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Posts Tagged ‘science

[LINK] “An Ancient Volcanic Cataclysm Spun Mars Off Its Poles”

Universe Today’s Evan Gough looks at new research suggesting a catastrophic history for Mars.

According to a new research paper from Sylvain Bouley at the University of Paris-South, and his colleagues, it may have been a massive, ancient outpouring of molten rock that threw Mars off kilter and helped change Mars into what it is today.

The Tharsis region is an ancient lava complex on Mars that dates back to between 4.1 billion and 3.7 billion years ago. It’s located in Mars’ Western Hemisphere, right near the equator. It’s made up of three huge shield volcanoes—Arsia Mons, Pavonis Mons, and Ascraeus Mons. Collectively, they’re known as Tharsis Montes. (Olympus Mons, the largest volcano in the Solar System, is not a part of the Tharsis complex, though it is near it.)

Tharsis is over 5,000 km across and over 10 miles thick, making it the largest volcanic complex in the Solar System. That much mass positioned after Mars was already formed and had an established rotation would have been cataclysmic. Think what would happen to Earth if Australia rose up 10 miles.

The new paper, published on March 2nd, 2016, in the journal Nature, says that the position of the Tharsis complex would have initiated a True Polar Wander (TPW.) Basically, what this means is that Tharsis’ huge mass would have forced Mars to shift its rotation, so that the location of Tharsis became the new equator.

It was thought that the emergence of Tharsis made Martian rivers—which formed later—flow the direction they do. But the study from Bouley and his colleagues shows that Martian rivers and valleys formed first—or maybe concurrently—and that the Tharsis TPW deformed the planet later.

The authors of the study calculated where the Martian poles would have been prior to Tharsis, and looked for evidence of polar conditions at those locations. The location of this ancient north pole contains a lot of ice today, and the location of the ancient south polar region also shows evidence of water.

The Nature paper is here.

The Tharsis region is the largest volcanic complex on Mars and in the Solar System. Young lava flows cover its surface (from the Amazonian period, less than 3 billion years ago) but its growth started during the Noachian era (more than 3.7 billion years ago). Its position has induced a reorientation of the planet with respect to its spin axis (true polar wander, TPW), which is responsible for the present equatorial position of the volcanic province. It has been suggested that the Tharsis load on the lithosphere influenced the orientation of the Noachian/Early Hesperian (more than 3.5 billion years ago) valley networks and therefore that most of the topography of Tharsis was completed before fluvial incision. Here we calculate the rotational figure of Mars (that is, its equilibrium shape) and its surface topography before Tharsis formed, when the spin axis of the planet was controlled by the difference in elevation between the northern and southern hemispheres (hemispheric dichotomy). We show that the observed directions of valley networks are also consistent with topographic gradients in this configuration and thus do not require the presence of the Tharsis load. Furthermore, the distribution of the valleys along a small circle tilted with respect to the equator is found to correspond to a southern-hemisphere latitudinal band in the pre-TPW geographical frame. Preferential accumulation of ice or water in a south tropical band is predicted by climate model simulations of early Mars applied to the pre-TPW topography. A late growth of Tharsis, contemporaneous with valley incision, has several implications for the early geological history of Mars, including the existence of glacial environments near the locations of the pre-TPW poles of rotation, and a possible link between volcanic outgassing from Tharsis and the stability of liquid water at the surface of Mars.

Written by Randy McDonald

March 9, 2016 at 7:36 pm

[LINK] “Whooping cranes are pretty terrible parents. Are humans to blame?”

The Washington Post’s Karen Brulliard notes notes that a much-hyped program to help whooping crane populations recover has failed, as it turns out humans can’t teach the birds how to parent their young.

For 15 years, whooping crane chicks have been hand-raised by scientists wearing white whooping crane costumes in Maryland, shipped to Wisconsin and taught to migrate by other white-robed people, before they are led south to Florida by costumed volunteer pilots flying ultralight aircraft.

It was one of the most quirky, beloved and interventionist American conservation efforts, meant to build a migratory population of endangered whooping cranes in eastern North America without making them used to humans. This month, the final graduating class of six young birds was released — yes, by people in white costumes — at St. Marks National Wildlife Refuge in northern Florida.

The program is ending, largely because whooping cranes have turned out to be lousy parents.

“They can establish pairs, they know how to mate, they can copulate, and they know how to lay eggs,” said Peter J. Fasbender, a U.S. Fish and Wildlife Service field supervisor for Minnesota and Wisconsin. “They’re just incapable of parenting.”

