Month: December 2020

Using a Slime Mold as an inspiration Mathematicians in Japan have developed a simple solution to the Traveling Salesman Problem.

Right now the entire world is working its way through one of the most difficult logistical problems it has ever faced. The Pfizer Covid-19 vaccine, which has some very stringent storage requirements, has to be distributed as quickly as possible, well everywhere on the planet! It’s not an easy problem to solve, trying to find the most efficient way of getting the vaccine to literally every human being, and remember the longer it takes to get the vaccine to everyone the more people will die!

The First shipments of the Pfizer Covid-19 vaccine was carried live on several news channels! When has the simple act of shipping a product ever received such media attention! (Credit: Marketwatch)

Obviously shipping directly from the factory to each individual would not be the optimal solution, even if the vaccine didn’t have to be stored at a temperature of -70ºC. So instead you designate a number of depots, hospitals in the case of a vaccine, that receive shipments from the factory and then the depots distribute the vaccine to individuals.

The distribution of the Covid-19 vaccine is an enormous and complex problem and remember, lives are dependent on getting it right the first time! (Credit: StirlingUltracold)

In that case how many depots? Where should they be? What about a multi-layered approach where the factory ships to major depots that ship to smaller, more local depots in turn who then distribute the vaccine to individuals? So, how many layers? It’s a lot of questions to answer, and remember, people are getting sick every minute!

Real life situations like the Covid vaccine are members of a class of mathematical problems known as the ‘Traveling Salesman Problem’ or TSP. In its most simple description a salesman is required to visit N number of cities and wants to calculate the shortest possible route connecting them all. Remember the longer the journey the more time it takes and time is money after all. TSP is considered to be one of the classic problems in mathematical optimization.

The Traveling Salesman Problem is a mathematical problem in combinatorial optimization. (Credit: Slideshare)

For two cities the solution is pretty obvious. Travel to one city, then straight to the other and then back home, which city you visit first doesn’t matter since going along exactly the same path in the reverse order still leads to the same total distance. As you add cities however the problem quickly becomes much more complicated. Consider three cities, which we shall name 1, 2, and 3. There are in fact six separate combinations that get you to all three cities as shown in Table 1.

The six different paths you can use to visit three cities. In terms of distance however the combinations in the top row are equal to the combination directly beneath them so there are really only three solutions. (Credit: R. A. Lawler)

However once again following the same path in exactly the opposite direction leads to the same total distance traveled so there are really only three solutions, see Table 2. Each of these distinct solutions now has to be evaluated to determine which is the shortest.

The three unique solutions for three cities. (Credit: R. A. Lawler)

Adding one more city to bring the number to four increases the number of different combinations to 24, see Table 3. And even after we after we reduce the number by half to account for symmetry that still leaves us with 12 distinct paths to be evaluated for total distance, see Table 4.

Adding only one more city greatly increases the number of different paths. This is typical of combinatorial problems in mathematics. (Credit: R. A. Lawler)
For four cities there are 12 distinct paths. (Credit: R. A. Lawler)

So if our traveling salesman wants to visit two cities there is only one path for him to follow, for three cities there are three distinct routes, for four cities 12. As more cities are added the numbers just explode, five cities yields 60 routes and before long you’ve reached the point where even a supercomputer will have to take a good bit of time to find the optimal, shortest path. In fact the TSP is so simple yet so enormous a problem that it is often used to evaluate the performance of new computer and software designs and methodologies.

The Traveling Salesman Problem is both enormous yet simple. Because of these factors it is often used to evaluate the performance of the world’s best computers. (Credit: CNET.com)

Now in real life it usually isn’t necessary to find the absolutely best route. Think about it, if there are 50 million possible solutions then there are probably at least a thousand that are within 0.1% of the optimal. If one of that thousand can be found quickly it may make more sense to get started with a good solution rather than wait for a supercomputer to find the perfect one.

This is certainly a good route but is it the best one? Maybe a good route quickly is better than the best route later! (Credit: Algorithm Repository)

That’s why mathematicians at Hokkaido University in Japan have developed an analog computer that quickly finds a good solution to the TSP by mimicking the feeding behavior of, Slime Mold! You see slime molds are large, single celled organisms that are capable of deforming their bodies in a manner similar to an amoeba. In their search for food a slime mold will send out a number of tendrils is several directions. Those tendrils can sense the chemical traces of nutrients so tendrils that sense food nearby get bigger and longer and form sub tendrils while those that don’t sense food shrink.

Slime Molds are single celled organisms that are experts at finding the nutrients they need and ignoring everything else. (Credit: Quanta Magazine)

In this way a slime mold will very quickly find any available food and shape its body to take advantage of any resource. Inspired by the slime mold’s search methodology Professor Seiya Kasai and his student Ph.D. candidate Kenta Saito designed an analog circuit where resistance values are used to represent distances. A breadboard circuit for a four city problem was built that quickly found a solution that, if not the best, was significantly better than the average solution.

Block Diagram for an circuit that would solve the eight city problem. (Credit: ResearchGate)

The circuit is so designed that additional cities can be easily added and the amount of time required to find a good solution only increases linearly with the number of cities added. In other words while it would take a digital computer five times longer to calculate the best five city solution than the best four city solution, it only takes the analog circuit 25% longer to find a good five city solution.

