Nature

Time Travel Simulation Resolves “Grandfather Paradox”

Scientific American

 

What would happen to you if you went back in time and killed your grandfather? A model using photons reveals that quantum mechanics can solve the quandary—and even foil quantum cryptography

Wormhole Created in Lab Makes Invisible Magnetic Field: Amazing!

magnetic wormhole

A new device can cloak a magnetic field so that it invisible from the outside. Here, a picture of how the wormhole would work.
Credit: ordi Prat-Camps and Universitat Autònoma de Barcelona

Ripped from the pages of a sci-fi novel, physicists have crafted a wormhole that tunnels a magnetic field through space.

“This device can transmit the magnetic field from one point in space to another point, through a path that is magnetically invisible,” said study co-author Jordi Prat-Camps, a doctoral candidate in physics at the Autonomous University of Barcelona in Spain. “From a magnetic point of view, this device acts like a wormhole, as if the magnetic field was transferred through an extra special dimension.”

The idea of a wormhole comes from Albert Einstein’s theories. In 1935, Einstein and colleague Nathan Rosen realized that the general theory of relativity allowed for the existence of bridges that could link two different points in space-time. Theoretically these Einstein-Rosen bridges, or wormholes, could allow something to tunnel instantly between great distances (though the tunnels in this theory are extremely tiny, so ordinarily wouldn’t fit a space traveler). So far, no one has found evidence that space-time wormholes actually exist. [Science Fact or Fiction? The Plausibility of 10 Sci-Fi Concepts]

The new wormhole isn’t a space-time wormhole per se, but is instead a realization of a futuristic “invisibility cloak” first proposed in 2007 in the journal Physical Review Letters. This type of wormhole would hide electromagnetic waves from view from the outside. The trouble was, to make the method work for light required materials that are extremely impractical and difficult to work with, Prat said.

Magnetic wormhole

But it turned out the materials to make a magnetic wormhole already exist and are much simpler to come by. In particular, superconductors, which can carry high levels of current, or charged particles, expel magnetic field lines from their interiors, essentially bending or distorting these lines. This essentially allows the magnetic field to do something different from its surrounding 3D environment, which is the first step in concealing the disturbance in a magnetic field.

So the team designed a three-layer object, consisting of two concentric spheres with an interior spiral-cylinder. The interior layer essentially transmitted a magnetic field from one end to the other, while the other two layers acted to conceal the field’s existence.

The inner cylinder was made of a ferromagnetic mu-metal. Ferromagnetic materials exhibit the strongest form of magnetism, while mu-metals are highly permeable and are often used for shielding electronic devices.

A thin shell made up of a high-temperature superconducting material called yttrium barium copper oxide lined the inner cylinder, bending the magnetic field that traveled through the interior.

magnetic wormhole device
A new device has created a magnetic wormhole, in which a magnetic field enters one end and seems to pop out of nowhere on the other side.
Credit: Jordi Prat-Camps and Universitat Autònoma de Barcelona

The final shell was made of another mu-metal, but composed of 150 pieces cut and placed to perfectly cancel out the bending of the magnetic field by the superconducting shell. The whole device was placed in a liquid-nitrogen bath (high-temperature superconductors require the low temperatures of liquid nitrogen to work).

Normally, magnetic field lines radiate out from a certain location and decay over time, but the presence of the magnetic field should be detectable from points all around it. However, the new magnetic wormhole funnels the magnetic field from one side of the cylinder to another so that it is “invisible” while in transit, seeming to pop out of nowhere on the exit side of the tube, the researchers report today (Aug. 20) in the journal Scientific Reports.

“From a magnetic point of view, you have the magnetic field from the magnet disappearing at one end of the wormhole and appearing again at the other end of the wormhole,” Prat told Live Science.

Broader applications

There’s no way to know if similar magneticwormholes lurk in space, but the technology could have applications on Earth, Prat said. For instance, magnetic resonance imaging (MRI) machines use a giant magnet and require people to be in a tightly enclosed central tube for diagnostic imaging.

