Is a ‘zombie apocalypse’ possible? Here, a scientific perspective

Zombies are one of the most common resources of post-apocalyptic fiction.

Zombies are one of the most common resources of post-apocalyptic fiction.

Much of the public has ever wondered how he would act in such a scenario; which, in turn, inevitably leads to the question of whether it is really possible that zombies exist and, if so, how they would be. Science, as always, comes to solve our doubts, even about the undead.

In the first place, we are going to deny one of the most impossible characteristics: the zombies as ‘machines of perpetual motion’ , whatever happens, they never stop; walking corpses that, whether they find food or not, continue to walk for months, years or all of non-life. This is totally impossible, then, no matter what the zombification has caused, these creatures must be subject to the limits of physics. No organism, alive or undead, can maintain its activity without receiving a contribution of energy that sustains it . Therefore, the zombies would disappear by simple starvation.

Different representations of zombies in movies. / AMC, Fox Searchlight and Screengems.

The next question is how the physical abilities of the zombies would be affected when they enter that state. In fiction we find three basic options: zombies with strength or agility similar to those of the living ( 28 days later ), with reduced abilities ( The Walking Dead ) or zombies with enhanced abilities, stronger and lethal than in life ( Resident Evil ) . From the scientific point of view, it is most likely that the zombies had inferior abilities to those they had in life , due to the physical deterioration of their organism . It would be possible, though less likely, to maintain the same capabilities if, instead of dying, they would only lose their conscious mind, in which case they could retain their strength or agility as long as they managed to stay well fed. What definitely does not seem possible is that their strength increases. Therefore, it seems evident that we could face the zombies and defeat them .

Another traditional idea of ​​the genre is that zombies feed on brains.

Another traditional idea of ​​the genre is that zombies feed on brains.

However, zombies can not be expected to be selective with food . In fact, the most modern sagas already present zombies that feed on anything to survive.

Neither does the gregarious behavior by which zombies tend to recognize and form groups seem very reasonable. They would be more likely to attack each other , unless their flesh was not useful to the zombies themselves and they retained the ability to detect and discard each other; something complicated but we could accept. In any case, if that were the case, at most they would ignore each other.

Analyzed these secondary characteristics (on which you can find more details here), we finally come to the most important of all: could there really be zombies? It seems impossible that after death something will make us leave the graves. On the other hand, if we accept as zombies those bodies whose brain has been partially destroyed or annulled , leaving a functional organism but reduced to an entity without consciousness that only seeks to satisfy its most basic impulse to feed itself , then we could get to face an epidemic zombie For that, it would be enough for a pathogen (virus, fungus or bacteria) to appear that could infect us, reach our brain and damage it in that way. Another possibility would be that a pathogen would infect us in another part of the body and that its activity would produce a substance that reached our brain and caused those symptoms, as if it were a potent drug.

But if all the above is pure speculation, there is something that is very real, and that is, in fact, there are already zombies among us . Although only in the case of animals infected by pathogens that make them a certain kind of zombies.

The simplest case would be rabies , caused by a virus and whose symptoms closely resemble those of zombie fiction (loss of control, aggressiveness, bites and infection through them), although the infected organisms are not dead living. ‘

To find animals whose behavior is closer to that of ‘living dead’ we could consider the insects that are hosts of parasites such as nematomorphic worms ( Nematomorpha or Gordiacea ). These worms in their adult stage live in the water (we can find them even in puddles of rain), where they lay their eggs, which are ingested by insects. The worms are born in the body of their host and feed on it until they grow enough to be able to live free. When the time comes to leave, the worm takes some control of the body of the insect and provokes the self-destructive need to search for water and dive in (Video above).

From that moment, even if the insect keeps moving, it is practically a living dead, because it does not own its actions, and literally commits suicide so that its parasite lives and continues the cycle.

The most extreme case is undoubtedly found in the fungus Cordyceps unilateralis , which infects ants such as those of the species Camponotus leonardi . The spores of this fungus that reach the ants grow inside them, eating them inside. In a short time they manage to alter the behavior of the ant, causing it to do strange things such as separating from other ants, biting leaves and hanging on them, or jumping from the vegetation to the ground. In this case we can talk about real ‘undead’, since the fungus completely infects your body and your mind. It even moves the ant’s jaw after it has died , which makes it an authentic zombie ant. In the end the fungus develops a mushroom that leaves the head of the ant, to disperse its spores and infect more ants. This also happens with other Cordyceps that infect other insects (as you can see also in this video).

