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Posts Tagged ‘extinction

“Human nature scares the hell out of me”*…

Henry Gee, paleontologist and senior editor of Nature, argues that we Homo sapiens are setting ourselves up for collapse. He cites population decline, a lack of genetic variation, our socioeconomic fixation on growth (and the way that that’s plundered the planet), among other factors. But he singles out one phenomenon in particular…

 The most insidious threat to humankind is something called “extinction debt.” There comes a time in the progress of any species, even ones that seem to be thriving, when extinction will be inevitable, no matter what they might do to avert it. The cause of extinction is usually a delayed reaction to habitat loss. The species most at risk are those that dominate particular habitat patches at the expense of others, who tend to migrate elsewhere, and are therefore spread more thinly. Humans occupy more or less the whole planet, and with our sequestration of a large wedge of the productivity of this planetwide habitat patch, we are dominant within it. H. sapiens might therefore already be a dead species walking.

The signs are already there for those willing to see them. When the habitat becomes degraded such that there are fewer resources to go around; when fertility starts to decline; when the birth rate sinks below the death rate; and when genetic resources are limited—the only way is down. The question is “How fast?”…

Eminently worth reading in full: “Humans Are Doomed to Go Extinct,” from @EndOfThePier in Scientific American (@sciam).

For chorus effect, see also “Headed for a sixth mass extinction? MIT geophysicist warns oceans are on the brink.”

And for a look at the (possible) aftermath, explore “The Earth After Humans.”

* Neil deGrasse Tyson

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As we remind ourselves that “hope is a discipline,” we might send expansively-creative birthday greetings to Freeman Dyson; he was born on this date in 1923. A theoretical and mathematical physicist, mathematician, and statistician, he made material contributions– both processes and concepts— in quantum field theory, astrophysics, the mathematical formulation of quantum mechanics, condensed matter physics, nuclear physics, and engineering.

He will forever be remembered by SciFi fans as the originator of the idea of (what’s called) the Dyson Sphere (or Dyson Shell): he proposed that a highly advanced technological civilization would ultimately completely surround its host star with a huge shell to capture 100% of the useful radiant energy. This Dyson Sphere would have a gigantic cluster of artificial planetoids (“Dyson cloud”) with billions of billions of inhabitants who would make use of the energy captured by the Dyson Sphere. He also made the intriguing speculation that a Dyson Sphere viewed from other galaxies would have a highly distinctive, unnatural light. He suggested astronomers search for such tell-tale colored stars, which should signify advanced, intelligent life.

Dyson was skeptical of some climate science, believing that the advantages of global warming (e.g., greater crop yields) were underweighted and that climate models were underdeveloped (and thus untrustworthy). Still he sounded the alarm (in a way resonant with Gee’s, above) as to the possibility of humanity poisoning its own future:

In the near future, we will be in possession of genetic engineering technology which allows us to move genes precisely and massively from one species to another. Careless or commercially driven use of this technology could make the concept of species meaningless, mixing up populations and mating systems so that much of the individuality of species would be lost. Cultural evolution gave us the power to do this. To preserve our wildlife as nature evolved it, the machinery of biological evolution must be protected from the homogenizing effects of cultural evolution.

Unfortunately, the first of our two tasks, the nurture of a brotherhood of man, has been made possible only by the dominant role of cultural evolution in recent centuries. The cultural evolution that damages and endangers natural diversity is the same force that drives human brotherhood through the mutual understanding of diverse societies. Wells’s vision of human history as an accumulation of cultures, Dawkins’s vision of memes bringing us together by sharing our arts and sciences, Pääbo’s vision of our cousins in the cave sharing our language and our genes, show us how cultural evolution has made us what we are. Cultural evolution will be the main force driving our future…

Biological and Cultural Evolution– Six Characters in Search of an Author

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“Appearances are a glimpse of the unseen”

A shower of comets rains down on Earth while violent volcanic eruptions billow up from below. Both events may follow our planet’s passage through dark matter concentrated in the Milky Way’s plane and help to trigger extinction events.

Are we on the verge of understanding the upheavals that have shaped the earth?