But if a device could funnel a magnetic field from one spot to the other, it would be possible to take pictures of the body with the strong magnet placed far away, freeing people from the claustrophobic environment of an MRI machine, Prat said.

To do that, the researchers would need to modify the shape of their magnetic wormhole device. A sphere is the simplest shape to model, but a cylindrical outer shell would be the most useful, Prat said.

“If you want to apply this to medical techniques or medical equipment, for sure you will be interested in directing toward any given direction,” Prat said. “A spherical shape is not the most practical geometry.”

Mother Earth weeps as Arctic Circle ice cap slides into the sea | Don’t believe in global warming? Watch!

Image credit:Jason Roberts, BBC-Cracked surface: The largest ice cap in the Eurasian Arctic – Austfonna in Svalbard -

The Austfonna ice cap is located in northeastern Svalbard within the arctic circle north of Scandinavia. “Roughly  28% of the ice cap bed lies below sea level and over 200 km of its southern and eastern margin terminates in the ocean [Dowdeswell, 1986; Dowdeswell et al., 2008], with parts resting on a retrograde slope.”

Like most glaciers that terminate at the sea, warm water from the Atlantic is making its way north to the Arctic ocean (including Berants sea) where the warmth helps to melt the underside of the glacier which in turn causes thinning resulting in rapid retreat. This process is also exacerbated by melt water and bedrock warming.  This is changing the flow dynamics of the glacier.

The Earth Story describes the dynamic change as follows:

This glacier appears to have come ungrounded, flowing out to sea at a rapid pace and draining ice from the ice cap in the process. The ice cap is now thinning by an average of 25 meters per year.

 The waters of the Arctic Ocean have warmed at a rapid pace relative to the rest of the world over recent years, and 2012 in particular was a year of exceptional melting and warmth in the arctic due to some extreme storms. The sudden movement in this glacier suggests that this pulse of heat has helped destabilize glaciers in the surrounding territory and it is happening at an exceptionally rapid pace.

The technical study concludes:

To date, the observed dynamical imbalance has propagated 50 km inland to within 8 km of the ice cap summit, producing widespread ice loss to the ocean. Currently, the glacier terminus rests on a broadly undulating bed; however, farther inland the bed deepens, providing the potential for future instability if further ungrounding occurs [Schoof, 2007]. The imbalance could have been triggered by a number of processes, including an internally generated surge, increased meltwater availability at the bed [Dunse et al., 2014], or enhanced ocean- or atmosphere-driven melting at the terminus; indeed, a combination of factors may have contributed [Nick et al., 2009; Jenkins, 2011]. Across Austfonna, however, there is a coherent pattern of ice margin thinning at all marine-based sectors, which is not apparent at land-terminating basins (Figure 1). This may suggest either a common ocean forcing or the influence of bed conditions specific to marine settings. Additional evidence of anomalously warm waters offshore [Polyakov et al., 2005, 2013] and insignificantly increased atmospheric melting in recent years leads us to favor the former mechanism, rather than one linked to increased melt water delivery to the bed, although a definitive link would require dynamical modeling and measurements at the calving front. Until then, it is unclear whether the moderate rates of thinning of other marine ice sectors are a prelude to similar widespread mass loss in these areas, or whether the large dynamical imbalance at basin 3 will be sustained over time. Nonetheless, the behavior recorded here demonstrates that slow-flowing ice caps can enter states of significant imbalance over very short timescales and highlights their capacity for increased ice loss in the future.

This video is from Chasing Ice where Adam LeWinter and Director Jeff Orlowski filmed a historic breakup at the Ilulissat Glacier in Western Greenland. Though not Austfonna, we get the idea of what is happening to our glaciers worldwide.

Christian group to schools: Stop filling kids’ heads with dinosaurs

Technically Incorrect: Insisting that dinosaurs are a 19th century invention and caused one child to become ‘bestially-minded,’ Christians Against Dinosaurs posts its displeasure on a popular parenting site. But surely this is satire.

cad89.jpg
Is the Ark To Salvation self-steering? I do hope so

There are few things more amusing than prehistoric views about prehistory.