The slime mold solution to the problem of designing the railroad network for the greater Tokyo area! Not bad! (Credit: ptc. Parking Consultancy and Traffic Engineering)

In the real world a good solution now is often better than the best solution later, remember time is money and in many cases lives. Slime molds took millions of years to evolve a practical way to solve the traveling salesman problem, now we can profit from their instinctive knowledge. Another example of science learning by studying nature.

Since increased levels of CO2 are causing Global Warming did low levels of CO2 cause the Ice Ages? New evidence from fossil diatoms indicates that it did.

We hear all of the time about how Carbon Dioxide (CO2) in our atmosphere traps the heat from our Sun causing the Earth to grow warmer. That’s the basic science behind the idea that burning of fossil fuels, which release large amounts of CO2 are causing the now obvious rise in our planet’s average temperature.

Every year we pour millions of tons of CO2 into the air. It’s almost hard to imagine a time when the Earth’s atmosphere didn’t have enough CO2 in it! (Credit: The Straights Times)

So if too much CO2 in the atmosphere can cause the Earth’s temperature to rise, then what part, if any, did CO2 play in the Ice Ages, those long periods of cold climate where huge sheets of glacial ice covered entire continents. The geological evidence for the Ice Ages is extensive and can be found across the temperate regions of the world. Whether it be the large number of fjords along coastlines or glacially carved valleys or deposits of boulders, rocks and soil pushed southward by the advancing ice and left behind as moraines when the ice retreated.

Over the past million years glacial ice has pushed down from the north to cover as much as half of North America several times. (Credit: Smithsonian Magazine)
As glaciers advance they push rocks and dirt out of their way. When the ice retreats the rocks and dirt form moraines that are evidence of the glacier’s existence. (Credit: www.geo.mtu.edu)

Ever since the existence of Ice Ages was first debated during the 18th and 19th centuries scientists have proposed many different theories to explain why the Earth goes from long periods of cold to equally long periods of warmth. One factor that is thought to possibly trigger the start of a glacial period is a shift in Earth’s orbit due to the gravitational pull of Jupiter and the other planets. These perturbations can occasionally lead to a slight increase in our planet’s average distance from the Sun.

Mighty Jupiter’s mass is as great as all the other planets plus their moons plus the asteroids and comets added together. It’s gravity can perturb Earth’s orbit pulling it a bit out from the Sun or pushing it a bit in changing the average distance a small amount. (Credit: UC Santa Cruz News)

Such an increase in distance would obviously cause a reduction in the Sun ‘s energy that Earth absorbs and there is in fact some correlation between the perturbations to Earth’s orbit as calculated by astronomers and the start of recent ice ages. However the variations in sunlight due to changes in Earth’s orbit are considered to be far too small to be the dominant factor causing an ice age.

In fact it is clear from both geological and climatological evidence that the conditions necessary for an Ice Age are only possible when the CO2 levels in the atmosphere fall below even the level at the start of the industrial age more than a hundred years ago. And chemical analysis of ice cores obtained from Greenland and Antarctica dating back tens of thousands of years have shown that the CO2 levels in the atmosphere during the glacial periods was as much as 30% less than during the warmer interglacial periods. 

Ice Cores obtained from glaciers in Greenland or Antarctica contain information about the atmospheric conditions tens of thousands of years ago. (Credit: Tallbloke’s Talkshop)

So where did all of that CO2 go? If there was 30% less CO2 in the atmosphere during the glacial periods what happened to it? Well, back in the 1970s oceanographers were able to show that oceanic diatoms, single celled algae with calcium-carbonate shells, absorb CO2 as a part of photosynthesis. When these diatoms die their protective shells then drop to the bottom of the ocean taking some of that CO2 with them. The huge amount of CO2 in the ocean depths has been measured from deep water samples gathered by submersible vehicles.

Diatoms come in a glorious variety of shapes and colours. Single celled plants in a calcium carbonate shell they live near the ocean’s surface and actually produce much of the Earth’s free oxygen. (Credit: Science Node)

Some of that CO2 is then brought back to the surface by deep ocean currents and under normal circumstances there is a balance between the CO2 sinking to the ocean floor and the upwelling currents bringing it back to the surface. However if anything was to change the rate of upwelling it could change the level of CO2 in the atmosphere and therefore the Earth’s climate.

Deep Ocean upwelling brings nutrients that have fallen into the ocean’s depths back to the surface. (Credit: Antarctic Glaciers)

Now researchers from Princeton University and the Max Planck Institute have succeeded in adding another piece of evidence to that model. The scientists, led by first author Ellen Ai, a graduate student at Princeton, recognized that the same upwelling currents that brought the CO2 to the surface also brought large amounts of nitrogen that would enrich the amount of dissolved nitrogen in the upper layers of the ocean. By measuring the ratio of nitrogen isotopes in the shells of the diatoms from deep sea cores they could obtain an indication of the amount of upwelling occurring as a function of time.

The gas Nitrogen comes in two stable isotopes. Both have seven Protons and Electrons. The most common isotope also has seven Neutrons while the rarer form has eight Neutrons. (Credit: The Fisheries Blog)

According to fellow author Alfredo Martinez-Garcia. “This allowed us to connect many features in the diatom nitrogen record to coincident climate and ocean changes from across the globe. In particular, we are now able to pin down the timing of upwelling changes, when the climate starts to cool, as well as to connect upwelling changes in the Antarctic with the fast climate oscillations during ice ages.”