In the past 11 years, the eastern population has grown to about 100 birds, but it has managed only to fledge 10 chicks. The culprit, government biologists think, is what made the program the fascination of legions of schoolchildren who followed it: the disguised people and the aircraft leading cranes. Though they never spoke to the birds and also directed them with crane puppets, Fish and Wildlife decided that humans were still too involved in teaching the cranes how to live. In January, the agency announced that this year’s would be the last ultralight-led migration.

Written by Randy McDonald

March 4, 2016 at 2:39 pm

Posted in Science

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[LINK] “Mysterious Chimpanzee Behavior May Be Evidence of “Sacred” Rituals”

The Dragon’s Tales linked to a remarkable paper, “Chimpanzee accumulative stone throwing”.

The study of the archaeological remains of fossil hominins must rely on reconstructions to elucidate the behaviour that may have resulted in particular stone tools and their accumulation. Comparatively, stone tool use among living primates has illuminated behaviours that are also amenable to archaeological examination, permitting direct observations of the behaviour leading to artefacts and their assemblages to be incorporated. Here, we describe newly discovered stone tool-use behaviour and stone accumulation sites in wild chimpanzees reminiscent of human cairns. In addition to data from 17 mid- to long-term chimpanzee research sites, we sampled a further 34 Pan troglodytes communities. We found four populations in West Africa where chimpanzees habitually bang and throw rocks against trees, or toss them into tree cavities, resulting in conspicuous stone accumulations at these sites. This represents the first record of repeated observations of individual chimpanzees exhibiting stone tool use for a purpose other than extractive foraging at what appear to be targeted trees. The ritualized behavioural display and collection of artefacts at particular locations observed in chimpanzee accumulative stone throwing may have implications for the inferences that can be drawn from archaeological stone assemblages and the origins of ritual sites.

The full paper is accessible via the link above.

One of the authors, Laura Kehoe, wrote an extended article for Scientific American.

We paused at a clearing in the bush. I let out a sigh of relief that no thorns appeared to be within reach, but why had we stopped? I made my way to the front of the group to ask the chief of the village and our legendary guide, Mamadou Alioh Bah. He told me he had found something interesting—some innocuous markings on a tree trunk. Something that most of us wouldn’t have even noticed in the complex and messy environment of a savannah had stopped him in his tracks. Some in our group of six suggested that wild pigs had made these marks, while scratching up against the tree trunk, others suggested it was teenagers messing around.

But Alioh had a hunch—and when a man that can find a single fallen chimp hair on the forest floor and can spot chimps kilometres away with his naked eye better than you can (with expensive binoculars) as a hunch, you listen to that hunch. We set up a camera trap in the hope that whatever made these marks would come back and do it again, but this time we would catch it all on film.

[. . .]

What we saw on this camera was exhilarating—a large male chimp approaches our mystery tree and pauses for a second. He then quickly glances around, grabs a huge rock and flings it full force at the tree trunk.

Nothing like this had been seen before and it gave me goose bumps. Jane Goodall first discovered wild chimps using tools in the 1960s. Chimps use twigs, leaves, sticks and some groups even use spears in order to get food. Stones have also been used by chimps to crack open nuts and cut open large fruit. Occasionally, chimps throw rocks in displays of strength to establish their position in a community.

But what we discovered during our now-published study wasn’t a random, one-off event, it was a repeated activity with no clear link to gaining food or status—it could be a ritual. We searched the area and found many more sites where trees had similar markings and in many places piles of rocks had accumulated inside hollow tree trunks—reminiscent of the piles of rocks archaeologists have uncovered in human history.

Videos poured in. Other groups working in our project began searching for trees with tell-tale markings. We found the same mysterious behaviour in small pockets of Guinea Bissau, Liberia and Côte d’Ivoire but nothing east of this, despite searching across the entire chimp range from the western coasts of Guinea all the way to Tanzania.

This, surely, is proof of chimpanzee minds.

Written by Randy McDonald

March 1, 2016 at 6:01 pm

[LINK] “Genetics reveal 50,000 years of independent history of aboriginal Australian people”

The Dragon’s Tales linked to this press release, which does indeed seem to suggest a lack of substantial Indian migration five millennia ago to Australia. It could be that, if contact with India was an issue, perhaps simple cultural diffusion was responsible. Might it also be that the reproductively successful migrants were women, not men?

The first complete sequences of the Y chromosomes of Aboriginal Australian men have revealed a deep indigenous genetic history tracing all the way back to the initial settlement of the continent 50 thousand years ago, according to a study published in the journal Current Biology today (25th February 2016).

The study by researchers from the Wellcome Trust Sanger Institute and collaborators at La Trobe University in Melbourne and several other Australian institutes, challenges a previous theory that suggested an influx of people from India into Australia around 4-5 thousand years ago. This new DNA sequencing study focused on the Y chromosome, which is transmitted only from father to son, and found no support for such a prehistoric migration. The results instead show a long and independent genetic history in Australia.