Do geologists dream of a final theory? Most people would say that plate tectonics already serves as geology’s overarching idea. The discovery of plate tectonics 50 years ago was one of the great scientific achievements of the 20th century, but is the theory complete? I think not. Plate tectonics describes Earth’s present geology in terms of the geometry and interactions of its surface plates. Geologists can extrapolate plate motions both back in time and into the future, but they cannot yet derive the behavior and history of plate tectonics from first principles.

Although scientists can interpret the history through the lens of what they see today, an important question remains: Why did geologic events — such as hot-spot volcanism, the breakup of continents, fluctuations in seafloor spreading, tectonic episodes, and sea-level oscillations — occur exactly when and where they did? Are they random, or do they follow some sort of a pattern in time or space?

A complete theory of Earth should explain geologic activity in the spatial domain, as plate tectonics does quite well for the present (once you incorporate hot spots), but also in the time and frequency domains. Recent findings suggest to me that geology may be on the threshold of a new theory that seeks to explain Earth’s geologic activity in time and space in the context of its astronomical surroundings.

The solar system oscillates with respect to the midplane of the disk-shaped Milky Way Galaxy with a period of about 60 million years. The Sun’s family passes through this plane twice each period, or once every 30 million years or so. The solar system behaves like a horse on a carousel — as we go around the disk-shaped galaxy, we bob up and down through the disk, passing through its densest part roughly every 30 million years.

Surely, it is too much of a coincidence that the cycle found in mass extinctions and impact craters should turn out to be one of the fundamental periods of our galaxy. The idea seemed almost too pretty to be wrong. But people searching for cycles have been fooled before, and we still had to answer the question: How does this cycle of movement lead to periodic perturbations of the Oort Cloud comets?

The idea of a roughly 30 million-year rhythm in geologic events has a long history in the geological literature. In the early 20th century, W.A. Grabau, an expert on sedimentary strata, proposed that tectonic activity and mountain building drove periodic fluctuations in sea level with an approximately 30 million-year cycle. In the 1920s, noted British geologist Arthur Holmes, armed with a few age determinations from radioactive decay, saw a similar 30 million-year cycle in Earth’s geologic activity…

If the cycles are real, what could be driving these long-term changes in volcanism, tectonics, sea level, and climate at such regular, if widely spaced, intervals? At first, I thought that the periodic energetic impacts might somehow be affecting deep-seated geological processes. I suggested in a short note in the journal Nature that large impacts might so deeply excavate and fracture the crust — to depths in excess of 10 miles (16 km) — that the sudden release of pressure in the upper mantle would result in large-scale melting. This would lead to the production of massive flood-basalt lavas, which would cover the crater and possibly create a mantle hot spot at the site of the impact. Hot spots could lead to continental breakup, which can cause increased tectonics and changes in ocean-floor spreading rates, and in turn cause global sea levels to fluctuate. Unfortunately, no known terrestrial impact structure has a clear association with volcanism, although some volcanic outpourings on Mars seem to be located along radial and concentric fractures related to large impacts.

The potential key to resolving this geological conundrum may come from outer space. Remember that Randall and Reece suggested that Earth passes through a thin disk of dark matter concentrated along the Milky Way’s midplane every 30 million years or so. Astrophysicist Lawrence Krauss and Nobel Prize-winning physicist Frank Wilczek of Harvard University, and independently Katherine Freese, an astrophysicist at the Harvard-Smithsonian Center for Astrophysics, proposed that Earth could capture dark matter particles that would accumulate in the planet’s core. The number of dark matter particles could grow large enough so that they would undergo mutual annihilation, producing prodigious amounts of heat in Earth’s interior.

A 1998 paper in the journal Astroparticle Physics (which I am sure few geologists ever read) provided a potential missing link. Indian astrophysicists Asfar Abbas and Samar Abbas (father and son, respectively) at Utkal University also were interested in dark matter and its interactions with our planet. They calculated the amount of energy released by the annihilation of dark matter captured by Earth during its passage through a dense clump of this material. They found that mutual destruction among the particles could produce an amount of heat 500 times greater than Earth’s normal heat flow, and much greater than the estimated power required in Earth’s core to generate the planet’s magnetic field. Putting together the predicted 30 million-year periodicity in encounters with dark matter with the effects of Earth capturing this unstable matter produces a plausible hypothesis for the origin of regular pulses of geologic activity.