The Earth’s temperatures have varied quite a lot over the last half million years. We are currently living in an inter-glacial period. (Credit: Utah Geological Survey)

So climatologists now have a new tool that will allow them to better understand the timing of past, and future ice ages. In fact scientists have long recognized that we are currently living in a warm period between two ice ages, and the next cold period is predicted to start about 50,000 years from now. It’s ironic therefore that our immediate problem is too much CO2 in the atmosphere causing global warming when our fate in the future may be decided on there being too little.

Sunspot cycle 25 has started and Solar astronomers have both new instruments and new theories with which they hope to learn more about the mysterious magnetic storms on the surface of the Sun.

We all learned about sunspots back in high school. You know those dark patches on the Sun’s surface that are actually magnetic storms the size of our entire planet or even larger. And you may recall that sunspots have an eleven year cycle starting with a minimum where few if any sunspots occur, growing to a maximum where the Sun’s face looks like it’s broken out in acne and then back to a minimum eleven years later. (That figure of eleven years by the way is approximate. The actual length of a solar cycle often varies by one or two years either way.) Finally, if you were interested you may have also heard that since sunspots are magnetic in nature they come in pairs with one being a north magnetic pole and the other a south magnetic pole.

Magnetic in nature Sunspots possess both a north and south pole but they are often so complex it’s hard to figure out which is which. (Credit: National Geographic)

Earlier this year the Sun went 200 consecutive days without a single sunspot showing on its visible face, and that was on top of a very small number of sunspots last year so obviously that period was a very deep minimum. Over the last four months or so however things have definitely started to pick up with a small number of fairly strong sunspots developing on the Sun’s surface.

The Sun as the ancients conceived it, an unblemished sphere. Earlier this year the Sun was in a deep minimum with no sunspot activity for 200 straight days. (Credit: Earthsky)

This increase in solar activity marks the beginning of solar cycle number 25, which since a solar cycle is about eleven years means scientists have been keeping track of sunspots for 260-270 years! The question now is whether the upcoming solar maximum, expected in 2025, will be another weak one as the last two have been, or will there be a dramatic increase in the number and strength of sunspots during the next maximum. The answer is important to our modern technological civilization because more solar activity means more solar flares blasting out powerful Coronal Mass Ejections (CMEs). These CMEs can collide with the Earth as powerful electrical disturbances that interfere with satellites in orbit, power grids here on the ground and radio transmissions around the world.

Remember that the Sun is really a hydrogen bomb that’s been exploding for the past 4.5 billion years. A occasional Coronal Mass Ejection (CME) is therefore hardly surprising. (Credit: Electroverse)

The official estimate coming from NASA and NOAA is that Cycle 25 will be a relatively weak one similar to the last two. However a team of solar scientists from the University of Warwick and the National Center for Atmospheric Research (NCAR) are using a new theory of solar activity to predict that the upcoming solar cycle will be one of the most powerful ever recorded.

Before our modern technological society began a CME was no threat to us. Today however we need to keep an eye on the Sun’s eruptions to protect the electronic services we all depend on. (Credit: The Sun)

The new theory pays attention to those sunspot cycles that are either longer or shorter than average and maps them against a 22 year long cycle. What they found was that a long solar cycle, such as cycle 23 which lasted 13 years, is followed by a weak sunspot cycle while a short cycle, cycle 24 was not only weak but also quite short at a little less than ten years, gets followed by a strong, active sunspot cycle.

By paying attention to the timing of sunspot cycles scientists at Warwick University believe they can better predict the strength of Solar activity. (Credit: University of Warwick)

The new theory already seems to be gaining evidence because cycle 25 is off to a strong start. In addition to several large sunspots there have been two powerful solar flares, one of which on December 7th sent a CME headed straight at Earth. The CME arrived here on the 9th producing auroras that were more powerful, and came further south than any in recent years.

The Sun today, 22 December 2020, courtesy of Spaceweather.com. (Credit: Spaceweather.com)

And solar astronomers now have newer, better more sensitive instruments with which to observe the forthcoming Solar Cycle. One of these is the Parker Solar Probe that is currently in an orbit around the Sun that is slowly getting closer and closer and which will come as close as 6 million kilometers in the year 2025. I wrote about the Parker probe in my posts of 12Feb20, 18Dec19, 3Nov18 and 5Sept18 but today I’d like to discuss the National Science Foundation’s brand new Inouye Solar Telescope.

The Inouye Solar Telescope and its target. Built on a high mountain on the big island in Hawaii I hope the recent eruption of Kilauea doesn’t disturb the telescope. (Credit: CSUN Today)

Now nearing completion as the world’s largest solar telescope, the Inouye is named for Hawaiian Senator Daniel J. Inouye, who was a strong supporter of the Mona Kea observatory on the island of Maui, the big island in the Hawaiian chain. Possessing a primary mirror 4 meters in diameter and with the latest advanced optics the Inouye will increase by a factor of 2.5 our resolution of Solar images showing previously unseen details that the theoreticians can use to check against their models.

A short video of solar activity as seen by the Inouye Solar Telescope. Those blobs are each about the size of continents! (Credit: Dzeen)

With that improved resolution it is expected that the Inouye will be able to see structures as small as 20 km across on the Sun’s surface. Since it is designed to capture and observe the light of the Sun the Inouye also has some equipment not normally found in a telescope, specifically a cooling system to keep the energy gathered from the Sun from overheating the entire system.

With advanced equipment like the Inouye Solar Telescope and the new theories developed by Solar astrophysicists Sunspot Cycle 25 promises to be an exciting one. Hopefully over the next few years many new discoveries will be made as we seek to learn the secrets of our nearest star.

