Category: Science

Social Distancing, Herd Immunity, and R-naught, just a few of the concepts developed by the science of Epidemiology.

With the Covid-19 virus continuing to spread, causing an ever growing number of illnesses and deaths across our planet the science of epidemiology has gone from being a little known branch of medicine to arguably becoming the most vital topic in the world. Literally ‘the study of what is on or among the people’ epidemiology was once the most successful branch of medicine, helping to eliminate such deadly diseases as cholera, typhus and yellow fever. Indeed the doctors and scientists who developed epidemiology succeeded in controlling many infectious diseases without any kind of a cure or in some cases having the slightest idea as to what was causing the illness.

It’s all Greek to me! (Credit: Pinterest)

The ancient Greeks recognized that while some diseases could spread from person to person throughout a population, other illnesses like epilepsy or cancer were not infectious. It wasn’t until 1543 however that an Italian doctor named Girolamo Fracastoro speculated that diseases could be spread by living particles too small to be seen that floated through the air. The invention of the microscope and the discovery that there actually were microscopic living creatures lent considerable weight to Fracastoro’s theory.

Fracastoro and a few other early researchers into the germ theory of disease. (Credit: Open Texbooks)

About a hundred years later in 1662 a part time mathematician, his day job was haberdasher, named John Graunt performed a statistical analysis of the mortality rolls of the city of London before and after the great plague of 1665-66. Graunt’s work provided much evidence supporting some theories about the spread of infection while at the same time disproving others and it established the use of mathematics in the study of diseases.

During the 16th and 17th centuries the city of London had so many plagues that the one of 1665 -1666 is know as ‘The Great Plague’. (Credit: The Lost City of London)

Another Londoner named John Snow became known as the father of modern epidemiology thanks to his work in 1854 leading to his discovering the cause of a number of cholera outbreaks striking the Soho section of London every few years. By simply marking the home addresses of cholera victims on a street map of London, see map below, Snow correctly concluded that the source of the infection was a water pump located on broad street. By disinfecting the water with chlorine and removing the pump’s handle Snow succeeded in ending the outbreak.

John Snow and his map of the distribution of cholera in London.(Credit: The Vintage News)

Another early pioneer was the Hungarian doctor Ignaz Semmelweis who dramatically reduced the infant mortality rate at his Viennese hospital by insisting on rules that promoted cleanliness. Then in the first decade of the 20th century Walter Reed achieved great success in fighting yellow fever in Cuba not by curing his patients who had contracted the deadly disease but by eradicating the mosquitoes who carried the disease from person to person.

Comic book describing how Walter Reed discovered it was mosquitoes that transmitted yellow fever. Yes they used to print comic books about real superheros! (Credit: news.hsl.virginia.edu)

You get the point; the purpose of epidemiology is not to treat the sick but instead to stop the spread of a disease in order to keep other people from becoming sick! That means that often times great advances in epidemiology are made by mathematicians rather than physicians. It has also allowed epidemiology to become the technique used to study social diseases such as obesity, deaths caused by smoking and even gun violence.

The science of Epidemiology being used to study homicides in the city of Detroit. (Credit: Alex B. Hill)

Right now of course the lessons learned from epidemiology are the only weapons we have with which to fight the viral disease Covid-19. Until we have either a vaccine or some really effective anti-viral drug all that each of us can do to protect ourselves is to practice the guidelines developed by epidemiology.

With that in mind it would be a good idea for all of us to understand some of the technical concepts that epidemiologists use to understand how a disease spreads and how we can reduce and control that spread. Probably the factor that is most important in determining, and controlling the spread of a disease is known as its Basic Reproduction Number oftentimes referred to as R-naught or just R0.

Simply put, for each person who becomes infected with a disease, R-naught is the average number of healthy people they will in turn infect. In others words, if you catch a cold and become infectious, R-naught is the number of members of your family, or your co-workers or just people you come into contact with that will catch a cold from you. This also means that if R0 for a disease is greater than one, then the number of people infected is going to grow. For example if R0 for a disease is two then one person will infect two people, those two will go on to infect four and the four will infect eight and so on until almost everyone has, or has had the disease.

A small change in R-naught, say from 2 to 3, can make a huge difference in the number of infected people in a very short period of time. (Credit: University of Scranton)

Under normal conditions in human society there are many diseases that have an R0 much greater than one.  The table below shows the estimated R0 numbers for some well-known diseases.

Table of R-naught for several well known diseases. (Credit: Wikipedia)

Obviously the goal of epidemiology is to find methods and procedures that a community can take that will reduce R-naught for a disease below one. Perhaps the simplest technique is called ‘Social Distancing’ and it just means having everyone in a community reduce the amount of contact that they have with everyone else. No shaking hands when you meet someone, no hugs for friends you haven’t seen in years, also no parties and no big crowds at sports events or concerts. Social distancing works because less contact between people makes it less likely that a germ will pass between them.

Some of the rules of Social Distancing. (Credit: Orange County N. C.)

Looking back at the table you can see how many diseases spread through particles or droplets in the air. Those particles can only travel through the air for about three or four meters so if everyone stayed more than four meters apart those diseases could not spread. R0 would go very close to zero.

Of course such extreme social distancing is not really possible, we live in families and the jobs of many people are so essential that society cannot get along without them. We live in a society and that society requires a certain amount of contact between its members. That’s why other procedures, such as washing hands, disinfecting everything other people touch, and wearing face masks become so important. In fact anything that we can do to reduce R-naught is important, it is at present the only way we have to fight Covid-19. 

Now for many viral diseases those people who are infected and recover acquire an amount of immunity to being re-infected. In such cases, once a majority of the population has been infected the spread of the disease is inhibited because there are now fewer victims left to infect. Not only that but actually the people who have become immune get in the disease’s way, getting between those who are infectious and those who have not yet been infected, effectively generating a macabre form of social distancing. This acquired immunity of the majority of a population is known as ‘Herd Immunity’.Herd immunity should be considered the last resort in fighting a disease however because it results in the maximum number of deaths and hospitalizations of sick people. Basically getting to herd immunity means not fighting a disease and just letting people get infected.

Herd Immunity without a vaccine, top. With a few people getting a vaccine, middle and with a large majority getting a vaccine. Which do you prefer? (Credit: Wikipedia)

Surprisingly there are many people who believe that is the best solution to Covid-19. Indeed the entire nation of Sweden has decided to forego all social distancing measures and just let the disease die out on its own.

One last point, when and if a vaccine is developed that is effective against Covid-19 it will grant immunity to people who have not yet been infected by the disease. In epidemiological terms a vaccine therefore works by getting a population to herd immunity without people dying or being admitting to a hospital, without them getting sick at all. Something I’m certain that we are all looking forward to!

Paleontology News for May 2020. What’s there to do when you’re ordered to stay at home during a pandemic? Why study dinosaurs of course!