Hongo Cordyceps unilateralis en hormiga y representaci%C3%B3n en humano The Last of US  Penn State y Naughty Dog

Fungus Cordyceps unilateralis in ant and human representation (The Last of US). / Penn State and Naughty Dog.

Could something like that happen in human beings? That is just the argument of the videogame The Last of Us , in which a mutation of Cordyceps infects people. However, this does not seem a real threat, because these fungi have co-evolved with insects, and are not adapted to infect us (a simple mutation would not be enough to get us to control them like ants). In any case, we could speculate that in some future it would appear (by natural evolution or intentionally by our intervention) a form of pathogen that manages to provoke a zombification . So we can conclude that, although it is unlikely, scientifically it is possible that we will become zombies.

* Omar Flores is a biologist at the CSIC in the National Museum of Natural Sciences .

Tags: 28 days later, zombie apocalypse, Biology, Cordyceps unilateralis, CSIC disseminates, scientific culture, disclosure, gordiacea, National Museum of Natural Sciences, nematomopha, parasite, parasites, resident evil, The last of us, the walking dead, zombies | Stored in: Biology

What does a blind person do by studying the universe? In addition to a researcher at

What does a blind person do by studying the universe? In addition to a researcher at

the Institute of Astrophysics of Andalusia of the CSIC, I am blind. I have a degenerative disease of the retina called retinitis pigmentosa for which I have been losing vision, which made me join the ONCE six years ago. Perhaps some think that this physical limitation prevents me from carrying out my profession, because it might seem that the sense of sight is important to perceive the universe, but the reality is that we are all almost as blind to what it contains . This is something we have discovered in the last century, in which increasingly larger telescopes have appeared, cameras capable of capturing imperceptible images with the naked eye, light sensitive detectors that the human eye can not see because it is found in other frequencies different from visible light, such as radio waves or X-rays. All this has led to the discovery of incredible things that we were not even able to imagine until recently.

Even the human being has put into orbit space probes that can visit other planets and satellites of our solar system. We have also launched space observatories that collect light that can not cross the Earth’s atmosphere.

Many of the things we know about the universe we know because we have designed artificial eyes that look beyond what our eyes can see. However, the universe has many other things that, even with the latest technical advances or the most sensitive telescopes or detectors, we can still observe . I’ll give you five examples.

Asteroids Our solar system is plagued by innumerable rocky bodies that are a vestige of the time when a part of the gaseous cloud that formed the whole system condensed into small fragments orbiting the Sun. Many of them were grouped in increasingly larger objects that gave place to the planets and their satellites, but many others remain loose and, from time to time, end up colliding against the other major bodies. From Earth we look for them and follow them, but most of the smaller bodies, up to 100 meters in diameter, are still an invisible threat to us . The greatest risk is those who do not reflect sunlight until they are very close to us to be detected, either because of their weakness or because of their position. The use of an infrared telescope located in an inner orbit could partly solve the scarcity of resources to make a more complete census of these bodies but, while this happens, we continue traveling around the Sun among a real swarm of these cars.

Exoplanets . We are living a revolutionary stage in the history of astronomy, since one of the most complicated observational barriers has been broken: the detection of planets outside our solar system. The Kepler space telescope has already cataloged more than 2,000 and some of them are similar in size to our Earth, and could hold life. In any case, do not look for many images of them because you will find them for us. Extrasolar planets are detected by the variation in the brightness of the stars or the movement of stars when the planets pass in front of them. We will have to wait for the new generations of giant telescopes that will be built in the next decade to see them directly.

Black holes . They are one of the greatest mysteries of nature. According to Albert Einstein’s theory of general relativity, they accumulate so much mass in such a small volume that they curve space and time in such a way that not even light can escape them because time is frozen on its surface. They have been detected by the radiation that emits the gas before falling in them or by the peculiar movement of the stars that pass by , but it is not known what physical laws govern what happens inside them. A promising way to study them is gravitational waves, detected last year in a special observatory called LIGO that measures the space-time oscillations that propagate when a large mass is accelerated. The sensitivity of these observatories has to improve much still, but they have opened the door to be able to look inside these ‘monsters’.

