Anthropoledge -

Seeing us in a different way

On 30 March 2020

Today days issues with climate are caused by homo sapiens, from its direct usage and consumption of goods, that indirectly produces what is called pollution. What scares us the most is the fact that one day we could get extinct by the effects of our own hand, but if that is what’s going to happen, so be it!
During time millions of animal species have been wiped off by way more dramatic changes of the environment conditions, so why our days should be so important? Through the geological eras, life on Earth encountered many difficulties: sometimes it even got extremely inhospitable for living beings, phenomena called mass extinctions. The biggest ones occurred in between the Permian-Triassic, Triassic-Jurassic and Cretaceous-Cenozoic boundaries (all of them belong to the Mesozoic era, going from 252 to 66 million years ago). They all have been caused by eruptions or magma extrusion coming from beneath the crust. In both cases the consequence was a release of enormous quantities of carbon dioxide. Today, it is us what’s producing the greenhouse gas, the only difference is in the temperature changes: in those ancient days Earth troposphere reached measurements so high on the thermometer that even the semi-solidified masses of water at the bottom of the oceans melted releasing the methane they contained in the atmosphere, enlarging the already conspicuous damage. Maybe, we should imagine ourselves just as one in thousands of animal species. Every animal has its habits; one of ours seems to be the production of pollution in form of CO2.
During the Archean and the Proterozoic, in a specific chunk of time going from 3,5 to 1,3-2 billion years ago, world’s oceans were inhabited only by monocellular microorganisms, called archaebacteria. Some of them were the ancestors of the modern cyanobacteria, whose habit is to produce oxygen as a waste, since they can photosynthesize. Yes, they were little, but many, and had had at least 2.2 billion years to metabolize as much carbon dioxide as they wanted. It happened that the Earth’s troposphere gas composition changed dramatically: from 78% nitrogen, 20% carbon dioxide , 1% oxygen, 1% other gases it went to be 78% nitrogen, 20% oxygen, 1% carbon dioxide, 1% other gases. Standards which permit the development of complex life in seas and on land.

An illustrative image of a cyanobacterium. Notice the thylakoid, the compartments which permit the process of photosynthesis

The high concentration of oxygen caused another big thing: the oxidation of iron, the second most abundant metal on the planet. The early hydric basins were acidic, containing enormous amounts of dissolved iron under ferrous and ferric forms, both capable of reacting with the new increasingly emitted gas. Even on the land, there were traces of pyrite, an unstable compound composed by unreduced quantities of the metal. The O2 generated by the sea bacteria started to react with these compounds, generating insoluble oxides which went straight to the seafloor. Afterwards, they got implemented in the deeper layers of the planet by subduction, a phenomenon caused by the motion of the tectonic plates, which sees one sliding under another. Because a large mass was moved from the crust to the surroundings of the Earth’s core, it is likely that the rotation period fastened up, making the days shorter. This is due to the principle that stands behind the conservation of energy: in order to maintain the same energy, a rotating body whose centre of mass has been moved elsewhere from its original place tends to slow down (if the mass centre in now further from the barycentre) or speed up (if the mass centre is now closer to the barycentre).
Not only those microbes chilled the environment, but they even made possible the development of multicellular organisms (although we have less time to sleep), because of the almost total replacement of the CO2 with O2.
What’s our footprint compared with the archaebacteria’s one? Almost nothing.

The First Stars

By anthropocene

On 27 September 2019

In Astronomy, Technology

Since the dawn of times, man has been keeping asking himself about what surrounds him, where he came from, what there is in the Universe, how everything formed. Today we may be able to answer a small chunk of this last question, and to do that, we have to look back in time, precisely around 13 billion years ago, when the first stars of our Universe started to grow up. I’ve already talked about how is possible to see things past in time here: https://anthropocene.altervista.org/new-horizons/ , but I’ll refresh the concept really fast. Since the light (so, the reflected or emitted rays of every object we see) travels at a certain speed, it takes some period of time to go from point A to point B. If A and B are really far away, let’s say 13 billion light years, it means that the light has to spend 13 billion years to reach point B leaving from A. And if B is the Earth and A is an ancient star, it means that we can see what that star was doing 13 billion years ago.

