Next month, NASA will give the sun its close-up. The Parker Solar Probe will begin a seven-year mission to examine the sun’s energy, in an effort to better protect people and spacecraft from the star’s potentially devastating effects. A particularly lofty milestone for the probe? “Touching the sun,” NASA says.
Considering the sun is a ball of sizzling gas — with no solid surface — what, exactly, does that mean?
Even more bizarre, the sun’s corona is 300 times hotter than the photosphere — the lowest layer of the sun’s atmosphere, where solar flares belch and sunspots form. (Why that’s the case is still a mystery – that’s one question Parker is designed to answer.) And as the corona billows out into space as a stream of charged particles known as the solar wind, the superheated gas cools. [See Gorgeous Images of the Sun’s Corona in Simulations]
Because of the extreme temperatures, sun-observing spacecraft have trouble getting close enough to get a complete picture of the corona’s activity. So, the Parker Solar Probe, equipped with special shielding, will zoom in to just 4 million miles (6.4 million kilometers) from the sun’s photosphere to get close-up views. That’s more than 14 times closer than Mercury is to the sun — a distance that averages of 58 million miles (93 million km). And it will be the closest that any human-made object has been to the sun — essentially, Parker will “touch the sun.”
“Parker is going to be the first time where we’re going to get close enough to the sun to see where the action is happening, where the corona is heated and where the solar wind is being accelerated,” Eric Christian, a research scientist on the Parker mission at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, told Live Science.
Parker’s main science goals are to understand how the solar wind is accelerated and why the corona is superhot. These are important science and exploration questions, Christian said. The sun periodically sends out solar flares and, along with them, coronal mass ejections that can carry dangerous charged particles across the solar system.
Parker’s heat shield is a lightweight, 4.5-inch thick carbon foam core that is 97 percent air, according to NASA. Surrounding it is two panels of superheated carbon-carbon composite. The side closest to the sun was spray-coated to reflect the star’s energy, allowing the spacecraft to stay as cool as possible.
The spacecraft will be so close to the sun that it won’t be able to take pictures while looking straight at it, because otherwise it will be damaged. So NASA will depend on its fleet of other sun spacecraft to show how the sun looks while Parker collects information about the star’s activity. The Solar Dynamics Observatory and the Solar and Heliospheric Observatory already do regular observations of the star from afar to monitor its sunspots, flares and other indications of solar activity, so they’ll continue doing that job while Parker gets its close-up view.
Parker’s first glimpse of the sun from up close will happen just four months after launch. First, it will do a quick flyby of Venus. However, Christian said science observations at the planet are unlikely because Parker’s instruments are designed to pick up charged particles, and Venus doesn’t have much of a magnetic field. Then, Parker will dip as close as 17 million miles (27 million km) from the sun in this particular flyby, autonomously collecting observations and then slowly transmitting them back to Earth the following year, Christian said.[
Why the delay? The sun is a powerful source of radio waves, and it can interfere with Parker’s communications. While Parker is close to the sun and orbiting near the sun (relative to Earth’s view), NASA will avoid getting in touch with the probe, so that the space agency’s commands don’t confuse the spacecraft. NASA is already used to such situations, such as when Mars gets close to the sun (from Earth’s perspective) and the agency suspends conversations with rovers on the surface.
Christian said he can’t wait to see what Parker will show us about the sun. Compared with terrestrial weather forecasting, he said, our solar weather predictions “are way behind … We can’t forecast when the sun will give off these storms,” he said. But with more data, scientists may someday understand solar weather as well as they do tornado formation on Earth today, he said.
It’s the stuff of nightmares: regaining consciousness while under general anesthesia.
But according to a group of doctors in Finland, it may be that we never fully lose consciousness under anesthesia. Two new studies, both published in the July issue of the British Journal of Anaesthesia, suggest that the brain is still partly conscious under the influence of anesthetics, even though the person who has taken the drug isn’t reacting or seemingly aware.