I have been woken several times over the last couple of days with rumblings and tremblings about a group that has publicly questioned the very existence of dinosaurs and railed against the bestialization of our children by teaching them dinosaur lore in schools.

The group in question is called Christians Against Dinosaurs. Those of a coarsely waggish nature might suggest that Christians ought not be against dinosaurs, given some of the archaic beings that run certain of the Christian branches.

I cannot begin to debate that, as I’m too busy giggling at some of this group’s postings on the popular parenting site Mumsnet.

These people are for real! Can you believe it?!?

A classic was headlined: “I’m getting sick and tired of dinosaurs being forced on our children.” Its author, claiming to represent the Christians Against Dinosaurs Ministry, exclaimed: “I for one do not want my children being taught lies. Did you know that nobody had even heard of dinosaurs before the 1800s, when they were invented by curio-hungry Victorians?”

The poster goes on to explain that Darwin’s Theory of Evolution “entirely disproved dinosaurs.” Worse that that, though: “Dinosaurs are a very bad example for children. At my children’s school, several children were left in tears after one of their classmates (who had evidently been exposed to dinosaurs), became bestially-minded and ran around the classroom roaring and pretending to be a dinosaur. Then he bit three children on the face.”

This caused a furor. The Huffington Post revealed that the poster had been thrown off Mumsnet for this scientific heresy.

Being of sanguine mind and chilly heart, I tried to investigate this group further. It has a Facebook page, where more than 8,000 claim to be members. It has a Twitter feed, with a mere 194 followers.

And then there are the YouTube videos. The most pulsating is one in which a presenter attempts to convince the world that the first fossil ever found was much later than when the first “idea” of a dinosaur was conceived. She insisted that paleontologists were just tools of a system.

To many ears, this may seem like bilge, but bilge designed to entertain. To my eyes, the woman presenting her argument could barely keep a straight face.

So I contacted the Christians Against Dinosaurs Twitter feed and asked who was its leader and was this all a joke. I received this reply: “We do not have a leader, we are a collective.” I was told this is most definitely not a joke.

Unlike many Christian groups, this one doesn’t seem to talk about God very much. At least not in its video.

I was informed by the group, however, that its aim to “respect Jesus and see through the various dinosaur deceptions.” The woman presenting the video is Kristen Auclair, whose Facebook page claims that she lived in Southbridge, Mass.

A LinkedIn profile for the same name, city and similar profile picture says she’s a commercial insurance account executive. It makes no mention of her antipathy toward dinosaurs. So she’ll insure any old CEO, then.

I was encouraged to join the group to see what it was all about. I made a request, which was approved by someone called Kate (she asked me to withhold her last name.) She told me she is an actor in the UK.

I could not find her among Auclair’s list of Facebook friends. I did, however, find Brontosaurus Rex (seriously).

We all know this? How do we all know this? I wasn’t aware that all of us knew anything at all. That’s just one of the amusements of life.

Still, the group’s welcome message concludes that it’s “a nice group to celebrate Gods wisdom in denying the existing of dinosaurs!”

This nice group says it plans a protest at Ken Ham’s Creation Museum in Kentucky. The date is as yet undetermined. The announcement of the protest was made by Amy Pavlovich, whose Facebook pageclaims that “hearts are for sissies.” And Happy Valentine’s Day to you, madam.

I contacted both Kate and Auclair to ask for further details of their involvement in what to some might seem a joke (of one kind) and to others a joke (of another kind).

“I assure you we are serious about our beliefs,” Kate explained. “The core members all follow Jesus’ teachings but, as I’m sure you’ve seen, since the recent publicity we have been swamped by a larger than usual number of ‘trolling, and people who seem to have joined just to mock.”

How, though, did she get involved in all this? She told me: “I got involved through a family member who worked in the palaeontological field and, as they rose up the ranks and more and more dodgy goings on were revealed their suspicions were aroused and further research ensued.”