To tell why we are studying protostars, a brief story of the primal Universe is needed. After the Big Bang, the space was rich of small particles such as quarks, which were moving at very fast speeds due to the momentum given by the explosion. Their speed (and temperature) was high enough to not permit to the strong interaction, or force, (the energy keeping together quarks to form neutrons and protons, and the same one binding these last two to form atom’s nuclei) to do it’s job. But eventually, they started to slow and cool down, to the point when the aforementioned force started to work, giving green light to the formation of the lightest elements: hydrogen (mostly) and helium. Thanks to the influence of the gravity force, the hydrogen atoms progressively formed clouds, that compacted into what we call stars. Since in Universe there where enormous amounts of those gases, the stars which build up where huge: we talk of an average of 200 Sun masses (stars 200 times bigger the our own). What stars do to produce electromagnetic waves we perceive mainly as infrared waves is nuclear fusion: the immense pressure in their core due to the mass squeezes the atoms and crushes them together, forming heavier elements and energy. The process goes on until the reaching of Iron-56, whose fusion requires energy rather than produce it. At this point, the star collapses under it’s own weight, generating different types of supernovas (depending on the mass) that bring to a newborn neutron star or a black hole. The supernova, and other explosions which tend to happen during the death of a collapsing star (a star which has exhausted the hydrogen) throw in the space all the matter previously produced. Now you’re probably thinking “where do the elements heavier than Fe-56 come from?”, well there is a theory to explain this: a type 2 supernova (a collapsing star bigger than 9 Sun’s masses) generates gigantic energy quantities and at the same time spreads out neutrons in addition to the fusion-born elements. The neutrons start a fusion process themselves, and thanks to the type 2 supernova’s energy, they can bind beyond iron-56 limit; so here you are.

Strange but effective

The radio telescopes used to gather infrared waves from those primal stars are rather unique: they go from a metal table placed in a desert to a complex of receptors placed in a range of thousands of kilometers. The study of those ancient objects is fascinating not only for the reasons just said, but also for their unique nature: only to give a taste, the bigger the star is, the short it’s life expectancy is. Our Sun is believed to have a lifespan of about 10 billion years; some calculation say that a big protostar is lucky if it lives up to a couple million years (1/5000).

Climate changes

By anthropocene

On 17 September 2019

In Biology, Paleontology

Today the main concern of every scientist working in the naturalistic field concerns the climate changes that we have witnessed progressively in recent decades. The greenhouse effect and the ozone hole are phenomena we hear about every day, but they are not the only ones to influence the increase in temperatures and related events on Earth. Obviously the polluting emissions produced by man are a big problem that must be fought, even if there is also a long list of factors related to geophysics. First of all, we must keep in mind that we are living in what can be called a minor ice age, which means that the temperatures on Earth are below average in its history. Life, from its origins (it’s supposed have been born somewhere around 3.6 billion years ago) has always evolved based on the environment. Just to give some examples, when the atmosphere was rich in carbon dioxide, wet and hot, there were immense forests of trees and “primordial” plants (Carboniferous, 320 M years ago ca.); when it was slightly colder and full of oxygen, the dinosaurs and the ancient great arthropods began to develop (Triassic 220 M years ago); during the great ice ages, mammoths and other mammals had to compensate for extremely low temperatures.

