Month: April 2020

NASA continues development effort on Ion rockets, are they the future of Space Exploration?

For over 60 years now rockets using highly combustible chemicals have dominated space exploration. Starting with the launch of Sputnik 1 on the USSR’s R-7 rocket to the latest Space X Falcon 9 reusable rocket virtually every rocket used to get into space or to travel to other planets has been a chemical rocket.

The liftoff of Apollo 11 on its way to the first Lunar landing. A rocket launch is an icon of our age with all of the smoke and flames produced by a chemical reaction. (Credit: Amazon.com)

That’s one of the reasons why human beings haven’t gone any further than the Moon and even our robotic probes take years to get to the other planets. You see chemical fuels simply aren’t very powerful; to be specific the exhaust velocities possible with chemical fuels are completely inadequate if you want to achieve the velocities needed for space travel.

Two ways to provide thrust to a rocket. Chemical reactions can only supply a small speed and therefore require an enormous amount of fuel. (Credit: qrg.northwestern.edu)

Let’s first consider a few facts. First, the velocity needed to just get into Earth orbit, is 7.9 kilometers per second while the absolute best known exhaust velocity for a chemical reaction, which is oxygen and hydrogen, is only about 4.5 kilometers per second.

The low exhaust velocities possible with chemical fuels are the reason that most rockets are little more than big bags of fuel and most space launch systems use a multistage approach to getting into space, throwing away 90% of the rocket, along with burning all that fuel, just to get a small payload into space!

In order to get the tiny Apollo Command Module, along with the astronauts, to the Moon and back it was necessary to throw away the entire rest of the massive Saturn V rocket in stages! (Credit: Kids News)

Rocket engineers have known about this problem since before the beginning of the space age. They also knew that in order to achieve the very highest exhaust velocities some form of electric propulsion, more commonly called Ion propulsion, would be needed.

NASA’s new X3 Ion Thruster developed by the University of Michigan with NASA’s assistance. It may look a lot gentler than a chemical rocket but the exhaust velocity is ten times greater and this engine can fire for months or even years! (Credit: Science Alert)

The main principles behind ion rockets are pretty simple. You take a normal, electrically neutral atom and strip off one or more of its electrons by means of an electric discharge. This leaves the atom as a positively charged ion. This ion can then be accelerated to very a very high velocity by placing it in a voltage field, the ion will be repelled by the positive voltage and attracted by the negative voltage, opposites attract after all. Once the ion has acquired the desired velocity it is directed out the back of your rocket generating a tiny thrust pushing you forward. Obviously the more atoms you fire out the back the greater the thrust generated.

Basic schematic of an Ion rocket engine. It is rather complicated and everything has to be precisely design but after all, this is rocket science. (Credit: Quora)

If this technology reminds you of the particle accelerators / atom smashers that physicists use to experiment with elementary particles you’re not far off. Ion rocket engines are in fact particle accelerators that, instead of smashing atoms into each other, use those accelerated atoms as propellant. Because of this similarity however, the potential exhaust velocity for an ion rocket is literally within a fraction of the speed of light.

In some ways an Ion rocket engine is like a single stage of a Linear Particle Accelerator. Such accelerators can speed up particles to nearly the speed of light. (Credit: Wikipedia)

One problem with ion rocket engines right at the start, those electrons you stripped off of the ions. Well if you don’t somehow get them back on the ions before they are fired out of the back your rocket will quickly build up a huge negative charge that will just screw everything up! Because of this fact ion engines are designed with a final, negatively charged grid or electron gun so that the ions regain their electrons.

A second, rather larger problem is that unlike chemical rockets that produce an enormous amount of thrust for a few minutes, the Saturn V produced over 34 million Newtons of thrust, an ion rocket produces only a tiny amount of thrust, but they can continue to do so for years, eventually producing a far greater total push. The reason for this difference is that the electric power needed to ionize and then accelerate the propellant’s atoms is so large that only a tiny amount of fuel can be consumed per second.

This low thrust makes ion rockets unsuitable for lunching from Earth’s surface, since you need to have enough thrust to overcome a rocket’s weight before it will even start to move. However it makes them excellent choices for robotic missions to other planets and several such ion powered missions have already flown.