Space News for December 2020.

Last month the big news from space was all about manned spaceflight. After all Space X had successfully launched its second manned mission to the International Space Station (ISS) just a matter of days after the ISS had celebrated its twentieth year of continuous occupation.

This month’s post on the other hand is going to be all about the robots who are exploring space and in particular two robotic missions that have just returned bearing with them samples of material from other worlds. This material will soon be analyzed in labouratories here on Earth in order to reveal some of the secrets of what the other bodies in our solar system are like. Another big difference between this post and the last is that whereas the construction and operation of the ISS has primarily been a US and Russian show the two nations who built, launched and operated the two robotic space probes were those two far eastern powers Japan and China.

JAXA is the space agency for the nation of Japan and who works closely with NASA. (Credit: Rocket Rundown)
CNSA is China’s Space agency which is basically a division of the Chinese military. For that reason the US congress has forbidden NASA from working closely with them. (Credit: Space.com)

I’ll start with Japan’s Hayabusa 2 probe because it was the first to leave Earth back in December of 2014 on its mission to the asteroid Ryugu. I’ve written about Hayabusa and its mission to Ryugu several times, see my posts of 27Nov2019, 20Apl2019, 6Mar2019 and 30Jun2018. Arriving at Ryugu in 2018 after a voyage of 300 million kilometers Hayabusa spent more than a year studying the space rock. During that time the robot dropped several small landers onto the asteroid’s surface, fired a copper projectile at Ryugu in order to dig a crater that allowed the main spacecraft to land and collect samples from beneath the asteroid’s surface.

The Hayabusa 2 space probe spent more than a year studying the asteroid Ryugu even touching down on the asteroid’s surface to collect some samples. (Credit: Universe Today)

Then in November of 2019 Hayabusa fired its rockets and began the return journey to Earth. As the main spacecraft skimmed past our planet on December 6th, it released a small 40cm in diameter capsule that contained the samples it had collected from Ryugu. That capsule reentered our atmosphere and deployed a parachute bringing it to a soft landing in the Woomer Prohibited Area of the Australian state of South Australia. Members of the Japanese Space Agency JAXA quickly found the capsule, declaring that the priceless cargo was in perfect shape and that the probe had brought back at least 100mg of material from Ryugu.

No that’s not a meteor streaking across the Australian sky. That’s the capsule from the Hayabusa 2 probe carrying a sample of Ryugu with it! (Credit: The New York Times)
Thanks to a radio beacon it didn’t take long to find the small capsule in the Australian desert. (Credit: Science)

As for the Hayabusa 2 probe itself, well it used Earth’s gravity to give it a velocity boost and it’s now on its way to another asteroid, one named 1998KY26. That will be another ten year journey but I think Hayabusa 2 is up for the challenge.

And if you think the mission of Hayabusa 2 was complex, well China’s Chang’e 5 robot mission went a step or two farther with an orbiter, lander, rover to gather samples, a blast off from the surface and docking in orbit. All that before a final return journey to Earth with the collected samples. To be honest the Chinese do have the advantage that the Chang’e 5’s target wasn’t 300 million kilometers away, it was right next door, the Moon.

The entire Chang’e 5 space probe being prepared for launch. A very complex spacecraft the lower section is the orbiter, with a return stage while the upper section is a lander, with an ascent stage. Four probes in one! (Credit: CollectSpace)

Building on the success of their Chang’e 4 lander and rover, which made the first ever landing on the lunar far side, the Chang’e 5 spacecraft was launched on November 24th from the Wenchang space facility on the Island of Hainan. Entering lunar orbit the landing module then detached from the orbiter and on December 1st the lander touched down in the Moon’s Ocean of Storms region at a volcanic area known as Mons Rümker.

By landing in the Mons Rumker area of the Moon’s Ocean of Storms the Chinese hope to collect the youngest rocks brought back from the Lunar surface. (Credit: Slate.com)

The lander then deployed a small rover, which was equipped with a scoop for the collection of as much as 2kg of lunar ‘regolith’. After spending two days, two Earth days that is, collecting and photographing the area around the lander the rover transferred its bounty to the lander’s ascent stage. Then on December 3rd the ascent stage blasted off carrying the samples with it and reached lunar orbit where it rendezvoused with the waiting orbiter.

Equipped with a scoop the Chang’e 5 rover spent two days collecting samples from the Moon’s surface. (Credit: Dhaka Times)
The blast off of the ascent stage was actually filmed from the lander’s base. (Credit: Spacenews)

The two spacecraft then successfully completed the first robotic rendezvous and docking in lunar orbit. Once docked the canister containing the lunar material was transferred from the ascent stage to the orbiter. With its job completed the ascent stage was jettisoned and ordered to crash back into the Moon’s surface in the central highlands region on December 7th. The orbiter then waited for a narrow launch window to open so that it could begin its return to Earth.

The Chang’e 5 capsule was quickly recovered, again thanks to a radio beacon. (Credit: South China Morning Post)

Firing its engine on the 13th of December set the recovery capsule on a three day journey back to Earth. Finally, on Wednesday the 16th the capsule entered our atmosphere, slowed its speed by air friction before releasing a parachute. At about 3AM local time the capsule came safely to the ground in the Siziwang district of China’s Inner Mongolian region. Following a transmitted radio beacon scientists with China’s space program quickly located the capsule and within hours it was on a airplane bound for a labouratory in Beijing where it will be opened up and its precious cargo removed.

