Month: June 2020

Two interesting examples of how the latest in technology is enabling archaeologists to learn more about some of humanity’s oldest settlements.

In the early days of archaeology the only way that an archaeologist could be certain whether or not a potential site was worth excavating was to actually start digging. Even finding a few coins or broken pieces of pottery on the surface only gave a general idea of where more artifacts might lay buried. Many days, weeks and even months could be wasted in fruitless digging just ten or twenty meters away from major discoveries.

When archaeologist Heinrich Schliemann went searching for the ruins of Troy all he had to go on were local stories about where the city lay buried. He got lucky but destroyed much of what he was looking for in his blind attempts at excavation. (Credit: Magnolia Box)

Enter modern technology, in particular the development of Ground Penetrating Radar (GPR). Like the better known version of radar used to locate and track objects in the sky GPR transmits a pulse of electromagnet (EM) energy and then receives the echoes that bounce back from any objects that are struck by the pulse. Of course the difference is that in GPR the pulses are aimed into the ground and are capable of not only detecting objects hidden in the soil but also changes in the material of the soil, say from loose sand to denser clay, or from soil to a buried stone wall.

Principle of Ground Penetrating Radar. (Credit: KCI Technologies)

GPR is not without its problems, for example wet clay readily absorbs the EM energy limiting the depth in which anything might be found. Also, since a GPR set must be dragged across the ground, rocky, uneven terrain makes using GPR difficult. In addition, GPR cannot always distinguish between natural or man-made objects that are buried in the ground, in order to be certain you often have to dig it up.

In spite of these drawbacks GPR is being employed more and more often in the earliest stages of an archaeological expedition. In fact a recent archaeological survey has gone further than ever before in exploiting the capabilities of GPR. A team of archaeologists from the University of Cambridge in the UK and Ghent University in Belgium has succeeded in mapping the entirety of an ancient Roman town using GPR.

Located just a short distance north of Rome the ancient town of Falerii Novi was a typical walled Roman town some 75 acres in size. During its heyday in the second and third centuries BCE Falerii Novi had a population of between two or three thousand people. Such a large site would require many years to excavate using traditional techniques so instead the decision was made to use GPR in order to locate the most interesting areas within the town.

Ground Penetrating Radar image of Falerii Novi superimposed on an aerial photograph of its actual location. (Credit: Archaeology Magazine)

Several factors combined in making the Falerii Novi a good choice for the first such extensive use of GPR. The terrain at the location where the small town was known to have existed was smooth and flat over a wide area while the composition of the soil was nice and sandy.

The full map of Falerii Novi required the collection of over seventy million readings with the GPR and a total of 28.68 billion data points. Thanks to that full map however the archaeologists have been able to locate many of the town’s important structures such as the local temple as well as the marketplace and a possible Roman bath.

GPR image of what is presumed to be the ancient Temple at Falerii Novi. (Credit: Archaeology Wiki)

By allowing archaeologists to quickly locate those areas of a site that are most promising for excavation Ground Penetrating Radar has become one of the most useful instruments in the archaeologist’s toolbox. But if GPR helps archaeologists locate where in space the artifacts they are searching for may be found they require other hi-tech tools in order to locate what period in time those same artifacts come from. Two of the most important and accurate techniques that archaeologists use to determine the dates of the ancient sites they study are carbon-14 and tree ring dating, formally known as dendrochronology. Now, for the first time these two techniques have been combined to precisely date the building of one of the most mysterious ancient sites known.

How the tree rings from different, in some cases ancient trees can be used to date archaeological sites. (Credit: Archaeology Magazine)

The deserted clay walled city of Por-Bajin is situated on an island in a lake in the Siberian region of Russia not far north of the border with Mongolia. Despite being in the middle of one of the most arid and least populated places on Earth the grassy steppes of central Asia are dotted with the ruins of cities like Por-Bajin that sprang up seemingly out of nowhere, flourished for a century or two and then fell into obscurity. Many, but not all of these ‘ghost towns’ were associated with the famous ‘Silk Road’ the trail of caravans that connected the Middle East with China for more than a thousand years.

The Silk Road was a series of caravan routes connecting Europe with China. Because of the wealth that flowed along that road many now forgotten cities and kingdoms flourished for a few centuries before vanishing into history. (Credit: Chinasage)

Based upon earlier expeditions by Russian archaeologists Por-Bajin was thought to have been built during the 8th century by the ethnic Uyghurs. If these estimates were true the question was then whether the founder of Por-Bajin was the great Uyghur Khan Moyanchur or his successor Bögü. In either case not long after its founding there is evidence that Por-Bajin became a monastery of the eastern ‘Manichaean’ version of Christianity. Then, after only about a century of occupation Por-Bajin suffered a devastating earthquake that caused a collapse of the southern and eastern walls and triggered a fire that destroyed most of the city’s buildings. The site was abandoned shortly after that although some investigators have speculated that Por-Bajin was actually deserted before the earthquake and point to the almost total lack of artifacts or provisions found there as evidence that the site was in fact empty when the earthquake struck.

The ruined city of Por-Bajin. Built in the 700s and abandoned less than a century later it had remained virtually untouched for more the 1200 years. (Credit: SciTechDaily)

Previous dating of the site by the Carbon-14 technique had given a date in the latter half of the 8th century; see my post of June 20th, 2018 for a description of Carbon-14 dating. But now a new study from the Center for Isotope Research at the University of Groningen in the Netherlands along with Lomonosov Moscow University in Russia have combined Carbon-14 dating with tree ring data from other areas of the world to give a much more precise dating for the founding of Por-Bajin.