The first demonstration of an ion rocket engine in Earth orbit took place on the Space Electric Rocket Test (SERT 2) launched in February of 1970. The two ion engines on board only produced 0.027N of thrust each but they managed to achieve a propellant exhaust velocity of more than 22 kilometers per second, nearly five times that of the best chemical fuels. The SERT 2 test vehicle also demonstrated the ability of ion rockets to work for long periods of time as one engine fired continuously for five months and the second for three before electrical problems caused them to fail.

The first test of ion rockets in space was NASA’s SERT 2 mission. The thrust provided by the ion engines was tiny but they fired for a combined total of 8 months. (Credit: Gunter’s Space Page)

The most successful use of ion rockets to date is probably NASA’s Dawn mission. Dawn was the first man made object to orbit two astronomical objects other than the Earth, the dwarf planet Ceres and the asteroid Vega. This space age first was only possible because of Dawn’s ion propulsion engine, which only provided a thrust of 90 mN but which operated throughout the mission, a total of 5.9 years. Just imagine a rocket engine firing for 5.9 years!

The Dawn robotic space probe firing its ion engine as it approaches its first objective the asteroid Vega. (Credit: Pressfrom.info)

NASA’s future plans include increasing use of ion rockets for interplanetary missions. To that end it has been funding the Advanced Electric Propulsion System (AEPS) a 50 kW ion rocket that is currently under development at the Glenn Research Center and Aerojet Rocketdyne. The design goals of this program include a nominal thrust of 1.77N for a full life of 50,000 hours, that’s 5.7 years! Testing is now underway with a possible first mission on NASA’s Deep Space Gateway in Lunar Orbit. (See my posts of 24 March 2018 and 29 May 2019 for more information about the Deep Space Gateway) Despite all of this progress it could be a considerable amount of time before ion engines are used to propel a manned mission to another planet. Nevertheless the enormous advantages inherent in the almost limitless exhaust velocity ion engines provide all but assures that they will be playing an important role in humanity’s future exploration of the Solar system.

Plant Intelligence. Wait; there is such a thing?

We humans like to think of ourselves as being special, not just more intelligent than ‘the animals’, but a higher sort of intelligence. In fact we used to insist that anytime an animal showed something resembling conscious thought we’d say that it was really just behaving by ‘instinct’, not intelligence.

I don’t know this Will Cuppy but I think I’m going to have to check him out! (Credit: AZ Quotes)

That way of thinking has been pretty much tossed into the dustbin of science as naturalists have studied the many different species of animals who use tools, those who can communicate in some pretty sophisticated ways and whose problem solving skills can almost seem to rival ours in some ways. The list of these, intelligent species is quite long and getting longer everyday. Not just dolphins and chimpanzees but also dogs, elephants and squirrels not to mention other animals like ravens, parrots and even octopi. So let’s be honest, animals in general can be quite intelligent, each in their own way!

Many species of animals have been observed to use tools but only Humans and our cousins the Chimpanzees are known to use more than one tool. (Credit: Britannica)

At least it’s only animals that show intelligence right? Plants don’t have anything like a brain. In fact plants don’t even move unless the wind blows on their leaves so how could you even tell if plants had anything like intelligence.

Not quite like that! (Credit: R. A. Lawler)

Actually of course plants do move, a sunflower will follow Sun across the sky each day and if you’ve ever had to keep ivy from twisting its way up a wall or tree trunk you’d know that plants can grow in a manner that displays a great deal of purpose if not intelligence. There is in fact growing evidence that plants are aware of their environment and can react to stimuli in ways that can be described as intelligent.

Take the Venus flytrap for example. Each individual trap has two hair like sensors that ‘tell’ the plant when something is in the trap. However in order to keep the trap from closing on a piece of a leaf or dirt it’s only when an insect triggers both hair sensors that the trap snaps shut. That’s certainly more awareness and intelligence than plants are generally given credit for.

Venus Flytraps live in soil so infertile that they have evolved to supplement their diet by eating the insects they catch! (Credit: New Scientist)

Now consider a few experiments that have been conducted by Doctor Katja Tielbörger of the University of Tübingen in Germany. Working with the plant Creepy Cinquefoil (Potentilla reptans) Dr. Tielbörger used strips of green coloured cellophane to simulate competing plants. In one setup the competing plants were low vegetation that surrounded the Cinquefoil test plant. The Cinquefoil responded by shooting upward in order to get above the competition. In a second test the competing plant was very tall, hanging over the Cinquefoil. The Cinquefoil responded by growing outward to get away from its competition. Finally, the competing plants completely encased the Cinquefoil so that only bits and pieces of light could get through. The Cinquefoil responded by staying small but growing large leaves in order to catch every bit of light possible.

