’s Hipparcos observatory, first published in 1997.

The ESA project’s named after Hipparcus. He was an astronomer, geographer, and mathematician who lived when Mithridates I was putting Parthia on the map. We lost his star catalog sometime during the two millennia that’s elapsed since then.

Finally, TIC stands for Third International Conference, Titanium Carbide, Thermal Imaging Camera and Thames Innovation Centre.

But in this context TIC means TESS Input Catalog.4

Twin Sub-Neptunes: Unlike Anything in the Solar System

Goddard Space Flight Center's illustration of transmission/absorption spectroscopy.
(From NASA’s Goddard Space Flight Center, used w/o permission.)

The diameters of HD 63935 b and c are about 2.99 and 2.9 times Earth’s. That’s big, but not as big as Neptune’s 3.883 Earth-diameters.

On the other hand, HD 63935 b has only around 10.8 times Earth’s mass, which makes its density 2.2 g/cm3. Give or take.

HD 63935 c is smaller but heavier, with around 11.1 Earth masses. Its density is about 2.5 g/cm3.

Neither is nearly as dense as Earth — 5.514 g/cm3 — but they’re more tightly packed than Neptune’s 1.64 g/cm3.

And they’re much warmer than either Earth (287 °K) or Neptune (72 °K where air pressure is like Earth at sea level).

HD 63935 b’s calculated ‘surface’ temperature is between 884 and 938 °K. HD 63935 b’s is a bit cooler, 663 to 705 °K. By comparison, the Solar System’s Mercury surface temperatures max out at around 700 °K at the equator.

That’s because their sun is nearly as bright as ours, and both their orbits are smaller than Mercury’s. HD 63935 b orbits the star every 9.06 days, while a year for HD 63935 c 21.4 days long. Earth’s 24-hour days, that is.5

Exploring the “Radius Cliff”

Fulton and Petigura's exoplanet radius distribution (2018), illustrated by Edwin S. Kite et al. to show 'radius cliff' at ca. 3 Earth-radii. (2019)Since they’re smaller than the Solar System’s Neptune, the recent paper calls HD 63935 b and c “sub-Neptunes.”

Although the label’s accurate by current standards, neither is particularly like Neptune. Or Earth.

The Solar System’s Uranus and Neptune are almost, but not quite, twin planets: almost exactly four times Earth’s diameter and 3.883 Earth-diameters, respectively.

Oddly enough, we’ve been finding a whole lot of planets less than three Earth-diameters, but not nearly as many in the Neptune-Jupiter range. Not with short-period orbits, at any rate.

Scientists have been calling this discontinuity the “radius cliff.”

One of the best, or least-improbable, explanations is that larger planets have a sort of plateau in their growth curves. If this is the case, then when a planet’s core and atmosphere reaches about three Earth-diameters, pressure at the surface of its magma ocean lets the magma start absorbing hydrogen.

The planet keeps on gathering gas, but won’t get bigger until the magma’s saturated.6

Or maybe there’s another explanation. If so, I figure we’ll discover it as we collect more data: and review what we’ve already learned.

“Space Oddities…” — or — Studying Starlight

NASA/STScI's illustration, showing how absorption spectroscopy works. (1998)
(From NASA/STScI, via Wikimedia Commons, used w/o permission,)

Light from HD 63935 travels some 159 light-years before reaching us, which is almost next door or unimaginably distant, depending on what distance scale is in play.

And that’s yet another topic.

The point is that HD 63935 isn’t a particularly dim star and it’s close enough to for spectroscopic analysis. “Spectroscopic analysis” is a five-dollar phrase that means taking a look at the colors in starlight.

And, since the two sub-Neptunes orbiting HD 63935 pass between their sun and our planetary system, scientists can measure what happens to light passing through their atmospheres. Assuming that they have atmospheres, which seems like a safe bet.

Three of the scientists who published the paper discussed in that Phys.org article made a case for follow-up observations back in January.7

  • “HD 63935’s Space Oddities: Two Atmospheric Targets in Sparse Regions of Mass-Radius Space”
    Nicholas Scarsdale, Joseph M. Akana Murphy, Natalie M. Batalha; American Astronomical Society meeting #237 (January 2021)

“Space oddities” is hardly an original phrase, and far from the erudite appellations bestowed upon many of yesteryear’s documents of natural philosophy.

