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Why Female Praying Mantises Devour Their Partners During Sex


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Why Female Praying Mantises Devour Their Partners During Sex

Yesterday 12:35pm

 http://gizmodo.com/why-female-praying-mantises-devour-their-partners-durin-1782818376
A female praying mantis with what’s left of her partner. (Image: Oliver Koemmerling)

Female praying mantises have a habit of killing and eating their partners during sex, which sucks for the male. Or does it? A fascinating new study shows this sacrifice is actually giving the males a distinct reproductive advantage.

Sexual cannibalism among praying mantises is well documented, but scientists have debated the reasons for it. A new study published inProceedings of the Royal Society B shows that females who eat their male partners after sex produce more eggs than those who don’t. What’s more, by eating the male, the widowed female ensures that her man is still providing for their offspring, even though he’s dead.

William Brown, a scientist at State University of New York at Fredonia and co-author of the new study, put it well: “Sexual cannibalism thus increases male investment in offspring.”

In praying mantises, around 25 percent of all sexual encounters result in the death of the male. The female typically begins by biting off her partner’s head, and she works down from there. Incredibly, this comprises about 63 percent of the female’s diet during the mating season. Scientists have speculated that it’s a way for the female to record a quick meal at a critical point in her reproductive life cycle, but this claim has largely remained unproven.

To see if this is actually the case, the researchers embedded traceable radioactive amino acids into crickets, which were subsequently fed to a population of male mantises. Each of these males was then paired with a female. Half of them were rescued from their two-faced lovers before cannibalism could take place, while the other half… well you know what happened to the other half. The researchers then set about the task of studying the reproductive success of each female involved.

By following the flow of radioactive proteins through the bodies of the females, the scientists could track the contribution of the recently-devoured male. Males who were devoured passed on nearly 90 percent of their tagged amino acids, while those who survived passed on about 25 percent—all of which were delivered via their ejaculate.

A significant portion of the amino acids were passed down to the baby mantises, which means they weren’t fully metabolized by the female. This means that, in addition to the male’s ejaculate, his body tissue is being used to produce eggs. The male—by virtue of his death—is providing nourishment to his offspring.

Those females who ate their partners produced more eggs than those who did not. On average, cannibalistic females produced about 88 eggs, whereas those who didn’t eat their partners produced about 37. That’s a big difference, one that gives cannibalized males a distinct reproductive advantage.

Well, at least in one-off situations. Males who survive mating encounters can potentially reproduce multiple times, which can also be seen as a reproductive advantage. Clearly, there’s an evolutionary tension here, one the scientists will have to look into a bit further.

Sexual cannibalism has also been observed in some spiders. But unlike these arachnids, whose reproductive organs become permanently damaged after sex, male mantises are able to copulate multiple times.

[Proceedings of the Royal Society B]

George is a contributing editor at Gizmodo and io9.

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Did Prehistoric People Watch the Stars Through This 6,000 Year Old ‘Telescope’?


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Did Prehistoric People Watch the Stars Through This 6,000 Year Old ‘Telescope’?

Yesterday 7:01pm

 http://gizmodo.com/did-prehistoric-people-watch-the-stars-through-this-6-0-1782759791
What we might have seen from Carregal do Sal megalithic structure, at dawn in late April, circa 4,000 B.C. All images: Fabio Silva.

Prehistoric humans may have observed the sky via primitive lens-less “telescopes,” according to a team of British astronomers who have studied the long passageways of ancient megalithic tombs. The details were presented today by Kieran Simcox, a student at Nottingham Trent University, at a meeting of the Royal Astronomical Society.

Technically it’s not a telescope (with or without a lens), per se. According to Simcox, it’s more like a very primitive version of a camera obscura, the basic concept behind the pinhole camera. All you need to create a camera obscura is a small hole in a shade or a wall, so that light can pass from a sunlit garden, for instance, into a darkened room, projecting an inverted image on the wall opposite the pinhole.

