Category: Science

Archaeology News for January 2021: Archaeology helps to reveal the power, or lack thereof, of invading Armies.

History is full of stories about invading armies. Records dating all the way back to the early Bronze Age chronicle war after endless war of conquest. And since it’s the winners who write the history those chronicles are packed with what today we would call spin, arguments to justify the murder and theft because we were right and the loser was wrong. Even modern historians, dependent as they are on original sources all too often take those biased records at face value. And so the distortions of the truth written down by some ancient supporter of a cruel, bloodthirsty conqueror are propagated to a new generation.

Many of our oldest stories, like the Iliad of Homer, are about conquests by invading armies. I guess things really haven’t changed that much! (Credit: Brewminate)

Archaeology has no such prejudice, the artifacts and architectural remains excavated by archaeologists cannot lie or deceive, the evidence they give is without bias. Of course that evidence is subject to interpretation but as more evidence accrues eventually a fairer, more balanced picture of the events of the past can be gained by archaeology than by accepting the one-sided chronicles of the victors. In fact, over the last 150 years archaeology has many times overturned accepted history by restoring, to some degree, the voice of the losers.

The actual walls of Troy, recovered by archaeology their story may be hard to read but at least they don’t lie to us! (Credit: YouTube)

Perhaps the greatest empire of them all was that established by the city of Rome. It is true that the very word empire comes from the Roman word imperator, originally just a title for a victorious general. How a single city could found so large and long lasting a political system is one of the great questions in history. The Roman system was quite simple, ‘You accept our rule, and pay our taxes and you shall have peace and order. (Remove sword for emphasis) But you will accept our rule!’ The Romans could be both fair and just, but when opposed they were one of the most brutal regimes in history.

Often considered the best fighting machine before the invention of gunpowder, the Roman legions were the first real professional soldiers instead of just noblemen playing at war. (Credit: Quora)

One part of their empire that the Romans spent nearly 200 years conquering and pacifying was the Iberian peninsula, modern Spain and Portugal. Roman influence in Iberia began during the Punic wars against Carthage in the second century BCE but it wasn’t until the early first century CE that the entire peninsula was finally secured with the conquest of the rugged northwestern quarter of the peninsula.

The Romans only succeeded in finally conquering the entire Iberian peninsula in 19 BCE. (Credit: Spain then and Now)

A new study by archaeologists at the Archaeology Institute of Merida in Extremadura Spain, the University of Santiago de Compostela in Galicia Spain and the University of Exeter in the UK has revealed the extent of Rome’s efforts to subdue the region. Using the latest high tech archaeological tools, such as Aerial Photography, Satellite Imaging and Light Detection and Ranging (LiDAR) the paper, published in the journal ‘Geosciences’ details the locations and sizes of 66 fortifications spread throughout northwestern Spain and northern Portugal. Those fortresses were built by the Romans during the first century BCE and ranged in size from small forts with only a thousand or so square meters of area to large fortresses of up to 150,000 m2. Based on their size the number of men garrisoning the forts could have been as small as a few score to thousands.

Distribution of Roman Forts discovered by archaeological team. (Credit: Sci-News.com)

Spread strategically around the countryside the large number of forts would have allowed the Romans to quickly attack any threat, strike back against any uprising, and from several directions at once. Typically such Roman military sites would have been used for training and storing supplies as well as quartering troops in both warm weather and the cold hard winters of that region.

All that remains of the fortifications that Rome built to control NW Iberia are a few lines in the soil but archaeologists can learn much from those few traces. (Credit: Blanco, Sanchez et al in Goesciences)

In a sense the fact that the Romans had to employ such military might to first conquer and then control northwestern Iberia speaks volumes about the resistance they faced from the indigenous population. The Roman historians may have portrayed that conquest as barbarians being civilized but the facts of archaeology clearly show how hard the Iberian people fought against Rome’s idea of civilization.