So in the space of less than a month robotic probes have brought back to Earth material samples of two different celestial bodies. In the long debate over whether humans or robots should explore space this month the robots won. Of course the debate isn’t over yet, it still has a long way to go! 

New study uses the gene editing tool CRISPR to finally discover how the wings of insects evolved.

After intelligence probably the most astounding ability created by evolution during the history of life is the miracle of flight. The ability to fly gives such an advantage to any living creature that wings have evolved at least four separate times in different animal groups. These groups include the insects, the birds, the mammals and even the reptiles.

Flight has evolved in many very different kinds of animals. (Credit: Pinterest)

The insects were the first to take to the air and fly. We have fossil evidence of flying insects from as far back as the Devonian period when our vertebrate ancestors were just climbing out of the water. Evolutionary biologists have for many years theorized that the first insect ‘proto-wing’ developed not as a organ of flight but instead as an organ to help an insect regulate its body temperature.

The largest insect of all time was named Meganeuridae who lived during the Pennsylvania Period and had a 60-70 cm wingspan. (Credit: Geology In)

You see insects are cold-blooded and on a chilly morning many use the light of the Sun to try to warm up their metabolism. A knob on the insect’s back would increase the amount of the Sun’s heat that the insect could absorb, just like a solar panel, and the bigger the knob the better. Natural selection would then act so as to increase the size of the knobs until they became ‘proto-wings’ that an insect could at first use to glide or even catch the wind for a free ride. As the new wings grew even larger, and acquired muscles that allowed them to move, eventually the insect was able to fly.

Before they evolved for flight Insect wings were used as solar collectors to help the insect warm up their metabolism. (Credit: Ohio’s Electric Cooperatives)

Some modern insects still use their wings in that way. If you’ve ever taken a walk in a swampy area early in the morning you can find dragonflies and damselflies climbing up the stalks of tall grasses or reed. Climbing not flying because their metabolism hasn’t warmed up enough to produce the energy needed to fly. Once near the top the dragonfly will spread it’s wings to face the Sun in order to absorb the warmth of the sunlight which will increase its body temperature so that it can fly.

 So the question for biologists to answer was, where did those original knobs come from? For over a century entomologists looked in vain among the closest relatives of insects the myriapods, that is the centipedes and millipedes for some structure that could have evolved into those knobs. The search was in vain however because, as modern DNA analysis has shown, insects are actually more closely related to crustaceans, shrimp, lobsters and crabs than they are to centipedes and millipedes.

For many years biologists thought that insects were most closely related to centipedes and millipedes. Here’s a quick way to tell the difference between them! (Credit: Seed to Feed Me)
Modern DNA analysis has shown that insects are actually more closely related to shrimp and other crustaceans. (Credit: Arizona Aquatic Gardens)

And now a new study from biologists at the Marine Biological Labouratory (MBL) at Woods Hole has discovered the original bump on a shrimp’s leg that developed into the wings of insects. In a paper published in the journal Nature Ecology & Evolution, Research Associate Heather Bruce along with MBL director Nipam Patel have used the gene editing tool CRISPR to demonstrate how a lobe on the seventh, innermost segment of a crustacean’s leg was incorporated into the body of the ancestors of early insects as they moved onto the land. This segment provided extra strength to the exoskeleton of the early insects. In time the lobe then grew to become the long sought after ‘proto-wing’.

The gene editing tool CRISPR is revolutionizing many different fields of biological research. (Credit: Vox)

Doctor Bruce began by comparing the genetic instructions for the segmented legs of a tiny beach hopper shrimp called Parhyale to those in the fruit fly Drosophila and the beetle Tribolium. Now Parhyale, like all crustaceans have seven segments in their legs while both Drosophila and Tribolium, like all insects have only six segments. However all three species have an identical sequence of five genes that code the instructions for leg development.

Morphology of the legs of an ancestral crustacean, a modern shrimp (Parhyale) and an insect. (Credit: Nature Ecology and Evolution, Bruce & Patel)
Comparing the legs of Parhyale and an insect it is now clear that the Coxal plate of the shrimp is the structure that evolved into the insect wing. (Credit: Nature Ecology and Evolution, Bruce & Patel)

Using CRISPR Bruce disabled those five genes in embryos of all three species one at a time and monitored the results. What she found was that eliminating the genes eliminated the six leg segments farthest from the body. She also found that the seventh, nearest segment of the leg of Parhyale corresponds to a section of the back of the exoskeleton of the insects. Most importantly, a lobe on that seventh segment, called the Tergal Plate moved with the segment becoming a perfect candidate for the knob that evolved into the insect wing. The story of the evolution of the insect’s wing clearly demonstrates the power of natural selection in taking a structure in the body of an animal and altering its shape to perform an entirely new function. The story of how DNA analysis and gene editing have enabled scientists to work out the details of that evolution clearly show the power of the newest tools that biologists possess in their study of life here on Earth.

Invasive Species alert for December 2020. Two little creatures that are little or no trouble in their own habitat but who have the potential to become big problems in other ecosystems.

Invasive species, those creatures that have succeeded in leaping out of their original environment into a foreign habitat are becoming more and more of an environmental problem. In many ways the problem of invasive species is one that is becoming as difficult to solve as global warming or pollution. Most of these invader species are animals that have managed to hitch a ride on the international and intercontinental traffic and trade that we humans have developed. Once established in new habitats without their natural predators to keep their numbers in check these trespassers can squeeze out native species often causing economic as well as environmental damage.