All those variations that strongly alter the biosphere during long periods of time must be attributed to the complex of the Earth’s movements and its magnetic field. Our planet not only rotates on its axis and on an orbit around the Sun, but its axis rotates in a circle that requires 21700 years to complete, the inclination of the axis varies from 21.39 ° to 24.36 ° over 41,000 years and the orbit itself changes from very elliptical to almost circular for over 98500 years. These alterations compete to vary the way the Earth receives solar radiation, thus making it warmer or colder. The main phenomenon involved, however, is what can be described as a movement of the magnetic field. As you know, the planet Earth is composed of multiple layers and the inner ones, near the solid nucleus, are made of liquid metal (mainly iron and nickel) at different temperatures depending on the depth. This temperature difference produces a convective movement, in which the warmer and less dense part moves towards the colder and denser part, and vice versa. Because in metals we find what is called metal bond, there is like a large cloud of electrons carried by the liquid iron itself. This constant displacement creates the magnetic field of the planet (at least it is the most accredited theory). But there are also variations in this displacement, variations that are probably the cause of the movement of the magnetic pole: at the moment the geographic north pole is north of Greenland, almost in the center of the Arctic Sea, and the magnetic north pole is northwest of Greenland, on its islands. Some times in history there were such big mutations that the magnetic field actually got reversed (this happened 183 in the last 83 million years!). Probably due to its behavior, it can also become stronger or weaker, exerting a great impact on the environment: it has the important role of containing all the gases in the atmosphere (not only our precious oxygen, but also those that are very important in higher places, such as CO₂, O₃ and H₄) near the surface, which would otherwise escape from space. The stronger it is, the more gas molecules are retained, protecting us from UV radiation but improving the greenhouse effect; the weaker it is, the less it succeeds in retaining, letting in more UV rays and reducing the greenhouse effect, with greater daytime temperature excursions. So neither end is good, and what man has done since the first industrial revolution is creating a deadly combination of the negative aspects of both. However, as I said earlier, today’s “extreme” climate changes are not only due to the hand of man, but also (and perhaps above all) to all the variables mentioned in the physics of the Earth. There were times when the climate was much more inhospitable, times when humanity was still far from making its first steps, and life has always found a way to get up again and again: it’s almost an excuse. Earth and nature should follow their path without interference of any kind, so we really do need to start doing something for our huge footprint and try to correct our mistakes.

James Webb Space Telescope

By anthropocene

On 11 August 2019

In Astronomy, Technology

Now talking about engineering aspects, this incredible instrument is composed by several modules:

the mirror: 18 hexagon-shaped refractors form a single body. They are made of beryllium covered with a foil of gold, to add better refraction capacities;
scientific instruments: the complex of cameras at near and mid infrared (depending on the focus we need, how far is the object we are looking at and what we want to observe) antennas for communication, two spectrographs, one operating at multiple resolutions and the other at near infrared, the guidance sensor, used to align the telescope in the desired direction and to operate micro adjustments;
the bus: the heart of the telescope, including the propulsion system, the energy generator, the main computer for data management, communication and thermal control system;
the sunshield: lower is the temperature of the components, better is the result in terms of accuracy of the final image, and in the Earth’s orbit the main heat source is the Sun. To achieve that, the whole structure is covered in a “screen” made of 5 layers of Kapton (a polymer chemically stable in a wide range of temperatures) with two upper coating of aluminum and silica. Is estimated an operative temperature of 23 K (-250 °C), counting the already mentioned active cooling system which utilize liquid helium.

One of the hexagonal refractors of the mirror

The James Webb will be launched on an Ariane 5 rocket, and reaching the second Lagrange point (L2) of the Sun-Earth system, as several other space telescopes. Even if this orbit is 1.500.000 km further from the Sun than the Earth’s one, the orbital period will be the same of the planet, since L2 is located on the line passing through the star and the smaller object. The centrifugal force generated by the orbital motion of the telescope will be exactly compensated by the sum of the gravitational forces of the two much more massive bodies. Explaining this in physics terms, we compare two different James Webb orbits: the radius is the same (149,600,000+1,500,000 km), but in the second one we are assuming that there is no Earth. In both, the Sun applies the same gravitational force, which is opposite to the centrifugal force of the telescope. What changes is that in the second case, with no Earth, the centrifugal force will be stronger and the telescope will tend to escape from his orbit, leading to a longer period. In the first case, contrarily, the centrifugal force will be weaker and the centripetal (the opposite of the centrifugal, or the pulling force originated from the center of the motion) stronger due to the additional gravity of the Earth, and orbital period will be shorter. In particular, in L2 centrifugal=centripetal, and the period is 365 days.

