A new study makes a compelling case for the origin of unexplained masses of underground rock causing changes to the Earth's magnetic field.
They're called "large low-shear-velocity provinces" (LLSVPs), and they're large anomalous globs of, well, some kind of rock deep inside the Earth. There's one under Africa and the other is beneath the Pacific Ocean. Together, they're apparently producing the South Atlantic Anomaly, a massive region of lower magnetic intensity sufficient to weaken the planet's corresponding magnetic field. This provides less protection from cosmic rays for our orbiting spacecraft, and some wonder whether its presence signals a flipping of the planets magnetic poles. It's believed the anomaly is nothing new, reappearing now and again for at least 11 million years and likely much longer.
A theory from researchers at Arizona State University (ASU) presented this month at the Lunar and Planetary Science Conference may explain what the LLSVPs actually are: They're what's left of the protoplanet Theia that crashed into the young Earth about 4.5 billion years ago, shearing off the debris that eventually became our Moon.
Credit: 3000ad/Adobe Stock
According to a widely held hypothesis, Theia was an at-least Mars-sized object that obliquely collided with Earth. It's a good thing it just glanced off us, too, since a direct hit would have obliterated our planet entirely. As it was, it's theorized, two big chunks were ejected from the collision, forming two moons that eventually coalesced into the one we see today.
The authors of the new research, led by ASU's Qian Yuan, explain in a summary of their findings: "Such a model is well-aligned with some key physical aspects of Earth-Moon system, including anomalous high angular momentum of Earth-Moon system, small iron core of the Moon and its high mass ratio compared to the Earth."
But if Theia was real, where did it go? The authors write, "The Giant Impact hypothesis is one of the most examined models for the formation of the Moon, but direct evidence indicating the existence of the impactor Theia remains elusive." It's reasonable that some material from both bodies was destroy. How much of Theia was captured has remained an open question.
Scientists have conclusively determined that the LLSVPs exist, though their origin and composition is unresolved. The ASU researchers say that while they could be thermal in origin, seismological examination reveals that they have distinct margins separating them from surrounding rock and are much denser chemically, suggesting that they're not of a piece with the rest of the mantle.
The researchers' modeling of Theia's likely composition supports the idea that its mantle was several percent denser than Earth's, and iron-rich, which would mean that after the bodies collided, the Theia mantle material could "sink to Earth's lowermost mantle and accumulate into thermochemical piles that may cause seismically observed LLSVPs."
The theory proposed in the new research, which is being evaluated for publication in the journal Geophysical Research Letters, has been proposed before. However, the ASU researchers have presented what may be the best supporting evidence for it yet. Yuan says his research supports the LLSVP-Theia connection in four ways:
- The LLSVPs' mass may be equivalent to the size of Theia's mantle, answering the question of where it went after impact.
- At a minimum of 250 million years old, the LLSVPs predate the Moon.
- The hypothesized makeup of Theia's mantle matches what is believed to be the composition of the LLSVPs.
- Simulations show how Theia's mantle could end up where the LLSVPs currently are.
Experts explain how lie detectors work, what happens in the brain when we tell lies and how accurate polygraph tests are.
- In a 2002 study, 60 percent of people were found to lie at least once during a 10-minute conversation, with most people telling an average of two or three lies. The polygraph, invented in the early 1920s, detects physiological responses to lying (such as elevated heart and respiratory rates as well as spikes in blood pressure.
- Three main areas of the brain are stimulated during deception: the frontal lobe, the limbic system, and the temporal lobe.
- According to the American Polygraph Association, the estimated accuracy of a polygraph can be up to 87 percent.
What happens in your brain when you lie?
Image by Shidlovski on Shutterstock
We all lie. Some might argue it's human nature. In a 2002 study, 60 percent of people were found to lie at least once during a 10-minute conversation, with most people telling an average of two or three lies. Some lies are small, some are bigger, some are done out of kindness, and some done out of malice. But a lie is a lie, and the way that your body reacts when you lie is the same.
Lying is an inherently stressful activity.
When you engage in a false narrative (or a lie), your respiratory and heart rate will increase and you may even start to sweat. While people may vary in the ability to tell a lie, most of the time your body will react in this same way. Exceptions to this rule are, for example, psychopaths, who lack empathy and therefore do not exhibit the typical physiological stress responses when telling a lie.
Brain imaging studies have shown what really happens in the brain when you tell a lie.
Lying generally involves more effort than telling the truth, and because of this, it involves the prefrontal cortex. A 2001 study by late neuroscientist Sean Spence (University of Sheffield in England) explored fMRI images of the brain while lying. Participants answered questions about their daily routine by pressing a yes or no button on a screen. Depending on the color of the writing, they were to answer either truthfully or with a lie.