Of course not all conquests are by civilized people defeating barbarians, just as often the exact reverse is what happens. One well-known example of an orderly, prosperous society being destroyed by nomadic warriors is the conquest of the Central Asian river civilizations by the Mongol hordes of Genghis Kahn. According to history the cities around the Aral Sea were for nearly 2,000 years major hubs along the famed ‘Silk Road’ between the Middle East and the Far East. This wealthy, long-lived culture, estimated to have had as much as 50,000 square kilometers of irrigated land, twice the area of fabled Mesopotamia, was destroyed early in the 13th century by the invading Mongols.

The Mongol tactics of swift horsemen firing arrows in lightning attacks succeeded in conquering the largest empire in history. It didn’t last long however. (Credit: Pinterest)

Or maybe not, for a recent paper published by the Proceedings of the National Academy of Science disputes that long held view. The paper, led by co-authors Dr. Willem Toonen of Vrijje Universiteit in Amsterdam and Dr. Mark Macklin of the University of Lincoln instead puts the blame squarely on a more than 200 year long cycle of drought that sapped the strength of the river cities before Genghis Kahn and his cavalry came riding from the east.

Today the region between the Caspian and Aral seas is a pretty harsh desert but a thousand years ago it was more fertile and an important hub on the Silk Road. (Credit: Nature)

The archaeologists based their conclusion on a detailed analysis of conditions from habitated sites and irrigation canals of the Otrar oasis at the junction of the Syr Darya and Arys rivers in modern Kazakhstan. So extensive are the archaeological remains at Otrar that it has been named as a UNESCO designated World Heritage Site. What the scientists discovered there was that many of the cities had begun to decline as early as the 9th century due to the onset of a drought that lasted for centuries. By the time the Mongols arrived in 1219 CE many of the cities and canals at Otrar had already been abandoned. Genghis Kahn only delivered the final blow to a culture already in deep trouble.

A large archaeological site at the Otrar oasis. Sites like this one have received little attention from archaeologists so we have little idea of what discoveries are there to be made. (Credit: www.icomos.org)
A few of the remains from the civilization around the Aral sea. Few of these sites have been adequately excavated so there’s an entire ‘lost civilization’ waiting to be unearthed. (Credit: Stanford Al Lab)

According to Dr. Macklin. “Our research shows that it was climate change, not Genghis Kahn, that was the ultimate cause for the demise of Central Asia’s forgotten river civilizations.” In fact the archaeologists were able to show that the people of the Otrar oasis had recovered quickly after the earlier Arab invasions of the 7th and 8th centuries because the climate at that time was much more favourable. Hummm, climate change causing harm to a civilization, sound familiar!

All that remains of an irrigation canal made a thousand years ago. Today there isn’t enough rain to even make using a canal worthwhile. (Credit: EurekAlert)

These two studies illustrate how the knowledge gained by archaeology can be used to paint a truer picture of the conflicts of the past. History may be written by the winners but the losers still have a story to tell and archaeology is helping to recover those lost voices.

Review: E-Book and Website: “False Steps, The Space Race as it Might Have Been” by Paul Drye.

I recently came across a fascinating website containing a large number of articles concerning proposed manned space projects that never succeeded in making it beyond the drawing board. In looking over the website I happened to notice that all of the material it contained was available as an E-Book so of course I quickly bought myself a copy, and borrowed my brother’s Nook so I could read it! To anyone who is as interested in the history of manned space exploration as I am you’ll find ‘False Steps’ to be both a trip down memory lane and a revelation of unknown projects.

I don’t know if ‘Front Cover’ really applies to an E-Book but here’s the front cover of ‘False Steps’ by Paul Drye. (Credit: Paul Drye)

The projects described in ‘False Steps’ date from as early as the 1940s to as recently as the 2010s. And the projects discussed don’t just come from the US or even the US and USSR, they come from every country that has ever thought about putting a man in space. Author Paul Drye must have expended a great deal of effort hunting down and reading some of the information about the Chinese 1970s space program or Hermes the spaceplane France tried to talk the European Union into building, not to mention the rival British Multi-Role Capsule.