Have a look on a related article: https://anthropocene.altervista.org/new-horizons/

New horizons

By anthropocene

On 4 August 2019

In Astronomy, Technology

You surely know about the Hubble Space Telescope, our biggest space telescope, operating since 1990. The reason because telescopes like Hubble are sent in the Earth’s orbit is due to the atmosphere of the planet, whose carbon dioxide and water molecules block or distort the light coming from distant objects such as suns, exoplanets and galaxies. Sending an infrared telescope (like Hubble) in orbit around our planet eliminates the problem.For almost three decades these telescope, named after Edwin Hubble, one of the most important astrophysicists ever, has been seeking the skies, giving us impressive imagines and data, but now we need something more. The next main space telescope has been already built: it’s name is James Webb Space Telescope and it was born by the cooperation of the NASA, the ESA and CSA. Now it is undergoing several tests, indispensable to ensure the correct working under the tough operating conditions. It’s main purpose is to investigate more into the origins of the universe, by the study of star clusters and dwarf galaxies. To explain how, it can be said that generally the farther you can look in the space, the older are the objects you are looking at; the light travels at a certain speed (299.792.000 m/s ca.), and for the universe we use the light year as metric unit: a beam of light employs 1 terrestrial year to travel for a distance of 1 light year, which is equivalent to 9.46^15 meters. If we will be capable of seeing, or to be more precise, perceiving the radiation coming from an object distant 2 billions light years from us, we will see what was happening at that object 2 billions of years ago. And not only, there might be stars, planetary systems and galaxy that are building up now, which we will observe and have the opportunity to study in the future. The second usage of the James Webb, surely not for importance, will be the search for exoplanets which posses fundamental life-related molecules, such as water, methane, ozone, carbon dioxide,ecc. Doing that isn’t really that hard: every celestial body emits a peculiar kind of light, and this phenomenon is bind to the fact that each element in the periodic table reflects a certain wavelength in the infrared spectrum. Splitting the electromagnetic radiation coming from the object in focus, we can understand what is this object made of, and if it has even a little percentage of biomolecules. Third concern of the newest space telescope is going to be making light on the concepts of dark matter and dark energy. If you are interested on, I made an article on this topic: https://anthropocene.altervista.org/matter-in-the-universe/ . The telescope will be sent in orbit on March 2021, and will be completely operating on September of the same year.

Left: Hubble Telescope, right: James Webb Telescope

Basic organic molecules

By anthropocene

On 26 July 2019

In Biology, Paleontology

One of the most exciting fields of science is certainly the molecular biology, whose efforts are today mostly focused on the research for primordial biological beings and simple organic structures.

The last achievement of this matter is the making of simple shells, similar to the cell membranes and with pretty much the same transport capabilities. It is strongly believed that life on Earth has started its journey as droplets similar to the ones we are talking about, generated by the interactions between fundamental organic compounds (made by carbon, hydrogen and oxygen). Those droplets have afterwards permitted the development of the most common cell structures, first for importance the ribonucleic acids. To make this possible, the scientists that have developed the theory employed organic chemical compounds (meaning that are based on carbon chains) called alpha-hidroxy acids, wich are nothing more than a short carbon chain attached to a carboxylic group to a side and to a hydroxyl group to the other.Then it has been proved that alpha-hydroxi acids are capable of starting by themselves a polymerization process, wich leads to the creation of a long chain of those molecules and eventually to a shell, able of ejecting the wastes and inoculate useful substances. Of course is something far from the complexity of a eucaryotic cell membrane developed with the natural selection in millions of years, but we are positive with the results and looking forward to future discoveries.