We tend to think of paleontologists as working out in the field, digging around in some barren, rocky terrain unearthing the remains of long extinct forms of life. That’s partly true of course, after all you have to find some fossils before you can study them. And most paleontologists do prefer being on site where the discoveries are made, never knowing what they’ll see in the very next rock they turn over.

Although it is often hard, dirty, sweaty work take it from me fossil hunting is the pure joy of discovery. (Credit: CBS Denver)

Still, a lot of the work in studying ancient life can only be accomplished back in the lab or in the office. Cleaning fossils, examining fossils, comparing them to similar fossils and of course, writing up the papers that will tell your colleagues, and interested laymen like me, what you’ve found. A lot of that work can safely be accomplished even during the ‘social distancing’ needed to stop the spread of Covid-19. So let’s take a look at some of the work that’s being accomplished by paleontologists even in the shadow of a deadly disease.

Cleaning fossils has to be done in the lab where you can take your time and do a meticulous thorough job. (Credit: Wikimedia Commons)

Spinosaurus aegyptiacus is one of the most intriguing dinosaur species known to science. Originally discovered in Egypt back in 1912, Spinosaurus is a large predatory dinosaur belonging to the group known as theropods, the group that includes the mighty T rex and Allosaurus along with the smaller Raptors. Spinosaurus lived during the middle to late Cretaceous period (112 to 93 million years ago) and had one distinguishing feature that set it apart from its relatives, a broad, sail like flap of skin along its back that was held up by spines coming off of the animal’s vertebra. See image below. Large, floppy skin features like Spinosaurus’ sail are usually either for thermal regulation or display or both.

Artist’s impression of a Spinosaurus with a human figure to give scale. (Credit: New York Times)

The loss of the only known skeleton of Spinosaurus during World War 2 brought all research into the creature to a halt, and Spinosaurus was almost forgotten by science. Then in the 1990s further fossils belonging to another species of Spinosaurus, S maroccanus were discovered in Morocco by a National Geographic team led by Doctor Nizar Ibrahim of the University of Detroit Mercy along with Professor Paul Sereno of the University of Chicago. Exploring a layer of rock that has been named the Kem Kem group and which is exposed across a wide area of Morocco the team has unearthed fossils of many different species including specimens of Spinosaurus that have allowed paleontologists to resume the study of this odd dinosaur.

University of Chicago paleontologist Paul Sereno with a skeleton of Spinosaurus. (Credit: The Telegraph)

Actually there is a lot of disagreement over whether S maroccanus is a second species. With the original S aegyptiacus destroyed it is impossible to make a direct comparison and the drawings that remain of the bones of S aegyptiacus are insufficient to determine just how different the new specimens are with certainty.

The new specimens have re-ignited several debates about the nature of Spinosaurus, these include whether or not the predator was actually larger than the famous T rex and whether or not Spinosaurus was at least semi-aquatic, spending a large fraction of its life in the water. Based on the examination of the fossils discovered during the 1990s the full length of Spinosaurus was between 12.5 and 18 meters while the animal’s weight was between 6.5 and 7.5 tonnes. If these estimates are true that would in fact make Spinosaurus a fraction larger than the venerable T rex.

As to the question of Spinosaurus being semi-aquatic the dinosaur’s long narrow, crocodile like snout along with its short, powerful legs do indicate a life style similar to that of…well crocodiles. Add in the fact that the fossils of Spinosaurus were discovered in the same rock beds that yielded numerous specimens of an ancient and extinct sawfish named Onchopristis and it seems clear that Spinosaurus lived in an environment that was as much water as land, such as a swampy river delta.

The extinct fish Onchopristis. Measuring eight meters in maximum length this creature was a monster itself! (Credit: Prehistoric Life -Wiki)
Artist’s impression of the sort of environment and life that Spinosaurus lived. (Credit: BBC)

Now perhaps the crucial piece of evidence has been unearthed, as bones from the tail of Spinosaurus have recently been discovered. Based on those bones the tail of Spinosaurus was a long, flexible and fin like. A tail well suited to providing propulsion in the water. This latest discovery pretty much clinches the hypothesis that Spinosaurus is the first type of dinosaur known to have evolved into a swimming creature.

Tail bones tell the story. The tail of Spinosaurus was big and powerful, perfect for propulsion underwater! (Sci-news.com)

These new discoveries make Spinosaurus an example of how varied and diverse the group we call dinosaurs was, and the research published by Ibrahim and Sereno provides an example of how scientists can continue their work even during a pandemic.

A star orbiting the black hole at the center of our galaxy provides direct observational evidence that Einstein’s theory of gravity is more accurate than Newton’s.

One of the basic laws of physics that students learn in high school is that the planets orbit around the Sun not in perfect circles by rather in the flattened circles formally known as ellipses, see image below. This idea of orbits being ellipses is Johannes Kepler’s first law of planetary motion.

Kepler’s first law is a direct consequence of Newton’s law of Gravity, but the gravity of a third body, not shown here, will cause the ellipse to wobble! (Credit: Quora)

A few decades after Kepler Sir Isaac Newton showed that it was the gravitational pull of the Sun that pulled the planets into those elliptical orbits. However, an orbit is only a precise ellipse if there is just a star and one planet. In our Solar system the other planets have their own gravitational pulls as well, although they are not nearly as strong as the Sun’s. Nevertheless because of the planets all pulling on each other those elliptical orbits aren’t exact, they all wobble around a bit.

In our Solar System the Planet Jupiter weighs as much as all the other planets combined so it causes most of the wobble in the other planet’s orbits! (Credit: Hubble Space Telescope)

In fact after the planet Uranus was discovered astronomers found that its orbit had a wobble in it that couldn’t be explained by the gravitational pulls of the then known planets. In the year 1821 it was suggested that another planet, further out than Uranus could be the culprit and after a lot of math, more than 20 years of calculations by hand, the planet Neptune was discovered in 1846 right where Newton’s gravity said it would be.

It was a wobble in the orbit of Uranus (l) that enabled astronomers to find Neptune (r). (Credit: Daily Mail)

Just a few years later, 1859 to be exact, a peculiar kind of wobble, known as the precession of perihelion, was found in the orbit of Mercury. Now perihelion is the closest point to the Sun in the orbit of a planet and a precession would mean a shifting of where, relative to the Sun, perihelion occurs. See image below.

The precession of perihelion could not be explained by the pull of the other known planets. Was there another planet even closer to the Sun? (Credit: Independent BD)

By the way, this shift measured by the astronomers was tiny, amounting to only 43 seconds of arc per century. If you recall that a complete circle has 360 degrees and each degree is made up of 60 minutes and each minute has 60 seconds then you can see that a change of 43 seconds in a century is very small indeed.

Once again it was suggested that another planet, one even closer to the Sun than Mercury, was the cause of the precession. After their success with Neptune the astronomers were so certain that they gave this ‘new planet’ the name Vulcan before they even found it. In fact they never found it, despite searching for more than 30 years.