She claimed she is still learning. However, one thing she has learned is that “the Museum Industry Complex are ruthless.” But can she change minds? “We already have,” she said.

Auclair confirmed that she had a child and was in insurance sales. She told me that not too many people in Massachusetts share her beliefs.

About the group, she said: “I only hope that it serves as an outlet for others too afraid to speak out about their doubts in the field of paleontology. It is healthy to question the world around us and not just take the word of science as gospel.”

She added: “I personally think that the reaction thus far has been a little crazy. Lol. An influx of Reddit people has made the group a little tougher to handle. I know I’m just trying to get my bearings together to handle the onslaught of berating messages and absolute vitriol flying from these people.”

Welcome to the Web, Kristen.

So remember, kids, fossils are just fossils. They’re not bits of old dinosaurs. Unless, oh, they are. Either way children, please don’t be beastly.

Laser pulse shooting through a bottle and visualized at a trillion frames per second | Amazing!

<a href="/channel/UC9ub18cYyrwIZ0kYTFOcFKQ" class=" yt-uix-sessionlink     spf-link  g-hovercard" data-name="" data-sessionlink="ei=0iepVKWyKYrpctb9ghg" data-ytid="UC9ub18cYyrwIZ0kYTFOcFKQ">cameraculturegroup</a>

And here is how it is done!

We have built an imaging solution that allows us to visualize propagation of light at an effective rate of one trillion frames per second. Direct recording of light at such a frame rate with sufficient brightness is nearly impossible. We use an indirect ‘stroboscopic’ method that combines millions of repeated measurements by careful scanning in time and viewpoints.

The device has been developed by the MIT Media Lab’s Camera Culture group in collaboration with Bawendi Lab in the Department of Chemistry at MIT. A laser pulse that lasts less than one trillionth of a second is used as a flash and the light returning from the scene is collected by a camera at a rate equivalent to roughly 1 trillion frames per second. However, due to very short exposure times (roughly one trillionth of a second) and a narrow field of view of the camera, the video is captured over several minutes by repeated and periodic sampling.

For more info visit http://raskar.info/trillionfps
http://femtophoto.info
http://www.nytimes.com/2011/12/13/sci…
http://web.mit.edu/newsoffice/2011/tr…
http://cornar.info
http://www.slideshare.net/cameracultu…

Music: “Rising” by Kevin MacLeod (http://music.incompetech.com/royaltyf…)

In 1911, Albert Einstein Told Marie Curie To Ignore The Trolls:One smart Dude, Einstein!

In 1911, Albert Einstein Told Marie Curie To Ignore The Trolls

On Friday, a digitized trove of Albert Einstein’s writings and correspondence was made available online. While perusing the collection, astrobiologist David Grinspoon found a letter addressed from Einstein to famed physicist, chemist, and two-time Nobel-Laureate, Marie Curie. That letter’s gist? Ignore the trolls.

The translated letter, originally dated November 23, 1911, appears below:

In 1911, Albert Einstein Told Marie Curie To Ignore The Trolls

Moon’s molten, churning core likely once generated a dynamo

Moon’s molten, churning core likely once generated a dynamo

New magnetic measurements of lunar rocks have demonstrated that the ancient moon generated a dynamo magnetic field in its liquid metallic core (innermost red shell). This dynamo may have been driven by convection, possibly powered by …more

Read more at: http://phys.org/news/2014-12-moon-molten-churning-core-dynamo.html#jCp

When the Apollo astronauts returned to Earth, they brought with them some souvenirs: rocks, pebbles, and dust from the moon’s surface. These lunar samples have since been analyzed for clues to the moon’s past. One outstanding question has been whether the moon was once a complex, layered, and differentiated body, like the Earth is today, or an unheated relic of the early solar system, like most asteroids.

Ben Weiss, a professor of planetary sciences in MIT’s Department of Earth, Atmospheric and Planetary Sciences, and members of his laboratory have found remnants of magnetization in some lunar rocks, suggesting that the moon once emitted a substantial magnetic field, much like the Earth does today. The discovery has opened a new set of questions: How long did this magnetic field last? How strong was its pull? And what sparked and sustained it?