A more distant view of Por-Bajin giving a better idea of how isolated the site is. (Credit: Amusing Planet)

Normally the use of tree rings to date archaeological sites requires that the wood from a particular site be compared to tree rings from wood at an already reliably dated site within the same climate so that the widths of the tree rings can be matched up, see my post of April 18th, 2020 for a description of using dendrochronology to date archaeological sites. Unfortunately the wood from Por-Bajin could not be easily compared to any known useful set of already dated tree rings however.

However the Archaeologists succeeded in finding one tree ring that possessed a spike of carbon-14, a spike that had been recognized in 2013 as existing in tree rings from wood around the world and was reliably dated to the year 775. Based upon the discovery of the spike in wood from Por-Bajin the archaeologists can now definitely say that the founding of the city took place in the year 777 CE, a date that eliminates Khan Moyanchur as it’s possible builder.

Thanks to the combining of Carbon-14 dating and Dendrochronology. Historians now know exactly when and by whom Por-Bajin was built. This will give them a much better chance of figuring out why it was built. (Credit: PNAS)

So by combining their dating methods the scientists had been able to definitively answer a question that had been a mystery for over a thousand years. Por-Bajin may be the first time that archaeologists have combined the two dating techniques of Carbon-14 and Tree Rings but you can be certain that it won’t be the last. Together with Ground Penetrating Radar and the other hi-tech instruments now being employed at ancient dig sites these new tools will enable archaeologists to better understand the history of all of our cultures.

We’ve sent a space probes to photograph the surface of every planet and the Voyagers are now exploring interstellar space, but we still know so little about what our own planet is like just beneath our feet.

When I was growing up I occasionally heard a remark that scientists knew more about the surface of the Moon or Mars than they did about the inside of our own planet. Back then all we really knew about the deep interior of our Earth was that the pressure just keep getting greater as you went down simply because of the weight of all of the rock above you. At the same time the temperature got hotter and hotter because of all of the heat generated by the radioactive elements down there.

Back around 1960 this was literally about all we knew about the interior of the Earth. (Credit: ProProfs)

By studying the seismic waves generated through earthquakes scientists knew that deep within the Earth, about 5500 kilometers down, there was a liquid core because certain kinds of waves, called shear waves, will not go through a liquid. We also knew that above the core there was a quasi-plastic region called the mantel composed of rock under enormous pressure. Finally on top, where we lived there was the crust only about ten kilometers thick, made of the kind of rock that we’re all familiar with.

Geologists study the waves generated by Earthquakes to learn about the Earth’s interior. The S waves (Shear Waves) will not go through the core because it is liquid however the P waves (Pressure Waves) will. (Credit: Views of the Solar System)

Then, during the late 1960s and 70s the science of geology underwent a revolution as the controversial theory of ‘Continental Drift’ was proven to be correct and became the basis for the modern model of ‘Plate Tectonics’. The idea that Earth’s outer, solid crust is actually broken into a number of large plates that floated on top of the planet’s quasi-plastic mantel carrying the continents with them explained so much.

First proposed by Alfred Wegener in 1912, the theory of Continental Drift was largely discounted because geologists couldn’t imagine how a continent could move. (Credit: Earth How)

According to plate tectonics, earthquake fault lines, volcanoes and even the process of mountain building were found to take place in regions where two plates were either banging into each other or spreading further apart. Nevertheless, despite its success plate tectonics still only broadly describes the processes in the top one hundred kilometers or so of the Earth.

Plate Tectonics incorporates Continental Drift by recognizing that the Earth’s crust is broken into pieces that flat upon the quasi-plastic Mantel. (Credit: National Park Service)

We had little detail about conditions and processes deep within our planet, after all the deepest well ever drilled was only 12.2 kilometers deep. How could we know anything about what’s below that? Are the Earth’s liquid core and mantel uniform, is there anything like structure down there. We just didn’t know.

Until now that is. Using the latest in machine learning software a team of geophysicists from the University of Maryland have analyzed 30 years of data collected by hundreds of seismographs to generate a detailed 3D map of the region where the Earth’s core and mantel meet. Concentrating their efforts on the Pacific Ocean basin the researchers were interested in trying to understand the regions directly below the Hawaiian and Marquesas islands, volcanic ‘hot spots’ that are not connected in any way to the motion of tectonic plates. Since the Pacific Ocean is surrounded by the volcano and earthquake prone ‘ring of fire’ the geophysicists were able to collect over 7,000 seismic events of magnitude 6.5 or greater, an enormous amount of data to work with.

Caused by the interaction of the Pacific Plate with other plates the Pacific ‘Ring of Fire’ is the most geologically active region on Earth. (Credit: Phys.org)

What they found were regions of greater density and heat than even the surrounding material, previously unknown structure directly beneath the Hawaiian and Marquesas hot spots as well as other areas of the core-mantel boundary. Because these regions are hotter and denser than nearby areas the seismic waves travel more slowly through them so the geophysicists have named them Ultra-Low Velocity Zones or (ULVZs).

Using the latest in computer learning and by studying the waves generated by thousands of Earthquakes Geologists at the University of Maryland have discovered structure deep beneath the Earth’s surface. (Credit: Sci-News.com)

At the interfaces between the ULVZs and the more normal material around them echoes of seismic waves can be produced. In the past these echoes have been difficult to distinguish from random noise but the machine learning algorithm was able to recognize them, adding a lot of detail to the nature of the ULVZs.