Excess heat from the planet’s core can raise the temperature at the base of the mantle. Such a pulse of heat might create a mantle plume, a rising column of hot mantle rock with a broad head and narrow tail. When these rising plumes penetrate Earth’s crust, they create hot spots, initiate flood-basalt eruptions, and commonly lead to continental fracturing and the beginning of a new episode of seafloor spreading. The new source of periodic heating by dark matter in our planet’s interior could lead to periodic outbreaks of mantle-plume activity and changes in convection patterns in Earth’s core and mantle, which could affect global tectonics, volcanism, geomagnetic field reversals, and climate, such as our planet has experienced in the past.

These geologic events could lead to environmental changes that might be enough to cause extinction events on their own. A correlation of some extinctions with times of massive volcanic outpourings of lava supports this view. This new hypothesis links geologic events on Earth with the structure and dynamics of the Milky Way Galaxy.

It is still too early to tell if the ingredients of this hypothesis will withstand further examination and testing. Of course, correlations among geologic events can occur even if they are not part of a periodic pattern, and long-term geological cycles may exist apart from any external cosmic connections. The virtue of the galactic explanation for terrestrial periodicity lies in its universality — because all stars in the galaxy’s disk, many of which harbor planets, undergo a similar oscillation about the galactic midplane — and in its linkage of biological and geological evolution on Earth, and perhaps in other solar systems, to the great cycles of our galaxy.

Dark matter’s shadowy effect on Earth“: Earth’s periodic passage through the galaxy’s disk could initiate a series of events that ultimately lead to geological cataclysms and mass extinctions. From Michael Rapino (@mrr1_michael)

For very different angle on the evolution of the earth, the wonderful Walter Murch: “Why Birds Can Fly Over Mount Everest.”

* Anaxagoras

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As we dig deep, we might spare a thought for Harlow Shapley; he died on this date in 1972. An astronomer known as “the Modern Copernicus,” he did important work first at the Mt. Wilson Observatory, and then as head of the Harvard College Observatory. He boldly and correctly proclaimed that the globulars outline the Galaxy, and that the Galaxy is far larger than was generally believed and centered thousands of light years away in the direction of Sagittarius: he discovered the center of our Galaxy, and our position within it.

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“In the landscape of extinction, precision is next to godliness”*…

There is a portion of the sky where no spacefarer wants to go. It causes Astronauts to see shooting stars in front of their eyes, sets off emergency sensors and renders satellites useless. This Bermuda Triangle of space isn’t just a cause for concern for our future of space exploration, it could be the sign of something far more deadly. This may herald an event that last happened 42,000 years ago, which wiped out our closest relative, the Neanderthals. Welcome to the terrifying world of the South Atlantic Anomaly.

In the 80s engineers noticed that most satellite errors happened over South America and the South Atlantic. These errors ranged from minor glitches, wiped data to full-blown crashed satellites. But they couldn’t quite pinpoint what was causing these troubling errors, they named this mysterious area the South Atlantic Anomaly (SAA).

We didn’t understand the dangers of this region for a long time. When the Hubble Space Telescope first turned on in 1990 they found that the computers kept crashing and data was corrupted almost every time it flew over the South Atlantic. Not wanting their billion-dollar telescope to crash to Earth, the engineers had no choice but to switch it off every time it passed over this deadly patch of sky, and still do today. Not ideal, but it saves the telescope from this mysteriously dangerous part of space.

So what makes the South Atlantic Anomaly so dangerous? It turns out it is all down to the Sun and a crack in Earths armour caused some very bizarre geophysics.

So what does struggling satellites means for us here on Earth? Well, quite a lot really. It could be a sign of something much more deadly, a geomagnetic reversal.

When we picture the Earth’s magnetic field we often think of it as unchanging. It is our eternal armour from deadly solar radiation as well as the guide for our sailors. Even some birds have evolved iron-rich cells in their eyes, enabling them to ‘see’ the magnetic field and navigate the globe. But the magnetic north pole hasn’t always been in the north.