Weiss and former MIT student Sonia Tikoo have written a review, published today inScience, in which they explore the possibility of a lunar dynamo—a molten, churning core at the center of the moon that may have powered an for at least 1 billion years. Weiss spoke with MIT News about the moon’s hidden history.

Q. How would a lunar dynamo have worked? What might have been going on in the moon, and in the , to sustain this dynamo for a billion years?

A. Planetary dynamos are generated by the process of induction, in which the energy of turbulent, conducting fluids is transformed into a magnetic field. Magnetic fields are one of the very few outward manifestations of the extremely energetic fluid motions that can occur in advecting planetary cores.

The motion of Earth’s liquid core is powered by the cooling of the planet, which stirs up buoyant fluid from the surrounding liquid—similar to what happens in a lava lamp. We have recently argued from magnetic studies of Apollo samples that the moon also generated a dynamo in its molten metal core.

Our data suggest that, despite the moon’s tiny size—only 1 percent of the Earth’s mass—its dynamo was surprisingly intense (stronger than Earth’s field today) and long-lived, persisting from at least 4.2 billion years ago until at least 3.56 billion years ago. This period, which overlaps the early epoch of intense solar system-wide meteoroid bombardment and coincides with the oldest known records of life on Earth, comes just before our earliest evidence of the Earth’s dynamo.

Q. Why is it so surprising that a lunar dynamo may have been so intense and long-lived?

A. Both the strong intensity and long duration of lunar fields are surprising because of the moon’s small size. Convection, which is thought to power all known dynamos in the solar system today, is predicted to produce surface magnetic fields on the moon at least 10 times weaker than what we observe recorded in ancient .

Nevertheless, a convective dynamo powered by crystallization of an inner core could potentially sustain a lunar for billions of years. An exotic dynamo mechanism that could explain the moon’s strong field intensity is that the core was stirred by motion of the solid overlying mantle, analogous to a blender. The moon’s mantle was moving because its spin axis is precessing, or wobbling, and such motion was more vigorous billions of years ago, when the moon was closer to the Earth. Such mechanical dynamos are not known for any other planetary body, making the moon a fascinating natural physics laboratory.

Q. What questions will the next phase of lunar dynamo research seek to address?

A. We know that the moon’s field declined precipitously between 3.56 billion years ago and 3.3 billion years ago, but we still do not know when the dynamo actually ceased. Establishing this will be a key goal of the next phase of lunar magnetic studies.

We also do not know the absolute direction of the lunar field, since all of our samples were unoriented rocks from the regolith—the fragmental layer produced by impacts on the lunar surface. If we could find a sample whose original orientation is known, we could determine the absolute direction of the lunar field relative to the planetary surface. This transformative measurement would then allow us to test ideas that the‘s spin pole wandered in time across the planetary surface, possibly due to large impacts.

Creationist Fail: Michigan State scientists and philosophers refuse to engage creationists

A student-sponsored conference, on Creationism has failed, Why? Read on. We at Notoriously White believe, the best way to deal with Creationists, and the way they try and argue their way threw science, is just not to meet them, that is not to say that we are afraid to debate them, but it is just better to leave these nut cases alone, with there own people, people who are somehow incapable of understanding the truth about science! Thanks to The Richard Dawkins Foundation for this article.

This is a good example of how scientists and science-lovers should deal with creationists. And that is not to deal with them, at least in debates and meetings.

A while back, religious students at Michigan State University announced that they would hold a one-day “Origin Summit,” a meeting about creationism at a public university. That was legal because the summit was actually organized by a student religious group (The Baptist Collegiate Ministry), which has the right to book rooms on campus for its own activities. According to a piece by Mark Joseph Stern in Slate, though, the students didn’t have much to do with the conference, which was organized by Outside Influences. (Could it be. . . . Satan?)

Here we see the speakers, and the workshops they were involved in.

Screen Shot 2014-11-04 at 5.44.41 AM

The Origin Summit“‘s speakers and program are shown below; note the distinguished lineup. Sadly, I have never heard of any of these scientists or science educators.