Part of the test setup for DR. Tielborger’s experiments on the decision making ability of plants. (Credit: Nature)

If you think that maybe those experiments only demonstrate that plants have evolved mechanisms that allow them to grow towards the light then consider this second experiment that Dr. Tielbörger performed with a different plant, Mimosa pudica, also known as the sensitive plant. M pudica and its relatives are fern plants that are known for their habit of closing up their leaves during the night. M pudica goes a bit further however because it will also close up its leaves when they are grabbed or even roughly brushed against. This behavior makes M pudica an excellent test subject for experiments in plant reaction to stimuli.

The experiment that Dr. Tielbörger conducted was this; whenever she turned on a bright light near an M pudica plant she would then puncture several of the plant’s leaves with a sharp poker. This damage caused the rest of the plant’s leaves to immediately close up. Doing this continuously for a month Dr. Tielbörger then discovered that the plant’s leaves began to close up as soon as she turned on the light and before she began to injure the leaves. The plant had learned to associate the light with the damage caused by the punctures and reacted in a fashion that can only be considered ‘learned’.

Dr. Tielborger poking the leaves of a Mimosa pudica plant in her experiment on plant learning. (Credit: VolkswagenStiftung)

But how can plants learn anything, they don’t have anything like a brain. They don’t even have any kind of a nervous system that would allow them to react to stimuli the way an animal would. Well now a study from the Massachusetts Institute of Technology (MIT) has uncovered one mechanism by which plants may be able to communicate different kinds and different levels of stress throughout their bodies.

Biochemists have known for several years that plant cells use the chemical hydrogen peroxide as a signal to induce production of chemicals known as secondary metabolites that help a cell repair damage to its structure. Some of these chemicals can also produce disagreeable flavours that help the plant to fend off predators. The way in which entire plants use hydrogen peroxide to communicate stress levels between cells has been more elusive however.

Gardeners have known for a long time about the healing effect a little hydrogen peroxide has on plants. (Credit: YouTube)

In a paper in the journal Nature Plants senior author Michael Strano, Professor of Chemical Engineering at MIT, has detailed how he and his team succeeded in inserting sensors made of carbon-nanotubes into plant leaves and stems into order to detect and measure the flow of hydrogen peroxide throughout the plant.

So far the chemists have used their technique on eight different plant species including spinach, arugula and strawberry and plan to try it on other species going forward. These new sensors could give biologists their first glimpse into the ‘nervous system’ of plants, which could lead to a better understanding of plant intelligence.

In another of his experiments Dr. Strano has ‘trained’ spinach plants to detect explosives! (Credit: ZME Science)

Simply put, intelligence is nothing more than an awareness of your environment and reacting to it. When you look at it that way intelligence is pretty much just a part of being alive.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

If only the politicians of different nations followed that example.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

What is a Virus?

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

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

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

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

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

Second: Living things metabolize those nutrients.

With the energy gained from those nutrients living things:

Three: Grow

Four: Move

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

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

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

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

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

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

Viruses attacking a bacteria. (Credit: PBS)

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Sage Advice! (Credit: Meme Generator)

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

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

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

Space News for April 2020.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Paleontology news for April 2020.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Robot Report for Mar 2020.

There have been some very interesting engineering developments in both robotics and artificial intelligence (AI) recently. These new designs clearly show what I consider to be the main theme of these subjects, a convergence of the artificial and organic as engineers learn how to copy the abilities of living creatures, taking advantage of the strengths of biological systems in order to improve the functioning of their designs.

Learning how to use the abilities of organic life in mechanical systems is about more than just making a robotic copy of ourselves. (Credit: YouTube)

We are all aware of how awkward and clumsy the movements of robots appear when compared to the grace and dexterity of living creatures. The mechanical walk of a robot as depicted in SF movies of the 50s and 60s may be a cliché, but nevertheless it’s still pretty much true. Because of this inflexibility robots are usually designed for a single, repetitive task. Multi-tasking for robots is usually just out of the question.