“The brain is working more than we have thought during general anesthesia,” said Dr. Harry Scheinin, an anesthesiologist at the Terveystalo Pulssi Hospital and adjunct professor at the University of Turku, both in Finland. But this “is not necessarily a problem.” [Social Surgery: A Gallery of Live-Tweeted Operations]
In both studies, researchers used data collected from 47 adults who were placed under anesthesia. The adults received one of two common anesthetics used in surgery: dexmedetomidine and propofol. The researchers gave the participants low doses of the drugs — just enough for them to lose responsiveness.
While still under the influence of the anesthetics, in one of the studies, the researchers shook the participants and spoke loudly to wake them up, and then asked them what their experience had been like. All the while, the researchers recorded the participants’ brain activity with a device called an electroencephalogram (EEG).
Most of the participants reported experiencing dreams mixed in with reality. These were pretty typical dreams, said Scheinin, who co-led the research effort. “There are people who thought [a] couple of years ago, that if you are dreaming during general anesthesia or surgery, … the anesthesia [dose] may be too low, but I don’t agree. I think dreaming can be relatively common and normal in surgical anesthesia.”
It’s possible that “general anesthesia can be [closer] to normal dreaming or sleeping than we have previously thought,” Scheinin added. (It is thought that a dreaming person, for example, is partly conscious, he said.)
In a second experiment that was also published in the first study, the researchers played unpleasant sounds while the participants were under anesthesia. Once the participants were awake, the researchers had them listen to more unpleasant sounds — some of which had been played to them while under anesthesia. The people reacted faster to the sounds that had been played while they were under anesthesia than the ones they hadn’t heard before. Again, this suggests the brain is somehow processing these sounds, even while under anesthesia, Scheinin said.
The second study focused on the results of yet another experiment done when the participants were under anesthesia. In this experiment, the participants were played a recording of regular sentences that ended with a really bizarre word — one that clearly didn’t belong in the sentence, such as “The bear walks on the moon” instead of “The bear walks in the forest.”
When people are awake, hearing that unexpected word usually causes a greater response in brain activity than an expected word would, Scheinin told Live Science. The researchers found that when the people were under anesthesia, however, their brain activity looked the same, regardless of which type of sentence was played — in other words, their brains couldn’t tell the difference between normal and weird sentences. But curiously, in the people given dexmedetomidine, the researchers observed a spike in brain activity that coincided with the end of the sentences.
Scheinin said that he thinks that both types of words — normal and bizarre — might have triggered this spike because the brain might lose context or expectations while under anesthesia. For example, it may be that the people under anesthesia can’t remember the beginning of the sentence by the time they hear the end, or they can’t integrate the words into sentence form, he said. But the spike in activity at the end of the sentences suggests that they are still hearing and processing the sentences.
Once the people were awake, however, none of them remembered what they heard.
These studies “confirm that consciousness is rarely ever lost,” said Allan Leslie Combs, the director of the California Institute of Integral Studies Center for Consciousness Studies, who was not involved with the new research. But what is commonly lost is memory, Combs said, which is what the second study suggested. In other words, even though a person may not fully lose consciousness while under certain anesthetics, that person does lose the memories that occur at this time.
“It’s worth pointing out that these studies all use very light anesthesia,” Combs told Live Science — much lighter than what would be used when a person is having surgery. So, it’s possible that the experience could be different for the levels of anesthesia used in surgery, he added.
Scheinin acknowledged that the doses of anesthesia used in the studies were light but thinks the results could also hold true for normal levels of anesthetics. However, there are many other drugs that are thrown into the mix during normal surgery, including opioids and muscle relaxants, which could also alter the results, Scheinin said.
The new findings could help develop technologies or drugs to eliminate what doctors call “unintended awareness,” Scheinin said, referring to terrifying stories of unlucky individuals who somehow end up awareduring surgery but are unable to notify the doctors. The phenomenon is rare — it occurs in only about 1 in 1,000 people — but that doesn’t mean researchers shouldn’t try to solve it, he added.
[Here’s a fascinating discovery. It shows trends that took place over tens of thousands of years! I have also come across mention that people interbred a bit with Neanderthals tens of thousands of years ago! Jan]
The ‘founding fathers’ of Europe: DNA reveals all Europeans are related to a group that lived around Belgium 35,000 years ago
Experts analysed data from humans who lived 45,000 to 7,000 years ago
Genetic data shows all Europeans come from a single founding population
This population occupied northwest Europe 35,000 years ago before being displaced when another group of early humans arrived 33,000 years ago
The original group then re-expanded across the continent 19,000 years ago
PUBLISHED: 16:00 BST, 2 May 2016 | UPDATED: 19:51 BST, 6 May 2016
Modern humans arrived in Europe 45,000 years ago but little is known about how they spread across the continent before the introduction of farming.