According to Doyeon Kim, lead author of the study. “By looking at thousands of core-mantel boundary echoes at once, instead of focusing on a few at a time, as is usually done, we have gotten a totally new perspective. This is showing us that the core-mantel boundary region has lots of structures that can produce these echoes and that was something we didn’t realize before because we only had a narrow view.”

Geologists are only beginning to understand the role that Ultra Low Velocity Zones (ULVZ) have on the movement of plates and the Earth’s volcanic ‘Hot Spots’. (Credit: www3.nd.edu)

Further refinements for the technique developed by the geologists at the University of Maryland will undoubtedly discover more structures in other sections of the core-mantel boundary while at the same time providing clearer images of those ULVZs already located. Even if the deep interior of the Earth is unreachable to us physically, scientists are still finding ways study it and learn its secrets.

Does the entire Universe spin like a top? Astronomers find evidence that it just might.

We see examples of spin, angular rotations everyday in our lives, the spinning of a child’s top, the rotation of our car’s tires or the blades of a fan. How about the spin of the water as we flush the toilet or drain our bathwater?

Much more than just a child’s amusement, spin is a fundamental part of the Universe. (Credit: NicePGN)

Spin in astronomy is even more common. Not only does the Earth spin on its axis it also orbits around the Sun, another form of angular momentum. In fact all of the planets both spin on their axis and orbit around the Sun. Going further up the cosmic ladder the Sun orbits around the center of our galaxy, as do all of the other stars of the Milky Way, so that means that the entire galaxy has a rotation to it, a spin. In fact astronomers have studied clusters of thousands of galaxies and yes, the galaxies in the cluster orbit around the center of mass of the cluster as a whole.

Our Earth not only rotates on its axis it also orbits around the Sun, both with anticlockwise spin. In fact every astronomical object we know of has some spin to it. (Credit: Pinterest)

Now remember that there are two kinds of rotation, clockwise and anticlockwise, also known as counterclockwise. Scientists prefer to think of the two spin states as right handed and left handed and here’s how to tell which is which. If you put your left hand in front of your face with the thumb pointed towards you the direction your fingers curl is clockwise, see image below, therefore clockwise is left handed.

The curling of the fingers of your left hand are in an anticlockwise direction. Therefore physicists call anticlockwise lefthanded spin. (Credit: R. A. Lawler)

Conversely the way your fingers curl on your right hand is anticlockwise; see image below, so anticlockwise is right handed. By the way if you point the thumb of your right hand parallel with the North Pole then the Earth rotates the way your fingers curl, the Earth’s spin is right handed. If fact the Earth’s orbit is also right handed, as is the spin of almost everything in our Solar System, our entire galaxy in fact.

The curling of the fingers of your right hand are in a clockwise direction. Therefore physicists call clockwise righthanded spin. (Credit: R. A. Lawler)

Back in high school you may remember hearing that angular moment, that is spin, has to be conserved. That means if you try to start something spinning clockwise you’re also going to start something spinning anticlockwise! Usually we don’t notice this because when we spin a top clockwise the tiny amount of anticlockwise spin created is absorbed into the Earth and appears to vanish. The astronauts in space are well aware of this law of nature however. Anytime an astronaut on the Space Station tries to screw in a nut if they’re not careful they’ll start spinning in the other direction because of conservation of angular momentum.

When NASA astronauts try to screw in a nut they have to be careful to make certain that they themselves are securely tied down or they will start rotating in the opposite direction. (Credit: Gateway Foundation)

Since anytime you try to generate one kind of spin you have to generate just as much of the other kind physics have always accepted the idea that the Universe in total had no spin. After all it was hard to imagine how the Universe could have begun with spin, and why it would have started with one kind rather than the other. That would mean then, that all of the many spins we see out there in the cosmos would cancel each other out, leaving the Universe as a whole without spin.

The Hubble Space Telescope’s deep field image. Every dot you see is a galaxy, all spinning in a random direction so that the Universe as a whole has a net spin of zero. Or does it? (Credit: NASA, Hubble Space Telescope)

Of course assumptions like that have to be tested and the way to determine whether the Universe has any total spin or not would be to add up all of the spins of the various parts of the Universe, that is all of the galaxies, and see if they do actually cancel each other out. Now that’s a lot of work, there are tens of billions of galaxies that we know of, only a few hundred thousand of which have been studied to any degree.

Still, those few hundred thousand can serve as a sampling poll. That’s right the same mathematical techniques that the Gallop Poll uses to estimate which candidate the American people prefer for President can be used to estimate whether or not the Universe has spin. That is just what Lior Shamir, a computational astronomer at Kansas State University has done.

Doctor Shamir developed a computer algorithm that was able to determine the direction of rotation of a galaxy from its image, far left. (Credit: Lior Shamir, Kansas State University)

Using the data collected in the Sloan Digital Sky Survey (SDSS) Doctor Shamir identified more than 170,000 spiral galaxies whose direction of spin he could resolve. Adding in a further 32,000 similar galaxies from the Pan-STARRS survey for a total of more than 200,000 Dr. Shamir found that that the number of clockwise galaxies outnumbered the number of anticlockwise galaxies by a fraction more than 1%.

If you’re thinking that 1% isn’t that much, well for a sample size of 200,000 the odds of such an imbalance being randomly generated is almost one in 300,000 against. More than that, the further away a galaxy is, and hence the older it is, the more likely Dr. Shamir found it to be rotating clockwise indicating that the early Universe may have had a more uniform clockwise spin.

