Welcome to Sott.net
Mon, 25 Sep 2017
The World for People who Think

Science & Technology
Map

Blackbox

Evolution's third replicator: Genes, memes, and now what?

Image
© Burneverything
Technological replicators are affecting human nature.
We humans have let loose something extraordinary on our planet - a third replicator - the consequences of which are unpredictable and possibly dangerous.

What do I mean by "third replicator"? The first replicator was the gene - the basis of biological evolution. The second was memes - the basis of cultural evolution. I believe that what we are now seeing, in a vast technological explosion, is the birth of a third evolutionary process. We are Earth's Pandoran species, yet we are blissfully oblivious to what we have let out of the box.

This might sound apocalyptic, but it is how the world looks when we realise that Darwin's principle of evolution by natural selection need not apply just to biology. Given some kind of copying machinery that makes lots of slightly different copies of the same information, and given that only a few of those copies survive to be copied again, an evolutionary process must occur and design will appear out of destruction. You might call it "design by death" since clever designs thrive because of the many failures that don't.

The information that is copied, varied and selected is called the replicator, and the process is well understood when applied to biology. Genes are copied, mutated and selected over and over again. Assemblages of genes are used to build vehicles that carry them around, protect them and propagate them. These vehicles - the lumbering robots, as Richard Dawkins calls them - are animals and plants, the prolific and exquisitely designed products of the first replicator.

Blackbox

Go Back To Sleep - Comet Collisions Won't Spark The End Of The World

© Unknown
Comet Hale-Bopp.
Evidence indicates that it is highly unlikely that a comet crash would result in Earth's demise, researchers at the University of Washington said on Thursday.

Writing in Science Express, the online edition of the journal Science, researchers acknowledged that while most scientists agree that an asteroid collision 65 million years ago caused the mass extinction of the dinosaurs, they tend to differ in opinion on how many other mass extinctions have resulted from similar events.

Researchers used computer models to simulate the formation of comet clouds in the solar system for 1.2 billion years. They pinpointed a body called the Oort Cloud as the source for many long-period comets that find their way into Earth's path.

Formed 4.5 billion years ago from the nebula that formed our solar system, the Oort Cloud spans from about 93 billion miles from the sun to about three light years away. Scientist said the Oort Cloud could contain literally billions of comets, many of which are so small and distant to be seen.

Comment: Regarding the claim that "the gravitational pulls of Jupiter and Saturn act as comet deflectors", let's see what Clube and Napier, British astronomers and writers of The Cosmic Serpent, have to say:
The giant comets normally reside far beyond the planets, in a spherical cloud surrounding the Sun, called the Oort cloud. There is also evidence for a flattened disk of comets closer to the inner solar system, called the Edgeworth/Kuiper belt. What prompts members of either of these comet repositories to enter the realm of the planets? Clube and Napier suggest a galactic influence. The solar system periodically passes through the plane of the galaxy as the Sun (and the solar system with it) orbits the galactic center. Each passage may dislodge giant comets and divert them closer to the Sun. The outer planets, particularly Jupiter, may then perturb some of these giant comets into orbits which enter the inner solar system. These comets, stressed both by gravity and by heat from the sun, may fragment into a cloud of smaller objects with dynamically similar orbits.

Chiron offers a good example of a giant comet as called for by Clube and Napier's giant comet hypothesis. Chiron is somewhere between 148 and 208 kilometers in diameter. Currently Chiron's unstable "parking orbit" lies mostly between Saturn and Uranus. Chiron may end up injected into the inner solar system within a hundred thousand years, or ejected from the solar system on a similar time scale. It is also possible that Chiron has already visited the inner solar system.

The Taurid complex and the Kreutz sungrazer group are two families of objects which most likely represent the fragmented remains of two giant comets in the current era. SOHO has recently discovered many new members of the Kreutz group which were previously unknown.

The Kreutz progenitor was injected into a retrograde orbit and attained the sungrazing state at a high inclination to the ecliptic. Hence the debris of its "children" does not pose a threat to the Earth. The Taurid progenitor on the other hand ended up in a short-period low-inclination prograde orbit. This is why the Earth can encounter its debris with potentially calamitous results.