In ‘Star Trek’ Mister Spock’s home world Vulcan was named for the hypothetical planet inside the orbit of Mercury! (Credit: Pinterest)

It was Einstein who finally figured out what was going on. In his General Theory of Relativity in 1915 the physicist described gravity not as a force that passed between two massive bodies but rather as a bending of space-time itself. This bending of space-time causes the motion of objects to deflect from a straight line and if the bending is enough, if gravity is strong enough, the ‘straightest path’ for an object can be a closed elliptical orbit.

In Einstein’s General Theory of Relativity the mass of an object bends Space-Time itself caused the path of other objects to bend, even into an orbit! (Credit: Extreme Tech)

For a weak gravitational field the difference between Newton and Einstein is extremely small. So small that when NASA sends a space probe to another planet it uses Newton’s equations not Einstein’s. The math needed with Newton is just so much easier, trust me.

Einstein’s equation for the gravitational field. This is actually shorthand for a system of 16 equations all of which must be solved simultaneously! (Credit: WordPress.com)

As the strength of gravity grows however the difference between the two theories grows exponentially. That’s why Einstein’s theory predicts the existence of black holes, objects with gravity so strong that nothing can escape them, while Newton’s theory doesn’t. And if you get close enough to our Sun, say where Mercury is, the difference becomes large enough to be measured, it works out to be 43 seconds of arc per century. When Einstein solved his field equations the solution to Mercury’s precession just popped right out. This was in fact the first evidence that Einstein’s theory was correct.

Now astronomers with the European Southern Observatory’s (ESO’s) Very Large telescope (VLT), located in the Atacama Desert in Chile have found another example of precession as predicted by Einstein. For the past 27 years the team have been studying a star called S2 as it orbits around the supermassive black hole Sagittarius A* in the very center of our galaxy.

The center of out Glalxy lies between the constellations of Sagittarius and Scorpio. Try to find it some clear night this summer! (Credit: EarthSky)
At the center of all large galaxies lies a supermassive black hole. Our galaxy’s is called Sagittarius A. (Credit: Daily Mail)

S2 completes an orbit around Sagittarius A* once every 16 years and at its closest point the star comes closer than 20 billion kilometers to the black hole, a distance that is about 120 times that between our Earth and the Sun. At that closet point S2 has to move at 3% of the speed of light in order to not be swallowed by Sagittarius A*. Just imagine that, an object as big and massive as a star moving at 3% the speed of light!

Artist’s impression of the star S2 at it’s closest approach to the supermassive black hole Sagittarius A. (Credit: Wikipedia)

Analyzing their data the astronomers, led by Reinhard Genzel, Director at the Max Planck Institute for Extraterrestrial Physics, have now published their results in an article in the journal Astronomy and Astrophysics. What the astronomers have found confirms Einstein’s theory once again. Even at a distance of 26,000 light years they were able to measure the precession of S2’s orbit around Sagittarius A* and it matches up with Einstein’s theory nicely. In fact their results have allowed them to make the most precise measurement yet of the mass of the black hole itself, 4 million times the mass of our Sun.

Because of the precession calculated from Einstein’s theory, S2’s orbit around the black hole will make a lovely Rosetta shape. (Credit: Syfy)

Future observations of S2 and the region around Sagittarius A* will be even more precise and detailed once construction is completed on the ESO’s new Extremely Large Telescope (ELT) in 2025. The astronomers hope to find fainter stars that come even closer to Sagittarius A*, perhaps even close enough to feel the dragging of space-time caused by the spin of the black hole. That’s another prediction of Einstein’s theory that has yet to be observed anywhere. That would be further proof that General Relativity is the most accurate theory for space-time outside of a black hole.

But as for what goes on inside a black hole? That’s going to have to wait for the physics of the future.

What is Soap?

In this era of Covid-19 we hear one piece of advice dozens of times everyday, ‘Wash Your Hands’, ‘Work up a good lather of Soap and Warm Water and Wash your Hands while singing Happy Birthday Twice!’ Which begs the question, what is Soap? Why is Soap so central to both cleanliness and good hygiene?

Just a little friendly advice!

Chemically soaps are a class of compounds known as salts of fatty acids and are produced by combining fats or oils with an alkaline base in solution under heat, a process technically known as Saponification. Soaps include a wide range of substances used for a variety of purposes from thickening agent to lubrication but the most familiar use of soap is undoubtedly as a cleaning agent and in this post I will mainly be referring to these types of soaps.

The Chemical reaction that produces soap, call saponificaction. (Credit: Thought Company)

Toilet soaps as they are known are produced by using either Sodium Hydroxide (NaOH) or Potassium Hydroxide (KOH) as the alkaline. When sodium hydroxide is combined with a thick fat such as lard or tallow the result will be a hard soap while potassium hydroxide and a light oil, such as olive oil, will produce a softer or even a liquid soap. When Lithium Hydroxide is used as the alkaline the result is lithium stearate a common industrial lubricant.

Making soap is actually pretty easy, many people do it as a hobby. (Credit: The Spruce Crafts)

So how do soaps perform their job as a cleaning agent? Well, remember that oil and water don’t mix because oils are non-polar molecules while water is a polar molecule. However a soap molecule is a combination of an alkaline and fat. That arrangement produces a molecule that is polar at one end, attracted to water, but non-polar at the other end, attracted to fats and oils.  

Basic layout of a soap molecule. One end can dissolve in water while the other end can dissolve in fats or oils! (Credit: Nature on the Shelf)

Because of that when used in combination with water soap acts as a surfactant, a material that breaks the surface tension of water allowing the water to more easily dissolve dirt and grime, along with such polar molecules as proteins and sugars, so that they can be washed away.

Soap’s greatest trick however is its ability to encase droplets of oil or fat in tiny spheres of soap molecules called micelles. Unlike oils and fats that do not dissolve in water, these micelles do dissolve allowing the oils and fats to be washed away with the dirt and grime. In other words not only does soap help water to better dissolve the substances it usually can, it also enables water to dissolve substances it generally can’t.

Molecules of soap form ‘Micelles’ around fats and oils allowing them to be dissolved in water and washed away! (Credit: Quora)

This also makes soap an effective anti-biotic because the harsh alkaline at one end of the soap molecule can break up the protein shells that protect viruses. At the same time the micelles can absorb the fats in the cell walls of bacteria, killing them. Of course modern, manufactured soaps often have various chemicals added to them in order to make them even more ‘anti-bacterial’ but it is worth remembering that any soap can be used as a disinfectant.