Creatures that are cute and cuddly in their own environment can become monsters as invasive species in a foreign land. Ask any Australian about rabbits! (Credit: Treehugger)

In this post I’d like to discuss two species that have recently been spotted in new ecosystems and for whom there are now efforts underway to eradicate the new colonies before they spread too far. One of the species you may never have heard of but I’ll start with the one who’s gotten a bit of press coverage because it has a ‘Murder’ nickname.

Let’s face it ‘Murder Hornets’ just plain look nasty! (Credit: The Cut)

And Asian Giant Hornets, now commonly referred to as Murder Hornets do in fact kill around one hundred human beings every year. At a size of 45mm in length their 6mm long stinger is quite painful and when you add in their venom the sting of a dozen or so can often prove lethal. It’s not human beings who have the most to worry about from these monsters however; it’s their insect relatives the honeybees that are most in danger.

When it comes to their relative the honeybees murder hornets are simply killing machines! (Credit: Insider)

Taxonomically the Asian Giant Hornet, Vespa mandarinia is the largest member of the genus Vespa, the true hornets. Native to East Asia, South Asia and Southeast Asia they are a predatory species that hunt medium to large sized insects, particularly bees, other hornets and mantises. With its large crushing mandibles a single Murder Hornet can decapitate 30-40 honeybees a minute and a score or more of the hornets can wipe out a hive of thousands of bees in just a few hours. While the adult Giant Hornets feed by sucking out the juices of their prey the whole carcass is fed to their larva, who digest the proteins to build their own bodies.

Now the Asian Giant Hornet is invading North America, specifically the Pacific Northwest region including British Columbia and the state of Washington. The first sighting came in August of 2019 when three hornets were found on Vancouver Island. Those three were traced back to a nest that was then destroyed. That did not end the threat however as more than a dozen other sightings were made over the next year cumulating in the discovery of a large nest in a tree in Blaine, Washington. When that nest was destroyed it was found to contain over 500 hornets, including 200 queens.

TOPSHOT – Sven Spichiger, Washington State Department of Agriculture managing entomologist, displays a canister of Asian giant hornets vacuumed from a nest in a tree behind him on October 24, 2020, in Blaine, Washington. – Scientists in Washington state discovered the first nest earlier in the week of so-called murder hornets in the United States and worked to wipe it out Saturday morning to protect native honeybees. Workers with the state Agriculture Department spent weeks searching, trapping and using dental floss to tie tracking devices to Asian giant hornets, which can deliver painful stings to people and spit venom but are the biggest threat to honeybees that farmers depend on to pollinate crops. (Photo by Elaine Thompson / POOL / AFP) (Photo by ELAINE THOMPSON/POOL/AFP via Getty Images)

So the odds are that there are other Asian Giant Hornet nests out there as well and that the pest will continue to spread.  Beekeepers and farmers in the region have been asked by their Departments of Agriculture to be on the alert and report any sightings. Like most invasive species they have no natural enemies in North American so human intervention is the only way the Asian Giant Hornet is going to be controlled. 

There is one good thing to report about the Asian Giant Hornets, they’re supposed to taste pretty good. In Japan the larva are consumed fried while several cultures roast the adults on skewers over a fire. Personally I’d rather not have the opportunity to try one.

Like many insects murder hornets actually taste good. Many Asian cultures have recipes for them but let’s hope American chefs never get the chance to develop new ones. (Credit:

The next invasive species I’ll talk about today is actually one I’ve already discussed in my post of 31May2018, hammerhead worms of the genus Bipalium. In that post I described how these alien looking worms, which are native to Asia, had invaded Southern France and were preying upon the beneficial native worms who help keep the soil fertile by aeration and mixing. In addition to having no natural enemies outside of Asia the hammerhead worms also excrete toxic chemicals through their skin that may not be harmful to humans but which will make any bird who tries to eat one very sick.

As I said in my earlier post these hammerhead worms are spreading across southern Europe, causing a great deal of damage, and now they’re in the United States. That’s right hammerhead worms have been collected in Texas, Illinois and now Georgia. Over one hundred of the creatures have been reported recently in the Atlanta area so there must be thousands going unnoticed.

They may not look as dangerous as murder hornets but hammerhead worms can do a lot of harm nevertheless. (Credit: New York Daily News)

If these predatory worms continue to spread they could become a real menace to agriculture, but presently we don’t even have a strategy to deal with them. To my knowledge we haven’t even identified how they are spreading across states, countries and continents. Much more research is needed on these invaders before we can even attempt to control, much less eradicate them.

Hammerhead worm attacking an earthworm. As predators hammerheads are actually quite deadly. (Credit: ThoughtCo)

Every invasive species is a Pandora’s box of its own. You can never tell what horrors are going to come out once opened and once they’re let out it’s almost impossible to put them back in.

In the legend of Pandora after all the ills of the world had been released only hope remained! (Credit: Mythman)

Extra: No sooner had I finished writing this post than a new study has announced how the Asian Honeybee protects itself from the Asian Giant Hornet. Researchers in Vietnam from the Vietnamese Academy of Science and Technology in Hanoi have observed that whenever a honeybee hive is threatened by a hornet attack the worker bees will gather animal feces and spread it around the entrances to the hive.