Now, researchers carrying out the most detailed genetic analysis of Upper Paleolithic Europeans to date have discovered a major new lineage of early modern humans.
This group, which lived in the northwest 35,000 years ago, directly contributed to the ancestry of present-day Europeans and is believed to have been formed of the ‘founding fathers’ of Europe.
Researchers carrying out the most detailed genetic analysis of Upper Paleolithic Europeans to date have discovered a major new lineage of early modern humans. This group, which lived in the northwest around 35,000 years ago, directly contributed to the ancestry of present-day Europeans (artist’s impression pictured)
Archaeological studies have previously found modern humans swept into Europe 45,000 years ago.
This ultimately led to the demise of the Neanderthals, despite the fact some modern humans interbred with these cousins.
During the Ice Age that ended 12,000 years ago, with its peak between 25,000 and 19,000 years ago when the melt started, glaciers covered Scandinavia and northern Europe all the way to northern France.
As the ice sheets retreated at the end of the last Ice Age, the region was repopulated.
David Reich and his colleagues from Harvard University analysed genome-wide data from 51 modern humans who lived between 45,000 and 7,000 years ago to study this repopulation.
TRACING EUROPEAN ANCESTRY
The genetic data shows that, beginning 37,000 years ago, all Europeans come from a single population that persisted through the Ice Age.
The founding population has deep branches in different parts of Europe, one of which is represented by a specimen from Belgium.
In fact, present-day Europeans can trace their ancestry back to this group of humans who lived in northwest Europe 35,000years ago.
However, this founding population, which was part of the Aurignacian culture, became displaced when another group of early humans arrived on the scene in many parts of Europe 33,000 years ago.
This group was made up of members of a different culture known as the Gravettian.
Around 19,000 years ago, a population related to the Aurignacian culture re-expanded across Europe.
It is thought these people went on to repopulate Europe after ice sheets retreated.
Based on the earliest sample in which this ancestry is observed, it is plausible this population expanded from the southwest – present-day Spain – after the Ice Age peaked.
Remains found from this period include three 31,000-year-old skulls from Dolni V?stonice in the Czech Republic, the lower jaw of the 19,000-year-old ‘Red Lady of El Mirón Cave’ and the skull of a 14,000-year-old individual discovered at the Villabruna in northeastern Italy, among others.
The genetic data shows that, beginning 37,000 years ago, all Europeans come from a single founding population that persisted through the Ice Age.
The founding population has deep branches in different parts of Europe, one of which is represented by a specimen from Belgium.
In fact, present-day Europeans can trace their ancestry back to this group of humans who lived in northwest Europe 35,000 years ago.
However, this founding population, which was part of the Aurignacian culture, became displaced when another group of early humans, members of a different culture known as the Gravettian, arrived on the scene in many parts of Europe 33,000 years ago.
Then, around 19,000 years ago, a population related to the Aurignacian culture re-expanded across Europe.
It is thought these people went on to repopulate Europe after the vast ice sheets retreated.
Based on the earliest sample in which this ancestry is observed, it is plausible this population expanded from the southwest – present-day Spain – after the Ice Age peaked.
The second event the researchers detected happened 14,000 years ago when populations from the southeast, around Turkey and Greece, spread into Europe, displacing the first group of humans.
Professor Reich added: ‘We see a new population turnover in Europe, and this time it seems to be from the east, not the west.