Soap by itself can help protect you from germs but modern soaps often have other chemicals added to make them true disinfectants. (Credit: Medium)

Archaeological evidence for the manufacture of soap dates all the way back to ancient Babylon with a cuneiform tablet dated to 2200 BCE that describes the earliest known recipe for soap making. The Egyptians, Greeks and Hebrews all had their own varieties of soaps, mostly produced with olive oil and potash, an alkaline solution made from the ashes of a fire, along with a bit of quicklime. This method of soap making produced a strong and particularly harsh soap.

Babylonian table with a recipe for making soap! (Credit: KU Chemistry)
Egyptian ladies washing themselves with soap! (Credit: Realm of History)

Surprisingly the Romans, who are well known for their baths, did not care very much for soap. They preferred to clean their bodies by rubbing them with olive oil and then scrapping the oil off with a dull knife called a strigil. They considered the harsh types of soaps made in the eastern Mediterranean as harmful for the skin. Only after becoming familiar with the milder soaps of the Celts and Germans did the Romans start using soap. (Imagine that, the fierce northern barbarians had the gentler soap!)

A Roman bronze Strigil used to scrap oil off of the body in a Roman bath. I think I’ll stick with soap and water! (Credit: Christie’s)

Both medieval Europe and the Islamic world had soaps but these soaps were generally harsh with an unpleasant smell and so expensive that only the very rich could afford to bathe frequently. Large-scale manufacture of soaps only began in the late 18th century and coincided with a campaign that linked daily washing with good hygiene, ‘cleanliness is next to Godliness!’

In the 19th Century Cleanliness, Hygiene and Morality were pretty much equated. (Credit: Alamy)

Today of course there is a tremendous variety of different kinds of soap available in your local supermarket. There are soaps that can remove the toughest dirt and grime, soaps that actually soften the skin and even soaps that are 9944/100 % pure soap. There are solid bar soaps and liquid soaps, advertised as ‘body wash’, there are even powered soaps. Whatever kind of soap you prefer we all know that regularly washing your hands with soap and warm water is our first line of defense against Covid-19. So wash up and remember, ‘I’m pulling for ya, we’re all in this together’! 

The BepiColombo Space probe is on its way to Mercury, this will be only the third mission to the Solar system’s innermost world.

The BepiColombo robotic probe to Mercury is in many ways the most complex space mission yet attempted. For one thing it is actually three spacecraft in one. Two Mercury orbiters, the Mercury Planetary Orbiter (MPO) designed and built by the European Space Agency (ESA) along with the Mercury Magnetospheric Orbiter (MMO) constructed by the Japanese Aerospace Exploration Agency (JAXA). These two scientific missions are stacked together on top of a propulsion module called the Mercury Transfer Module (MTM). Simply organizing a mission combining two probes from two space agencies had to be a challenge.

Artist’s impression of BepiColombo approaching Mercury. (Credit: New Scientist)
Breakout of the separate modules of the BepiColombo space probe. (Credit: YouTube)

Still, that was child’s play when compared to the task of getting BepiColombo to Mercury. Launched on 20 October 2018 the spacecraft will not enter orbit around Mercury until 5 December 2025. During that long voyage BepiColombo will flyby and receive gravity assists from Earth once, Venus twice and Mercury itself six times. The difficulty of getting to the Sun’s closest planet is the big reason why there have been more unmanned missions to distant Saturn, two Voyagers plus Cassini, than to comparatively nearby Mercury, one Mariner along with the Messenger mission.

BepiColombo’s complicated flight path to Mercury. (Credit: SlidePlayer)

That true, although Mercury is actually only about 20% further away from Earth than Mars is, 90 million kilometers versus 75 million. On the other hand Saturn is fully 17 times further from Earth than Mars is. So why have we sent more spacecraft to Saturn than Mercury?

Speed is one big reason. Orbiting so close to the immense gravity of the Sun Mercury has to possess a very high orbital velocity. In fact if you consider the difference in their orbital velocities, delta vee as astronauts put it, Mercury is only a little ‘closer’ to Earth, 18 km/sec, than Saturn is, 20km/sec. And when you’re sending an unmanned robotic probe to an extraterrestrial body the length of time the journey takes doesn’t matter, which makes speed matter more than distance since that requires more fuel.

Another reason that sending a spacecraft to Mercury is difficult is that the nearby Sun’s gravity is so strong, while Mercury’s is rather weak. This makes finding a stable orbit around Mercury rather difficult, especially an orbit that allows you to investigate all of the areas on the planet you want to observe.

Tiny Mercury is so close to the enormous Sun that finding a stable orbit around the planet isn’t easy. (Credit: Forbes)

BepiColombo has just completed the first if it’s flybys, saying a last Goodbye to Earth on the 11th of April, see image below. Later this year in October the probe will make the first of two consecutive flybys of Venus. Hey you known, Venus is big and bright in the evening sky right now so if you go outside on a clear night not long after sundown, BepiColombo will be somewhere between you and that big, bright evening star to the west.

One of the last images of Earth taken by the BepiColombo space probe as it flew by on 11April2020. The spacecraft used Earth’s gravity to give it a push on its way to Venus for its next flyby. (Credit: European Space Agency (ESA))

Once the combined spacecraft finally settles into Mercury orbit the two orbiters / instrument packages will separate and begin their studies of Mercury. The ESA’s MPO orbiter is outfitted with an array of cameras and spectrometers along with a radiometer, a laser altimeter magnetometer and accelerometer for the study of Mercury’s composition as well as compiling a more accurate map of the planet’s surface.

The planet Mercury as photographed by the Messenger space probe. Nice as this image is scientists would like to see a lot more of the details on the planet’s surface. (Credit: The Independent)

Japan’s MMO probe on the other hand carries instruments designed to study Mercury’s extremely thin atmosphere, the planet’s magnetic field and the way in which they both interact with the power of the Solar wind blowing past the planet. The results of these observations could be especially interesting since they will tell us a great deal about how the evolution of both Mercury and nearby Venus were influenced by the power of the Sun.

The Solar Wind has been buffeting the planet for billions of years. How much damage has it caused on Mercury? And how much will it cause on Earth over the next few billion years? (Credit: Scirence / How Stuff Works)

The proposed time frame for the scientific portion of BepiColombo’s mission is for one year after orbital insertion but with the possibility of an additional one-year extension for both orbiters. It’s possible that the success of BepiColombo will not only provide much valuable data about the Sun’s closest planet, but an example of how the space agencies of different nations can work together.

If only the politicians of different nations followed that example.

Some new discoveries that demonstrate that our Stone Age ancestors weren’t the dumb brutes we like to picture them as.

Our Stone Age ancestors, often dismissively referred to as ‘Cave Men’ are usually portrayed in movies and TV as being hardly more intelligent than the animals they hunted, or were hunted by. Little by little however archaeologists are uncovering evidence that Stone Age peoples were capable of flashes of genius in solving the problems they faced despite their lack of resources or tools.