On the whole, I’ve enjoyed watching scientists unstarching their collars in recent decades, and that’s yet again another topic.

Worth a Closer Look

Nicholas Scarsdale et al.'s chart of radial velocity points for HD 63935. (2021)With two sub-Neptunes, HD 63935 is already a two-for-one research opportunity.

But there’s a good chance there’s at least one more planet in that system.

After Scarsdale et al. sorted out radial velocity measurements attributable to HD 63935 b and c, the remainder looked a lot like a wobble made by a third planet.

Or maybe it’s the star’s surface bouncing, but these scientists figure that’s not likely.

The radial velocity remainders probably aren’t linked to the star’s rotation period, 30 to 35 days, either.

On the other hand, Scarsdale et al. didn’t find reasonably certain evidence of a third planet. Which, if it’s there, doesn’t produce effects that would affect the data they did analyze.8

Bottom line? HD 63935 b and c are high-value targets for scientists, and their planetary system may include more worlds for us to study.

Perspectives and Paying Attention

NGC 4848 and other galaxies, image by Hubble/ESA.

“Indeed, before you the whole universe is as a grain from a balance, or a drop of morning dew come down upon the earth.”
(Wisdom 11:22)

We’ve learned a bit about this universe during the two millennia that have passed since those thoughts were recorded.

But as I see it, they’re still true. From God’s viewpoint, a drop of morning dew and our world of planets, stars and galaxies are — all pretty much the same size.

Which, I suppose, could be a scary thought.

Or a reassuring one, since:

“Our God is in heaven
and does whatever he wills.”
(Psalms 115:3)

So, again as I see it, God is large and in charge. And if we pay attention to this wonder-filled creation, we can learn a little more about the Almighty.

“For from the greatness and the beauty of created things their original author, by analogy, is seen.”
(Wisdom 13:5)

And that, I think, is a good idea:

1 Planets past and present:

2 Units of measure and stars:

  • Wikipedia
  • TKS V. Twin sub-Neptunes Transiting the Nearby G Star HD 63935
    Nicholas Scarsdale, Joseph M. Akana Murphy, Natalie M. Batalha, Ian J. M. Crossfield, Courtney D. Dressing, Benjamin Fulton, Andrew W. Howard, Dnaiel Huber, Howard Isaacson, Stephen R. Kane, Erik A. Petigura, Paul Robertson, Arpita Roy, Lauren M. Weiss, Corey Beard, Aida Behmard, Ashley Chontos, Jessie L. Christiansen, David R. Ciardi, Zachary R. Claytor, Karen A. Collins, Kevin I. Collins, Fei Dai, Paul A. Dalba, Diana Dragomir, Tara Fetherolf, Akihiko Fukui, Steven Giacalone, Erica J. Gonzales, Michelle L. Hill, Lea A. Hirsch, Eric L. N. Jensen, Molly R. Kosiarek, Jerome P. de Leon, Jack Lubin, Michael B. Lund, Rafael Luque, Andrew W. Mayo, Teo Močnik, Mayuko Mori, Norio Narita, Grzegorz Nowak, Enric Pallé, Markus Rabus, Lee J. Rosenthal, Ryan A. Rubenzahl, Joshua E. Schlieder, Avi Shporer, Keivan G. Stassun, Joe Twicken, Gavin Wang, Daniel A. Yahalomi, Jon Jenkins, David W. Latham, George R. Ricker, S. Seager, Roland Vanderspek, Joshua N. Winn; The Astronomical Journal (Submitted October 13, 2021) via arXiv
  • The Extrasolar Planet Encyclopedia
  • Fireplace Safety
    Adapted from Shawn Shouse, Iowa State University Extension Field Specialist/AG Engineering; Backyards & Beyond; The University of Arizona

3 Some stars have names, many don’t:

4 Names, catalogs and descriptions:

5 Introducing the HD 63935 planetary system; and, for comparison, Mercury:

6 Background: planets and magma oceans:

7 Starlight and science:

8 Looking ahead:

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New on My Blogroll+: mr o shays (Still Learning)

I’ve added “mr o shays (Still Learning)” to my link list page: Blogroll+ > Bloggers and other writers.

And, while I was at it, reviewed and updated the page’s other links.

Now I really should start writing. Or maybe get a cup of coffee.

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A Trilobite With a Hyper-Compound Eye

It’s barely over two weeks since scientists at the University of Cologne published what they’d learned about a trilobite’s unique eye.