Dolmen da Orca, a typical structure in Western Iberia, part of the megalithic cluster of Carregal do Sal.

The key difference with the megalithic clusters is that the narrow entrance creates an aperture of about 10 degrees, sufficiently restricting the view by naked eye to make it easier to observe the sky—specifically, certain stars—during pre-dawn and twilight hours. Simcox and his colleagues are exploring the precise conditions under which this might work in the laboratory. Is it just a question of eye adaptation, or do other factors, like the size of the aperture or background color of the sky, play a role?

“In a sense, the long passage of the passage grave would act as a long tube that would not only focus the attention on a narrow band of the horizon, but also block out most of the light, as well as the atmospheric scattering that brightens the sky around the point where the sun is about to rise,” Fabio Silva of the University of Wales told Gizmodo. “By spending the night inside the passage grave, the eyes will be dark-adapted and, therefore, might be able to see the faint star rising, whereas someone outside the megalithic structure, already with light-adapted eyes due to the pre-dawn scattering, wouldn’t.”

(Left) The “window of visibility” while standing in the dolmens’ chamber. (Right) Orca de Santo Tisco, a dolmen with a much smaller passage.

It’s always a tricky proposition to speculate about how such ancient structures may have been used by prehistoric peoples. But Simcox et al.’s work is based on an earlier pilot project focusing on passage graves in Carregal do Sal in Portugal. That yielded a new way of identifying alignments between how the passages and entrances of the prehistoric are oriented, and celestial objects. Based on this, Silva said that the mostly likely target would be the star Aldebaran.

“From the wider archaeological record connected to the societies that built the passage graves, we know that these were pastoral communities, that still practiced hunting and gathering,” he said. Such communities would pass the colder winter months in river valleys (where the dolmens are located) and move to higher ground in the spring—most likely to Serra da Estrela (“mountain range of the star”).

Six thousand years ago, people would have been able to see Aldebaran’s first rise at dawn in late April or early May. Silva thinks this suggests those communities may have relied on such observations to tell them when it was time to move to higher pastures.

However, it could also be the case that such sites were used in initiation rituals, similar to the ritual use of caves in Mediterranean regions during the Neolithic era. “When the youth would hit a certain age, they would be shown this ‘special’ way of viewing a star before it would usually be visible,” Simcox said.

Along with forensic astronomy, the field of cultural astronomy is booming of late, although some form of so-called “archaeoastronomy” has been around since the late 1800s, according to Silva. “Because the sky is often ignored by the wider archaeological and anthropological communities, [such interdisciplinary work can yield] many insights,” he said. These include the use of celestial cycles as primitive calendars. how those cycles become encoded in myth and folklore, and illuminating deeper connections between the night sky, rock art, and architectural structures.

[Royal Astronomical Society]

SETI Eavesdrops on Nearby Star in Smart Alien Hunt


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SETI Eavesdrops on Nearby Star in Smart Alien Hunt

 http://www.livescience.com/55180-seti-looks-for-alien-civilizations.html

SETI Eavesdrops on Nearby Star in Smart Alien Hunt

The SETI Institute’s Allen Telescope Array (ATA) is hunting for radio signals from hypothetical intelligent alien life in our galaxy.

Credit: SETI Institute

Astronomers seeking out extraterrestrial intelligence have used a powerful radio telescope to eavesdrop on a star system that is relatively close to Earth in the hope of hearing the faint radio whisper of an alien civilization.

Using the Allen Telescope Array (ATA) located in California (pictured top), members of the SETI Institute chose Trappist 1 as they know the red dwarf-type star plays host to at least 3 exoplanets. Traditional SETI searches have looked to random stars in the sky in the hope of detecting an artificial radio signal using luck and some educated guesses. But now we know certain stars play host to exoplanets, alien hunters can be a little more discerning with the selection of stellar targets.

RELATED: Sending Messages to Aliens: Could It Kill Us?

