Category: Science

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!

Extraterrestrial Life and Extraterrestrial Intelligence how likely could they be and what are the chances that we may soon discover one or the other.

Certainly one of the biggest questions that anyone can ask is, is there life out there? Are there other planets that have life or even intelligent life living on them? At the present time we really have no idea, our exploration of the Universe has only just begun. We have landed robotic probes on only a very few celestial bodies and even on those we have see so little that some form of life could be hiding from us! Still as the famed science fiction author Arthur C. Clarke once asked, the question of whether we are alone in the Universe can have only two answers and either one is awe inspiring.

Thanks to Steven Spielberg this is most people’s idea of an Extraterrestrial. (Credit: Dred Central)
Unless that is you prefer this one! (Credit: Paramount)

Many would say that the Universe is so large, there so many places that life could exist and evolve into intelligence that surely there must be some life out there. That position, however reasonable, isn’t evidence. So the study of extraterrestrial life remains a science without a subject, a science of conjecture and hypothesis rather than solid fact.

Every little dot in this image is an entire galaxy with billions of stars. In such a huge Universe how can we possibly be alone? (Credit: NASA)

When I was an undergraduate all of that conjecture was summed up in ‘Drake’s Equation’ named for a U.S. astronomer who first explicitly wrote down all of the factors in one equation. Using Drake’s equation it is possible to calculate the number of intelligent species in a galaxy, assuming you have accurate numbers for all of the factors in the equation.

                                Equation 1

In this equation I is the number of intelligent species in a galaxy, say our own Milky Way. You calculate I by multiplying the factors on the right hand side.

N is the number of stars in that galaxy, about 200 billion for the Milky Way.

FP is the fraction of those stars that have planets orbiting them. Therefore FP must have a value of between zero and one.

FH is the fraction of planets that orbit in a ‘habitable zone’ around their star; I’ll explain what that means below. Again, FH is somewhere between zero and one.

FL is the fraction of habitable planets where life actually arises. Again, zero to one.

FI is the fraction of planets with life on them where intelligence evolves. Zero to one.

Back when I was in college the only factor on the right hand side of Drake’s equation that astronomers had any accurate measurement for was N, the number of stars in the Milky Way. Every other factor was totally unknown so any attempt to actually use the Drake equation was just pure guesswork.

Our Milky Way itself contains 200 Billion stars, any one of which could have planets with life on them! (Credit: Forbes)

We’ve made some progress since then. In particular thanks to the discoveries made by the Kepler space telescope and other astronomical programs we now know of the existence of thousands of planets outside of our solar system. Because of these discoveries we can now say with reasonable confidence that at least half of all stars must have planets orbiting them, perhaps 90% or even more. So if even half of the Milky Way’s 200 billion stars have planets, then there are an awful lot of planets out there.

Thanks to the Kepler Space Telescope we know of the existence of thousands of planets outside of our solar system. (Credit: Vox)

We’ve also made some progress with FH, the fraction of planets that could be habitable for life. Thirty to forty years ago ‘habitable’ would have meant liquid water on the planet’s surface, which in our solar system meant only Earth, one out of eight planets. However our space probes to the outer planets have discovered that Mars once had oceans and maybe still has water beneath its surface. Also, data from other probes have raised the possibility that Europa and Enceladus, the moons of Jupiter and Saturn respectively, may have large oceans of liquid water beneath their icy surfaces. That means that our solar system might actually have at least four habitable bodies, not just the Earth. So it appears that FH might actually be larger than we thought just a few decades ago.

Both Jupiter’s Moon Europa (L) and Saturn’s Moon Enceladus (R) are believed to have oceans of water beneath their icy surfaces. This means that more planets than we thought might actually be ‘habitable’. (Credit: NASA)

That leaves us with just the last two factors, FL that fraction of planets with a habitable environment that possess life and FI the fraction of planets with life where intelligence evolves. The only way to get an accurate measurement for these two numbers would be to closely study a few hundred or more habitable planets or moons and just see how many have developed life and how many go on to evolve intelligence.

The evidence from geology is that it didn’t take long for Earth’s Primordial Soup to evolve into living things. (Credit: Scoopnest)

We can’t do that however; it will probably take decades for our space technology to even find life on Mars or Europa if it’s there. The only real example we have to study is Earth. Can we learn anything about FL and FI from studying the history of life on here?

A new study says that we can. Authored by David Kipping of Columbia University’s Department of Astronomy “An objective Bayesian analysis of life’s early start and our late arrival” uses probability mathematics to calculate values for FL and FI that would best simulate life’s history here on Earth.

Bayesian analysis is a mathematical technique for studying complex problems with a large number of parameters. Heavy on calculations it’s often performed by computers. (Credit: Mondo 2000)

You see we know that our planet is about 4.5 billion years old and there is growing evidence that life was well established here as far back as 4 billion years ago. Indeed it looks as though life began on Earth as soon as its surface had cooled enough for life to exist. On the other hand complex, multi-cellular life took 4 billion years to evolve and even then intelligence took another half billion years.

Life may have existed early in Earth’s history but it took a very long time to evolve into complex multi-cellular forms. (Credit: Expii)

So what Doctor Kipping did was to develop a computer program that would vary FL and FI across all of their possible values and see which values succeeded in reproducing life’s history here on Earth. The result that Dr. Kipping obtained is that while life itself could be quite common in the Universe, intelligence is very rare. Mathematically what he found was that FL is close to one but FI is very, very close to zero. Thousands of planets may have life on them for every one that possesses an intelligent species.

I have to admit that I agree with Dr. Kipping. The more we learn about life at the biochemical level the more it seems to be something that will inevitably happen at least once on any planet that it can happen on, and once it happens it spreads everywhere on that planet. However intelligence is so complex, so dependent on the twists and turns of evolution that intellect, mind may be the rarest thing in the Universe.

The philosopher Socrates advised us all to “Know Thyself”, the world would still be a better place if more of us followed his suggestion! (Credit: New Intrigue)

Maybe we should take a lesson from Dr. Kipping’s work. If intelligence is the rarest, most valuable thing in the Universe it might behoove us to use ours a little more often, to appreciate it a little more, to realize that it is all that really separates us from… just biochemistry.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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