A Robot from the 1039 World’s Fair in New York City. He looks like he could hardly move! (Credit:History.com)

With that in mind I’ll start today’s post by describing some of the work of Doctor Fumiya Iida of the Department of Engineering at the University of Cambridge in the UK. Throughout his 20-year career Dr. Iida has studied the anatomy of living creatures in an effort to improve the agility of his own robotic creations.

Doctor Fumiya Iida with some of his work. (Credit: Phil Mynott)
Doctor Lida’s robotic hand for playing the piano. (Credit: Linked In)

Dr. Iida has found inspiration from a wide range of different anatomical structures. Everything from the prehensile tail of a monkey to the sucker mouth of a leech can become for him a new way for a robot to move and manipulate objects. Dr. Iida and his colleagues refer to this program as ‘Bio Inspired Robotics’. Dr. Iida’s latest success has been the demonstration of a robot that can perform a labourious and backbreaking job that before now could only be accomplished by humans, picking lettuce.

Picking lettuce is extremely labour intensive. Automating this, and other vegetable harvesting would eliminate a great deal of low paid, hard labour. (Credit: Flickr)

Now at first you might think that picking lettuce would be an easy job to design a robot to handle. After all lettuce heads are all planted evenly spaced in straight rows. All a robotic picker has to do is go along the rows and grab the lettuce heads.

It’s not that simple, first of all a lettuce head is fairly soft and every individual head of lettuce is a somewhat different size and shape. This makes picking the lettuce heads difficult for most robots, resulting in a considerable amount of damage to the lettuce. Also, the outermost leafs of a lettuce head are generally so dirty or damaged that they have to be removed, a task that hitherto no robot has been able to carry out reliably.

Putting all that he’s learned into the problem Dr. Iida utilized a combination of visual sensors, soft grippers and a pneumatically activated knife for his robot picker. First the robot uses its cameras to locate a lettuce head before positioning itself directly above it. Then lowering itself onto the lettuce the robot pushes the unwanted leaves down and out of the way before cutting the head at its base. The robot’s soft grippers then lift the head up and place it in a basket.

Procedure used by Doctor Iida’s robot lettuce picker. (Credit: Wiley Online Library)
The lettuce picking robot in action. (Credit: The Robot Report)

So far Dr. Iida’s robot has been able to achieve an 88% harvest success rate, good but it still needs improvement before it can replace human pickers. Nevertheless when perfected this technology could be adapted to other types of produce, finally automating what has remained one of the hardest and lowest paying of all jobs.

So, if engineers are starting to construct robots to harvest our vegetables for us, what other boring repetitive jobs can they be built to take off our hands? Well researchers at the Massachusetts Institute of Technology (MIT) are actually developing robots that can learn to do common household chores like setting the table by watching us do it!

The technology has been given the name ‘Planning with Uncertain Specifications’ or PUnS and the idea is to enable robots to perform human like planning based on observations rather than simply carrying out a list of instructions. By watching humans completing a task, like setting a table, the robot learns the goal of the task and a general idea of how to accomplish that goal. Known as ‘Linear Temporal Logic’ or LTL these computer generated formulas serve as templates for the robot to follow in order to accomplish its goal.

Robotic Vacuum clears are a simple example of PUnS. Whenever they bump up against an obstacle they just make a turn and head off in a different direction. Eventually they will clean the entire floor! (Credit: The New York Times)

In the study the PUnS robot observed 40 humans carry out the task of setting a table and from those observations generated 25 LTL formulas for how to complete the task. At the same time the computer assigned to each formula a different confidence of success value. Starting with the highest value formula the robot was then ordered to attempt to complete the task and based on its performance it is either rewarded or punished.

A Robotic arm that has learned, not be programmed to set a table! (Credit: YouTube)

In a series of 20,000 tests starting with different initial conditions the robot only made a mistake 6 times. In one test for example, the fork is hidden at the start of a test. Despite not having all of the items required to completely set the table the robot went ahead and set the rest of the dinnerware correctly. Then, when the fork was reveled the robot picked it up and placed it in the correct position, completing the task. This degree of flexibility in an automated system is unprecedented and points the way to robots learning how to accomplish different jobs not by mindlessly following a long list of instructions, in other words a program, but rather the same way humans do, by watching someone else do it. So, robots are now being designed to move more like a living creature does, and computers are being programmed to learn more like a human does. It took evolution billions of years to give living creatures those abilities but by observing and copying biological systems our robots and computers are quickly catching up. Who knows where they’ll be in another few decades.