Known as “targeted SETI”, the ATA has been used to “listen in” on star systems that NASA’s Kepler Space Telescope and other exoplanet-hunting missions have confirmed the presence of exoplanets. Even better than that, as Kepler can identify the physical size and orbit of a given exoplanet, astronomers can deduce whether that planet is located in the star’s “habitable zone.” The habitable zone around any star is the distance at which a hypothetical rocky planet can orbit that is not too hot or too cold for liquid water to exist. As we know from life on our planet, where there’s water, there’s life; could intelligent alien life be living on one of these potentially habitable worlds?

If so, they might be transmitting radio waves. However, for us to stand a chance of detecting their signals, they either need to be deliberately blasting a radio beacon in our direction with the explicit purpose of communication or they need to live in a relatively nearby star system for us to detect their accidental leakage of radio waves into space.

Earth has been leaking a faint radio signals into space for over 100 years since the advent of commercial radio transmissions around the globe at the beginning of the 20th century. More recently, we’ve been pinging asteroids and the planets with powerful radar. And let’s not forget the controvercial Messaging Extraterrestrial Intelligence, or METI, a practice that has unsettled some scientists. Therefore, in theory, any intelligent aliens living within 100 light-years of Earth — assuming they possess sensitive enough radio receivers — could be aware of our presence.

And this is what SETI is doing: listening out for alien transmissions that, so far, have proven inconclusive.

RELATED: Alien Megastructure? SETI Spies No Intelligent Signals

However, last year, Kepler discovered a bizarre transit signal from the star KIC 8462852, otherwise known as Tabby’s Star. Kepler detects exoplanets by detecting their faint shadows cross the faces of their host stars. When Kepler detected Tabby’s Star transit, it was like nothing it had ever recorded; the brightness dip dimmed around 20 percent. Though the generally-accepted hypothesis is that a swarm of comets may have caused this strange transit signal, there’s another idea that it could be evidence of an advanced alien civilization building a “megastructure” around their star.

Tabby’s Star quickly became a target for SETI, but no transmissions were detected by the ATA.

According to a SETI Institute news release on Wednesday, even if there were transmitting aliens at Tabby’s Star, the fact it’s nearly 1,500 light-years away would make the detection of alien radio signals extremely unlikely, unless said aliens were deliberately beaming extremely powerful radio waves right at us.

RELATED: The Hunt for Alien Intelligence is Going Infrared

This is why Trappist 1 was selected for a follow-up SETI investigation. Though there’s no evidence of weird transit signals around this small star, it is an ancient compact planetary system that might, after some assumptions, be considered habitable. What’s more, Trappist 1 is only 40 light-years away — pretty much on our interstellar doorstep. Any signal transmitted from the Trappist 1 system would be a thousand times stronger than a signal of identical strength transmitted from Tabby’s Star.

So, for 2 days in May, the ATA focused on Trappist 1, seeking out an artificial narrowband signal of around 1 Hz or less. As the headline of this article isn’t “Aliens Found!” you can guess what the outcome was: no aliens were detected on this pass. But the ATA did put a valuable upper limit on the strength of a signal if there is a hypothetical alien civilization transmitting a signal at us.

RELATED: Galactic Ecosystem Survival: Keep Your Head Down

SETI researchers estimate that if aliens are transmitting from that star system, they’d have to build a 300 meter-wide radio antennae (the approximate size of the Arecibo telescope in Puerto Rico) with a transmitter power of 300 kilowatts. Interestingly, the most powerful radio transmitter on Earth operates at around 700 kilowatts, so building a transmitter for interstellar messaging purposes is well within the realms of technological possibility.

So this latest directed SETI campaign drew a blank, but it’s helping us probe regions of the radio frequency spectrum and the expected power output from a hypothetical alien civilization — valuable research if we are to detect and recognize a signal from extraterrestrials in the future.

Photos: Butterflies Snag Goo from Unwitting Ants


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Photos: Butterflies Snag Goo from Unwitting Ants

Tau Day: Should Pi Be Downgraded?