The results showed participants needed more time to formulate a dishonest answer than an honest one, and certain parts of the prefrontal cortex were more active when they were lying.
Further research explains that three main areas of the brain are stimulated during deception - the frontal lobe works to suppress the truth, the limbic system activates due to the anxiety that comes from lying, and the temporal lobe activates in response to retrieving memories and creating mental imagery (fabricating a believable lie).
Research also suggests lying becomes easier the more you do it.
In a 2016 study, Duke psychologist Dan Ariely and his colleagues showed how dishonesty can alter your brain, making it easier to tell lies in the future. When people told lies, the scientists noticed a burst of activity in the amygdala, the part of the brain involved in fear, anxiety, and emotional responses. When the scientists had their subject play a game in which they won money by deceiving their partner, they noticed the negative signals from the amygdala begin to decrease.
"Lying, in fact, desensitized your brain to the fear of getting caught of hurting others, making lying for your own benefit down the road much easier," wrote Jessica Stillman for INC.
How do lie detectors work?
The polygraph will be able to detect if someone is telling the truth 87 percent of the time.
Image by OllivsArt on Shutterstock
In 1921, a California-based police officer and physiologist John A. Larson created an apparatus that simultaneously measures continuous changes in blood pressure, heart rate, and respiration rate to aid in the detection of deception. This was the invention of the polygraph, which is commonly referred to as a lie detector.
Seven years before this, in 1914, an Italian psychologist (Vittorio Benussi) published findings on "the respiratory symptoms of a lie," and in 1915, an American psychologist and lawyer (William M. Marston) invented a blood pressure test for the detection of deception.
The accuracy of polygraph tests has been called into question for nearly as long as they've existed. These machines detect typical stress responses to telling a lie. This means increased heart rate, blood pressure, and respiration rate. Some people are naturally good liars, or become better with controlling these stress responses, and can manage to stay calm during a lie detector test.
According to the American Polygraph Association (made up largely of polygraph examiners), the estimated accuracy of a polygraph can be up to 87 percent. That means that in 87 out of 100 cases, the polygraph will be able to detect if someone is telling the truth.
If the person lies but doesn't have the stress symptoms of telling that lie, they will pass the test. Similarly, innocent people may fail the test due to being anxious about taking it to begin with and therefore emitting the elevated heart, respiratory, and blood pressure rates that can be detected.
The sudden prevalence of an artery in the forearm is evidence that we're still very much a work in progress.
- Australian scientists see signs of accelerating human evolution.
- Exhibit A is the rapid rise in the prevalence of the median artery in adults.
- Other emerging traits, like shorter baby jaws, support their finding.
There's no reason to think humans have stopped evolving. We see natural selection causing change in other animals all the time. For example, there has been an increase in tuskless elephants in Africa as a response to the poaching of ivory, and the skulls of urban foxes have changed as they adapt to scavenge cities. Within our bodies, scientists estimate there are trillions of mutations occurring each day. Meanwhile, our species eagerly awaits the emergence of a trait that allows us to put down our phones.
A new study finds evidence that not only are humans continuing to evolve, but we may be doing so at a faster rate than seen before. The research cites several examples of rapidly emerging traits such as an increasing lack of wisdom teeth, the shortening of babies' faces with smaller jaws, the increased presence of a fabella (the small bone in the back of the knee joint) and extra bones in the feet.
The report's primary focus, though, is a sudden increase in the appearance of the median artery in the adult human forearm.
The researchers say these trends constitute "micro evolution."
The rise of the median artery
The median artery supplies blood to a fetus' forearm in the womb during early gestation. It typically atrophies and is replaced by the radial and ulna arteries before birth. Few adults have historically had all three arteries — median, radial, and ulna — but this has been changing.
The study's senior author Maciej Henneberg says, "This is micro evolution in modern humans and the median artery is a perfect example of how we're still evolving because people born more recently have a higher prevalence of this artery when compared to humans from previous generations."
The phenomenon was first noticed in the 18th century, and a study of the artery's persistence was conducted in 1995. The more recent study extends that work, finding that the occurrence of the artery trio is accelerating.
"The prevalence was around 10% in people born in the mid-1880s compared to 30% in those born in the late 20th century," says lead author Teghan Lucas, "so that's a significant increase in a fairly short period of time, when it comes to evolution."
Why this is occurring isn't clear. "This increase could have resulted from mutations of genes involved in median artery development or health problems in mothers during pregnancy, or both actually," says Lucas.
However, she says, one thing is clear: "If this trend continues, a majority of people will have median artery of the forearm by 2100."