Their research vindicated an amateur paleontologist’s observations, and very likely will raise more questions than it answers.

That’s par for the course.

Answering a few questions and raising many more, I mean.

So is discovering something new. New to us, that is. This trilobite’s ‘hyper-compound’ eye last saw the light of day — or dark of the ocean floor — 390,000,000 years ago.

I had fun writing this, and hope you enjoy reading it. Who knew trilobite eyes could be so entrancing?

Welcome to the Devonian Period

Map of Earth in the Early Devonian, 390,000,000 years ago, from Christopher R. Scotese's PALEOMAP Project at scotese.com
(From Christopher R. Scotese, used w/o permission.)
(Earth, 390,000,000 years ago: early or middle Devonian, depending on who’s talking)

Dragons flight's 500 million years of climate change, via Wikimedia Commons, used w/o permission. (2004)Most of Earth’s land was in the southern hemisphere 390,000,000 years ago.

The climate was nice, if you like it warm.

We’re pretty sure that water near tropical beaches was around 86 °F, 30 °C, and didn’t get much cooler near the poles.

Wattieza forests were home to insects that flew and tetrapods that did well to galumph from one bit of water to the next.

Wattieza weren’t ferns, exactly, but they were much like today’s ferns and horsetails.

Don’t bother trying to remember all those names. There won’t, as I’ve said before, be a test on this.

We started calling this era the Devonian about two centuries back, after Roderick Murchison, Adam Sedgwick, Henry De la Beche and George Bellas Greenough didn’t agree about how old a bunch of rocks were.

What matters, sort of, is that Murchison and Sedgwick’s name for a particular slice of Earth’s history has been used ever since: Devonian. They named the era after Devon, British real estate between Cornwall and Somerset.1 Again, don’t bother with those names.

And never mind the plants that aren’t ferns and galumphing tetrapods.

This week I’ll be mostly talking trilobites. Mostly.

Good Times for Trilobites

Major trilobite clades summarized. Figure 6, 'The Evolution of Trilobite Body Patterning,' Nigel C. Hughes, Annual Review of Earth and Planetary Sciences (2007)
(From Nigel C. Hughes, used w/o permission.)
(Trilobite diversity: the trilobite family tree, from the Cambrian to the Permian.)

The Ordovican, Silurian and Devonian eras were good times for trilobites. Judging from how diverse the critters were, at any rate.

Agnostida, Asaphida and Ptychopariida trilobites had gone the way of Nineveh and Tyr by the early(ish) Devonian, 390,000,000 years ago. Although those two cities wouldn’t exist until after the most recent glacial melt, and I’m drifting off-topic.

Agnostida may or may not nave been trilobites. There’s ongoing discussion of that, partly because they look funny.

That’s how I see it, at any rate. They look like they’ve got two front ends. Most agnostid species didn’t have eyes.

Which reminds me. Trilobite eyes, in species with eyes, had calcite lenses.2

I’m not sure whether the main question is why trilobite eyes had calcite lenses, or why only Ophiomastix wendtii have calcite lenses today. O. w. is a sort of brittle star.

The Trilobite With a Hyper-Eye

Phacops geesops. The trilobite's eyes have 200 single 'outside' lenses each. Behind each 'outside' lens is a six-facet compound eye.
(From University of Cologne, used w/o permission.)
(Phacops geesops: Devonian trilobite with unique eyes.)

Primordial ‘hyper-eye’ discovered
PD Dr. Brigitte Schoenemann, Press release, University of Cologne (September 30, 2021)

“Trilobites of the suborder Phacopina had a unique eye in which about 200 large lenses in each eye spanned at least six individual facets, each of which in turn formed its own small compound eye / 40-year-old X-ray photographs by amateur paleontologist Wilhelm Stürmer show fossilized eye nerves.

“An international research team has found an eye system in trilobites of the suborder Phacopina from the Devonian (390 million years B.P.) that is unique in the animal kingdom: each of the about 200 lenses of a hyper-facet eye spans a group of six normal compound-eye-facets, forming a compound eye itself. In addition to the hyper-facetted eyes, the researchers, led by zoologist Dr. Brigitte Schoenemann at the University of Cologne’s Institute for Didactics of Biology, identified a structure that they believe to be a local neural network which directly processed the information from this special eye, and an optic nerve that carried information from the eye to the brain. The article, ‘A 390 million-year-old hyper-compound eye in Devonian phacopid trilobites,’ has been published in Scientific Reports….”

