This is the month of holidays and gatherings, family traditions and new experiences, giving and sharing. No matter how one celebrates the end of the year, it's a time to sit back and reflect on all which came before. We in the Den wish you and yours the best this holiday season has to offer with all the magic in the conclusion of 2025 and a bounty of joy in the new year.

We couldn't produce a year-end newsletter without sharing something related to the season. Rudolph-the-Red-Nosed Reindeer is one of the most enduring symbols of the season - be it the song we hear over and over in elevators, stores, and on holiday radio-stations; the movies he's starred in; or even the antlers our cat wore this time of year. Rudolph - first shunned and then heralded as a hero by guiding St. Nick's sleigh through the stormy weather one holiday eve.

His bright nose may appear as amazing as his ability to fly, but a glowing body-part needs no holiday magic. Given what science has discovered about real animals, Rudolph's glowing nose would not be an unusual occurrence. After all, it's just bioluminescence. Where a simple chemical reaction lights up cells in certain body parts. Rudolph only needs two key ingredients to have a glowing nose - a compound called luciferin and a very specific enzyme called luciferase. Both of these ingredients come in a variety of forms - differing colors are created by mixing the two in varying amounts within the cells. When luciferin and luciferase mix with oxygen in a cell they produce light. Though most bioluminescent animals glow near the blue-end of the spectrum - some (fireflies, railroad battles and dragonfish) can glow red. Similar to Rudolph and his need to guide the sleigh through a foggy dense atmosphere, red-lit animals use their red glow to navigate dark places. 

There is another thing about the specific color of Rudolph's nose - red has the longest wavelength of light within the visible spectrum (made up of the colors: red-orange-yellow-green-blue-indigo-violet - the colors of the rainbow which appear in that specific order. There is a mnemonic to remember the colors of the visible spectrum - ROY G BIV). Red has the longest wavelength and violet the shortest. Colors with longer wavelengths (red to orange) would penetrate the gloom and not be scattered by the water-droplets which make up the fog. Though Rudolph is a mammal and flies through the air - most red-glowing animals live in the oceans. So he is truly a rare and unique guy!

Even though science tells us Rudolph has the best possible attribute for the job and his glowing nose saved the holiday that year - there are other scientific hurdles St. Nick has to overcome to  make it around the globe and down countless chimneys on his package delivery route. The most amazing is the overall speed the sleigh must travel to complete his global journey. The speed needed for his global journey is 8.2 million kilometers per hour (5 million miles per hour) or about 1% the speed of light.

Traveling at those speeds and fueling his glowing nose, Rudolph (and the other eight reindeer) would need a lot of energy. According to Dr. Nathaniel Dominy, an evolutionary biologist at Dartmouth College, all the reindeer would need a huge amount of sugar-rich foods. So, when putting cookies out for St. Nick - leave the carrots in the frig and put out cookies and other sweets for the reindeer, too. (Only the nose knows)

"Are you using clock time or solar time? What time is it really?"

Last month we talked about the impact Daylight Savings Time has on humans and animals alike. How the act of changing our clocks by one hour - forward or back - disturbs our circadian rhythm and impacts our health and mental acuity with increases in accidents, strokes and heart attacks. Remember, the Earth's axis is tilted and through one rotation, the planet wobbles like a slowing top. So, the time we read on a clock isn't the only time to consider when someone asks you for the time. There are actually two distinct times to consider - solar time and clock time.

If you think about it - having different times would cause a problem - which time are you using? After all, we're driven by our clocks. When we get up, when we go to bed, when we need to be somewhere to make an appointment are all set at a specific time of day. More and more of our day is driven by the device on our wrist - whether that device is digital or analogue.

My digital device shows me a plethora of information on its face: the orbital position of the inner four planets of our solar system as they move around the sun, the position of the sun's shadow cast on the globe (which defines nighttime and daytime at any given spot), the time of moon rise and the lunar phase, minimum and maximum temperature outside, and of course the day, date and time. Thats a lot of information on the 42mm face of my digital device (we'll ignore the notification of texts, direct one-touch call to my number one, and all the stuff about exercise).