Our Stone Age ancestors certainly had it rough but they still possessed technology way beyond that of any animal they completed with! (Credit: Wikipedia)

Finding food is of course the biggest problem any animal faces and a large part of the success of our species, Homo sapiens is the wide variety of different kinds of food we eat, and that includes seafood. Think about it, what are we, an ape scarcely out of the jungle trees doing eating not only fish but clams and mussels, squid and even whale meat.

We humans enjoy a wide variety of food from the oceans, lakes and rivers. No other primate consumes such an abundance of seafood which begs the question, when did we start? (Credit: Miss Vicki Pressure Cooker)

Over the last several decades anthropologists have even developed the hypothesis that it was learning how to make use of the food resources they found along the coast of West Africa that spurred a small population of Homo erectus to become H sapiens. There has even been speculation that the brain boosting fatty acids in the seafood those H erectus ate might have contributed to the growth of the larger brains of their descendants, that’s us.

Homo erectus is generally considered to be our direct ancestor. Was it learned to live off of seafood that turned them into us? (Credit: Ancient News)

Nice idea, but there’s new evidence coming from the field that is starting to show that other species of humans were also learning how to feast off of the bounty of the sea. I’m talking about our cousins the Neanderthals in Europe as much as 106,000 years ago.

The new evidence comes from a cave site along the southern coast of Portugal at Figueira Brava near the town of Setubal. The interior of the cave has been excavated by a team of archaeologists led by Doctor Joăo Zilhăo from the University of Barcelona in Spain.

The cave complex at Figueira Brava in Portugal. It’s easy to see that any inhabitants would be likely to start eating some of the food right on their doorstep. (Credit: CNN.com)

Those excavations have unearthed the bones and other indigestible remains of the animals that the Neanderthals were eating. Those remains clearly show that the Neanderthals were not only hunting the local land fauna of deer, goats, ancient cattle and even horses but were also catching and consuming large amounts mussels, crabs and such fish as eels and sharks! Even the bones of sea mammals like seals and dolphins were discovered in the garbage piles left by the Neanderthals. In fact Doctor Zilhăo and his team estimate that just about half of the diet of the inhabitants of Figueira Brava was in fact seafood.

Patella vulgata shells, a kind of edible snail from the cave at Figueira Brava. (Credit: CNN)
Cracked crab claws from the cave. (Credit: CNN)

So it seems as if our direct ancestors were not the only humans smart enough to realize the enormous benefits to be gained from dinning off of seafood.

Another recent discovery that also demonstrates the intelligence of Neanderthals is the unearthing of the earliest known piece of string from a site in Abri du Maras in southern France. According to the study co-authored by Marie-Hĕlĕne Moncel, Director of Research of the French Nation Centre for Scientific Research (CNRS) the string fragment is dated to between 41,000 and 52,000 years ago. Composed of fibers from the inner bark of a conifer tree the section measures 6.2mm in length by 0.5mm in maximum width.

Fragment of string that’s over 40,000 years old. (Credit: Phys.org)

The string fragment is more than just a few fibers twisted together however. In fact the fragment consists of three separate twisted cords that have been interwoven together, indicating a considerable level of experience in textile production. But more than that the fragment also indicates a considerable knowledge of available natural resources since the fibers come from the inner part of the bark of a tree that, according to botanists, is best obtained during the spring or early summer.

The discovery of this single strand of cord opens up the possibility that Neanderthals may have made extensive use of textiles, perhaps to manufacture bags, nets, ropes, mats or perhaps even cloth? In any case this, oldest piece of string provides further evidence that Neanderthals were anything but brutish animals. 

Moving a bit forward in time, to about 25,000 years ago we begin to see the first evidence for actual construction projects by human beings. Some of the most interesting sites come the fertile steppes of Russia south east of Moscow. Here Stone Age hunter-gatherers lived off of one of the largest and most dangerous animals ever pursued by humans, woolly mammoths.

There is plenty of evidence that our Stone Age ancestors did in fact hunt the massive and dangerous Wholly Mammoth. (Credit: The Vintage News)

We know that our ancestors hunted those ice age relatives of elephants because they had the curious habit of building circular walls out of the bones of the mammoths they killed. In a paper published in the journal Antiquity a team led by Alexander Dudin of the Kostenki Museum-Preserve describes the latest, and largest of these mammoth bone structures. Unearthed about 500 kilometers south of Moscow at a site known as Kostenki 11, the ring measures more than 12 meters across and was made from the bones of at least 60 of the huge beasts.

The ring of Mammoth bones at Kostenki 11. (Credit: New York Times)

Because the other mammoth bone structures found across Eastern Europe are smaller than the new one at Kostenki scientists had speculated that the circular walls had once possessed roofs and were used as shelters by the people who made them. At 12 meters across however the mammoth bone circle at Kostenki is too large to be easily roofed in, leaving the researchers to think of some other possible usage for the structure.

Whatever purpose the hunter-gatherers may have had when they built the structures like Kostenki the fact that they did so clearly shows that like modern humans they felt the need to adapt their environment to suit their needs by building.

While it’s true that the earliest structures we humans built were probably used as dwelling places there is evidence that by 7000 years ago people were already learning how to build other types of structures as well. Archaeologists in the Czech Republic have recently discovered a well that they assert is the oldest known wooden structure.

In a study co-authored by Jaroslav Peška head of the Archaeological Centre in Olomouc the well is described as being built in a square shape some 80 cm to a side and 140 cm in height. Each corner of the square consisted of a vertical oaken tree trunk that had been grooved on its sides to allow flat wooden planks, also oak, to be inserted between them to make the square’s sides. This degree of woodworking ability particularly impressed the researchers. “The shape of the individual structural elements and tool marks preserved on their surfaces confirm sophisticated carpentry skills,” they wrote.

7,000 year old well unearthed in the Czech Republic. The woodworking skills of the makers are still evident after all these years. (Credit: New Scientist)

The technique that was used by the archaeologists to date their discovery is known as dendrochronology and is based on an analysis of the tree rings in the well’s wood. Over the past 50 years or so the tree rings in the wood found at many different archaeological sites across Eastern Europe, and from many different time periods, have been matched up, one to another in order to create a exact timeline that can now be used to very precisely date the wood unearthed at any ancient site in Eastern Europe. This same technique has also been developed in other areas of Europe and the different areas of North America and has been used to precisely date many archaeological sites. Using dendrochronology Doctor Peška and his colleagues have succeeded in dating the year that the trees were felled to either 5255 or 5256 BCE.

By comparing the tree rings in wood from different sites archaeologists have developed an extremely accurate dating technique called dendrochronology. (Credit: Museum of Ontario Archaeology)

As different as these three archaeological discoveries are, each in its own way demonstrates that, for all of their primitive tools and crude materials our ancestors nevertheless were able to think up clever solutions to the problems they faced in their daily lives. In fact think about it, if they hadn’t been so bright, we’d still be living in caves ourselves wouldn’t we!

What is a Virus?