Though it went through several revisions the Hermes Spaceplane was a smaller version of the American Shuttle intended to carry passengers but little cargo. (Credit: Pinterest)

Some of the most interesting topics include the two, that’s right two failed Russian manned Lunar Programs, which I discussed a bit in my post of 14June2019. It’s a fact that the Soviets hoped to send men to loop around the Moon as early as 1967(!) using a completely different main rocket than their landing mission would use a few years later. While there were many reasons why the Soviets failed with both attempts certainly one of them has to be the competition for resources between two completely different programs.

The Russian Zond 5 mission actually succeeded in sending a few animals, like these turtles, around the Moon three months before the Apollo 8 astronauts!

But at the same time NASA, the American space agency also received several proposals from McDonald Aircraft Corporation, who build the highly successful Gemini spacecraft, to use the Gemini as a basis for a Lunar orbiter. Those proposals never became more than back of the envelope ideas however because NASA committed itself to Apollo and avoided any of the distractions that plagued the Russians.

Detailed configuration of McDonald Corporation’s plan to send a Gemini spacecraft around the Moon. NASA wisely just stuck to Apollo but the alternate possibilities discussed in ‘False Steps’ are fascinating! (Credit: The High Frontier Blog)

As I mentioned above ‘False Steps’ also contains a wealth of information about projects that came close enough to manned launches that there was some public discussion of them, i.e. I heard about them. The US air Force’s Manned Orbiting Labouratory (MOL) and the USSR’s Buran space shuttle are two examples. But ‘False Steps’ also contains information about projects that I had never heard of such as NASA’s plan to use Apollo technology to perform a manned flyby of the planet Venus in 1973. Another way out project was the Lunar Escape System or LESS that in the case of a disastrous Moon landing by the LM, would allow the stranded astronauts to use parts of the LM to built, on the Moon, an escape rocket!

The Manned Orbiting Labouratory (MOL) was another variant using the Gemini spacecraft that almost got into orbit. I remember reading about it when I was growing up. Only years later did we find out it would have been a manned spy satellite! (Credit: Secret Projects Forum)

Now in a sense ‘False Steps’ is all about might have beens. Reading it you think about how things could have been different. What if von Braun had been allowed to launch a satellite in 1956, a year before Sputnik? He was ready. What if Sergei Korolev hadn’t died in 1966? What if Nixon hadn’t done everything he could to kill the space program as president?

One problem with ‘False Steps’ is that Paul Drye only includes one image per article, and not always one. There are so many images available that there easily could have been more. For example Mr. Drye mentions the X-20 Dyna-Soar several times but never includes an image of the proposed spaceplane. (Credit: YouTube)

As I said at the beginning ‘False Steps’ is both a webpage, address below, and an E-book. So what you can do is visit the site, read a few of the articles and decide if you’d like to get the E-book, which you can do right from the site! If you find yourself as I did reading a half a dozen articles before you even realize it, get the book! You’ll be glad you did. The address is https://falsesteps.wordpress.com/. Have Fun!

Paleontology News for January 2021.

In this blog I have often discussed some of the latest research in paleontology. Sometimes the discussion was about the discovery of a new species of dinosaur or trilobite. Or perhaps I discussed the latest understanding about the way those ancient animals lived, or in the case of mass extinctions died.

I freely confess however that I haven’t talked a great deal about the fossil evidence from ancient plants. So when a story about a 100 million year old flower encased in amber caught my eye, well you’re reading the result.

There are a wealth of fossil plants that have been collected and cataloged but let’s be honest, they’re just not as cool as Dinosaurs! (Credit: WCAI)
Nevertheless a fossil flower encased in amber is a real find of great importance. (Credit: Sci-news.com)

The chunk of amber in question came from that mine in Myanmar that has produced some very amazing fossils during the last 3-4 years from a period of time some 100 million years ago ; see my posts of 16Dec2016, 1Jun2019, and 2Aug2020.  Part of the reason that this fossil flower is so important is that the evolution of flowering plants is thought to have begun only a few million years earlier and indeed many of the details of the flower point to its being rather primitive.