That’s a rather pugnacious program, and includes attacks on the Big Bang (really?) and on Rich Lenski’s well-known experiments on bacterial evolution. They also played the Hitler Card, i.e., Hitler’s genocides were strongly influenced by Darwin’s theory of evolution. (For the definitive refutation of that ridiculous canard, see my colleague Bob Richards’s essay, “Was Hitler a Darwinian?“, free online. Hint: the answer is “no.”)

What the creationists really wanted was a debate, in particular a debate with MSU philosophy professor Rob Pennock, a well-known opponent of intelligent design and author of what I think is the best anti-ID book,Tower of Babel. Pennock also testified for the prosecution in the famous Kitzmiller et al. v. Dover Area School District et al. case, a case in which ID was resoundingly trounced as “not science.”

Pennock wouldn’t bite, and good for him. As Slate reports:

The summit’s website asks whether Pennock’s arguments can “withstand the scrutiny of debate” and suggests that he’s too cowardly to stand up for evolution.

The summit had one thing right: Pennock refused to respond to its request. But it wasn’t out of timorousness.

“Scientists have already shown that there is no substance worth debating in these old creationist challenges to evolution,” he told me. Evolution is fact, creation is fiction, and there’s just no point in pretending like there’s a real scientific debate between reality and fantasy. I asked Pennock whether he was alarmed by the conference.

“It’s a sign of how desperate creationists have become,” he said. “[T]hey have to make schoolyard bully taunts, blame evolution for Hitler, and raffle a free iPad (‘Must be present to win’) to try to create a controversy and draw an audience.”

The rest of the Michigan State scientists also refused to engage, though of course they were peeved that such a stupid event could take place on a respectable campus. But it’s the Baptists, Jake!

Thwarted in their attempt to validate the conference with a debate, the summit leaders might at least have hoped for an attention-grabbing outcry among scientists at the school. There, too, they were foiled. Once MSU’s science professors caught wind of the event, they collectively decided to ignore the conference and refuse requests for comment. (Indeed, no professor would speak to me until I promised not to publish a story before the summit occurred.) The summit leaders were counting on the school’s scientists to criticize the conference and give them free publicity. So the scientists kept their mouths shut.

Kudos to my colleagues at MSU! The only pushback by Team Science was a pro-evolution table at the conference organized by some students.  But faculty resolutely refused to either engage or attend. In the end, it wasn’t much of a win for the creationists:

The summit’s leaders were expecting an uproar, but MSU’s scientists, unlike Bill Nye, refused to take the bait. To debate creationism and evolution, they realized, was to imply that evolution is plausibly disputable. To ignore creationist calls for debate, on the other hand, relegates the theory to lowest rung of evangelical pseudoscience, where it so obviously belongs.

Ultimately, thanks to the university’s emphatic silence, the conference drew fewer than 100 attendees, according to Baskett—only about one-third of whom appeared to be younger than 30. There were no debates or shouting matches, and the creationists were, by all accounts, gracious and civil. A handful of MSU students sat in out of pure curiosity, Pennock told me, including a resolutely pro-science graduate student who studies evolutionary microbiology. At the end of the event, the student won the iPad raffle.

“Chance?” Pennock asked, “or a sign from above? You be the judge.”

My advice to all, and that included Bill Nye, who I think erred in debating Ken Ham, is to not engage creationists on a public platform, and that means in conferences or debates. Issues like the worthlessness of creationism are not decided by rhetoric, but by thoughtful contemplation. I fight creationism not by talking to its advocates in public, which only gives them credibility, but by criticizing their ideas in articles and book reviews, which can be read at leisure. But I do this as little as possible, and only when they’ve said something that, I think, needs rebutting. My strongest critique of creationism was not in fact a critique, but an exposition of the massive and irrefutable evidence for evolution, laid out in WEIT.