Asian honeybees have learned to use animal feces as a defense against murder hornets. Wish we could teach our honeybees the same trick! (Credit: Global News)

It is currently not known whether the smell of the poop actually repels the hornets or if it simply disguises the smell of the hive confusing the hornets but it certainly does appear to work. This also represents the first discovery of bees using a tool in the wild adding these social insects to the small by growing group of animals that know how to use tools.

Unfortunately the European honeybees that are most common here in the US have not acquired this defensive strategy so the threat posed by the Giant Asian Hornet to American bees populations is still present.

Whale Strandings, what causes such bizarre and self-destructive behavior, and could we be to blame?

On the 24th of November a mass stranding of over 120 pilot whales along with a half dozen dolphins was discovered on the Chatham Island group some 600 km east of the main Islands of New Zealand. Now the Chatham islands have long been known as a whale ‘hot spot’, an area were large numbers of many different species of aquatic mammals congregate, and unfortunately often die by swimming right up onto the sandy beaches.

One of the unexplained tragedies of nature, Whale strandings. Here are a pod of pilot whales lying helpless on the beaches of the Chatham Island. (Credit: Sky News)

Because of the remoteness of the islands getting help to the beached animals was difficult and in the stranding on the 24th ninety-seven pilot whales were dead before rescuers could arrive and the remaining twenty-eight were in such bad shape that they had to be euthanised. Such mass deaths are common on the Chatham islands with an average of over 300 dolphins and whales dying there each year. Indeed the largest mass stranding in recorded history, over 1,000 animals, occurred there in 1918.

So why do such mass beachings happen, what causes otherwise healthy marine whales and dolphins, collectively known as cetaceans, to just swim onto a beach where, unable to get back into the water, they die of exposure? To scientists it’s pretty much of a mystery but there are historical records of such events happening dating back thousands of years so at least this time it’s not our fault. Well, not all our fault as we shall see.

The world’s largest predatory is the Sperm Whale. Here are two dying slowly on the shore. No one knows exactly why these creatures do this! (Credit: New Scientist)

One important clue to the beachings is the fact that virtually all of the animals involved are toothed whales and dolphins, active hunting animals who prey on fish and other marine life. The big filter feeding baleen whales appear to be relatively immune to whatever it is that causes the strandings. Another clue is that it is whale and dolphin species that usually live in deep water that are most susceptible to beachings, animals that are more familiar with shallow water environments rarely strand themselves.

The filter feeding Baleen Whales only rarely strand themselves and most of those sightings appear to be animals who died at sea and were washed ashore postmortem. (Credit: Scientific American)

Some of the most often discussed hypothesis to explain the mass beachings include animals chasing their prey too close to unfamiliar shores and getting caught by a falling tide. Or in some cases the animals themselves could be chased by their predators onto the shoreline. Animals who normally live in deep water and are using their echolocation ability to navigate might be fooled by the gently sloping rise of a sandy beach into thinking they are in deeper water. Also mass beachings often occur in species with strong herd instinct and it might be that an illness in the lead animal, even just an earache, could lead to the stranding of the entire pod.

Whales and Dolphins invented SONAR long before we humans did. But just as mirages can confuse us sometimes the echolocation of Whales and Dolphin’s can be in error. (Credit: ffden-2.phys.uaf.edu)

Some scientists have also suggested that, if whales navigate by using Earth’s magnetic field, as Pigeons appear to do, Solar storms could be the cause. A few researchers have even suggested that global warming and ocean pollution, that is plastics, could be making the problem worse. Finally there is growing evidence that high-powered Sonar pulses generated by naval warships searching for submarines does cause damage to the ears of whales and dolphins and a link between Sonar and some cetacean strandings now seems very likely.

For the US Navy Sonar is the eyes and ears, especially ears looking for enemy submarines. (Credit: YouTube)

There was a time, not so long ago that people considered beached whales to be a fortuitous event and they would rush to kill and harvest the helpless animals for food or their oil. It’s really only been in the last 50-60 years that serious attempts have been made to help the stranded animals and refloat them back into the ocean. So far those efforts have had mixed results, often because the beachings are not discovered until it is too late for many of the animals.

To the Eskimos a stranded whale is still a bonanza to be carved up for food and other resources. (Credit: PRI.org)
Today humans are more likely to help stranded cetaceans then take advantage of them. I guess that we are slowly becoming more responsible. (Credit: Thisness of a That – Blogger)

Still we are trying to help and the more we try the better at it we will get. It’s nice to see that for a change human beings are doing what they can to alleviate a tragedy in the natural world rather than being of cause of one.

Backyard astronomers get ready for some interesting sights in 2021 and a big one that’s happening shortly before the end of 2020.

Every year there are events taking place in the sky above our heads that are worth taking a few minutes to check out. Problem is that, unless you know that something like an occultation or conjunction is coming up it’s easy for even someone who keeps his eyes to the sky like I do to miss them.

The Universe, the Show that never ends!! (Ohio State University)

That’s even true of big events like a lunar or a partial solar eclipse. O’k a total solar eclipse is kinda hard to miss but let’s be honest most people wouldn’t notice a partial eclipse that covers half of the Sun unless they’d heard about it on the news. It helps therefore to have a listing of upcoming astronomical events to refer to over the course of a year in order to catch at least a few of them. That’s what I hope this present post will be, and if I can get a few of my readers out there to take a few minutes now and then to go outside on a clear night and appreciate the view of heaven above them I’ll have done my job.