Dr. Shamir also found that the degree of the imbalance depended on which area in the sky you were observing with the greater number of extra clockwise galaxies concentrated along Earth’s poles. A finding that has allowed Dr. Shamir to actually identify a possible axis of rotation for the entire Universe.

Possible directions of the spin axis of the entire Universe in Earth’s sky. They ate not too far from our poles which sit along the center line at 90 and 270 degrees. (Credit: Lior Shamir, Kansas State University)

Now to be honest, Dr. Shamir’s paper has yet to be published in a peer reviewed journal and even then it will be subjected to criticism and checking. The idea that the Universe as a whole spins clockwise would pretty much mean that the initial Big Bang must have had a tiny amount of spin to it.

How the Big Bang could have had spin, and how that would have effected the early Universe is just unknown at present.

Book Review: ‘The Better Angels of Our Nature’ By Steven Pinker.

Turn on the news for ten minutes in the morning and you’d be forgiven for thinking that we live in a world saturated with violence. The events that take place everyday can seem like an endless list of war, crime, and brutality. Even our movies and the entertainment shows we watch on TV are full of violence and aggression.

The entire genre of slasher movies simply consists of one violent murder after another! (Credit: India.com)

As I begin this post my television is showing the funeral of George Floyd, the black man who while handcuffed was slowly choked to death by the knee of a Minneapolis police officer. A so-called peace officer who had sworn an oath to protect the people of his city. It’s understandable then that many people recoil from the violence of our period in history and dream about returning to a more peaceful time in the past.

The Garden of Eden was a time before the here was any violence, Yea, Right! If you believe that you’ll believe anything! (Credit: Trumpet Call)

Ah, just when was that? To be honest the only events we know of from the Bronze and Iron Ages were wars, battles and massacres. The Roman Empire was founded and maintained by the sword of the legionary while the Dark ages began with barbarian invasions and just got worse from there. I assume I don’t need to go on, and war is just the wholesale side of violence, we mustn’t forget the person to person violence like robbery, rape and murder.

Achilles slaying Hector in the Iliad. The earliest stories we have are all about war and murder. (Credit: Quora)

So it takes a brave man to declare that things are actually getting better, that human beings and human societies are actually becoming less violent. Nevertheless that’s the thesis of Steven Pinker’s book ‘The Better Angels of our Nature’ and Professor Pinker has the evidence to back it up. As the Johnstone Professor of Psychology at Harvard University Professor Pinker has gathered together a huge mass of data from subjects like anthropology, history, philosophy, crime statistics, psychological studies and the mathematics of game theory in his examination of how violence has declined through human history.

Cover for ‘The Better Angels of our Nature’ by Steven Pinker. (Credit: Amazon)
Professor Steven Pinker of Harvard University, author of ‘The Better Angels of our Nature’. (Credit: Britannica)

A warning, when I said that Professor Pinker has amassed a lot of data I wasn’t kidding. The 696 pages of ‘The Better Angels of our Nature’ are completely crammed with both historical accounts and statistical data. More than that, over the course of the book Professor Pinker employs a greater number of distinct analytical concepts than most of the Physics textbooks I’ve read in my life. In fact, a degree of familiarity with some of the mathematical techniques for analyzing data is a big help when reading ‘The Better Angels of our Nature’.

One of the mathematical techniques used regularly in ‘The Better Angels of our Nature’ is the correlation function in order to to discern trends in large amounts of data. (Credit: Medium)

Right from the start of ‘The Better Angels of our Nature’ Professor Pinker realizes that he has to convince you that violence has in fact gone down through the centuries. One of Pinker’s techniques for doing so is to examine the historical record for examples for violent behaviors that were once commonplace but have largely disappeared.

Whereas executions were once popular entertainment, even such grisly ones as crucifixion and drawing and quartering, many countries today have banned the death penalty altogether. Whereas torture was once routinely used to extract confessions from suspects, today no country openly practices it; even authoritarian states like North Korea officially deny using torture. Whereas looting and burning and rape were once considered a part of a soldier’s wages today they are classified as war crimes and some world leaders are actually being prosecuted for them. Whereas slavery was once the very foundation of many civilizations today it is at least illegal everywhere on Earth. In many ways, Professor Pinker points out, violent behavior that was once simply taken for granted as a part of life have today become sources of horror.

When the Romans defeated the slave army of Spartacus they crucified all of the survivors! (Credit: Pinterest)
Just a few of the many ways that we humans have invented to cause pain to our fellow creatures! (Credit: Life’s Pleasures)

At the same time Professor Pinker reviews the historical evidence for all of the wars throughout history, concluding that centuries in the past nations were in a constant state of conflict while it is only slowly over time that peace has become the norm and war the rarity. Pinker then goes on investigate the idea that even while it appears that wars may have become rarer, because of new technology they have become much more destructive. That argument is demolished by demonstrating that wars like the Thirty Years War or the Mongol invasions of Genghis Khan actually killed an even larger proportion of the populations involved then did the two World Wars despite the more advanced weaponry of the 20th Century. 

It’s easy to get them mixed up! (Credit: Reddit)

Convincing you that violence has actually decreased over the centuries is only the beginning of Professor Pinker’s task. In subsequent sections of the book the various influences on human violence, both those causing it as well as those that seek to control it are not only discussed but put to the test by examining records of war casualties, crime statistics and other evidence. Even the results of modern psychological testing and advances in neurology are brought to bare as evidence to better understand why it is we commit violence, and why century by century we are committing less of it.