Recreation of stellar orbits around SgrA *, a supermassive black hole candidate at the center of our galaxy (Credit: ESO).

Dark matter . Its existence is only known because its presence is necessary to explain the movements of stars in galaxies and of galaxies in galaxy clusters. It is also essential to understand how light curves when it comes propagating from the first stages of the universe and has to cross large distributions of mass. Not interacting with light in any other way can not be directly observed, but it is estimated to be four times more abundant than all other types of matter that we know and composes everything we can perceive . All the attempts made so far to discover what it is about have been unsuccessful and its nature is still completely unknown.

3D map of dark matter through the data analysis of the Hubble Space Telescope./ ESA; Richard Massey

Dark energy Finally, I will talk about the most mysterious energy and, at the same time, the most abundant. It is estimated that dark energy makes up more than 70% of the total mass and energy of the universe . Taking into account that the majority of the rest of the mass is dark matter, this leaves in only 5% the relative amount of the matter that we know. Dark energy is again a theoretical requirement to explain why the universe is accelerating its expansion movement after the Big Bang. If it did not exist, the galaxies would slow down their expansion movement and end up attracting each other until they rejoin in a single singularity. However, this does not happen, which has made postulate to theorists the existence of a repulsive force at a great distance that would make the universe continue to expand endlessly.

Most of everything in space, from the smallest scales near our planet to the largest, which dominate the movement of all space, is full of unknown objects and yet to be discovered. Possibly we end up knowing what they are with the help of our improved eyes and our awakened minds.

February 11: a day to rescue our inventors from oblivion

February 11: a day to rescue our inventors from oblivion

Next Sunday, February 11, 2018 the International Day of Women and Girls in Science is celebrated with the aim of breaking gender barriers in the scientific field. One of these barriers is the low visibility of women scientists and the existence of stereotypes that make girls less interested than children by some disciplines such as physics and engineering, and that produce involuntary biases in the evaluation of the merits of investigators.

Among the many women invisible in the history of science and technology, are also the inventors and, among them, of course, the Spanish inventors .

On one occasion Voltaire said that he had met many very intelligent ‘scientific’ women, but no inventors. It seemed thus to deny them inventive capacity, something that has been perpetuated in the false belief of the incapacity of the women for the engineering. The historical facts show us the error of that idea: Josephine Cochran (dishwasher), Mary Anderson (windshield wipers), Rachel Fuller Brown and Elizabeth Lee Hazen (the antibiotic nystatin), Gertrude Ellion (the drugs Inmuran and Zovirax, among others), Hedy Lamarr (communications encryption and more) or Stephanie Kwolek (Kevlar fiber) are some significant examples.

Also here we have had and we have inventors for a long time. The first woman to register an invention was Fermina Orduña , who in 1865 patented a special car to sell donkey, cow or goat milk on the street . But I want to bring here the case of two inventions that, like their inventors, followed very different lots: the mop and the mechanical book.

It is customary to point out Manuel Jalón, in 1964, as the Spanish inventor of the mop (there had been a similar patent in the US in 1901). But Julia Montoussé Frages (of French origin, although avilesina of adoption) and her daughter Julia (Julita) Rodríguez-Montussé obtained, in 1953 , a patent many years before the aircraft mechanic. The Utility Model Patent No. 34,262 was called “device attachable to all kinds of containers such as buckets, buckets, cauldrons and the like, to facilitate the scrubbing, washing and drying of floors, floors, corridors, baseboards and rooms in general”. A name much harder to remember than the simple ‘mop’! Of course, if we examine the plans contained in the application, there is no doubt that it is a real mop.

Little is known of these women, beyond their kinship and the date of their deaths: the mother in 1971 and the daughter in 2005; or that they were from a wealthy family without higher education, which shows that creativity, inventiveness and concern for human situations (the fact that women had to scrub floors on their knees, day after day) can be a good incentive to find solutions

The other woman I want to bring to light is Ángela Ruiz Robles (1895-1975), a Leonese from a well-to-do family, with higher education degrees, a great innovative and creative capacity, and always concerned about improving the education of her compatriots. Prolific author (sixteen textbooks), her inventions were many and varied, but perhaps the most interesting was that of the mechanical book .