the most basic alpha-hydroxy acid (each corner of the line represents a carbon atom)

A new prospective of organisms

In the last decade the biggest moon of Saturn, Titan, has been and continues to be the major concern of all the astrobiologists. The reason of that are the peculiarities of the planetary body. Living beings similar to the ones wich populate the Earth have no possibility to withstand the adversities on Titan: the average temperature is about -180°C due to the distance from the Sun (maximum 1.517 x 10^9km), the atmosphere is almost made only of nitrogen and there is no water. Nevertheless, there are molecules that have led us to tink about a different kind of live based on unlike organic structures, but similar in the behaviour. What we have found on Titan are hydrocarbons (methane and ethane for the most) in liquid form due to the temperature, wich create lakes, rivers and even underground flowing of these materials. Up in the skies of Titan there are clouds made of the same compounds, wich can create precipitation. These factors, combined with vulcanic activity, create an environment characterized by an hydrogeologic process similar to what we call “the water cycle” on our planet. Last but not least, we found traces of a molecule called vinyl cyanide, whose polymers are used in different industries to crate plastics and rubber. On the moon in question, for the temperature and for the proprieties of chemical support provided by the liquid hydrocarbons, wich facilitates intermolecular interaction as water does, vinyl cyanide chains start to form droplets with similar to the Earths lipidic cell membranes . With the next drone-driven exploration missions on Titan we hope to find something more about these structures and understand if the theory of a different kind of living organisms is plausible.

Modern forensics for ancient murders

By anthropocene

On 22 July 2019

In Anthropology, Technology

Today we want to analyze two human fossils of two different eras: one is know as Ginger, or the Gebelein man, the most ancient Egyptian mummy, and the Ciclovina man, from the upper Paleolithic.

The first one, Ginger, found in the Gebelein desert, is not a proper fossil: in fact he is so well preserved to be considered as a mummy, although he is more than 5000 years old and belongs to the Predynasitc period, when the mummification process wasn’t invented yet. The reason of hes status of preservation is due to the way he was buried and to the heat of the desert, wich kept away all the necrophages creatures wich would have instead consumed him. One of the most advanced methods to study remains with this grade of conservation is using the CT scanning (computerized tomography scan), wich permits to see through the various layers of the specimen. Talking about mummies, we are not only able to bypass the coffin and the wrappings (whose undoings would irreparably damage the body), but even the various tissues of the human body, as the skin, the muscle layers and the bones. In the case of Ginger, using CT scanning it was discovered a wound in his left flank, the side wich he was laying on in the grave. Those kind of cuts are usual in younger Egyptian bodies, when the mummification process was already developed, and were practised by the embalmers to extract the inner organs. But as said before, that’s not his case. With the modern forensic science, it has been found that the wound is actually due to a stab, carried with a sharp object wich broke the underneath rib.

Now switching to the Ciclovina man, first we have to say that we have only the cranium of this ancestor of ours. It was found in a cave in Transylvania during the second world war by a group of miners. Because of that information, the first paleoanthropoligists who had studied the specimen hadn’t given much attention to the cracks on the parietal and frontal skull, wich were thought to be damages from a mishandling from the inexpert hand of the discoverers. Only recently has been made the hypothesis of a damage belonging to the time of the decease; so it has been analyzed with the computerized tomography. With that technique and with the study of the behaviour of the bone shards, turns out that the man to whom the skull belongs was hit with a blunt weapon, probably a bat. The pattern is clearly visible, as it forms a curve line in the direct point of the impact.