As this country becomes more secular, creationism will disappear of its own accord, for its umbilical cord is religion. There are virtually no creationists who aren’t motivated by religious origin tales, and when those tales lose credibility (granted, it will take a long time), creationism will no longer be with us. The IDers and creation-mongers know this, so they try to pump life into their movement by seeking the credibility and visibility of debates with scientists.

Don’t engage them, at least in person.

 

Humans And Neanderthals Interbred, 36,000-Year-Old Genome Reveals

skull

A genome taken from a 36,000-year-old skeleton has helped scientists shed new light on interbreeding between humans and Neanderthals. The ground-breaking study of DNA recovered from a fossil of one of the earliest known Europeans – a man who lived in western Russia – shows that the genetics of the earliest inhabitants of the continent survived the last ice age, helping form the basis of the modern-day population.

Known as the Kostenki genome, the DNA also contained evidence the man shared, as with all people of Eurasia today, a small percentage of Neanderthal genes, confirming previous findings which show a period when Neanderthals and the first humans to leave Africa for Europe briefly interbred.

This means that, even today, anyone with a Eurasian ancestry – from Chinese to Scandinavian and North American – has a small element of Neanderthal DNA. But despite Western Eurasians going on to share the European landmass with Neanderthals for another 10,000 years, no further periods of interbreeding occurred, the study said.

Robert Foley, a University of Cambridge professor, said: “Were Neanderthal populations dwindling very fast? Did modern humans still encounter them? We were originally surprised to discover there had been interbreeding. Now the question is, why so little? It’s an extraordinary finding that we don’t understand yet.”

The Ancient skull from which the genome was taken that helped scientists shed new light on interbreeding between humans and Neanderthals

Lead author Eske Willerslev said the work revealed the complex web of population relationships in the past, generating for the first time a firm framework with which to explore how humans responded to climate change, encounters with other populations, and the dynamic landscapes of the ice age.

Led by the Centre for GeoGenetics at the University of Copenhagen, the study was conducted by an international team of researchers from institutions including the University of Cambridge’s departments of archaeology and anthropology, and zoology.

Scientists now believe Eurasians separated into at least three populations earlier than 36,000 years ago. Western Eurasians, East Asians and a mystery third lineage, all of whose descendants would develop the unique features of most non-African peoples – but not before some interbreeding with Neanderthals took place.

The new study allows scientists to closer estimate this as occurring around 54,000 years ago, before the Eurasian population began to separate. By cross-referencing the ancient man’s complete genome – the second oldest modern human genome ever sequenced – with previous research, the team discovered a surprising unity running from the first modern humans in Europe, suggesting that a “meta-population” of hunter-gatherers with deep shared ancestry managed to survive through the last ice age and colonise the landmass of Europe for more than 30,000 years.

While the communities within this population expanded, mixed and fragmented, this was a “reshuffling of the same genetic deck”, researchers said. European populations as a whole maintained the same genetic thread from their earliest establishment out of Africa until Middle Eastern populations arrived in the last 8,000 years, bringing with them agriculture and lighter skin colour.

Marta Mirazon Lahr, from Cambridge University’s Leverhulme Centre for Human Evolutionary Studies, said: “That there was continuity from the earliest Upper Palaeolithic to the Mesolithic, across a major glaciation, is a great insight into the evolutionary processes underlying human success.

“For 30,000 years, ice sheets came and went, at one point covering two-thirds of Europe. Old cultures died and new ones emerged – such as the Aurignacian and the Grevettian – over thousands of years, and the hunter-gatherer populations ebbed and flowed. But we now know that no new sets of genes are coming in: these changes in survival and cultural kit are overlaid on the same biological background.

“It is only when farmers from the Near East arrived about 8,000 years ago that the structure of the European population changed significantly.”

 

The birth of a planet: Astronomers hail unprecented

‘Baby picture’ that could reveal the origin of the solar system’

You’d be forgiven for thinking this incredible picture is an artist’s impression of a planet forming around a star.

But it is in fact the most detailed real image of a planet’s birth ever taken, revealing a phenomenon astronomers could only theorise about a few decades ago – and one that could help explain how the solar system formed.