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Tau Day: Should Pi Be Downgraded?

June 28. National Paul Bunyan Day, National Insurance Awareness Day, National …  Tau Day?

Today (June 28) is the unofficial holiday Tau Day, meant to celebrate the number tau, that works out to approximately 6.28, or the ratio of a circle’s circumference to its radius.

While pi may be the most famous irrational number, or a number that can’t be expressed as a ratio of two integers, a small but dedicated band of nerds and mathematicians has argued that pi should take a backseat to tau, a more perfect circle constant.

Tau should be the real headliner because it directly relates a circle’s circumference to the shape’s radius; its irrational little brother pi relates the circumference to the diameter, which is less important mathematically, said Michael Hartl, the author of “The Tau Manifesto” and the “Ruby on Rails Tutorial” (Google Books, 2012), and the founder of education website learnenough.com. [The Most Massive Numbers in Existence]

It’s not clear why Archimedes, who first described the number pi, chose to go with the less intuitive irrational number. One possibility is that it was simply easier to measure a circle’s diameter than the shape’s radius using a rod or something similar, “but that doesn’t make it good math,” Hartl said.

Pi cemented its place in the math pantheon in the 1700s when Swiss mathematician Leonhard Euler, a prolific mathematician who significantly advanced the fields of trigonometry and calculus, enshrined the convention of using pi to describe certain angles, Hartl said.

Pi’s dominance remained unquestioned for centuries. Then, in 2001, University of Utah mathematician Robert Palais wrote a paper subtly titled “Pi is wrong” for the 2001 issue of the journal Mathematical Intelligencer. In it, he itemized the shortcomings of the most famous irrational number. And he advocated for a new constant to take its place: tau.

Tau, which equals 2 times pi, is a more natural and direct way to grasp how a circle’s radius relates to the shape’s circumference, Palais argued. That makes tau a more powerful constant, he said.

For instance, there are an infinite number of shapes with a constant diameter (for instance, a Reuleaux triangle), but only one (the circle) with a constant radius, Hartl wrote in “The Tau Manifesto.”

What’s more, tau creates a more intuitive way to think about portions of the circle, he added.

“The biggest place this shows up is in trigonometry,” Hartl told Live Science.

For instance, every high-school trig student learns that a right angle equals pi divided by 2 radians. But a right angle actually delineates a quarter of a circle, Hartl said. The math would be easier to remember and work with if the angle were represented by tau, because the angle would then be tau divided by 4 radians.

“These special angles people had to memorize in high-school trigonometry don’t have to be memorized at all,” Hartl said.

What’s more, tau makes a number of other calculations and equations more elegant, such as the equation used to calculate imaginary numbers (Euler’s identity), Hartl said. Using tau instead of pi also creates a beautiful symmetry between the equation for a circle’s area (1/2 * Tau * radius^2) and other iconic equations, such as those for kinetic and elastic energy (1/2*k*x^2), as well as the equations for how far an object under the influence of gravity will fall in a given time interval, Hartl argued.

Whatever the case, there’s no doubt that tau has risen in popularity, especially amongst the mathematically inclined. For instance, if someone types the Greek letter tau into Google’s calculator, the irrational number will appear, Hartl said.

The Massachusetts Institute of Technology has even changed its admissions routine, announcing acceptances at tau o’clock on pi day: 6:28 p.m.

There are, of course, unequivocal downsides to enshrining Tau Day instead of Pi Day, Hartl said.

“You don’t have quite the same food-based pun potential,” Hartl said, referring to the tradition of serving pie on Pi Day.

However, the biggest reason Pi Day may forever overshadow the Tau holiday is simply that the former falls during the school year, giving math teachers everywhere a built-in way to celebrate their beloved subject matter, Hartl said.

Original article on Live Science.