Remember the dinosaur tail found in amber? Well the flower comes from the same mine which has produced a huge number of very important specimens. (Credit: The New York Times)

The flower had only male parts and comes from a new species, which has been given the name Valviloculus Pleristaminis. With a length of only 2mm, it is thought that the preserved specimen was probably one in a cluster of tiny flowers, something resembling a modern bluebell, with both male and female flowers.

Despite its small size the flower was preserved so perfectly that 50 individual stamens along with many other details can be easily discerned. The flower was described in a new paper by emeritus Professor George Poinar of Oregon State University who is a longtime expert on fossils in amber and whose work is considered to be part of the inspiration for the original novel “Jurassic Park”.

George Poinar of Oregon State University with a small part of his collection of fossils in amber! The idea for the book, and movie ‘Jurassic Park’ came from his work! (Credit: Oregon State University)

Paleontologists have many questions regarding the early evolution of flowering plants, technically known as angiosperms. It is hoped that this fossil flower, along with others from the same site, will provide new evidence to help answer some of those questions.

My second story for this month comes from almost the opposite end of the world, the land of my forebears, Ireland. Now Ireland is a small country and geologically the island is built on a bedrock of very old Paleozoic rock with a layer of much more recent glacial deposits on top. That means that while Ireland has a lot of fossils they are virtually all either more than 250 million years old, or less than about 20 million years old. In other words no dinosaur fossils!

Ireland has a wealth of fossils but virtually all, like these primitive amphibians are much older than the dinosaurs! (Credit: The Irish Times)

Now that doesn’t mean that Ireland never had any dinosaurs, it’s just that the evidence, the rocks that formed during the age of dinosaurs has been worn away by the Ice Ages of the last few million years. There could have been dinosaurs roaming around the Emerald Isle but without evidence we couldn’t be certain.

Until now, for the first reliably identified dinosaur bones have been discovered in county Antrim in Northern Ireland. The two bones were discovered by the late Roger Byrne, a schoolteacher and fossil collector who donated his collection to the Ulster Museum. Chemical analysis has determined that the two bones came from a small outcrop of Jurassic age rocks on the isle of Islandmagee along the east coast of County Antrim, dating the fossils to about 200 million years ago.

Dr. Mike Simms holds the first two dinosaur fossils ever collected in Ireland. (Credit: The Irish Times)

Mister Byrne believed that the two bones came from the same animal but an analysis of the fossils by a team from the University of Portsmouth and Queen’s University Belfast led by Dr. Mike Simms has concluded that they actually come from two very different species of dinosaur. One bone is a femur, heavy and dense that came from a four-legged plant eating armoured dinosaur similar to the ankyosaurus named Scelidosaurus. The other bone is lighter and much less dense and is part of the tibia from a two-legged meat eating theropod similar to the genus Sarcosaurus.

An artists impression of Scelidosaurus. (Credit: The Irish Times)
A reconstruction of Sarcosaurus. (Credit: The Irish Times)

And the importance of these two fossils goes beyond simple national pride in being Ireland’s first dinosaurs because they also represent the most westerly dinosaur fossils ever discovered in Europe. On top of that there has been a growing theory that the armoured plant eater Scelidosaurus lived a life similar to that of marine iguanas today, eating algae along shallow seacoasts. The Jurassic rocks on Islandmagee are considered to have been laid down in just such an environment so the discovery of a Scelidosaurus there lends further evidence to that theory.

The fossil of Scelidosaurus found in Ireland adds evidence to a growing theory that the dinosaur lived a life similar to the modern marine iguana. (Credit: Go Galapagos)

So there you are, two more discoveries from opposite sides of the world adding a few more details to our knowledge of the world of the dinosaurs. You can be sure that there are more discoveries to come and I will do my best to let you know about them.    