Researchers from Harvard University analysed genome-wide data from 51 modern humans who lived between 45,000 and 7,000 years ago. The location and age of these humans is shown. Each bar corresponds to an individual, the colour represents the genetically defined cluster, and the height is proportional to age
The team studied three 31,000-year-old skulls from Dolni V?stonice in the Czech Republic (pictured). For 5,000 years after this group lived, all samples, from Belgium, the Czech Republic, Austria and Italy, were found to be closely related, reflecting a population expansion associated with the Gravettian archaeological culture
An early branch of the European founder population was displaced across much of Europe for around fifteen thousand years before becoming widespread again. The lower jaw of the 19,000-year-old ‘Red Lady of El Mirón Cave’ is pictured. This is the first individual in the study to show the resurgence of ancestry
BATTLE OF THE CULTURES: AURIGNACIAN VERSUS GRAVETTIAN
The genetic analysis shows the Aurignacian culture was displaced by the Gravettian culture, but later re-emerged.
Radiocarbon dating shows the Aurignacian culture from Europe and southwest Asia dominated from 47,000 to 41,000 years ago, although emerged in smaller groups earlier than this.
The group is categorised by its tools made of bone or antler points with grooves cut in the bottom.
The Aurignacian culture is categorised by its tools made of bone or antler points with grooves cut in the bottom as well as bladelets (pictured)
Elsewhere, they made flint tools include blades and bladelets.
The people of this culture are also linked with early cave art, including animal engravings and imagery in the Chauvet cave in southern France.
By comparison, the Gravettians were a Stone Age culture known for making small pointed blades who lived across much of Europe.
This group of hunter gatherers lived in central and Eastern Europe between 30,000 and 20,000 years ago.
Remains of this prehistoric culture have been found in caves in southern France and more open sites on the plains of Central Europe and Russia.
Isotopic studies of human remains from the Czech Republic have also revealed that mammoths formed a large part of the Gravettian diet.
‘We see very different genetics spreading across Europe that displaces the people from the southwest who were there before.
‘These people persisted for many thousands of years until the arrival of farming.’
The study, published in Nature, also detected some mixture with Neanderthals, around 45,000 years ago, as modern humans spread across Europe.
The prehistoric human populations contained three to six per cent of Neanderthal DNA, but today most humans only have about two per cent.
‘Neanderthal DNA is slightly toxic to modern humans’ and this study provides evidence that natural selection is removing Neanderthal ancestry,’ Professor Reich added.
The genetic analysis shows the Aurignacian culture was displaced by the Gravettian culture, but later re-emerged. Radiocarbon dating shows the Aurignacian culture from Europe and southwest Asia dominated from 47,000 to 41,000 years ago (locations pictured), although emerged in smaller groups earlier than this
During the first major warming period at the end of the Ice Age, a new population swept in from the southeast, drawing the gene pools of Europeans and Near Easterners closer together. The skull of a 14,000-year-old individual discovered at the Villabruna in northeastern Italy is pictured
Ancient specimens are frequently contaminated with microbial DNA, as well as DNA from archaeologists or lab technicians who have handled the specimens.
The arm bone of a 35,000-year-old individual from Belgium who was part of a previously undiscovered major lineage
To solve this problem scientists used a technique called in-solution hybrid capture enrichment.
They used about 1.2 million 52-base-pair DNA sequences corresponding to positions in the human genome that they were interested in as bait to target specific segments of DNA.
After they washed the ancient DNA over the 1.2 million probe sequences, the researchers sequenced the ancient DNA that was captured by the probes.
Prior to the Harvard Medical School study there were only four samples of prehistoric European modern humans 45,000 to 7,000 years old for which genomic data were available.
This made it difficult to understand how human populations migrated or evolved during this period.
Using a new technique, more samples could be assessed.
Professor Reich continued: ‘Trying to represent this vast period of European history with just four samples is like trying to summarise a movie with four still images.
‘With 51 samples, everything changes; we can follow the narrative arc; we get a vivid sense of the dynamic changes over time.
‘And what we see is a population history that is no less complicated than that in the last 7,000 years, with multiple episodes of population replacement and immigration on a vast and dramatic scale, at a time when the climate was changing dramatically.’
The study also detected some mixture with Neanderthals, around 45,000 years ago, as modern humans spread across Europe. The prehistoric human populations contained three to six per cent of Neanderthal DNA, but today most humans only have about two per cent (plotted in this graph)
[It is astounding how the boundaries of science are being pushed back and we are seeing older dinosaurs which show how evolution really worked. Jan]
Scientists found the remains of the dinosaur, named Ingentia Prima, meaning ‘great cousin’, in Argentina.