Seems like right now all anybody can talk about is the Covid-19 coronavirus and its effects on our society. That begs the question, or questions, just what is a virus, how do they differ from other pathogenic organisms such as bacteria and what makes them such deadly diseases? Oh, and one more question, are they even living things?

The new symbol of fear for this generation. A false colour electronmicroscopic image of a coronavirus. The protein structures in red form the ‘corona’ that gives this class of viruses their name. (Credit: Live Science)

In order to answer that last question we need to consider exactly what it means to be a living thing. What characteristics do living creatures exhibit that non-living things do not. Without getting too technical I think we can all agree on five characteristics.

If you think about it, exactly what makes a living thing ‘alive’ is really rather complicated. (Credit: Transformation Coaching Magazine)

One: All living things, whether plant or animal, ingest nutrients.

Second: Living things metabolize those nutrients.

With the energy gained from those nutrients living things:

Three: Grow

Four: Move

Five: And this is perhaps the most distinguishing characteristic of living things, they reproduce, using a part of their metabolism to create copies of themselves.

Probably the most important difference between living and non-living things is the ability of living things to make copies of themselves, to reproduce. (Credit: SlideShare)

So what about viruses? Well first of all viruses do not ingest nutrients of any kind, ever. And without any nutrients viruses simply do not metabolize, at all. Without the material and energy provided by metabolism viruses neither grow nor move very much, we’ll see in a moment about the only kind of motion a virus is capable of.

So what do viruses do? They reproduce, but they can only do so parasitically inside a normal living cell. Basically once a virus is “born” it is little different from a tiny grain of sand or minute crystal, neither growing nor moving by itself.

A few of the many different kinds of Viruses. (Credit: 123RF.com)

However, if a virus ever comes into contact with a living cell within which it is capable of reproduction it will grab that cell like a mousetrap snapping and inject its own genetic material into the cell. That grabbing, snapping and injecting are the only movements that the virus is ever capable of.

Viruses attacking a bacteria. (Credit: PBS)

Once the genetic material is inside the host cell the virus takes over the cell’s life functions and uses the cell’s own metabolism to reproduce hundreds if not thousands of copies of itself. Eventually the host cell bursts apart releasing the new viruses so that they can infect other cells. Viruses are the ultimate parasite having given up all of life’s functions except reproduction and even requiring another life form to do that. Because of this many microbiologists regard viruses as “organisms at the edge of life” rather than true living things. By the way, since viruses do reproduce they are still able to evolve, just like a living thing!

Viruses can only reproduce inside a living cell. The cell is then destroyed in the release of the new viruses. (Credit: Lumen Learning)

O’k, so if that’s the ‘life cycle’ of a virus, what are they physically? How do they manage to do what they do?

Well, physically viruses do have genetic material, which can either be in the form of DNA or RNA. All viruses will then have a shell of protein called a capsid surrounding the genetic material and protecting it. Additionally some viruses also have an envelope of fatty, lipid material around the proteins for further protection. That’s it, that’s all a virus consists of, and that’s why most viruses are so small, averaging only about 1/100th the size of a bacteria. In fact viruses are so small that the vast majority can only be seen with the high magnification possible in an electron microscope.

Typical structure of a virus. Not much here just DNA and a protective covering. (Credit: Florida State University)

Now if you’re wondering how did viruses ever evolve to become such complete parasites, how did anything that’s part alive and part not alive ever come into existence? Well you’re not the only one; microbiologists have been debating that question ever since the first virus was discovered back in the 1890s. Currently there are three leading ideas for where viruses came from.

The first idea is that viruses were once more normal cells, probably like bacteria, that became parasitic on other cells for their reproduction. There are in fact bacteria; chlamydia is one example, which can only reproduce inside a host cell. These proto-viruses then would have abandoned all other life functions in order to concentrate on reproduction. Again there are numerous examples of parasites that do this in nature. A tape worm for example has no digestive system, since it lives in your stomach you do its digesting for it. That way it can put more of its metabolism into reproduction. Perhaps viruses went even further, completely giving up metabolism of any kind outside of its host cell.

Tapeworms are common parasites among mammals, including humans. Living in our stomachs and intestines they have lost their own digestive systems in order to concentrate on reproduction. (Credit: Pinterest)

This idea has gotten a boost recently from a study led by Frank Aylward, Assistant Professor of Biological Science at Virginia Tech. Professor Aylward and his colleagues have been studying ‘Giant Viruses’, which are more then ten times the size of typical viruses. Carrying out a DNA analysis of the ‘Brown Tide Virus’ the researchers found genes directly related to metabolic processes, but why would organisms that don’t metabolize possess genes for metabolism?

Professor Aylward speculates that the virus uses the metabolic genes to better control the metabolism of the algae cells it infects. Still that leaves the question of where did a virus did metabolic genes from in the first place. One logical answer is that the metabolic genes were simply left over from the time when viruses were independent cells with a metabolism.

The second idea for a possible origin for viruses is that they evolved from ‘escaped’ bits of DNA or RNA outside of more normal cells. Such ‘Plasmids’ have been observed to move from one normal cell to another. Indeed single celled organisms like amoeba are occasionally known to exchange genetic material in this fashion. Perhaps some of these plasmids began to act for themselves, taking over the cell that absorbed them, becoming parasitic viruses in the process.

The final theory for the origin of viruses is simply that viruses evolved in parallel with normal living cells. The problem with this idea is that it’s logically difficult to understand how a proto-virus could use a proto-cell to make copies of itself if the proto-cell is still developing the processes needed to reproduce itself!

As life evolved from the primordial soup to high structured Eukaryota cells where did viruses break off and degenerate into parasites? (Credit: ViroBlogy)

All three of these hypotheses have some evidence in their favour, all three have big problems. Which will turn out to be true will only become clear when more evidence can be gathered.

By the way if you’re wondering, since viruses are so different from living cells, maybe not even alive, how can we kill them? Well, I don’t want to get into a philosophical argument over whether viruses die or are destroyed but fortunately soap and or alcohol will shatter that protein coating they have, exposing the fragile DNA that quickly breaks up. A good reminder to wash your hands often and use hand sanitizer!

Sage Advice! (Credit: Meme Generator)

Most people I suppose pretty much equate viruses with bacteria, after all they both cause diseases in human beings and that’s what we really care about. Most bacteria however are actually beneficial, they spend their lives breaking down dead and decaying organic matter into nutrients that other living things, mostly plants, can ingest. Only a few species of bacteria attack living cells and thereby cause disease.

False colour electronmicroscopic image of viruses attacking bacteria giving an idea of relative sizes. (Credit: Physics World)

Viruses on the other hand are purely destructive. They don’t do anything other than reproduce and that reproduction requires the death of a living cell. They are the ultimate parasite.

Space News for April 2020.