Istanbul Ataturk airport attack: At least 36 dead and dozens injured


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Istanbul Ataturk airport attack: At least 36 dead and dozens injured

Media captionBBC reporter Mark Lowen reports from on board a plane stuck on the tarmac

A gun and bomb attack on Istanbul’s Ataturk international airport has killed 36 people and injured about 90.

Three attackers opened fire near an entry point to the terminal and blew themselves up after police fired at them, officials say.

Prime Minister Binali Yildirim said early signs suggested the so-called Islamic State was behind the attack.

Recent bombings in Turkey have been linked to either IS or Kurdish separatists.

Tuesday’s attack looks like a major co-ordinated assault, says the BBC’s Mark Lowen.

Ataturk airport was long seen as a vulnerable target, our Turkey correspondent adds, reporting from a plane stuck on the tarmac in Istanbul.

There are X-ray scanners at the entrance to the terminal but security checks for cars are limited.

Media captionFootage shows passengers taking cover inside the airport

Turkish President Recep Tayyip Erdogan said the attack should serve as a turning point in the global fight against militant groups.

“The bombs that exploded in Istanbul today could have gone off at any airport in any city around the world,” he said.

The US called the attack “heinous”, and said saying America remained “steadfast in our support for Turkey”.

German Foreign Minister Frank-Walter Steinmeier said: “We grieve for the victims. We stand by Turkey”.

‘Dressed in black’

Speaking several hours after Tuesday’s attack, Mr Yildirim said at least 36 people were killed and many wounded, some seriously.

Media captionWill Carter, eyewitness: “We saw a flash of fire”

He also said foreigners were likely to be among the dead.

Footage has emerged on social media that appears to show a police officer shooting one of the attackers, who detonates a suicide belt as he is lying injured on the ground.

Flights in and out of the airport were suspended after the attack.

The US Federal Aviation Administration grounded all flights between the US and Istanbul.

People walk away from Istanbul Ataturk airportImage copyrightREUTERS

Image captionTerrified passengers were seen leaving the airport on foot
A Kalashnikov assault rifle is seen on the floor at Ataturk airport
Image copyrightREUTERS

Image captionA Kalashnikov assault rifle was later found at the scene of the attack
Ambulances arrive at Turkey's largest airport, Istanbul Ataturk, Turkey, following a blast June 28, 2016
Image copyrightREUTERS

Image captionAmbulances flocked to the airport after the explosion
Medics take an injured man to hospital in Istanbul
Image copyrightEPA

Image captionA number of injured people were taken to local hospitals

Taxis were used to rush casualties to hospital after the attack.

Eyewitness Paul Roos told the Associated Press news agency that he was due to fly home to South Africa when the attackers struck.

“We came up from the arrivals to the departures, up the escalator when we heard these shots going off,” he said.

“There was this guy going roaming around, he was dressed in black and he had a handgun.”

Charles Michel, the Prime Minister of Belgium whose capital city was targeted by bombers in March, tweeted from the EU summit in Brussels: “Our thoughts are with the victims of the attacks at Istanbul’s airport. We condemn these atrocious acts of violence.”

In December, a blast on the tarmac at a different Istanbul airport, Sabiha Gokcen, killed a cleaner. That attack was claimed by a Kurdish group, the Kurdistan Freedom Falcons (TAK).


Major recent attacks

2016

7 June, Istanbul: Car bomb kills seven police officers and four civilians. Claimed by Kurdish militant group TAK

19 March, Istanbul: Suicide bomb kills four people in shopping street. IS blamed.

13 March, Ankara: Car bomb kills 34. Claimed by TAK.

17 February, Ankara: 29 killed in attack on military busses. Claimed by TAK

12 January, Istanbul: 11 Germans killed by Syrian bomber in tourist area

2015

23 December, Istanbul: Bomb kills cleaner at Istanbul’s Sabiha Gokcen airport. Claimed by TAK

10 October, Ankara: More than 100 killed at peace rally outside railway station. Claimed by IS

20 July, Suruc, near Syrian border: 34 people killed in bombing in Kurdish town. IS blamed


Security concerns and a Russian boycott over last year’s downing of a Russian military jet on the Turkey-Syria border have hit the Turkish tourist sector this year.