This trilobite’s eyes are “hyper” because a compound eye lay behind each outer lens. The inner compound eyes had at least six facets, in one or two rings. These eyes were exactly like nothing else we’ve discovered.

I think Wilhelm Stürmer’s trilobite was a Geesops sparsinodosus, but haven’t confirmed it. That’s one of five species in the Geesops genus.

Like all trilobites, the critters in the Geesops genus had clacite lenses in their eyes. The ones that had eyes, at any rate.3

Look at That!

From 'A 390 million-year-old hyper-compound eye in Devonian phacopid trilobites,' B. Schoenemann et al., figure 4. Structure of the visual unit of phacopid trilobites. Scientific Reports (September 30, 2021)
(From Schoenemann et al., via Scientific Reports, used w/o permission.)
(Trilobite eyes.)

You’re looking at:

  • (o) Schematic drawing of Ampelisca’s eye
  • (p) Schematic drawing of Geesops schlotheimi’s eye.

There’s more at “A 390 million-year-old hyper-compound eye in Devonian phacopid trilobites,” Science Reports. (September 30, 2021)

More than you may need, or want, to know.

Now, back to Wilhelm Stürmer and X-rays.

X-Rays and an Amateur Paleontologist

From 'A 390 million-year-old hyper-compound eye in Devonian phacopid trilobites,' B. Schoenemann et al., figure 3. Structure of the hyper-compound eye of phacopid trilobites. Scientific Reports (September 30, 2021)
(From Schoenemann et al., via Scientific Reports, used w/o permission.)
(More trilobite eyes.)

Stürmer’s day job was running the Siemens X-ray department. Off the clock, he was a paleontologist; doing field work and making x-rays of fossils.

“…To facilitate his palaeontological research, he bought a minibus, installed an X-ray machine within it, and between 1960 and 1986, travelled from quarry to quarry in the Hunsrück, part of the Central German uplands, and visited numerous collectors to investigate the faunas of dark-coloured slates, originally intended to be roofing tiles…”
(“A 390 million-year-old hyper-compound eye in Devonian phacopid trilobites,” B. Schoenemann et al., Scientific Reports (September 30, 2021))

At any rate, Stürmer had spotted and marked fossilized soft tissue in and near trilobite eyes. He said the filaments were probably optic nerves. Or maybe light guides, optical fibers.

But this was the 1970s.

Many professional paleontologists assumed that soft tissue doesn’t fossilize. Just teeth and bones and hard stuff like that. And that animals don’t have optical fibers.

At the time, given the data they had, those were reasonable assumptions.

And, as it turns out, they were wrong.

Then, in the 1980s, scientists found deep-sea crab eyes with optical fibers. Recently, by my standards, scientists have been finding fossilized soft tissues. Sometimes with traces of the original organic matter.

Fossilized soft tissue is very rare, but it does exist.

Anyway, one of Stürmer’s heirs gave zoologist Dr. Brigitte Schoenemann his marked-up x-rays. She found that he’d marked structures that almost certainly include optic nerves.4

A Little History: Geissler Tubes, Lenard Windows and the Royal Society

From 'A 390 million-year-old hyper-compound eye in Devonian phacopid trilobites,' B. Schoenemann et al., figure 3. Structure of the hyper-compound eye of phacopid trilobites; detail highlighting Stürmer's red arrow. Scientific Reports (September 30, 2021)X-rays aren’t new.

No, that’s not quite what I meant.

X-rays have been part of this universe from the start.

An X-ray is electromagnetic radiation with a wavelengths that’s shorter than ultraviolet and longer than a gamma ray. We’ve known about X-rays since about 1895.

That’s when Wilhelm Conrad Röntgen noticed, measured and defined that particular sort of radiation. He had been experimenting with cathode rays from a tube designed by Philipp Lenard.

Lenard had been studying cathode rays, high-speed electrons from a the cathode in a vacuum tube, since 1888.

Scientists had been experimenting with cathode rays since 1857, when Heinrich Geissler invented the Geissler tube.

Assorted researchers tweaked the Geissler tube design between 1869 and 1875. We call one version the Crookes tube, maybe because William Crookes invented it. He’s English.