A Fusion Reactor experiment in South Korea has succeeded in maintaining a temperature of 100 million degrees for 20 seconds. Is this a breakthrough or just steady progress?

Most people know that the energy source of our Sun is nuclear fusion. That deep within the Sun’s core, at temperatures and pressures far beyond anything here on Earth the nuclei of hydrogen are squeezed together to form helium releasing massive amounts of energy in the process.

The Process of Fusion in the Sun. Starting with four Hydrogen Nuclei (Protons) we end up with a Helium Nuclei and a lot of energy! (Credit: Quora)
However Fusion is only possible under the immense pressures and temperatures found in the very centers of Stars. (Credit: Physics LibreTexts)

We’ve known for decades that if we could harness the power of fusion our energy problems would be over. We could obtain huge amounts of energy from a cheap fuel; there are two atoms of hydrogen in every molecule of water after all, and do so without producing any CO2 or other pollutants to poison our planet. Not only that but fusion is safer than nuclear fission because there are no long term radioactive waste products produced and since fusion requires such extreme conditions if anything goes wrong the whole reaction instantly shuts down. In other words no Chernobyls.

Once started a Fission Chain Reaction is hard to control, that’s what happened at Chernobyl. Fusion, on the other hard is so hard to keep going that after 70 years of trying we still haven’t succeeded in doing it! (Credit: USA Today)

So physicists and nuclear engineers have been working on the development of a fusion reactor since the 1950s, so far without success. The conditions needed to produce fusion, millions of degrees under enormous pressure are simply so difficult to achieve and sustain that for decades a successful experiment was one that lasted for milliseconds.

There has been progress however and in just the last ten years the second barrier has been broken. The current record, just achieved on the 24th of November, is continuous operation for 20 seconds at a temperature of over 100 million degrees Celsius. That success was made by the Korean Superconducting Tokamak Advanced Research (KSTR) project located in the City of Daejeon in South Korea.

The Basic Design of a Tokamak Fusion Reactor. The plasma in contained within very strong magnetic fields. (Credit: Iter)

KSTAR is a Tokamak design where the hydrogen atoms are heated until they break apart into protons and electrons forming what is known as an electrically charged plasma. This plasma is then contained within a doughnut shaped ring by powerful magnetic fields. The plasma is then further heated by a variety of means such as radio frequency heating, just like your microwave, or neutron beam injection. If the plasma can be kept enclosed within the doughnut and brought up to high enough temperature fusion can be achieved. For the last 70 years containment has been the problem.

The interior of the KSTAR Tokamak. (Credit: Steemit)

In KSTAR the doughnut containment vessel is 1.8m across with a thickness of 0.5m. The major improvement in KSTAR has been the use of superconducting magnets generating a field of 3.5 Tesla, that’s about 70,000 times the strength of Earth’s magnetic field, a field strong enough to contain a maximum plasma current of 2 million amperes.

The exterior of the KSTAR Tokamak in South Korea. (Credit: Slashgear)

And KSTAR is not the only Tokamak based experimental reactor trying to push forward the technology needed to make fusion power a reality. In fact KSTAR is just one facility in the largest multi-national scientific program ever, the International Thermonuclear Experimental Reactor or ITER. With seven main partners, the European Union, Russia, the US, China, India, Japan and South Korea, and 35 other contributing nations the goal of ITER is a Tokamak reactor that will actually produce more energy than it requires in order to run.

Construction of the ITER reactor is already underway in the Provence region of southern France with a scheduled completion date of 2025. The planned energy output of ITER is 500 Mega Watts for as long a time as twenty minutes. Experiments at ITER are expected to run from 2025 to 2035.