More than 61 million passengers travelled through Ataturk airport in 2015.

A US state department travel warning for Turkey, originally published in March and updated on Monday, urges US citizens to “exercise heightened vigilance and caution when visiting public access areas, especially those heavily frequented by tourists.”

2016 Istanbul airport attack

From Wikipedia, the free encyclopedia

On 28 June 2016, explosions and gunfire erupted at Atatürk Airport in Istanbul, Turkey.According to Turkish Prime Minister Binali Yıldırım, at least 36 people were killed and 147 people were injured in addition to the attackers. The gunfire occurred at the airport’s parking lot,[6] while the explosions occurred at the entrance to the international arrivals terminal and appear to have been caused by suicide bombers. Some reports state that the explosions occurred in different parts of the airport. our armed men were seen running away from the scene after the explosions

Passengers leave Ataturk airport in Istanbul on June 28, 2016 after two explosions

Turkey has been the victim of several terrorist attacks in 2016, including two suicide attacks (the January 2016 Istanbul bombing and the March 2016 Istanbul bombing) and two car bombings (the June 2016 Istanbul bombing and the June 2016 Midyat car bombing). The Islamic State of Iraq and the Levant (ISIL) claimed responsibility for the two suicide attacks, which were the seventh and eighth attack in Turkey and the fourth in Istanbul in 2016. Two of these attacks, in Ankara in February and March that killed dozens, were claimed by the Kurdistan Freedom Falcons (TAK), described as a “radical splinter group of the outlawed Kurdistan Workers’ Party(PKK)”.

Turkish rescue services members help a wounded person outside Istanbul’s Ataturk airport.

The attack

Shortly before 10 p.m. Istanbul time two assailants approached the x-ray scanner at a security checkpoint, and opened fire. Then police officers started firing. The assailants then detonated bombs on their person.

Based on security camera video, one of the bombers was about 80 feet or 24.4 meters inside terminal 2, the Internationalterminal, when he bomber detonated his suicide bomb. In the CCTV video the explosion can be seen within or near a group of people. It is also believed that one of the explosions was in the parking lot across the street of the terminal.

EDS NOTE GRAPHIC CONTENT – Turkish forensic police officers work at the scene of a blast

A video posted on Twitter soon after the incident clearly shows an armed assailant walking and firing at people within the terminal. The assailant is then shot by a security official—either Turkish police or airport security—at close range, and falls on the ground. The video shows the security officer first approaching the assailant, then running away as he presumably notices the explosives. The dying assailant then detonates his explosives.

During and immediately after the attacks hundreds of terrified passengers and people inside the airport hid anywhere they could in small shops, bathrooms and under benches.

Two of the attackers detonated explosive devices, killing themselves; three were killed, presumably by security forces. The fate of the others is currently unknown.

Turkish special forces members secure the area after a suicide bomb attack at Ataturk Airport in Istanbul, Turkey, 28 June 2016. SEDAT SUNA / EPA

Accounts

Many travelers gave accounts of what they saw during the attack to reporters after the attack ended. One South African man stated, “We came right to international departures and saw the man randomly shooting. He was just firing at anyone coming in front of him. He was wearing all black. His face was not masked. I was 50 metres away from him.” He continued, “We ducked behind a ticket counter but I stood up and watched him. Two explosions went off shortly after one another. By that time he had stopped shooting. Lastly he said “He turned around and started coming towards us. He was holding his gun inside his jacket. He looked around anxiously to see if anyone was going to stop him and then went down the escalator … We heard some more gunfire and then another explosion, and then it was over.

Other people not yet in the terminal said that multiple taxicab drivers were screaming “Don’t enter! A bomb exploded!” from their windows to incoming traffic.