The planet-forming disc surrounds HL Tau, a sun-like star around 450 light-years from Earth in the constellation Taurus.

Pictured is the best image ever of planet formation revealing multiple rings and gaps that herald the presence of emerging planets as they sweep their orbits clear of dust and gas

Pictured is the best image ever of planet formation revealing multiple rings and gaps that herald the presence of emerging planets as they sweep their orbits clear of dust and gas

The image was taken as part of the testing and verification process for the Atacama Large Millimeter/submillimeter Array’s (Alma) new high-resolution capabilities.

Alma, located in Chile, uncovered never-before-seen features in this system, including multiple concentric rings separated by clearly defined gaps.

An artist's impression of a planet-forming disc. Newly formed planets can be seen traveling around the central host star, sweeping their orbits clear of dust and gas. These same ring-link structures were observed recently by ALMA around the young star HL Tau

An artist’s impression of a planet-forming disc. Newly formed planets can be seen traveling around the central host star, sweeping their orbits clear of dust and gas. These same ring-link structures were observed recently by ALMA around the young star HL Tau

All stars are believed to form within clouds of gas and dust that collapse under gravity.

Over time, the surrounding dust particles stick together, growing into sand, pebbles, and larger-size rocks, which eventually settle into a thin protoplanetary disk where asteroids, comets, and planets form.

Once these planetary bodies have enough mass, they dramatically reshape the structure of their natal disk.

THE SECRET TO THE SUCCESS OF ALMA – HEIGHT AND DISTANCE

Alma's highest receivers sit on a plateau some 16,500ft (5,000 metres) above sea level.

Alma’s highest receivers sit on a plateau some 16,500ft (5,000 metres) above sea level.

The secret to Alma’s incredible resolution comes from two factors: height and distance.

The observatory’s highest receivers sit on a plateau some 16,500ft (5,000 metres) above sea level.

This is far above most of Earth’s atmosphere and water vapour, which obscures observations. Astronomers working in Alma’s facility at 9,500 feet (2,900 meters) must use supplemental oxygen for extended stays.

The system currently comprises about 50 functional antennas. When the array is finished, there will be 66 of these receivers that can be moved as far as 16km (9.9m) apart.

The antennae capture astronomical signals from the sky individually, then combine their results in a supercomputer to get precise information about where the signals come from.

Researchers say it is similar to how we use our two ears to locate sounds around us, but on a universe-size scale.

This high-resolution not only lets Alma observe young planetary systems, but also pin down hydrogen and life-building blocks in gas clouds. The array can also track the evolution of galaxies.

They fashion rings and gaps as the planets sweep their orbits clear of debris and shepherd dust and gas into tighter and more confined zones.

The new Alma image reveals these striking features in exquisite detail, providing the clearest picture to date of planet formation.

Its new high-resolution capabilities were achieved by spacing the antennas up to 9.3 miles (15km) apart.

HL Tau’s surroundings, as seen by Hubble. HL Tau is a sun-like star around 450 light-years from Earth 

HL Tau’s surroundings, as seen by Hubble. HL Tau is a sun-like star around 450 light-years from Earth

Final antenna is added to Alma array to help explore the cosmos

Images with this level of detail were previously only seen in computer models and artist concepts.

‘This new and unexpected result provides an incredible view of the process of planet formation,’ said Tony Beasley, director of the National Radio Astronomy Observatory (NRAO).

HL Tau is hidden in visible light behind a massive envelope of dust and gas. Since Alma observes at much longer wavelengths, it is able to peer through the intervening dust to study the processes right at the core of this cloud.

This is an artist’s impression of a young star surrounded by a protoplanetary disc in which planets are forming

This is an artist’s impression of a young star surrounded by a protoplanetary disc in which planets are forming

‘This is truly one of the most remarkable images ever seen at these wavelengths,’ said NRAO astronomer Crystal Brogan.

‘The level of detail is so exquisite that it’s even more impressive than many optical images.

‘The fact that we can see planets being born will help us understand not only how planets form around other stars but also the origin of our own solar system.’