In 1949 he registered the patent No. 190.968, entitled “Mechanical, electrical and air pressure for reading books.” The lessons of each subject were separated into different sheets. When pushbuttons were pressed, they went up mechanically or by compressed air and the student could see the lesson. In addition, you could increase the size and even light up.

Subsequently, Ángela Ruiz Robles perfected the mechanical book by creating the Mechanical Encyclopedia , a device to improve the encyclopedias used by schoolchildren. It was patented in 1962 (nº 276.346), but although a prototype was built in bronze, wood and zinc, it was never commercialized. In 1970 she received an offer from the US to exploit it in that country, but she wanted the benefits to be especially for the Spaniards. Although there was some Spanish company that was interested in commercialization, the amount of money that the inventor had to contribute made it unfeasible. However, Ángela was well known in her time and received a lot of awards and prizes in various competitions of inventors and national and international exhibitions.

Two of these women are very different. The first ones, Julia Montoussé and Julia Rodríguez-Montussé, have been hidden like many other women in history , being replaced, as so many times, by a man. The latter was recognized at the time, but its achievements have also been obscured, although now it is recognized, at least in our country, as the precursor of the electronic book . Thus, one of the work rooms of the National Museum of Science and Technology bears his name.

What is albinism? The lack of pigmentation is not the correct answer

What is albinism? The lack of pigmentation is not the correct answer

We are walking down the street and we meet a young girl, with very white hair and skin and wearing dark glasses. We will probably think that it is an albino person who needs glasses so as not to be dazzled by the sun and should take care of his skin with protective creams. Most of us would unknowingly carry out this quick analysis and we would continue walking, without imagining that this albino person actually suffers from a severe visual disability so relevant as to be considered legal blindness; that is, the one that supposes a visual acuity inferior to 10% of the normal vision.


In albinism, the lack of pigmentation, which is what we all perceive, is not the most relevant. What is really disabling is the visual deficit associated with this genetic condition, which is not disease, although it is investigated and treated as one of the more than 7,000 rare diseases. Albinism is present in 1 of every 17,000 people, which means that in our country there are around 3,000 albino people . It is a congenital disorder caused by mutations in some of the 20 genes (of the more than 20,000 that we have in the human genome) that we nowadays know as associated with this genetic condition.

The 20 types of albinism have a very limited vision, with variations according to the type of albinism and according to each person. Now, not all people with albinism have that obvious lack or absence of pigmentation . For many years it was believed that the lack of melanin (the pigment we have in our skin, eyes and hair) was the cause of albinism. Today we know that the loss of pigmentation is a consequence of albinism that only appears in some types, but not in all.

Albinism and visual disabilities

People with albinism have various visual alterations that are the cause of their deficit vision. First, your retina has no fovea. The fovea is a tiny central region of the retina in which the vast majority of our rod photoreceptors accumulate; These allow us to clearly perceive shapes and colors to define objects and people when we look at them from the front. People with albinism only have in their central zone a vision similar to peripheral vision, which we usually use to “look out of the corner of the eye”. This is a very poor vision, with little definition, which allows us to respond to objects that move (we instinctively separate if we perceive that something is going to fall on us or our side), but it does not help us to appreciate the details. We could imagine that the retina of a person with albinism is like a sensor of a camera that has many fewer pixels, and therefore less sensitivity and resolution.

The genetic mutations that cause albinism are recessive. This means that a person to be albino must inherit two anomalous copies of their parents, one from the father and one from the mother. Assuming that their parents are carriers, that is, they carry an intact and an anomalous copy of the gene, in each pregnancy they will have a 25% chance that the son or daughter will be born with albinism. The exception is ocular albinism, called OA1 for its acronym in English, whose affected gene is on sex chromosome X. Males, having only one X chromosome (males are XY and women are XX), directly manifest albinism if they inherit a single anomalous copy.