What would happen should the Earth pass through the orbit of a disintegrating giant comet just before or after the comet passes that same point? Since larger fragments tend to cluster close to the nucleus of the comet, chances would increase that the Earth would be bombarded by these larger fragments. The severity of this comet fragment shower would far exceed any ordinary meteor shower. Not only would "shooting stars" and bright fireballs caused by small debris appear, but so too would large airbursts and possibly ground impacts. These would result in significant destruction should they occur over an inhabited area. If a large enough fragment struck in the ocean -- say, 200 meters or so in diameter -- it would raise tsunamis even at a great distance that would sweep away coastal habitations.

Duncan Steel, a colleague of Clube and Napier, refers to this process as coherent catastrophism. Widespread destruction derives from the coherent arrival of many impactors within a few days, as opposed to the sporadic arrival of objects spread randomly in space. The shower repeats for a period of years until the cometary orbit precesses so that the Earth no longer encounters the dense part of the debris field. (Of course, sporadic debris unrelated to the disintegrating comet may impact at any time as well.)



Info

Unique Second Temple Inscription found in Jerusalem, but no one knows what it means

Image
© Stephen Pfann/UHL
Two lines of the Aramaic inscription.
A unique Aramaic inscription on a stone cup commonly used for ritual purity during the first century has been uncovered in a dig on Mount Zion in Jerusalem, an archeologist said Wednesday.

The six-week excavation is being carried out within the Gan Sobev Homot Yerushalayim National Park, close to the Zion Gate of the Old City.

The 10-line Aramaic script, which is clear but cryptic, is being deciphered by a team of epigraphic experts in an effort to determine the meaning of the text, said Prof. Shimon Gibson, of the University of North Carolina at Charlotte, who is co-directing the excavation.

Magnify

Discovery about behavior of building block of nature could lead to computer revolution

A team of physicists from the Universities of Cambridge and Birmingham have shown that electrons in narrow wires can divide into two new particles called spinons and a holons.

The electron is a fundamental building block of nature and is indivisible in isolation, yet a new experiment has shown that electrons, if crowded into narrow wires, are seen to split apart.

The electron is responsible for carrying electricity in wires and for making magnets. These two properties of magnetism and electric charge are carried by electrons which seem to have no size or shape and are impossible to break apart.

Better Earth

Extraterrestrial platinum was 'stirred' into the Earth

Image
© Unknown
Outcrop of komatiite lava from the type locality in the Komati Valley, Barberton Mountainland, South Africa, showing the distinctive 'spinifex texture' formed by dendritic plates of olivine. The plates get smaller and more randomly oriented towards the top of the flow, at the top of the image.
The research is reported in a Nature paper titled "Progressive mixing of meteoritic veneer into the early Earth's deep mantle".

Report author CSIRO Minerals Down Under Flagship researcher Dr Stephen Barnes said the study group collected a large body of data on the platinum content of lava flows called komatiites, which host some of the world's major nickel deposits.

"We found that the oldest komatiites have the lowest platinum content," Dr Barnes said.

"The platinum content gradually increases from about 3.5 billion years to 2.9 billion years ago.

"This tells us that the deep source where the komatiite came from, down near the boundary between the Earth's core and mantle, was gradually gaining platinum over time".

Magnify

Babylon's Ancient Wonder, Lying in Ruins

Maytham Hamzah cast his eyes toward the remains of King Nebuchadnezzar's guest palace in Babylon, one of the world's first great cities. He smiled, bitterly.

'They destroyed the whole country,' Hamzah, the head of the Babylon museum, said of U.S. forces in Iraq. 'So what are a few old bricks and mud walls in comparison?'

U.S. forces did not exactly destroy the 4,000-year-old city, home of one of the world's original seven wonders, the Hanging Gardens of Babylon. Even before the troops arrived, there was not much left: a mound of broken mud-brick buildings and archaeological fragments in a fertile plain between the Tigris and the Euphrates rivers.

But they did turn it into Camp Alpha, a military base, shortly after the U.S.-led invasion in 2003. Their 18-month stay there caused 'major damage' and represented a 'grave encroachment on this internationally known archeological site,' a report released this month in Paris by the United Nations' cultural agency, UNESCO, says.

Meteor

Jupiter's cosmic smash: what does it mean for Earth?