The dramatic discovery winds back the clock on the emergence of giant dinosaurs by a staggering 30 million years – shedding fresh light on their evolution.
The colossal Ingenta Prima was about 33 feet long, 14 feet tall and weighed up to 10 tons.
It roamed South America around 210 million years ago during the the Late Triassic.
The dinosaur was among the first huge sauropods that turned into into the largest animals that walked the planet.
Palaeontologist Dr Cecilia Apaldetti said: “It was enormous. It was at least twice as large as the other herbivores of the time.”
The creature changes our understanding of how this group of species became such an immense size.
Its growth was fuelled by bird like lungs that would have made it remarkably light on its feet – for its size.
SWNSCOLOSSAL: The Ingenta Prima was about 33 feet long, 14 feet tall and weighed up to 10 tonsDr Apaldetti said: “Until now it was believed the first giants to inhabit the Earth originated during the Jurassic – about 180 million years ago.”But with this discovery we can see the first steps toward gigantism occurred 30 million years before the giants dominated practically the entire planet.”
This period was a pivotal stage in the history of dinosaurs, but the fossil record is so incomplete it obscures details of this crucial evolutionary change.
Dinosaurs first appeared around 230 million years ago, and it was believed to have taken them about 50 million years to become massive.
But the new discovery shows it happened in less than half that time.
The plant eater, described in Nature Ecology & Evolution, is an ancestor of its famously freakish Titanosaur cousins Brachiosaurus and Diplodocus, renowned for their enormous necks and tails.
Among the most iconic of dinosaurs they stretched to 130 feet and weighed up to 80 tons.
But the earliest examples of this group were small, two-legged creatures. To turn into towering behemoths, it was believed the development of straight legs for support and continuous, rapid growth were essential.
“It was enormous. It was at least twice as large as the other herbivores of the time”
Dr Cecilia Apaldetti
But Ingentia Prima, which was found alongside the remains of three individuals belonging to the already known species Lessemsaurus Sauropoides, changes this.
They all belonged to a family of dinosaurs called ‘lessemsaurids’ and lived in what is now Argentina, but was then the southeast corner of the supercontinent Pangaea.
Dr Apaldetti said the climate would have been warm, with periodic monsoons producing an African savannah-style landscape, with plenty of shrubs on which Ingentia Prima would feed.
Its size would also have put it at less risk of being eaten by flesh eating dinosaurs that were already around.
Dr Apaldetti said: “Gigantism is an evolutionary survival strategy, especially for herbivorous animals.”
The remarkably preserved specimens were discovered in a dinosaur ‘nest’ unearthed at a World Heritage site known for its fossils in Argentina’s north western San Juan province.
They included shoulder blades, cervical vertebrae and bones from the forelimbs, feet and skull of the four dinosaurs.
Dr Apaldetti, of the National University of San Juan, said they weighed in at an estimated seven to 10 tonnes. Like their notorious descendants, they also had elongated necks and tails.
GETTYGIANT: A dinosaur the size of a double decker bus has been discovered
And they had the same bird like air sacs – respiratory structures which are thought to have been necessary to keep large animals cool.
Explained Dr Apaldetti: “This respiratory system is related to the development of air sacs inside their bodies – like modern birds.
“It allowed them to have large reserves of oxygenated air, and also helped them to keep cool despite being so big.
“In addition, this kind of breathing implied the presence of cavities, or deep holes, in their bones – known as a pneumatic skeleton – that lightened the weight and would have favoured a large body size.”
But unlike their more recent counterparts they stood on bent legs and had bones that grew thick through accelerated bursts – showing there is more than one way to ‘make’ a giant dinosaur.
The last iconic sauropods had the benefit of a long history of evolutionary innovation in this regard, said Dr Apaldetti.
Dr Apaldetti said: “Sauropods were the first successful group of herbivorous dinosaurs, dominating most terrestrial ecosystems for more than 140 million years, from the Late Triassic to Late Cretaceous.”
Their expansion in the Late Triassic is evident from the appearance of many small, agile two legged types recorded throughout the world.
Dr Apaldetti added: “Sauropods evolved from these smaller forms and became the largest land animals that ever lived on Earth.”