While it may seem that peace movements have made little progress it’s worth remembering that before the late 20th century they hardly even existed!
The Rights Movements are another aspect of how humanity has grown more peaceful. The very concept of treating someone different from you fairly and justly is a very recent invention. (Credit: The Birmingham Times)

As I said ‘The Better Angels of our Nature’ is a dense book, a book about a very sobering topic. Nevertheless Professor Pinker has a habit of dropping in references to popular culture that occasionally lighten the mood. Sprinkled through the book are quotations from authorities as diverse as Martin Luther King Jr. and Conan the Barbarian.

Sometimes it’s really just a question of good manners. Even Conan knows that! (Credit: Pinterest)

‘The Better Angles of our Nature’ is not an easy book to read, but it is A VERY IMPORTANT BOOK. If you have the time, and are willing to undertake the effort you will be well rewarded. 

Paleontology News for June 2020.

There have been a number of small but important discoveries recently illuminating portions of the history of life here on Earth. As usual I think I’ll start with the earliest and move forward in time.

One of the most common modes of life in the natural world is parasitism, where an individual of one species spends a large part of its life literally living off of a member of another species. While parasitism is technically a form of symbiosis it differs from mutually beneficial symbiosis in that the parasite gains at the expense of its host.

In addition to feeding off of our blood, external parasites such as this tick cab carry illnesses like Lyme disease. (Credit: Science Insider)
Internal parasites, such as this tapeworm, may also cause illness. (Credit: WebMD)

A very large number of different species, spread across every major taxonomic group of both animals and plants are parasites for at least a part of their lives. There are so many parasites out there that you would expect that there would be a lot of evidence of parasites in the fossil record.

A lice from the Cretaceous period preserved in amber. Could it contain any dino DNA? (Credit: Daily Mail)

It’s not that easy, a lot of parasites don’t fossilize well, think of a tapeworm. Or consider a dinosaur that is infected with fleas. If that dino dies the fleas will quickly leave to try to find another host, they won’t be fossilized with the dinosaur.

Even if you do find two different species fossilized together you have the problem of determining whether your fossil is a true example of parasitism. For example in my collection I have a small clamshell from the cretaceous period that has the tube of a feather duster worm attached to it. For all I know the worm could have built its home on the shell after the clam had died. So trying to figure out when one creature is benefiting by harming the other isn’t easy.

Fragment of clam shell from the Cretaceous period in my collection with the tube of a feather duster worm attached. This is not an example of parasitism because the tube is on the inside of the shell which means the clam was already dead when the worm attached itself. (Credit R. A. Lawler)

Nevertheless a team of paleontologists from Northwest University in Xi’an China, the Swedish Museum of Natural History and Macquarie University in Sidney Australia has announced what they assert is the earliest known example of parasitism. Their evidence comes from the Cambrian period, approximately 515 million years ago and resembles in many ways my fossil mentioned above.

The fossils consisted of a large number of shells of a species of brachiopod, a creature whose shell resembles that of a clam although the animal inside is totally different. While brachiopods today are quite rare, in the early period of life’s history, more than 250 million years ago, they were more common than clams.

Some of the Brachiopod shells used in the study of ancient parasitism. (Credit: Macquarie University)

Examining the brachiopod shells the paleontologists found that approximately half were encrusted with the tubes of worms, just like my fossil, while the other half were not. Measuring the shells of the brachiopods and using that as an indication of the animal’s health the researchers discovered that the encrusted brachiopods were consistently smaller, by about 26%. This is clear evidence that the worms were harming the brachiopods. In other words the worms were parasites.

Artists impression of a Brachiopod shell infested with parasitic worms. (Credit: Ars Technica)

Not only that, but because like a clam, the shells of brachiopods grow outward from their edges the scientists were able to determine how early in the life of a brachiopod it had become encrusted. Again, those brachiopods that were encrusted earlier in their lives showed the most pronounced size reduction, further evidence of parasitism.

So it appears that parasitism as a mode of life has existed for nearly as long as multi-cellular creatures have. Another common mode of life that has also recently been found to have ancient roots is suspension feeding; animals that swim with their mouths wide open, filtering plankton and other small creatures out of the water. In today’s oceans baleen whales and basking sharks are the best known suspension feeders and are among the largest creatures on Earth.

Now a new study by paleontologists at the Universities of Bristol and Zurich of an ancient fish from the Devonian period, about 380 million years ago, has provided strong evidence that at least one of the ocean’s largest inhabitants back then lived in much the same way. The animal in question belongs to the group of armored fish known as placoderms and is formally called Titanichthys. A giant for its time Titanichthys measured more than five meters in length but crucially its jaw was more than a meter in length. Modern suspension feeders also have greatly elongated lower jaws allowing them to scoop up the greatest amount of water as they swim.

School of Titanichthys feeding as they swim. At five meters in length Titanichthys was one of the largest living things during the Devonian age. (Credit: Sci-News.com)

The new research also found that while the lower jaw of Titanichthys was long it wasn’t very strong, neither the bones themselves nor the muscles attached to the jawbones would have been sufficient to deliver a strong bite, further evidence of the fishes lifestyle as a suspension feeder.

The fossilized skull of Titanichthys. That huge open mouth certainly could have collected a lot of food. (Credit: Black Hills Institute)

Moving forward in time we come to my final story for this month, which concerns the asteroid that is presumed to have caused the extinction of the dinosaurs. It was only about twenty years ago that geologists succeeded in finding actual site of that impact, the Chicxulub crater in the Yucatan peninsula of Mexico.