Like everything else nowadays even developments in space exploration are being impacted by the worldwide coronavirus pandemic. With the disease spreading like wildfire even NASA hasn’t been spared with personnel at both Cape Kennedy and the Manned Spaceflight Center in Houston having been tested as positive for the virus. In fact the need for ‘Social Distancing’ by the space agency’s personnel has seriously affected, if not actually brought to a halt the work on nearly every NASA program.

This includes the final tests and preparations for the James Webb space telescope, which was due to be launched just a year from now in March of 2021. The space telescope itself is currently in California where it had been undergoing its final assembly and testing. However California’s governor has ordered that all ‘non-essential’ workers remain at home so the entire effort on NASA’s largest unmanned program has come to a complete halt. How much of a delay this will add to the already behind schedule launch of the Webb telescope is impossible to say at present.

Shortly after this last unfolding test of the main mirror of the James Webb Space Telescope all work was halted due to the threat of Covid-19. (Credit: Space News)

However there are other programs that simply cannot be put on hold for one reason or another. The new Mars rover, recently given the name ‘Perseverance’ is perhaps the best example of this. You see the spacecraft’s launch window, the period of time when Mars is in the right position relative to Earth in the Solar system for a spacecraft to reach it, is only open during July and August of this year. If Perseverance doesn’t launch during that time frame then the mission will have to be delayed for a full 26 months until the next window opens in late 2022.

Technicians in Florida working on the Perseverance Mars rover can’t stop work. The rover has to launch in July or August! (Credit: CNN.com)

Because of that hard deadline NASA personnel are working around the clock on the final preparations for the spacecraft’s launch. Fortunately Perseverance has already been delivered to Cape Kennedy and is now undergoing prelaunch assembly but there’s still a considerable amount of work remaining. And even with the threat of a covid-19 shutdown looming over their work the technicians at Kennedy still have to do a meticulous, almost perfect job, anything less could compromise the success of the entire mission.

Part of the preparations for Perseverance’s launch included the last test here on Earth of the little drone helicopter that will accompany Perseverance down to the Martian surface. Before being packed into the rover vehicle for its long trip the helicopter’s two rotor blades were spun at 50 RPM on a test stand, the last time they will spin before they do so in the thin Martian atmosphere. While the helicopter is not considered an integral part of the Perseverance mission, officially it is referred to as a technology demonstration, if successful the little drone will take the first flight of any manmade object on another planet.

Final test of the little Helicopter that will travel to Mars aboard the Perseverance Rover. It’s now got to be packed up and made ready to go! (Credit: NASA JPL)

Another mission that could be delayed because of Covid-19 is Space X’s long anticipated first manned mission to the International Space Station (ISS). It was only a few weeks ago that Space X announced that this long awaited first manned mission of their Dragon capsule would take place the second week of May. That time frame however could very well put the mission right at the peak of the pandemic in Florida! Since this first mission of NASA’s commercial crew program is already more than two years behind schedule perhaps the wisest course at present would be to just delay the mission until well after the pandemic has run its course, until September or even later.

An unmanned Space X crew Dragon docking at the ISS. The first manned mission is scheduled for May but will Covid-19 cause a delay? (Credit: Space News)

Speaking of the ISS, what happens to the astronauts who are aboard the station if Cape Kennedy has to be shut down because of the pandemic?  While the astronauts themselves may be safe from Covid-19 their supply chain is definitely threatened by the situation here on Earth. All of the countries that are capable of resupplying the ISS are dealing with severe coronavirus outbreaks that may limit their ability to launch unmanned supply ships.

The Crew aboard the ISS may be safe from any viruses but what about their supply link with Earth? (Credit: NASA)

No doubt if the supply situation on the ISS should become critical then either the US or Russia would certainly, and ‘carefully’ assemble a resupply mission, but what if that launch should fail? In any case there is certainly a great risk that the normal operations of the ISS will be curtailed because of the virus.

The expedition 63 crew to the ISS was just launched from Russia after a prolonged quarantine period to make certain they weren’t infected with Covid-19 (Credit: NASA)

All of this is just another sign of how much the coronavirus outbreak is now dominating almost every aspect of human life, and not just here on Earth.

Paleontology news for April 2020.

As you know the science of paleontology is about origins, where did life on this planet come from and how did it find its wandering way to us? Well the big story this month fills in a rather large piece to that puzzle. Fossil hunters in Australia think that they may have discovered evidence of the first animal!

As you may guess the first animal evolved during the time of the very first multi-cellular life, a period now known as the Ediacaran period some 550 to 570 million years ago, see my posts of 16June2018, 15August2018 and 22January2020. Fossils of creatures from the Ediacaran were first unearthed back in 1946 but even from the beginning evolutionary biologists had problems connecting them to later, better understood groups of animals.

The Ediacaran creature Dickinsonia costata. Is that an animal, plant or what? (Credit: Wikipedia)

In fact analysis of the Ediacaran fossils indicates that these creatures were constructed in a manner totally unlike that of any life form that exists today. One example of this is the complete lack of anything resembling a mouth, anus or digestive tract in the Ediacaran fossils leaving scientists to wonder how the creatures consumed their food and excreted their waste.

Artists illustration of life during the Ediacaran period. Very different from the animal life of today! (Credit: Science Photo Library)

Additionally the very body shape of the Ediacaran fauna is strange, paleontologists often describing them as having a ‘quilted’ pattern, something like an air mattress. Another way in which the Ediacaran creatures differ from all modern animals is that, although at first glance they may appear to possess right-left symmetry a closer inspection reveals that in fact they are not bilaterally symmetric.

Bilateral symmetry is one of the cardinal features that connects all modern animals together. While it is true that individuals are rarely right-left mirror images, you may have a small mole on your right cheek for example. In general however people have as many moles on their left sides as their right. As a species we, and other animals are strongly bilaterally symmetric.

Bilateral Symmetry is a defining factor amongst almost all living animals. (Credit: Study.com)

Looking at the image below of a member of the Ediacaran genus Dickinsonia you might say that the creature’s segments are also bilaterally symmetric. However, taking a look at the second figure below, which is a blowup of the area where the right and left segments come together, we can see that the segments are actually offset from each other in a fashion known to mathematicians as glide reflection.

Dickinsonia and how it grew! Not like any animal alive today! (Credit: Wikipedia)
Closeup of the center line of Dickinsonia. Notice how the segments do not match up but are offset from each other. This pattern is called glide reflection and is unlike anything alive today! (Credit: Wikipedia)

Glide reflection shows up in a number of Ediacaran creatures such as Spriggina, Andiva and Yorgia. For glide reflection to be so prevalent among the Ediacaran creatures is also a clear sign that the manner in which they grew must have been very different from the way modern animals grow.