Aftermath

Following the blast, all departure flights were suspended but the arrival flights remained operational for some time until they were diverted. The Islamic State of Iraq and the Levantis suspected of being behind the attack.Turkish President Recep Tayyip Erdogan has released a statement condemning the attack on Istanbul’s Ataturk airport, which took place during the Muslim holy month of Ramadan. He says the attack “shows that terrorism strikes with no regard to faith and values,” calling on the international community to take a firm stand against terrorism and vowed to keep up Turkey’s struggle against terror groups. Erdogan also stated, “Turkey has the power, determination and capacity to continue the fight against terrorism until the end.

PHOTO: Crime scene investigators work next to a body after an attack at Ataturk Airport

ISTANBUL – Two suicide bombers opened fire before blowing themselves up at the entrance to the main international airport in Istanbul on Tuesday,

People stand outside the entrance as they leave the airport after two explosions followed

Turkish rescue services gather outside Istanbuls Ataturk airport, Tuesday, June 28, 2016

PHOTO: Passengers who survived the suicide bomb attack leave Turkeys largest airport, Istanbul Ataturk

New Evidence Suggests Human Beings Are a Geological Force of Nature


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New Evidence Suggests Human Beings Are a Geological Force of Nature

For years, the term “Anthropocene” has been used to informally describe the human era on Earth. But new evidence suggests there’s nothing informal about it. We’re a true force of nature — and there’s good reason to believe we’ve sparked a new and unprecedented geological epoch.

A team of international geoscientists say the time has come for us to formally recognize the Anthropocene as a new epoch, one as significant as previous geological eras like the Holocene and Pleistocene. According to the new study, which appears in the latest issue of Science, it began sometime around the midpoint of the 20th century, and is fueled by a number of unquestionably human influences — including elevated greenhouse gas levels and the global proliferation of invasive species, along with the spread of materials such as aluminium, concrete, fly ash, and even fallout from nuclear testing.

In geology, stratum describes a layer of sedimentary rock, soil, or ice with consistent characteristics that distinguish it from other layers. By studying strata, scientists can track changes to the Earth over time. (Image credit: Strata in Salta, Argentina, Flickr)

The study was co-authored by 24 members of the Anthropocene Working Group, including Jan Zalasiewicz and Colin Waters from the British Geological Survey. These scientists are studying the extent to which our actions can be recorded as measurable signatures in geological strata — layers of sedimentary rock, soil, or ice with consistent characteristics to distinguish between them — and how our activities and byproducts are driving Earth into an entirely new geological epoch.

“Our evidence suggests that the kind of earth system changes, and their stratigraphical products, that humans have generated are comparable with those of the geological past,” Zalasiewicz told Gizmodo. “There is significant geological reality underlying the Anthropocene concept, on a scale that is consistent with potential formalization.”

Zalasiewicz says it’s important to characterize the Anthropocene more precisely, and to make it more useful in wider communication. What’s more, it shows that “our species is clearly capable of altering the course of Earth history rather more than the average species.”

(Credit: C. N. Waters et al., 2015/Science)

New evidence presented by the researchers shows that our current world is markedly different than the stable Holocene Epoch of the previous 11,700 years. The Holocene began at the end of the last ice age, but unlike other epochs, it features a highly intelligent and resourceful species that’s been dramatically influencing the environment.

Early efforts to define and circumscribe the Anthropocene cite the advent of agriculture, animal domestication, deforestation, and tiny — but measurable — increases in atmospheric carbon dioxide and methane levels. Other major developments include the colonization of the Americas and the subsequent exchange of New and Old world species, and the beginning of the Industrial Revolution.

Pulp and Paper Mill (Credit: Akexvye/CC BY 3.0)

But none of these activities, say the Anthropocene Working Group, has done as much to change the very fabric of the planet itself as the so-called “Great Acceleration” — a critical transition point during the mid-20th century after which our civilization experienced accelerated technological development, rapid population growth, and increased consumption of resources.