(Fore)armed with insight
The researchers tracked the presence the median artery in cadavers. They examined the 78 upper limbs obtained from Australians who died between 2015 and 2016. The deceased were from 51 to 101 years of age at death. In 26 of the limbs, the median artery was present.
Says Henneberg, "We've collected all the data published in anatomical literature and continued to dissect cadavers donated for studies in Adelaide, and we found about one third of Australians have the median artery in their forearm and everyone will have it by the end of the century if this process continues."
The scientists' conclusion is that we're evolving more quickly now than at any point in the last 250 years of study.
Ground-penetrating radar allows the non-invasive virtual excavation of Falerii Novi.
- Using ground-penetrating radar, layers of an ordinary field in Italy are pulled back to reveal a lost Roman town.
- Without disturbing a single artifact, an incredible level of detail is uncovered.
- The buried town, Falerii Novi, has been quietly awaiting discovery since it was abandoned at the start of medieval age.
It doesn't look like much to the naked eye. It's basically an empty field, but if you caught it on the right days, you'd have seen a quad-wheel bike going back and forth while pulling an unremarkable-looking bit of not-really-farm gear. What's been going on there is the layer-by-layer discovery of an ancient Roman town, Falerii Novi. While archaeological finds like this are always interesting, this one is special: The long-buried city has been exposed without the removal of a speck of dirt.
Technology and patience
Image source:Frank Vermeulen/University of Cambridge
Falerii Novi was unearthed using ground-penetrating radar, or GPR. With each pass across that field, the bike pulled a rolling frame outfitted with a GPR instrument that bounced radio waves off of whatever lay beneath it. The device took a reading every 12.5 centimeters, eventually imaging the entire 30.5-hectare area. Without disturbing a single ancient artifact, GPR generated a remarkably detailed look at the lost city, with its various different layers depicting changes that occurred over time.
In the end, the researchers were confronted with 28 billion GPR data points to be processed, an almost impossibly huge task. Each hectare takes about 20 hours to work through, and the team is currently developing automation techniques that will allow them to fully explore the data collected by the GPR.
"The astonishing level of detail which we have achieved at Falerii Novi, and the surprising features that GPR has revealed, suggest that this type of survey could transform the way archaeologists investigate urban sites, as total entities."
A preliminary version of the Falerii Novi map
Image source: University of Cambridge
Quite a bit was already known about the walled town of Falerii Novi. It was first occupied in 241 BC, and lasted until around 700 AD., the early days of the medieval period. It's located about 30 miles north of Rome. The town, which was about half the size of Pompeii, has been the subject of other scanning research before, but has never been so thoroughly revealed until now.
Image source: L. Verdonck/University of Cambridge
The visible Falerii Novi contains a number of surprises.
In a broad sense, the town's layout appears less standardized than archaeologists would expect for an ancient Roman community, with a number of notable features.
There's the mysterious pair of large structures facing each other within a porticus duplex located at the town's northern gate at the upper edge of the image above. Experts have no idea what these buildings are, though they conjecture that they may have been some sort of massive monument overlooking the city's edge.
In addition, for a small city, the temple, market building and bath complex are unexpectedly elaborate.
GPR also revealed the existence of an intriguing network of pipes that may have been a large public bathing system featuring an open-air natatio, or pool. The pipes terminate at a large rectangular building and run not just along the town's streets, as might be expected, but also under its city blocks.
With the Falerii Novi project serving as such a stunning reason to keep using this technology for archaeology, Millet envisions many more such projects: "It is exciting and now realistic to imagine GPR being used to survey a major city such as Miletus in Turkey, Nicopolis in Greece or Cyrene in Libya. We still have so much to learn about Roman urban life and this technology should open up unprecedented opportunities for decades to come."
Coke, meth, ecstasy, amphetamines: each drug has a different 'capital'
- A large-scale survey of wastewater across Europe shows which illicit drugs are popular.
- The use of four main drugs was up across the board last year, but regional variation persists.
- Cocaine is popular in the west and south, meth in the east and north.
How to trace illicit drug use
Some examples of MDMA, a.k.a. ecstasy, in pill form.
DM Trott / The Drug User's Bible - CC BY-SA 4.0
Europe's drug capitals? Antwerp for cocaine use, Stockholm for amphetamines. Prague tops the list for crystal meth, Amsterdam for ecstasy. So says a study by the EU's official drug monitory body, analysing sewage samples from 68 cities in 23 European countries. The standardised surveys of urban wastewater, conducted since 2011, are a good indicator of regional preferences in illicit drug use, and their evolution over time.
It's not easy to establish the size of Europe's appetite for illicit drugs. Most users would prefer not to discuss their habit, and seizures of drugs shipments provide only a very partial picture. Fortunately for the scientists, urine doesn't lie.