The magnetic poles have flipped repeatedly over the millennia. The field weakens, disappears and then reappears in the opposite direction. We know this because iron-rich lava aligns to the magnetic field and then sets, so we can look at ancient rocks and see what direction magnetic north was when it formed.

We don’t have a complete understanding of how the magnetic field is generated and why it flips. We know that convection currents of iron-rich mantle create the field, but the interactions between these immense systems are complex and hidden from us. What’s more, there are no patterns to the past flipping events, so it is very hard to predict when one will happen.

But, models and simulations show that when the field gets weaker at the beginning of a magnetic flip, it seems to happen in a random area and then grows from there. The poles also start to drift quite dramatically and chaotically. This is worrying because not only does the South Atlantic Anomaly look like the weakening in a simulation, it is also growing, and the North pole is drifting further each year.

… So, it seems at least plausible that the South Atlantic Anomaly is the start of the next geomagnetic flip. If so, it could have enormous consequences for us!

The last time a flip happened was 42,000 years ago, but it was only a temporary event, and the poles returned to their previous locations, this is known as the Laschamps Excursion, and it lasted for about a thousand years. That meant Earth was without its essential protective shield for an awfully long time.

Now, 42,000 years ago is a significant time. This was when Neanderthals died out. We (Homo Sapiens) also started using caves, red ochre body paint, and the global craze of cave painting started. It was also when a lot of ice-age megafauna died out. All of which has been linked to the flipping of the poles during this period. This extinction event and Sapien revolution has been called the Adams Event (after Douglas Adams and the infamous 42).  

This theory suggests that when the poles flipped, the Earth had a thousand years without its protective layer, so the planet was bombarded with radiation. This depleted ozone, increased radiation on the surface, messed with weather patterns and caused abrupt climate change.

Scientist even suggests that this is why we suddenly took to living in caves and using red ochre. We had to hide from the deadly rays of the Sun, and if we ventured out, we needed a powerful suncream, like powdered red ochre. This is why red ochre hand paintings became so widespread around this time.

But these immense changes hit one species particularly hard. Neanderthals were likely red-headed, light-skinned and mostly dwelt in steppes (grassy plains) and woodlands. They probably got sunburnt a lot. Unlike Homo Sapiens, it seems as though Neanderthals didn’t use red ochre much at all! All of this means that cancers would have been a deadly problem for them.

To make all this even worse, the radiation increased the strength of electrical storms, changed the weather patterns and screwed up many ecosystems. So the food that the Neanderthals hunted my have been driven away or gone extinct. It seems Neanderthals died out because they starved to death while being baked by the Sun. Meanwhile, we Homo Sapiens hid from the Sun, used weird sunscreen and adapted to new foods…

These flipping events take hundreds or thousands of years to pass due to the amount of heavy magma that needs to shift to cause a flip (however it is hypothesised it could take as little as a month in extreme circumstances). So we aren’t in any danger of waking up to a new direction for North. But, over the next few decades or hundreds of years, we will see the South Atlantic Anomaly grow and potentially be joined by many other areas of weak magnetism. We may even see some local flips in a few hundred years.

So, it seems at least plausible that the South Atlantic Anomaly is the start of the next geomagnetic flip. If so, it could have enormous consequences for us!

The South Atlantic Anomaly: Earth’s deadly weakness: “Do Failing Satellites Foretell An Imminent Extinction?” From Will Lockett (@welockett).

* Samuel Beckett

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As we search for true north, we might send charged birthday greetings to a man whose life work could be at risk if there’s a flip (or an intense solar storm), Elihu Thomson; he was born on this date in 1853. An engineer and inventor, he was instrumental in developing the practical applications of electricity, especially alternating current. He invented electric welding and other important advances in electric lighting and power (among his lifetime total of about 700 patents). Thomson was also a cofounder of the General Electric Company (in 1892, in a merger of his Thomson-Houston Electric Company with the Edison Company.