© NASA
The Apollo 11 moon landing is not the only significant space anniversary that falls this week. It is also 15 years since fragments of the Shoemaker-Levy 9 comet smashed into Jupiter, in July 1994, giving astronomers a first-hand look at the devastation that follows such cosmic collisions.

With uncanny timing, a similar impact event seems to have happened again. On Sunday, an amateur astronomer named Anthony Wesley observed a strange black blob on the surface of Jupiter. When he alerted Nasa professionals, they confirmed that it indeed appears to have been caused by another impact event.

The resulting debris cloud has been reported as covering an area with roughly the same diameter as the Earth. Astronomers have told me today that the likely cause is the impact of a comet, or comet fragment, between 500m and 2km in diameter. It all raises a potentially terrifying question. What might have happened had such an object struck not Jupiter, but the Earth?

Blackbox

Centuries-old sketches solve sunspot mystery?

Image
© Royal Swedish Academy of Science
The sun's warning signs
A second look at sunspot drawings from the 1700s has clarified a puzzling episode in the sun's history, and could lead to more accurate forecasts of dangerous solar outbursts.

The sun sometimes hurls clouds of plasma our way, which can fry satellites and knock out power grids on Earth. The outbursts are most common during solar maxima, when the dark blemishes of sunspots appear in greatest abundance on the sun.

Although there is an average of 11 years between solar maxima, predicting the exact timing and height of each peak is difficult as there is little historical data to plug into models. About two dozen solar cycles have occurred since reasonably complete records began. Now an analysis of historic sunspot drawings suggests that this patchy record had omitted a solar cycle from the late 1700s.

Sunspot numbers for this period were compiled by Swiss astronomer Rudolf Wolf in the 19th century, who based his tallies on drawings of the sun made by Austrian amateur astronomer Johann Staudecher. Wolf's numbers suggested there was a 15.5-year-long solar cycle between 1784 and 1799, the longest on record. However, astronomers have long questioned the reliability of these numbers, since Staudecher's observations from this period are sparse - he made just two drawings in the second half of 1793, for example. Even in the 19th century, some suspected that it might have actually been two short solar cycles.

Meteor

Mysterious bright spot found on Venus

Image
© Melillo/Maxson/ESA/University of Wisconsin-Madison/ALPO
A new, bright spot in the clouds of Venus was found by amateur astronomer Frank Melillo on 19 July
A strange spot emerged on Venus last week, and astronomers are not sure what caused it. They hope future observations will reveal whether volcanic activity, turbulence in the planet's atmosphere, or charged particles from the sun are to blame.

Amateur astronomer Frank Melillo of Holtsville, New York, first spotted the new feature, which is brighter than its surroundings at ultraviolet wavelengths, on the planet's southern hemisphere on 19 July. That same day, an amateur observer in Australia found a dark spot on Jupiter that had been caused by a meteoroid impact.

The Venus spot was confirmed by other observers, and images from Europe's Venus Express, the only spacecraft in orbit around the planet, later revealed that the spot had appeared at least four days before Melillo saw it.

Observations show that the spot had already spread out somewhat by the end of last week, and astronomers are awaiting more recent observations from Venus Express.

The spot is bright at ultraviolet wavelengths, which may argue against a meteoroid impact as a cause. That's because rocky bodies, with the exception of objects very rich in water ice, should cause an impact site to darken at ultraviolet wavelengths as it fills with debris that absorbs such light, says Sanjay Limaye of the University of Wisconsin-Madison and a member of the Venus Express team.

Comment: These are possibilities, of course. One may want to consider this as well: Military Hush-Up: Incoming Space Rocks Now Classified


Magnify

Scientists to Unlock Great Barrier Reef Genome

© Unknown
345,000-square-kilometre Great Barrier Reef which runs along the northeastern coast of Australia. Australian scientists have announced a ground-breaking genome-mapping project that could help the Great Barrier Reef fight off the twin threats of climate change and toxic farm chemicals.
Australian scientists on Thursday announced a ground-breaking genome-mapping project that could help the Great Barrier Reef fight off the twin threats of climate change and toxic farm chemicals.

Geneticists said they would unlock the secrets of the colourful 'acropora millepora' coral, one of the main components of the northeastern tourist attraction, the growth of which has slowed markedly in recent years.

"This gene-mapping project has both practical and scientific significance," said professor David Miller of Australia's Centre of Excellence for Coral Reef Studies and James Cook University.