But I'm going to call TMI on this (please note I did not call this digital device a watch). It will never teach our kids how to tell time by using the analogue hands of a clock as we are lost in the minutia of a day. When going out in the evening I often leave my digital device at home on its charger and wear my Breitling Chronomat Automatic, designed in 1940 by Willy Breitling - this chronograph is a simple gear-driven device, powered by the inertia generated by my arm's movement (no charger or battery needed), lacking numbers on its face - but with three moving pointer needles which tells me the time, the date in a small window which mechanical changes every 24 hours, the elapsed time on a timer dial, and a count up or down feature using a mechanically-rotating bezel. Thats a lot of information for an analog device. But, it is a clock in all intents and purposes. It counts time in days, hours, and seconds - using only an intricate interwoven mesh of gears and cogs - pretty cool right. Clocks which told the hour were first invented in 1275, minutes and seconds were instituted on clocks in the late 1600s.

But I digress, what does all of that have to do with time - time is just set by the 24 hours it takes for our planet to rotate once about its axis while it revolves around the sun in 365 days? So time is measured by these astronomical phenomenon - only it's not.

One of the local weathermen in Denver Colorado - Chris Bianchi, 9News - stated last Saturday that our earliest sunset would be 4:36:51 PM on December 1st through the 7th this year. Wait a minute: what about the winter solstice when we have the shortest day of the year, on December 21st. Shouldn't that be the day with the earliest sunset and latest sun rise? Turns out there are two types of time - clock time and solar time - and a not so simple mathematical formula called the Equation of Time which occurs due to the weirdness of Earth's rotation and revolution about the sun.

Let's start with solar time. Solar time is the apparent time recorded directly from the diurnal motion of the sun or in other words - the time indicated on a sundial - the east to west motion or analemma of the sun across the celestial sphere as viewed from your position on the surface of the Earth. If you're thinking this isn't a very precise measure you are correct. And solar time varies throughout the year as the Earth precesses through one 24-hour rotation (remember the Earth's axis is tilted 23.44 degrees and this causes the Earth to wobble as it rotates -  like a wobbly top as it slows down). Sundial time can be as fast as 16 minutes and 33 seconds in a 24-hour period (around November 3) and as slow as 14 minutes and 6 seconds in a 24-hour period (in early February). Thats a lot of variation and would wreak havoc on our daily lifestyle which are so tied to a precise time. Given these variations with solar time, the equation of time is used to smooth out the variations to have a mean difference of variation equal to zero - 24 hours is then 24 hours on our clocks in our 365 day year.

Therefore, the equation of time calculates clock time or the time my Breitling counts throughout one rotation of the Earth or my digital device tells me is the time recorded on the atomic clocks on the satellites above my head. Clock time or Mean Solar Time is the time indicated by a steady clock set such that the differences in solar time as measured each day = zero in 24 hours as calculated by the equation of time.

The equation of time is not applicable on a planet with a zero axial tilt (as tied to a day's rotation) and zero orbital eccentricity (the variation in a planet's orbit about the sun in a year). There are only two planets in our solar system which meet these criteria - Mars and Uranus. On those two planets time is time throughout the day whether measured by a clock or a sundial and throughout their planetary year (Mars' year = 685 Earth Days and Uranus' year = 30,687 Earth days).

Whether you use a digital device or an analogue clock to tell time - your time is everyone's time as adjusted by the equation of time on Earth. And this is why the earliest sunset does not occur on the shortest day of the year - the solstice. (Time is not Time all the Time)

Gray hair - another sign of time passing

Gray hair - a sign of aging or something more? A recent study in Nature Cell Biology on how cells responsible for pigments in our hair and skin (melanocyte stem cells) behave when they  experience DNA damage - the disintegration of the DNA. The researchers concluded that gray hairs may be the 'scars' left by our bodies war against cancer. Further, they discovered that under specific types of damage these pigment cells shut themselves down rather than continuing to divide and potentially spread mutated cancer cells resulting from DNA cellular changes. So your grey hair may be a more than sign of old age, it may be a sign of an important anti-cancer defense your body is using. 

How old is old? These nanoscopic fossilized remnants of ancient organic carbon seen in the Josefsdal Chert in the Mpumalanga province of South Africa are thought to be the oldest fragmentary remains of biotic chemistry - signs of life - dating to 3.33 billion years ago. Pushing the earliest signs of photosynthesis back 800 million years. Credit: Juan Gaertner/Science Photo Library/Getty Images

Photographer Mary Schrader captured this portrait of a young female mountain gorilla entranced by a butterfly in Bwindi Impenetrable Forest in Uganda. Winner of the 2025 animal portrait category of Nature Photographer of the Year awards. Ms. Schrader commented: "It seemed to embody the delicate balance and fragile interconnectedness of our natural world - where two creatures paused, noticing each other, bound by wonder and discovery."