Through animal models of the various types of albinism, many aspects of this genetic condition have been investigated. The results obtained in mice have allowed us to discover that the administration of several drugs could improve the vision of people with albinism. Human clinical trials will soon determine the scope of these investigations and, where appropriate, their eventual transfer to the clinic.

OCA africa 620x414

In Africa, in addition to all the above, people with albinism can unfortunately suffer harassment, persecution, kidnapping, mutilation and murder. Unjustifiable beliefs and witchcrafts presuppose good fortune to the possessors of parts of the body of a person with albinism, be it a hand, an arm, a foot, a nose or an ear, which causes continuous attacks and a black market of human fragments that it is necessary to denounce and fight to get rid of these atrocities. To this end, the UN instituted on June 13 of each year as the International Albinism Awareness Day.

In Spain since 2006 the ALBA association helps people with albinism and is responsible for providing couples with albino newborns with the basic information to understand what happens to their children.

William R. Hamilton: the child prodigy who emulated Archimedes

It is not usual for a 17-year-old to feel challenged to occupy a prominent place in the history of science. And even less that such a feeling ends up becoming reality, making true the old aphorism that only those who pursue their dreams with determination can reach them. This is the story of William Rowan Hamilton (1805-1865).

Hamilton was educated by his uncle James, a scholar in classical languages ​​graduated from Trinity College in Dublin. It is not surprising, then, that the education of young William had a special emphasis on language learning. At an early age, William’s incredible ability was evident: at age ten, according to his father Archibald, he knew and spoke, to a greater or lesser extent, Hebrew, Persian, Arabic, Sanskrit, Chaldean, Syriac, Hindustani, Malay, Bengali, Greek, Latin and several modern European languages. Given the gift of his son, Archibald hoped that in the future William would make a career with the prestigious British East India Company. However, arithmetic got in the way of the father’s wishes. William discovered that he was gifted not only to learn languages ​​but also for arithmetic calculations.

His uncle began to prepare William for his entry into Trinity College . There, in spite of James’ reluctance, Hamilton began to study different branches of mathematics and showed a special interest in the application of geometry to the study of the propagation of light. Since Euclid’s time, a geometric model of light had been used, postulating that light propagated as a family of straight lines, called rays of light.

Hamilton was not limited to studying what was known about the geometry of light but

Hamilton was not limited to studying what was known about the geometry of light but

despite his youth (17 years), aspired to create something new. He was fully aware of his intellectual value and preferred the natural sciences to humanistic studies, because, he wrote: “Who would prefer to have more the fame of Archimedes than his conqueror Marcelo, or any scholar of the classics, whose maximum ambition to be familiar with the thoughts of other men? […] The powerful minds of all times have united to elevate the vast and beautiful temple of Science, inscribing their names in imperishable characters; but the building is not finished: it is not too late to add a new pillar or ornament. I have not just reached the foot of this temple, but I aspire, one day, to reach its peak. “Such a position did not imply that Hamilton despised the humanities. In fact he always loved poetry, which he saw as the fruit of the same creative spirit that science emanates from.

His studies on optics boomed. In 1823 he wrote to his cousin: “In optics I made a very curious discovery”. Only a year later, Hamilton sent his first scientific article – entitled ‘On caustic’ – to the Royal Irish Academy . During the following years Hamilton would establish a completely original theory on geometric optics based on a new determining principle that he discovered and called “Constant Action Principle” . It was known that a family of light rays always has a surface associated orthogonal to all of them called the wavefront. Étienne-Louis Malus (1775-1812) showed that a family of rays with an associated wavefront continued to maintain it even though those rays suffered reflection in a mirror or a change of medium (what is called refraction). Well,

Hamilton’s principle of constant action established that the same ray family, when propagated by a system of lenses or mirrors, fulfills the property that all rays reach the surface of the wavefront at the same time . Figure 2 shows an illustrative scheme of this principle. The family of rays associated with the wave front W when refracted on the surface R is transformed into a new family of rays with the wave front W ‘. The principle that Hamilton discovered establishes that the rays A, B, C of W arrive at the points A ‘, B’, C ‘belonging to W’, investing for it the same time. This has very deep and practical implications in the field of geometric optics and therefore in the design of optical systems, such as cameras, telescopes, etc.