The Chicxulub crater in the Yucatan peninsula of Mexico. The asteroid that struck here is generally considered to have caused the extinction of the dinosaurs. (Credit: Wikipedia)

Ever since that discovery geologists have surveyed Chicxulub, hoping to learn as much as they can about how the 10 kilometer wide space rock caused so much damage. Destruction so great that it led to the extinction of about 75% of all of the species on Earth. In a paper published in Nature Communications scientists from the University of Texas at Austin, the Imperial College London and the University of Freiberg in Germany have used computer simulations to investigate what the likely initial conditions of that asteroid strike were in order to order for it to have produced the effects seen in the Yucatan today.

Based upon the diameter of the Chicxulub crater, its depth and the observed distribution of ejected material from sites around the world the team of geologists have concluded that the asteroid struck the Earth at an angle of 60º, an angle that they argue produced the greatest amount of destruction. According to the simulations a steeper angle, say 70-90º would have produced a deeper crater but one where the ejecta was more confined to the area around the crater, in other words the other side of the Earth might have been subjected to considerably less devastation. On the other hand, if the asteroid had struck at a shallower angle, say 30º or less, the crater would have also been shallower and the distribution of ejecta would have been much more concentrated in the direction of the asteroid’s motion, which again might have spared some parts of the Earth from baring the full brunt of the asteroid’s destructive power.

Computer simulation of the asteroid strike with the asteroid coming in at an angel of 60 degrees. (Credit: Collins, Patel, Davidson et. al.)

If the simulations produced by the team of geologists do in fact correspond to what actually happened 66 million years ago then the dinosaurs were doubly unlucky. Not only did the asteroid strike suddenly from out of the depths of space but it also struck in just the right way to both produce the maximum destruction and to spread that destruction evenly around the entire world.

Of course as mammals we should remember that what was bad luck for the dinosaurs was good luck for us!

Astronomers debate whether or not there is a ninth planet in our Solar System, and I’m not talking about the argument over Pluto.

The argument over Pluto’s status as a full fledged planet or not has been going on now for almost 14 years and there appears to be no end in sight. I grew up without ever questioning Pluto’s designation but admittedly even back in the 1960s Pluto was considered something of an oddball for a planet. Smaller even than Mercury, much smaller than it’s gas giant neighbors Pluto’s orbit even occasionally brought it closer to the Sun than the eighth planet Neptune. Crossing the orbit of another planet seemed like something no self-respecting planet would ever do.

The dwarf planet Pluto with its largest moon Charon to the upper left. Both are now considered to be Kuiper Belt Objects (KBOs). (Credit: Astronomy Magazine)

Then, starting in the 1990s a number of other icy bodies with even more unusual orbits were discovered not far beyond Pluto. These objects were grouped together as Kuiper Belt Objects (KBOs) and the debate over what kind of body Pluto was, a planet or a KBO began.

The dwarf planet Eris, artists impression shown, is also a KBO and may even be a bit larger than Pluto. (Credit: Space.com)

The current definition of a planet basically consists of two criteria. One, a planet must be large enough, massive enough that it’s gravity pulls it into a nice spherical shape. Pluto passes this criterion easily, as does Ceres in the asteroid belt.

The second criterion is that a planet’s gravity must be strong enough to sweep out any other object from its orbital region. This is the test that Pluto and Ceres both fail. Ceres fails because of the other asteroids while Pluto fails because of the other KBOs. That is the official position and I don’t intend to take sides one way or the other. I’ve never liked arguing over definitions. To me Pluto is what it is no matter what we choose to call it.

The eight recognized planets in our solar system. This image clearly shows the great difference between the rocky inner planets like Earth and the enormous gas giants like Jupiter. Maybe these eight should be split into two groups? (Credit: Britannica)

All of which has nothing to do with today’s actual topic, the continuing search by astronomers for an as yet undiscovered ninth planet, a tenth planet if you insist on Pluto being a planet. So why do astronomers think that there could be another planet out there, and how are they going about looking for it?

It all has to do with the pulling and tugging that the gravities of the planets have on each other’s orbit around the Sun. Because the Sun’s mass is so huge, about 500 times the mass of all of the planets, moons and everything else in the solar system added together, the orbits of the planets are pretty close to ellipses, just as Kepler’s first law requires.

Kepler’s First Law states that planets orbit the Sun in ellipses. This isn’t absolutely accurate because of the gravitational pulls of the other planets. (Credit: Quora)

Nevertheless the pulling of the gravities of the other planets does have an effect that astronomers can measure and compare to their calculations. If any discrepancy is found, even the tiniest will cause astronomers to start searching for the cause.

This happened in the first half of the 19th century when the measurements of the orbit of Uranus, the seventh planet, did not match calculations. It was suggested that another planet beyond Uranus might be the cause and after twenty years of calculations planet number eight, Neptune was found exactly where the math said it would be.

Then the same thing happened to the orbit of Neptune, the planet wasn’t quite moving as the calculations said it should be. So the hunt was on for a ninth planet, which finally led to the discovery of Pluto in 1930. Pluto was so small however that it didn’t seem able to account for all of the discrepancy in Neptune’s orbit. So, for the next five decades astronomers kept looking for a tenth planet beyond even Pluto without success.