Construction is underway for the ITAR Tokamak reactor in Southern France. It is hoped that while ITAR will not produce commercially useful energy it will for the first time sustain a fusion reaction for a long enough period of time where useful energy could be produced. (Credit: BBC.com)

But ITER will still be an experimental reactor; there are no plans to even attempt to produce useful electricity from the heat generated by the reactor. Instead the lessons learned from ITER will be used to finally build and operate a commercial power plant using nuclear fusion. This planned power plant has tentatively been named DEMO although at present it has not been decided whether DEMO will be an actual reactor or a design that contributing member nations can then use to construct commercial power plants in their own countries. So there is real progress being made. Someday, in the not too distant future we will finally achieve the production of energy by nuclear fusion. However it is worth remembering that back in the 1960s people were predicting that fusion power was only 20 years away. That prediction has since become something of a joke. ‘Fusion power is 20 years away, and always will be!”

As Searches for Dark Matter continue to come up empty Physicists are beginning to reconsider theories of Modified Gravity.

Physicists and Astronomers have had a big problem now for a very long time. Once astronomer Carl Hubble recognized that a large number of the fuzzy objects out in space called nebula were in fact entire galaxies astronomers and astrophysicists starting trying to work out the dynamics of how those galaxies behaved. Take a typical spiral galaxy like our own Milky Way, it has a central globe about 20,000 light years in diameter surrounded by a thin disk 200,000 light years in diameter but only about 5,000 light years thick, see image below. The density of stars is greatest in that central sphere and slowly but steadily decreases the further out you go along the disk.

The galaxy M33 (Triangulum) is a typical spiral like our Milky Way with a concentration of stars in the center and the density growing less the further you go out from the center. (Credit: Astronomy Picture of the Day – NASA)

Physicists immediately recognized that such a galaxy would only be stable if all of its stars orbited around the center and indeed our Sun is calculated to orbit around the Milky Way’s center once every 200 million years. If astronomers could estimate the mass distribution of the stars then the physicists could use Newton’s law of gravity to work out a velocity profile for the galaxy. Basically that would give them a formula for the velocity a star would have as a function of its distance from the center of its galaxy. That formula could then be checked by using the Doppler effect to measure the actual velocities of stars at various places in a galaxy.

Capculated (expected) versus measured radial velocity as a function of distance from center for the spiral galaxy M33. It’s easy to see that something is wrong somewhere! (Credit: Dark Energy, Dark Matter, Dark Gravity)

It didn’t work. Dozens of studies, dating back to 1933 have shown that the stars near the outer edge of a galaxy are moving too fast. Indeed the whole profile of velocity versus distance indicated that galaxies should have more than twice the mass that we can see and that mass should be spread out more evenly from the center.

That’s where the idea of ‘Dark Matter’ comes from, some form of matter that doesn’t radiate light but possesses a great deal of mass. There have been a lot of ideas about what dark matter could be, several of which have even been given ‘cutesy’ names. MACHOS, which stands for Mass Concentrations, could be anything from brown dwarfs, objects too small to become stars but larger than planets, to stellar mass black holes. Problem with either alternative is that you need huge numbers of them; remember we have to more than double the mass of the galaxies. Astronomers have found a few brown dwarfs and stellar mass black holes but nowhere near enough to solve the problem of the missing mass.

Every now and then a physicist will suggest that Dark Matter is an enormous number of undetected primordial black holes. There is no evidence to support that idea and circumstantial evidence against it. (Credit: The Tribune)

Then there are the WIMPS or Weakly Interacting Massive Particles.  These are elementary particles like electrons or quarks except that they are electrically neutral so they don’t interact with light, and they are very massive. Particle physicists like WIMPS because they can connect them to the particles predicted by theories of ‘Super-Symmetry’. Problem is that despite decades of searching, and building powerful particle accelerators like the Large Hadron Collider (LHC) at CERN no evidence for any super-symmetric particles has ever been found.