Modern humans arrived in Australia about 50 thousand years ago, forming the ancestors of present-day Aboriginal Australians. They were amongst the earliest settlers outside Africa. They arrived in an ancient continent made up of today’s Australia, Tasmania and New Guinea, called Sahul, probably thousands of years before modern humans arrived in Europe.

Five thousand years ago, dingos, the native dogs, somehow arrived in Australia, and changes in stone tool use and language around the same time raised the question of whether there were also associated genetic changes in the Australian Aboriginal population. At least two previous genetic studies, one of which was based on the Y chromosome, had proposed that these changes could have coincided with mixing of Aboriginal and Indian populations about 5 thousand years ago.

Anders Bergstrom, first author on the paper at the Wellcome Trust Sanger Institute, said: “We worked closely with Aboriginal Australian communities to sequence the Y chromosome DNA from 13 male volunteers to investigate their ancestry. The data show that Aboriginal Australian Y chromosomes are very distinct from Indian ones. These results refute the previous Y chromosome study, thus excluding this part of the puzzle as providing evidence for a prehistoric migration from India. Instead, the results are in agreement with the archaeological record about when people arrived in this part of the world.”

Written by Randy McDonald

February 29, 2016 at 5:06 pm

[BLOG] Some Saturday links

  • Dangerous Minds shares one video club of David Bowie in London in 1967, and another of the controversies around the Cocteau Twins in 1985 Ohio.
  • The Dragon’s Gaze notes a study of the winds of hot Jupiter HD 189733b.
  • The Dragon’s Tales looks at the evolution of Titan’s atmosphere from an early date.
  • Joe. My. God. and Towleroad each note the failure of PrEP to protect a Toronto man against infection.
  • Language Hat links to a study looking at the spread of Austronesian languages.
  • Marginal Revolution writes on the economics, and the culture, of used book sales.
  • The NYRB Daily notes the problems with staging Wagner.
  • Savage Minds shares a list of new ethnographic texts.
  • Torontoist examines how Ontario’s cap and trade and other green initiatives could impact Toronto.
  • Towleroad and Joe. My. God. note the Australian government’s belated apology for the repression of gay demonstrators in Sydney in 1978, during the first Mardi Gras.
  • Window on Eurasia writes about the reasons for the support of diasporic Russian Jews for Putin’s Russia and notes the Russian government’s hostility towards open regionalism on its borders.
  • Arnold Zwicky shares and dissects a Japanese-style poem of his.

[LINK] “Fossil Fuels Just Lost the Race Against Renewables”

Bloomberg’s Tom Randall makes the point that renewables, now competitive against oil, are set to displace oil.

The race for renewable energy has passed a turning point. The world is now adding more capacity for renewable power each year than coal, natural gas, and oil combined. And there’s no going back.

The shift occurred in 2013, when the world added 143 gigawatts of renewable electricity capacity, compared with 141 gigawatts in new plants that burn fossil fuels, according to an analysis presented Tuesday at the Bloomberg New Energy Finance annual summit in New York. The shift will continue to accelerate, and by 2030 more than four times as much renewable capacity will be added.

“The electricity system is shifting to clean,” Michael Liebreich, founder of BNEF, said in his keynote address. “Despite the change in oil and gas prices there is going to be a substantial buildout of renewable energy that is likely to be an order of magnitude larger than the buildout of coal and gas.”

The price of wind and solar power continues to plummet, and is now on par or cheaper than grid electricity in many areas of the world. Solar, the newest major source of energy in the mix, makes up less than 1 percent of the electricity market today but could be the world’s biggest single source by 2050, according to the International Energy Agency.

Will it? What about other sources, like nuclear?

Written by Randy McDonald

February 23, 2016 at 6:41 pm

[BLOG] Some Sunday links

  • Centauri Dreams considers gravitational waves.
  • Discover‘s D-Brief notes our Neanderthal genetic legacy.
  • The Dragon’s Gaze looks at an inflated hot Neptune.
  • The Dragon’s Tales considers how much sulfur dioxide Mars had.
  • Joe. My. God. notes Dan Savage’s criticism of Log Cabin Republicans.
  • Marginal Revolution considers ways to be happy.
  • The Planetary Society Blog looks at Ok Go’s new zero-gravity music video.
  • pollotenchegg notes trends in urban population growth in Ukraine, the Donbas faring particularly badly.
  • The Power and the Money’s Noel Maurer wonders, after Ross Douthat, about the durability of stereotypes of American militarism and European pacifism.
  • Strange Maps notes a map of xenophobia, tracking rumours.
  • Torontoist notes that Drake got the keys to the city of Toronto.
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