Clyde Tombaugh discovered Pluto by noticing the movement of a tiny dot of light, indicated by the arrows, between images taken a week apart. (Credit: The Planetary Society)

Things have gotten a lot more complicated since then, and I’m not talking about whether or not Pluto is a planet. I mean with all of those Kuiper Belt Objects orbiting around out there it’s difficult to calculate just what all is going on. Do the KBOs together account for the problem with Neptune’s orbit or do we still need another planet, or would several more KBOs do the trick? And what about the orbits of the KBOs themselves? Are their orbits matching the calculations or does it seem as if there could be another big body out there affecting their motions? Plotting the orbit for one object in our Solar System is a lot of math, even using a computer. I know, I had to do it back in grad school. Trying to do the same for the over 1500 known KBOs is beyond my programming skills.

Sample of an old fashioned FORTRAN computer program. This is the way I had to calculate planetary orbits back in grad school! (Credit: Stack Overflow)

Fortunately it’s not beyond the skills of Samantha Lawler, Assistant Professor of Astronomy at the University of Regina in Canada. Using observations and discoveries made by the Outer Solar System Origins Survey Dr. Lawler, no relation, has calculated the orbits of the known KBOs for the purpose of finding where that ninth planet could be hiding. If it exists that is.

A fair amount of Dr. Lawler’s work actually consisted of recognizing observational biases in earlier searches for KBOs. First of all since KBOs are so far from the Sun they hardly move at all against the background of fixed stars. Because of that the regions of the Kuiper belt that lay in the same direction as the Milky Way have been ignored because of the enormous difficulty in distinguishing a small icy body from one of the millions of distant stars in our galaxy. Other biases arose when certain telescopes were employed in searching the Kuiper belt during certain times of the year, again neglecting whole sections of the solar system.

The orbits of KBOs as discovered by the best conducted surveys to date. Notice how the region to the lower left is empty. Is this because there are no KBOs in the region or is it because of unconscious bias in the surveys. (Credit: Sci-News.com)

Adjusting for these biases in her simulations Dr. Lawler has shown that KBOs are actually more uniformedly distributed that other surveys had indicated and that the orbits of the known KBOs can be explained without the need for the gravity of a ninth planet to shepherd them.

So it appears that there probably isn’t another planet out there beyond Neptune and Pluto waiting to be discovered after all. Instead there are thousands of small, icy KBOs. Tiny little worlds that never managed to come together to form a single big planet.

Maybe, in some ways that’s even more interesting.

U.S. Navy successfully tests shipboard Solid-State Laser system for anti-aircraft defense. Is the time of Gunpowder’s dominance on the battlefield coming to an end?

On the 29th of May in the year 1453 CE one of the turning points in world history occurred as the great city of Constantinople fell to the might of the Turkish military. Often referred to as the final end of the Roman Empire it is fitting that the massive walls of Constantinople were breached not by any weapon that Julius Caesar would have recognized but rather by the cutting edge, high-tech weapon of its day, the cannon.

Contemporary depiction of the fall of Constantinople emphasizing the Turkish use of artillery. (Credit: Ancient History Encyclopedia)

For the past 600 years wars have been fought with guns, cannons, shells, mines and rockets of various kinds, all of which derived their lethal force from the explosive release of chemical energy. It is true that bayonets, lances and even swords can still be seen today at parades and other military pageants but it is gunpowder and its derivatives that dominate today’s battlefield.

With today’s plastic explosives you can mold your bomb into almost any shape you want and yes that’s an explosive penis he is holding. (Credit: Reddit)

That may not be true for much longer. You see for the last decade or so the U.S. Military, particularly the Navy, has been putting a great deal of money and effort into the development of what are officially known as ‘Directed Energy Weapons’ or DEWs, weapons that derive their power from electricity instead of explosives.

In an earlier post, see post of August 2nd 2017, I discussed the Navy’s Rail Gun which employs magnetic fields to hurl a shell up to 400 kilometers at a velocity of 5 to 6 times the speed of sound. The shells fired by the rail gun travel so fast that they don’t even need an explosive warhead to destroy their target. The shell is solid metal and kinetic energy does all the damage. Meanwhile the Army has been testing an anti-personnel microwave generator that causes pain by radio waves.

The U.S. Navy’s Rail Gun being tested. No explosives are needed, it’s all electricity and magnetic fields! (Credit: YouTube)

Now the Navy has tested a shipboard solid-state laser, using it to intercept, that is shoot down a robotic drone aircraft. Many of the details of the test are secret but it is known that the laser was mounted aboard the U.S.S. Portland, an Amphibious Transport Dock Ship and the test took place on the 16th of May 2020 in the ocean somewhere south of the Hawaiian Islands.

USS Portland firing the Navy’s new Laser Weapons System Demonstrator. (Credit: US Naval Institute)

The two most important parameters of the test, and therefore the most secret, are the power of the laser and the range at which it destroyed its target. Based on a 2018 report from the International Institute for Strategic Studies however it is estimated that the laser’s power was somewhere in the range of 150 kilowatts while from the released images of the test the target was destroyed at a distance of at least several kilometers.

Earlier version of the LWSD mounted aboard the USS Ponce. (Credit: Wikipedia)

Officially the laser on board the Portland is called a ‘Laser Weapons System Demonstrator’ (LWSD) and current plans are for the LWSD to be used to provide protection for naval vessels against small attacking boats as well as aircraft. According to the Portland’s Commanding Officer, Captain Karrey Sanders. “With this new advanced capability, we are redefining war at sea for the navy.”