A Total Eclipse of the Sun is kinda hard to miss but many other interesting sights are more subtle so it helps to know when one is coming up. (Credit: Inc. Magazine)

Now conjunctions are the most common astronomical event and the easiest to miss. A conjunction is simply two bright objects in the sky coming close together and since the real stars don’t move that means at least one object has to be either the Moon or a planet.

This month a very close conjunction between two of the planets is going to occur. At about midnight UTC on December 21, that’s around 7PM EST for folks on the US east coast like me, Jupiter and Saturn will appear closer in our sky than they have since the 4th of March in the year 1226, that’s nearly 800 years! The angular distance between the two planets will be less than 1/5th the diameter of the Moon making them look like a double planet.

As seen along the east coast of the US the conjunction of Jupiter and Saturn will be close to the horizon but still easy to spot. (Credit: Space.com)
As seen through a small telescope not only will the two planets be visible but several of their larger moons as well! (Credit: Fox News)

Now if you live a part of the world where midnight UTC is daytime for you or if it happens that your sky is cloudy on December 21st don’t panic. You see Jupiter and Saturn both move pretty slowly across the sky so they’ll be real close together for several days. For nearly ten days, from Dec 16 to the 25th the two planets will be closer than the width of the full Moon.

 And I hope everybody realizes that when I say the two planets will be close together that only means that they appear close together from our point of view. Jupiter and Saturn will still be hundreds of millions of kilometers apart but the Earth, Jupiter and Saturn will basically be in a line across the Solar system more than a billion kilometers long. This is true for all conjunctions, the two planets, or Moon and planet only appear to be close from our point of view.

During the conjunction Jupiter and Saturn will only LOOK like they’re close together as seen from here on Earth. In reality they will still be millions of kilometers away from each other. (Credit: Time and Date.com

Then during 2021 there will be another four planet to planet conjunctions. On the 5th of March, at about 5AM UTC the planets Jupiter and Mercury will be a little more than half the width of a full Moon apart. Now remember Mercury never gets very far from the Sun so it’s only visible shortly before dawn or shortly after sunset. During March it will be a morning star so you’ll have to get up early in the morning to see it so close to Jupiter.

Then on the 29th of May at 3AM UTC Mercury will be close to Venus, just about a full Moon diameter apart. This time Mercury, and Venus will be evening stars, and quite close to the Sun so make certain that you have a clear horizon to the west as the Sun goes down if you want to see their conjunction.

On the evening of May 29th in 2021 it will be Venus and Mercury who will be putting on a show. (Credit: Star Walk)

At the height of the summer it will be Venus and Mars who will be coming together. On the 13th of July around 1AM UTC the two planets will be about a full Moon diameter apart and get this, the Moon itself will be right above them so close that you could cover all three of them with the palm of you hand!

Paul McCartney and Wings had an Album called Venus and Mars but I don’t think it was about a conjunction. (Credit: Wikipedia)

The last planet to planet conjunction of 2021 will take place on the 19th of August when Mercury and Mars will approach to less than one sixth of a Lunar diameter at 3AM UTC. Again this conjunction will take place in the evening very shortly after sunset.

Now remember, all of the times I gave are for the moment of closest approach of the two planets but as I said above planets don’t move very fast in our sky so if it happens that it’s daytime where you are at the precise time I gave, or if it’s cloudy don’t panic. You can still see a good show anytime within say 48 hours on either side of the time I listed.

Now as I mentioned above the Moon can also come close to a planet, in fact it can even pass in front of one completely covering it in a way similar to a solar eclipse. These events are known as occultations and like eclipses only a small part of the Earth actually sees the Moon pass in front of the planet, the rest of us only get to see a conjunction. The first occultation takes place on the 17th of April at about 1500 hrs UTC when the Moon will cover Mars. At least it will for those people in India and southeast Asia, the rest of us will see Mars come closer than a fifth of the Moon’s diameter.

As the Moon moves through its cycles it often passes in front of a planet or star. This is called an occultation. Here the Moon is about to cover the star Aldebaran, of eye of Taurus the Bull, back on July 29th of 2016. (Credit: Skymania)

The second occultation will involve the planet Venus when the Moon passes in front of it on the 8th of November as seen by people in Japan, Korea and the far east Russian city of Vladivostok.   This occultation or conjunction, depending on where you live, will take place in the early evening after the Sun sets.

Like Total Solar Eclipses only a small portion of Earth’s surface gets to see an occultation. This is a map of the area that will be able to view the November 8th occultation of Venus. (Credit: In-The-Sky.org)

Finally, and appropriately on the last day of the year December 31st, the Moon will pass in front of Mars putting on a great New Year’s Eve show for people in Antarctica and southern Australia. The rest of us will get to see the Moon pass by close to Mars.

O’k so what about the big celestial events, the eclipses. Well it turns out that 2021 will be a good year for Solar eclipses, if you happen to live at one of the poles. On June the 10th the North pole and a bit of Northern Quebec will be treated to an annular eclipse of the Sun, that’s where the Moon doesn’t quite cover the Sun but instead blots out most leaving a ‘Ring of Fire’. Then on December 4th the South pole gets to see a total eclipse, the rest of us will just have to wait for other years. There is going to be one total Lunar eclipse on the 26th of May at 1:20AM UTC that will be visible for Southeast Asia, Australia and the West Coast of North America.

There will be two total Solar eclipses in 2021 but not many people are going to get to see them. (Credit: TimeandDate.com)

Those are going to be the major astronomical events over the next year. I hope to be able to check out a few of them and I hope that you will too.