Ocean sounds

By anthropocene

On 18 July 2019

In Biology

Sometimes, you may have thought about the motionless of the ocean, the total quiet wich reigns down there, the unreal world home of so many living organisms on the Earth. Well, that is not quite correct: down there, expecially in places where there is an hight density of species, there is also a big variety of noises. Steve Simpson, a marine biologist, described his experience in Belize and Bahamas, when he was conducing researches on the corral reef. With we most basic equipment he could carry, he recorded the sounds the Reef has to offer, during both daytime and nighttime. He came out with an incredible amount of distincted noises, from different fishes, crustaceans and marine mammals: the point is that when we dive into the water, our ears stop functioning as they should; the eardrums can’t vibrate anymore because of the water pressure, and we can hardly hear something. Water is way more dense than the air, and the aquatic organisms have developed a different hearing apparatus compared to our: they exploit bones called otoliths, wich can sense the changes pressure of the water, associated to sounds. In order to dissolve any doubt, is a good thing to precise that at the beginning of the 19^th century was conduced an experiment, wich proved that sound waves travel at a much higher speed in water (about 1480 m/s at 20°C, up to 1530 m/s in sea water) than in the air. (about 343 m/s at 20°C). That’s just for the higher density of water, wich provides more energy-saving capacities for the sound waves and for longer distances. The last concept explains how Steve could have heard sounds generated by mammals such as dolphins or whales, wich usually don’t swim near the costal area. It is incredible to realise that even a little creature as the snapping shrimp can produce a peculiar sound, or a sea urchin, that scrapes the rocks of the reef with his spines. The purposes of those sounds are so many, variating from communicating territory, warnings from upcoming predators, sexual appeals. They sometimes even variate from male to female, and of course from nocturnal and diurnal creatures.

What we have to keep in mind is that even us are producers of noises: large ships as cargoes tend to make a lot of noise, wich has a bad impact on the ocean life, interfering with the normal propagation of oceanic sounds fishes use to communicate, to the point when they can’t do part of their basic biological routines. And so, we should start to be as silent as possible, in a place wich doesn’t belong to us.

Our knowledge of the Universe…

By anthropocene

On 17 July 2019

In Astronomy

Hundreds of years of research, discoveries and theories. Hundreds of years of science, everything to know and understand (maybe) only 5% of what the Universe is made of. From a side this is just disconcerting, but we have to take it as a push in our trip toward the definitive knowledge of the Space. This 5% I’m talking about is all the “physical” matter we can interact with, meaning all the elements on the periodic table. So, everything that is made of neutrons and protons. Half way through we have the neutrinos, subatomic particles wich are only capable to interact with the weak force and the gravitational force. The “remaining” 95% is made of a thing called dark matter, and a less “thinghy” one named dark energy. You probably have already heard of those two, but what you may not know is the purpose of their names: for both, dark means that we don’t know what they actually are, so they are “obscure to us”. For the first one, matter means that is capable of generating gravitons, the quantums with whom gravity spreads, so we can assume that is could be made out of particles ; for the second one, energy means that is not made of particles, but it has to have some kind of interaction with the matter (the 5%). This supposition is the most interesting one and it is kind of hard to describe it without and physical equation: first of all we have to point out some concepts. 1: the universe is in expansion, 2: the galaxies are moving since the universe is in motion, 3 some of the galaxies are rotatig (like our Milky Way). These 3 points are correlated by the fact that they all generate kinetic energy: this energy tends to separate the particles to whom is applied, but as we can see, the celestial bodies forming the galaxies keep sticking together. After some calculations , it turns out that the gravitational energy produced by the matter of these celestial bodies isn’t nearly enough to keep a galaxy from falling apart! So, there must be something that generates the most of the energy needed to this purpose, and it is the dark energy.

Making a step back, we will now focus on the dark matter. We don’t know why it is there, but we know that it is there; that’s strange to say, but is the best way to describe it. The most powerful telescopes in the world (The Hubble, for example) work exploiting a phenomenon called “gravitational lensing”: basically, something capable of emitting gravitons deforms the space-time, and we are able to see these because the path of light (electromagnetic radiation) passing by is deflected, as a glass deforms an image. So we don’t see the dark matter directly, but we know that is around us because in some spots of our galaxy electromagnetic rays are strangely deflected, and there is nothing physical there capable of doing all these, nothing but dark matter.