Official Navy image of drone aircraft being shot down by Laser aboard USS Portland. (Credit: US Navy)

Currently most of the effort being carried out to develop these new DEWs is being undertaken by the Navy. Still, you have to know that in some defense contractor’s labouratory somewhere they’re looking at putting a laser, or perhaps a rail gun on a tank. Slowly but surely the new high-tech weapons of war are becoming powered by electricity not explosives.

Science Fiction has had ray guns for decades. I guess we’re finally catching up to Buck Rogers! (Credit: NASA Science and Entertainment Exchange)

“…Redefining war…,” that’s what Captain Sanders said. And maybe he’s right; maybe gunpowder’s dominance of the battlefield is nearing its end. Too bad we just can’t get rid of battlefields instead!

NASA’s Commercial Crew Program finally begins with the first manned launch of a manned space mission by a private company, Space X.

In the beginning of the Obama administration NASA, the U.S. space agency faced a major dilemma. It’s remaining fleet of three Space Shuttles was growing older, increasing of possibility of another space disaster. At the same time the International Space Station (ISS), which NASA had spent so many years and so many billions of dollars constructing, was only starting its useful lifetime.

The International Space Station (ISS). NASA would like to both keep it manned while at the same time move beyond it to explore beyond Low Earth Orbit (LOE). (Credit: NASA)

To make matters worse, during the Bush administration NASA had been directed to develop a program called Constellation for returning America to the Moon, a program whose enormous cost Obama had little liking for. Without the shuttle or an equivalent man capable launch system how would NASA astronauts get to their brand new ISS?

Often referred to as ‘Apollo on Steroids’ the constellation program was an ambitious program for a return to the Moon. It’s huge cost caused it to be canceled. (Credit: Wikimedia Commons)
The Space Launch System (SLS) is a remnant of the constellation program. Plagued by delays and cost overruns it may fly someday, maybe. (Credit: NASA)

It was decided that NASA would use launch systems that would be developed and operated by commercial aerospace corporations. Contracts had already been given to several such companies to develop robotic capsules to ferry supplies to the ISS. Why not fund those companies to develop manned capable capsules that could take astronauts to Low Earth Orbit (LOE) as well? NASA could then ‘hire’ space capsules to take their astronauts to the ISS while the companies would then be free to use their technology to further the commercial development of space.

So it was that in 2011 four aerospace companies, Boeing, Space X, Blue Origins and Sierra Nevada submitted design proposals for a man capble space capsule and after two rounds of review and competition in 2014 Boeing was awarded a contract for $4.2 billion while Space X was awarded a contract of $2.6 billion to aid them in the design and development of their manned space capsules.

Despite failing to win a contract from NASA’s Commercial Crew Program, Sierra Nevada Corporation continues to work on its version of the shuttle called the ‘Dream Chaser’. (Credit: Space News)

With the retirement of the shuttle in 2011 NASA became dependent on Russian Soyuz rockets to take its astronauts to the ISS so it was hoped that either Boeing or Space X would be ready to begin manned operations by 2017. Developing a man capable space system is not that easy however and the delays mounted.

Taking Cosmonauts to orbit since the mid 1960s the venerable Soyuz has been the only way to reach the ISS for the past 9 years. (Credit: The Verge)

At first everyone expected that Boeing, with its long history in aerospace technology, and with the larger amount of money, would be the first to actually succeed in taking astronauts into space. Over the last several years however the aerospace giant has been plagued with a series of problems. So it was that the mini-space race between Boeing and Space X was finally won by the younger, more aggressive company. See my post of 28 December 2019.

Boeing’s Starliner has flown into orbit on an unmanned test flight but problems with the craft’s software caused the test flight to be considered a failure and the necessary fixes are ongoing. (Credit: Boeing)

Designated as the Demonstration Mission 2 (DM-2) the flight of the Space X Crew Dragon capsule was originally scheduled to take off from Kennedy Space center in Florida on the 27th of May. Less than twenty minutes before take off however bad weather caused the flight to be scrubbed for the day. The next possible launch date was three days later but again the Florida weather was questionable. This time however the rain and winds held off and at 3:22:45 EDT the engines on the Space X Falcon 9 rocket ignited and astronauts Bob Behnken and Doug Hurley had a flawless eight-minute ride into LOE. To make their success complete Space X even managed to recover the Falcon 9 first stage so that it could be used again, an operation that has now become routine for Space X.

The launch of the Space X Falcon 9 rocket with the Crew Dragon capsule carrying astronauts Bob Behnken and Doug Hurley to the ISS. (Credit: SciTech Daily)

About 45 minutes after take off the Dragon capsule, crewed by veteran space shuttle astronauts Bob Behnken and Doug Hurley, completed an orbital adjustment burn, the first of five that would bring them to their rendezvous with the ISS. On the morning of the 30th of May, just 19 hours after lift off the Dragon capsule smoothly docked with the ISS.

The Crew Dragon with Astronauts Behnken and Hurley as seen from the ISS moments before docking. (Credit: NASA)

Now the mission of astronauts Behnken and Hurley is ongoing. For at least the next month they will function as members of the ISS crew but NASA could extend their mission to as much as three months. Then astronauts Behnken and Hurley will complete their mission with a return to Earth in the Dragon capsule, splashing down in the Atlantic off the Florida coast. The next manned launch of the Dragon is currently scheduled for September and will be the first official mission of NASA’s Commercial Crew Program. A little late perhaps but nevertheless, so far so good!