A fossil of Andiva ivantsovi. It’s little wonder that paleontologists have problems trying to connect creatures like this with our modern forms. (Credit: Wikipedia)

So if the best known fossil creatures from 550 to 570 million years ago were not related to modern animals then where was our ancestor? Well in a paper published in the Proceedings of the National Academy of Science (PNAS) Professor Mary Droser and lead author Scott Evans, a recent Doctoral graduate, both from the University of California Riverside claim to have found crucial evidence of our early ancestor in rocks from the original Ediacaran region of southern Australia. Recognizing that the first animal would certainly lack hard parts that could fossilize easily, otherwise it would have been discovered by now, they searched for small impressions in the rocks that might remain after the creature had died and decayed.

What they found were numerous rice grain sized depressions, 2 to7 millimeters in length and 1 and 2.5 in width, that showed hardly any clear indication of what the creature that made them looked like. Modern technology to the rescue however as the researchers used 3D laser scanning to precisely measure the outlines of the depressions. Based on those measurements the creature that made the depressions was basically tube shaped, bilateral, and was thicker at one end, presumably the front. In other words it was basically built like us. It was an animal. See image below.

Those little depressions inside the chalk square are all that remain of the first animal. (Credit: Albany Herald)
Result of Laser scan of an impression left by Ikaria wariootia. (Credit: Geology Page)

The paleontologists gave their new species the name Ikaria wariootia where Ikara means ‘meeting place’ in the local Adnyamathanha language and Warioota is the name of a creek that runs through the Ediacaran region. The laser measurements were so precise that Evans and Droser could even make out the faint body curves made by I wariootia’s muscles which bore a distinct resemblance to those of a modern earthworm indicating both how the creature moved as well as its mode of life.

Artists impression of Ikaria warioota. (Credit: University of California Riverside)

According to Doctor Droser. “This is what evolutionary biologists predicted. It’s really exciting that what we have found lines up so neatly with their prediction.”

The evidence is growing that the best known creatures from the Ediacaran period, Spriggina, Dickinsonia and their relatives, were evolutionary dead ends leaving no descendents in our modern world. Instead the future belonged to little worm-like Ikaria wariootia, and millions of years later to us.

The Phenomenon of Coffee Rings, can they be used to identify different brands of Whiskey?

With the coronavirus dominating all of the news going on in the world today I thought it might be a good idea today to have a more lighthearted post for a change.

We’re all familiar with coffee rings, the way a bit of spilled coffee or wine will dry to produce a hard, dark line around it’s edge while the center is relatively much paler. See images below.

A typical coffee ring. Notice how the edges form nice dark lines outlining the original area of the stain. (Credit: Inspiration Hut Marketplace)
Not all coffee ‘rings’ have to have a nice circular shape however. Again the dark edges clearly enclose a much lighter interior of the stain. (Credit: Wikipedia)

The cause for this phenomenon is a combination of two factors. The first factor is that evaporation of the spilled liquid occurs more rapidly at the edges simply because there is more surface area exposed to the air. Because the edges evaporate faster you would think that the area of a spill would get smaller as it dries but it doesn’t and that’s because of the second factor, capillary action.

A droplet of clear water on a surface. The roundness of the drop along its edges gives it a greater surface area there leading to greater evaporation. (Credit: Buggy and Buddy)
Instead of the evaporation around the edges causing the area of the droplet to shrink in size water flows from the center to the edges. (Credit: Robert D. Deegan et al)

Remember back in your High School Chemistry class when your teacher showed you the way water in a thin glass tube seems to try to climb up the sides of the tube, that was capillary action. Capillary action happens because of the fact that water molecules are more strongly attracted to molecules of other substances than they are to other water molecules. In the case of the glass tube the water molecules are attracted to the glass walls of the tube rather than other water molecules so they literally climb up the walls, forming what is known as a meniscus. See images below.

In a glass tube water molecules are more strongly attracted to the glass molecules than to each other. This generates capillary action as the water seems to try to climb the walls of the tube. (Credit: USGS.gov)

In a spill, the water molecules are more strongly attracted to the surface they are resting on than other water molecules so even though the edges are evaporating faster the area of the spill remains the same. In order to keep the area the same water flows from the center of the spill to the edges and any larger, darker molecules, like coffee, that are dissolved in the water are carried toward the edges by that flow. As the spill continues to evaporate more and more of the larger molecules are pushed toward the edges to be deposited and left there as the familiar ring once the water is completely gone.

The coffee ring effect can be a problem in some technologies that require an even deposition of a chemical across a surface, such as in printed electronics. Chemists studying the phenomenon have found that adding chemicals known as surfactants, that’s soap to you and me, can reduce the effect.

In an interesting twist on the subject, Stuart Williams, a Professor of Mechanical Engineering at the University of Louisville in Kentucky has been studying the patterns left behind after the evaporation of one of his state’s best known products, Bourbon Whiskey. What Professor Williams has found is that under controlled labouratory conditions instead of forming rings at their edges American whiskeys, and only American Whiskeys, form spider web type patterns. Not only that but each brand of American whiskey has its own unique pattern, a pattern so distinctive that it might be possible to use the technique to identify counterfeit whiskeys. See images below.

A sample of the spidery webs formed by different brands of whiskey. (Credit: Ars Technica)

Now I said that Professor Williams studied the phenomenon under labouratory conditions and that requires a little explanation because you see alcohol is another chemical that inhibits the formation of coffee rings. Too much alcohol, more than 30% and you’ll only get a uniform coating, no pattern of any kind. At the other end of the scale, too little alcohol and you only get the normal coffee ring effect at the edges. Only when the alcohol content was between 20-25%, or 40 to 50 proof, did Professor Williams obtain his spidery patterns. That means the doctor had to dilute his whiskey samples a bit, a horrible thought but remember this was all in the interest of science!

Doctor Williams in his labouratory. To his left you can see some of his test subjects. Nice work if you can get it! (Credit: Ars Technica)

  In his lab Williams tested 66 different brands of American whiskey, 56 bourbons and 10 from outside Kentucky along with 13 foreign whiskeys ( I don’t know how many were from Scotland or Ireland). To date only one of the American brands has failed to produce a web like pattern while none of the foreign brands has formed a web.

As for what could be causing the difference between the American and foreign whiskeys Williams says, “We believe that the increased solids extracted from American whiskeys is responsible for these patterns. The chemicals originate in the fermentation and distillation, but really undergo dramatic changes during maturation.”

Once again each different brand of American forms its own unique spidery pattern. With this in mind Professor Williams is taking numerous samples of each brand and averaging the results in an effort to build up a library of brand patterns. Williams hopes that the whiskey industry will be able to use this library both for quality control as well as spotting counterfeit products.

To be considered a true bourbon a whiskey must be distilled in Bourbon County Kentucky. That’s what makes counterfeiting profitable. (Credit: World Map)

It’s amusing to think that something as familiar and innocuous as coffee rings may wind up as a way to identify top shelf bourbons. At least I hope it got your mind off of covid-19 for a few minutes!