As the researchers write in their study:

These have combined to result in increased use of metals and minerals, fossil fuels, and agricultural fertilizers and increased transformation of land and nearshore marine ecosystems for human use. The net effect has been a loss of natural biomes to agriculture, cities, roads, and other human constructs and the replacement of wild animals and plants by domesticated species to meet growing demands for food.

Consequently, the researchers point to the 1950s and 1960s as the true start to the Anthropocene; our civilizational residue has become — and is increasingly becoming — a pervasive and persistent part of the geological record.

As Zalasiewicz explained, “There are an array of markers associated with previous epochs that make post-mid-20th century strata distinguishable from older strata.”

Millions of years from now, the traces of our civilization will be found buried in the geological record, and will include stratigraphic layers filled with concrete, elemental aluminum, plastics, and other characteristically human byproducts. Geologists of the future — or perhaps extraterrestrial archaeologists, for that matter — will also find signs of carbon particulates from atmospheric pollution, abnormally elevated levels of nitrogen and phosphorus from fertilizers and pesticides, and the radionuclide fallout from nuclear weapons. Other signatures will include dramatic changes to coastal sedimentation, and signs of widespread species extinction.

Increased rates of vertebrate extinctions. (Credit: C. N. Waters et al., 2015/Science)

Some of these “signals,” explains Zalasiewicz, are simply markers, such as radioactive fallout. But others signal more pervasive change, while still others are effectively irreversible, such as the “homogenization” of the biosphere through invasive species. Taken together, they all characterize strata — prompting scientists to consider the onset of a new geological era.

“Geological time units, including epochs, are typically established around systematic changes to stratal characteristics that typically reflect changes to the earth system of one form or another,” said Zalasiewicz. In other words, evidence of human activities is being stamped onto rocks, sediments, and glacier ice.

For comparison, consider the Carboniferous period. This era, which began about 358 million years ago, marked time when trees grew across all the planet’s land masses. After these trees died, they left a distinctive carbon footprint in the geological record, hence the term “Carboniferous.”

The Anthropocene Epoch, should it become formally recognized, will become one of many epochs in the Quaternary period, which began 2.6 million years ago. “Not only would this represent the first instance of a new epoch having been witnessed firsthand by advanced human societies,” the authors conclude, “it would be one stemming from the consequences of their own doing.”

(Credit: NASA)

Yet some scientists have raised objections to the formalization of the term. It’s possible that the greatest changes to the planet, and thus the strata, are still to come, such as the long term effects of global warming and rising sea levels. Others complain that the Anthropocene characterizes a painfully brief geological interval of time.

“These are all legitimate points,” said Zalasiewicz, “but it’s worth pointing out the scale speed, diversity and (in many cases) long-lived nature or irreversibility of the changes related to the Anthropocene.” He admits that the Anthropocene could be a short-lived era, one that will most certainly evolve over time, particularly as human influences accelerate and spread, and in consideration of future technologies. Regardless, Zalasiewicz said that nothing will “take us back to the Earth of the Holocene or of previous times.” The key point is that the Earth is now evolving along a new trajectory, and there’s “bound to be an evolution of different states,” which is true of previous major changes to the Earth system.

The timing of this study is not an accident. Back in 2013, the Anthropocene Working Group submitted a proposal to the International Commission on Stratigraphy to formally accept the term. This proposal is scheduled to be reviewed by the ICS later this year. From there it’s expected to be a long and hard process. Should it be accepted by the Subcommission on Quaternary Stratigraphy and the ICS itself, it’ll still have to be ratified by the International Union of Geological Sciences.

The group plans on carrying out further analyses, and addressing board responses to their new and previous papers. And as Zalasiewicz told Gizmodo, his team has further manuscripts in preparation, and they’re working to summarize available evidence and provide interim recommendations by mid-2016.

Read the entire study at Science: “The Anthropocene is functionally and stratigraphically distinct from the Holocene”.


Email the author at george@gizmodo.com and follow him at @dvorsky. Top image of the US Eastern seaboard at night by NASA