One of the problems with Weakly Interacting Massive Particles (WIMPS) as Dark Matter is that there are so many possibilities that it’s hard to keep them all straight. (Credit: Physics (APS) American Physical Society)

A completely different approach was taken back in 1983 by Israeli physicist Mordehai Milgrom. Maybe he asked, Newton and Einstein were wrong about gravity, and then Milgrom proceeded to modify the gravitational field equations so that they would accurately predict the behavior of galaxies. Milgrom referred to his theory as MOdified Newtonian Dynamics or MOND the name by which it has since been known. If MOND or some similar altered theory of gravity is true then the failure to detect dark matter is easy to understand, there simply is no such thing as dark matter, gravity is different than what we thought.

Physicist Mordehai Milgrom has challenged both Newton and Einstein, not something for the faint of heart to try! (Credit: Wikipedia)

Now according to Newton and Einstein gravity obeys what is known as an inverse square law, see equation. 1. This means that the strength of gravity gets weaker the further two masses are by the square of the distance between them. Double the distance and gravity is one quarter as strong, triple the distance and gravity is one ninth as strong, four times the distance yields one sixteenth the strength and so on.

Newton’s law of Gravity is an Inverse Square Law and has been measured to be extremely accurate within our Solar System. (Credit: Wikipedia)

The changes Milgrom proposed to the inverse square law where very small. They had to be because Newton-Einstein works extremely well in our solar system and recently astronomers have even shown that stars orbiting around the supermassive black hole at the center of our galaxy follow Newton-Einstein very accurately, see my post of 6May2020. Crucially however, the small change proposed by Milgrom doesn’t grow weak as quickly with distance as inverse square. This means that at enormous distances, much larger than our solar system, tens to hundreds of light years, it is the modified term that starts to dominate over the Newtonian inverse square term.

In MOND a constant Ao is introduced that must be extremely tiny so that MOND only differs from Newton over huge distances. Physicists don’t like this kind of tweaking of equations just to make them fit the observed data without some rational behind it. (Credit: Slideserve)

All that makes it very difficult to test MOND or any similar small changes to Newton-Einstein. There is one difference however that just might be measured. One of the quirks of a pure inverse square law is that if you are sitting at the center of a mass distribution then you are being pulled by the gravity of those masses equally in every direction so that you literally feel no force! Think about it, if you are at the center of a planet there is a lot of matter all around you but you’re being pulled down just as much as up, back just as much as forward and to the left just as much as to the right. Being pulled equally in every direction you end up not being pulled in any direction, so you feel no gravity. This is known as the lack of effect from an external field.

Newton first performed the calculation that showed how there is no net gravitational force inside a uniform shell of matter. (Credit: Slideplayer)

In MOND however an external field can be felt and so the rotation curve of a galaxy at the center of a large cluster of galaxies would differ from the rotation curve of a similar galaxy that is far from any other large galaxy. To test this idea a group of astrophysicists from Sejong University in South Korea, Cardiff University and the University of Oxford in the UK along with Chase Western Reserve University and the University of Oregon in the USA has examined the rotation curves of 153 galaxies to see if there is any trace of such a difference. The study is entitled ‘Testing the Strong Equivalence Principle: Detection of the External Field Effect in Rotationally Supported Galaxies’ and has been published in the Astrophysics Journal.

What they discovered was that of rotational speeds of galaxies inside an external gravitational field were slowed when compared to the rotations in more isolated galaxies, something contrary to Newton-Einstein but exactly as predicted by MOND. Statistically the results so far give a 4σ confidence level, just below the golden 5σ confidence that physicists use to declare a ‘discovery’. With results so provocative you can be certain that the researchers will be working to both find more evidence as well as improve the data they already have.

Some of the data from the study in Astrophysical Journal in chart form. (Credit: Kyu-Hyun Chae et al)

If MOND does turn out to be correct it will not only eliminate the need for dark matter it will force a reevaluation of many other well established theories. Much of Cosmology and the Big Bang Theory are rooted in Einstein’s gravitational field equations but so far no one has ever been able to expand MOND to describe the Universe as a whole. So even while MOND has gained strong new evidence in its favour there’s still a long way to go before it becomes generally accepted by the majority of physicists. The problem of galactic rotation has been around a long time and it looks like it will continue to be so for a little while longer.

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.