Increases of 10% yield a 64% rise in risk. Those are the numbers associated with an increased consumption of ultra-processed foods. In a group of overweight or obese 17 to 22 year olds, a 10% increase in eating ultra-processed foods led to a 64% higher risk of pre-diabetes and a 54% higher risk of blood sugar issues.

Since James Watson's death on 6 November 2025 at the age of 97, I debated including his obituary this newsletter. For though this is a story of great discovery it was overshadowed by the behavior of a flawed human being who was touted by one biographer as "the most important and famous scientist of the 20th century and the most infamous of the 21st." A misogynistic man who believed genetics placed him (white, male, privileged, well-educated, genetically-superior) above all others. Though one cannot argue that Watson and Crick's 1953 discovery of the internal structure of the double-helix shape of DNA laid the foundation for the advancement of biology over the last 72 years - for, we would not have today's gene therapies, an understanding of genetic inheritance, knowledge of how cells synthesize proteins, the successful sequencing of the human genome, messenger RNA, the use of monoclonal antibodies for COVID treatments and vaccines nor cancer treatments - we must pause and temper the impact of this discovery with the behavior of one of its discoverers. (A Flawed Titan)

James Watson and Francis Crick worked at the University of Cambridge, UK, and published their discovery of the double helix in a 1953 Nature article which concludes with the statement "It has not escaped our notice that the specific pairing we have postulated immediately suggest a possible copying mechanism for the genetic material." Yes, a truly monumental discovery. So great, the pair won the 1962 Nobel Prize in Physiology and Medicine. But, how was the discovery made, whose data did the two use without permission, how did this fraud lead to a Nobel?

Neither Watson nor Crick acknowledged the origin of the famous Photo 51 which showed the two strands of DNA joined in the middle, taken using x-ray diffraction of DNA molecule by Rosalind Franklin and Maurice Wilkins at Cambridge. These two chemists were pushed aside by James Watson who went so far as to denigrate Franklin in his book - The Double Helix: A Personal Account of the Discovery of the Structure of DNA - in 1968. Franklin died in 1958 at the age of 37 from ovarian cancer and unfortunately would have been ineligible for the 1962 Nobel. Nobels are not given posthumously. Watson further dismissed her work since she was female. Writing in his book: "The thought could not be avoided that the best home for a feminist is in another person's lab." 

Though instrumental in initiating and propelling the Human Genome Project forward, laying the groundwork for the creation of the Broad Institute for molecular biology at Harvard, contributing to the discovery of messenger-RNA, and saving the financially-struggling Cold Springs Harbor Laboratory, Watson became notorious for his history of racist and sexist comments and beliefs which led to his firing from the Cold Springs Harbor Lab and ultimately the financial need to sell his Nobel medal. So the question remains: How does one balance such a monumental contribution to human knowledge against such unrepentant behavior of a human? 

Ultimately it is for each of us to weigh the value of the discovery versus behavior and decide how to remember James Watson. I believe the discovery is great enough that an acknowledgment of his passing deserves a place here, if it is tempered with the caveat of his failings. I for one believe his contribution to biology though great was overshadowed by who he was as a human - flawed yes, but ultimately so very damaging to improving diversity in science and protecting the tenets of scientific discovery. 

Science is a collaborative endeavor. One made on the shoulders of those who came before - shared with those we work beside. All efforts and contributions must always be acknowledged. This is why this newsletter and all scientific research is always referenced when the science, images, learnings are presented. Why scientific papers list all the authors who contributed. The act of referencing is 'tipping the hat' to the discoveries and efforts of those involved and those who laid the basis for our work. 

May the joy of the season and the hopes of the New Year be yours. However you celebrate the passing of time - celebrate it with your loved ones.

Take a moment to look around at the wonders of nature, gaze up at the sky and revel in the vastness of the universe we are a part of. Don't wait for a special day, because everyday is a special day in the course of humankind.

AI is never used in the design, construction or editing of our newsletters.

We'll be back next month with another installment. Be well, be kind. CA