Since its original use in the 1990s to monitor the environmental impact of liquid household waste, wastewater analysis has rapidly improved, and is now able to provide near real-time data on the quantity, the geography and the evolution over time of illicit drug use.
The most recent study, published earlier this month by the European Monitoring Centre for Drugs and Drug Addiction (EMCDDA), took samples in March 2019 at treatment plants processing sewage for a total of 50 million Europeans, concentrated in the continent's major urban centers.
The sewage was tested for traces of four illicit drugs: cocaine, MDMA (popularly known as ecstasy), amphetamines and methamphetamines (a.k.a. crystal meth). These leave clearly detectable biomarkers in sewage, unlike cannabis or heroin.
- Compared to previous years, consumption was on the increase for each of the four drugs.
- Residues for all four drugs were higher in larger cities – a reflection of the fact that this is where younger people tend to congregate.
- Three out of four cities reported higher levels of amphetamine, cocaine and ecstasy use during the weekend, indicating recreational use.
- Crystal meth use tended to stay even over the whole week, indicating more chronic, problematic use.
Cocaine: popular in west and south
The Belgian port city of Antwerp tops the list for highest average cocaine use
The Belgian port city of Antwerp – and in particular the district of Antwerp-Zuid – topped the list of European cities with the highest average cocaine use, both on weekdays and at weekends.
The figures – expressing average mg/day of cocaine biomarker per 1,000 persons – show the Belgians out-consuming the runners-up in Amsterdam by a considerable margin. Also remarkable: four of Europe's top 10 coke cities are Swiss; and London barely makes the list.
As recently as 2015, London was Europe's cocaine capital, with a wastewater count of 909mg of benzoylecgonine (BE) per 1,000 people. BE is the compound produced by the body when it breaks down cocaine. Other research at that time showed 4% of Londoners between 15 and 34 years of age had taken cocaine in the preceding year.
But recent figures show the BE count in London's sewage has been dropping for years now, from 895mg in 2016 to 619mg in 2019 – a reduction by nearly a third. Why is that? Wastewater research can't tell you that. But the three most likely theories are:
- The samples are non-representative anomalies.
- The London market for cocaine is saturated.
- After consistent rises in the previous years, the purity of the product has gone down.
The actual answer could be any combination of those three possibilities.Seen across the whole of Europe, cocaine use is highest in western and southern European cities, particularly in Belgium, the Netherlands, the UK and Spain. Despite some increase, cocaine use remains low in eastern Europe.
|Cocaine capitals of Europe||mg|
|3||St Gallen Hofen||Switzerland||909.8|
Ecstasy: from 'niche' to mainstream
Ecstasy is now being used by a broader range of young people in mainstream nightlife settings.
MDMA, commonly known as ecstasy, is most popular in Belgium, the Netherlands and Germany. Until recently, overall MDMA use seemed to be declining from a peak in the early to mid-2000s; however, more recent data provides a mixed picture, with MDMA consumption falling in London, for example, but remaining high in some cities. Sharp increases were noted in particular for Antwerp, Amsterdam and Eindhoven.
In fact, the study reports an increase in MDMA use for more than half of the 42 cities with comparable data for 2018 and 2019 – leading the researchers to conclude that ecstasy no longer is a 'niche' drug, linked to the sub-culture of dance clubs. It's now being used by a broader range of young people in mainstream nightlife settings, like bars and house parties.
|Ecstasy capitals of Europe||mg|
Meth: breaking out of its Czech heartland
Prague is Europe's meth central.
For years, methamphetamine was popular particularly in the Czech Republic. In recent years, the drug has made inroads in surrounding countries – Slovakia and eastern Germany – but also further afield, in various Nordic cities, in Cyprus and Spain.
Overall 21 of the 41 cities with data on meth use for both 2018 and 2019 showed an increase. Despite this, meth use remained negligible outside the established hotspots.
In 2015, Oslo and Dresden topped the meth league tables, in 2016, Slovakia's capital Bratislava took the crown. In 2019, Prague was Europe's meth capital.
|Meth capitals of Europe||mg|
Amphetamines: popular in the north
Germany, Belgium and Sweden occupy all but two spots in the amphetamine top 10.
Antwerp was Europe's amphetamine capital back in 2016, but the city has to content itself with its top spot in the cocaine ranking, having gone down a few places in this league table. Sweden rules the roost, occupying first and second place; with Belgium and Germany occupying three spots each.
No wonder then that the highest levels of amphetamine use were reported in northern European cities, with much lower levels in southern Europe.
Wastewater analysis has its limits when trying to establish quantities or patterns of illicit drug use, but it offers support to other indicators of drug consumption, for instance the amounts of drugs seized by the authorities, and it confirms the picture of a remarkably divergent market across Europe.
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