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“Have you ever heard a blindfolded octopus unwrap a cellophane-covered bathtub?”*…

The relentless progression of human technology leaves us with many relics: the Walkman, the Game Boy, the payphone, the VCR. But there’s an aspect to these devices that isn’t preserved when you let them gather dust on a basement shelf: their signature beeps, clicks, and whirrings.

In the interest of salvaging these obsolete noises, Brendan Chilcutt has since 2012 maintained the Museum of Endangered Sounds, for which he aims to complete data collection by 2015. Then he’ll “spend the next seven years developing the proper markup language to reinterpret the sounds as a binary composition.” Suggestions of exhibits to include are welcome.

The site is already fascinating place to click around; depending on your age, you’ll be transported by the original default Nokia ringtone, or the Windows 95 startup chords. The AOL Instant Messenger alerts in particular take me back—someone wants to chat! Is it the devastatingly cute girl I have a crush on? No, just one of my fellow nerds. But hope lives on.

When technology reaches a stage of silent frictionlessness, Chilcutt says, these audio files will offer some of the most direct links to our mechanical past. Nice to have them all in one place…

The din of typewriters and Tamogatchis lives on: “Museum of Endangered Sounds keeps vintage noises alive.” Explore the museum here.

See also: Conserve the Sound’s “Projekt.”

* Norton Juster, The Phantom Tollbooth

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As we listen carefully, we might recall that it was on this date in 1830 that the Anti-Masonic Party, the official first third-party in United States political history, convened its convention. The Anti-Masons formed, as the name suggests, to combat the perceived secret government influence Freemasonry held in the U.S. While the party quickly dissolved after anti-Masonic public feelings died down (most of its members folded in the Whig Party), It did pioneer presidential nomination conventions and the adoption of a party platform.

For more on the Anti-Masons see “Nearly two centuries ago, a QAnon-like conspiracy theory propelled candidates to Congress.”

“So profound is our ignorance, and so high our presumption, that we marvel when we hear of the extinction of an organic being”*…

 

Human skull

A Neanderthal skull shows head trauma, evidence of ancient violence

 

Nine human species walked the Earth 300,000 years ago. Now there is just one. The Neanderthals, Homo neanderthalensis, were stocky hunters adapted to Europe’s cold steppes. The related Denisovans inhabited Asia, while the more primitive Homo erectus lived in Indonesia, and Homo rhodesiensis in central Africa.

Several short, small-brained species survived alongside them: Homo naledi in South Africa, Homo luzonensis in the Philippines, Homo floresiensis (“hobbits”) in Indonesia, and the mysterious Red Deer Cave People in China. Given how quickly we’re discovering new species, more are likely waiting to be found.

By 10,000 years ago, they were all gone. The disappearance of these other species resembles a mass extinction. But there’s no obvious environmental catastrophe – volcanic eruptions, climate change, asteroid impact – driving it. Instead, the extinctions’ timing suggests they were caused by the spread of a new species, evolving 260,000-350,000 years ago in Southern Africa: Homo sapiens.

The spread of modern humans out of Africa has caused a sixth mass extinction, a greater than 40,000-year event extending from the disappearance of Ice Age mammals to the destruction of rainforests by civilisation today. But were other humans the first casualties?…

More at “Were other humans the first victims of the sixth mass extinction?

* “… so profound is our ignorance, and so high our presumption, that we marvel when we hear of the extinction of an organic being; and as we do not see the cause, we invoke cataclysms to desolate the world, or invent laws on the duration of the forms of life!”
Charles Darwin, The Origin of Species

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As we wonder about our lost siblings, we might spare a thought for Marie Jean Pierre Flourens; he died on this date in 1867.  A physiologist, he was the founder of experimental brain science and a pioneer in anesthesia.  He was the first to demonstrate the general functions of the major portions of the vertebrate brain; more generally, through the study of ablations on vertebrate animals, he was the first to prove that the mind was located in the brain, not the heart (as was then believed).

Ironically, he was a Creationist– an opponent of Darwin and the theory of natural selection.

220px-Pierre_flourens source

 

Written by (Roughly) Daily

December 6, 2019 at 1:01 am

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