At any rate, Philipp Lenard invented Lenard Windows, thin metal surfaces that kept air out of cathode ray tubes but let radiation out. That let scientists measure cathode rays outside the not-quite-vacuum tubes.

Lenard also denounced Einstein’s work as “Jewish physics.” I’ll get back to that, briefly.

Röntgen analyzed, defined — and so “discovered” — X-rays in 1895 or thereabouts.

But Geissler and company had noticed them the 1850s.

Then again, William Morgan and Joseph Priestley arguably did the same in the 1780s. The Royal Society got a paper describing Morgan’s research in 1785.5

Now, about Lenard, Einstein and attitudes.

Seeking Truth and Other Options

From NASA/ESA: Galaxy UGC 9391.As I said before, Philipp Lenard denounced Einstein’s work as “Jewish physics.”

Back in 1905, when Lenard got his Nobel Prize and Einstein published his theory of special relativity, physicists had legitimate reasons for testing Einstein’s new ideas.

Testing, not denouncing.

By the 1930s, when Lenard published his “Deutsche Physik,” physicists had decided that general relativity made sense. Although it wasn’t until around the 1960s that they saw it as more than a sort of footnote to Newtonian physics.

Meanwhile, Lenard had asserted that relativity was a “Jewish fraud” and became Chief of Aryan Physics. I am not making that up.

I’m a Christian. And I’ve been talking about scientific stuff.

So, how come I’m not supporting “creation science”6 and condemning paleontology as a Satanic snare?

Basically, it’s because I’m a Catholic and think truth is important.

Even if I hadn’t decided to become a Catholic, I’d value truth. If I had my head on straight, that is. (Catechism of the Catholic Church, 2467)

And because I’m a Catholic, I must respect folks who have other faiths; recognizing that, like pretty much everyone else, they’re seeking truth. (Catechism, 839-843)

Then there’s the whole ‘faith and reason, science and religion, don’t mix’ viewpoint.

Again, I’m a Catholic: so I must recognize that although faith isn’t reason, faith and reason get a long fine, or should. And that seeking truth is a good idea. (Catechism, 31-35, 159; “Fides et Ratio;” “Gaudium et Spes,” 36)

Another point, also an important one. Being a Catholic means I must think that being anti-Semitic is a bad idea. Or being anti-anyone, for that matter.

On the other hand, it also means I must be against actions and beliefs that aren’t right. Like genocide, and that’s another topic. (Catechism, 2313)

Next Step: Educated Guesses

Dwergenpaartje's photo of trilobite Phacops rana's schizochroal eye. (October 2011) via Wikimedia Commons, used w/o permission.Figuring out why Phacopina trilobites had ‘hyper-eyes’ would be easier if we could study living Phacopina trilobites.

The last of those critters died about 360,000,000 years ago, give or take a bit; and the last trilobite of any sort that we know of died some 352,000,000 years back.

So studying hyper-eyed trilobites in their natural habitat isn’t an option. Or in laboratories, for that matter.

But scientists can make educated guesses about why they had such complex eyes.

“…The trilobite’s ‘hyper-eye’ may have been an evolutionary adaptation to life in low light conditions, Schoenemann believes. With its highly complex visual apparatus, it may have have been much more sensitive to light than a normal trilobite eye. ‘It is also possible that the individual components of the eye performed different functions, enabling, for example, contrast enhancement or the perception of different colours,’ the biologist said. So far, such an eye has only been found in the trilobite suborder Phacopinae: ‘This is unique in the animal kingdom,’ she concluded. In the course of evolution, this eye system was not continued, since the trilobites of the suborder Phacopinae died out at the end of the Devonian period 360 million years ago.”
(“Primordial ‘hyper-eye’ discovered,” PD Dr. Brigitte Schoenemann, Press release, University of Cologne (September 30, 2021))

The trick will be figuring out how to test those educated guesses. The good news there is that we’ve been learning a great deal about how vision and visual processing works.7

At least, I see that as good news; and I talked about truth and making sense earlier.

We may even learn why these ‘hyper-eyes’ are unique to that one suborder of trilobites.

Finally, the usual link list of stuff I’ve said before:

1 Plants, animals and names:

2 Trilobites, mostly:

3 More trilobites and crystal eyes:

4 Vindicating Stürmer:

5 A radiographical ramble:

6 Science and attitudes:

7 Miscellany:

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