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Sat, 10 Dec 2016
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Better Earth

Earth may have largest ripples in the solar system

They may look like low dunes, but the cresting ridges on Argentina's Puna Plateau are the world's largest "megaripples". Geological features of this size had been thought impossible on Earth.

Wind-formed ripples are not the same as dunes because they are shaped by the airflow less than 2 metres above the ground. The key factor for dunes is air fluctuations as high as 4 kilometres up.

Most such ripples are no bigger than those created by waves on a beach. Given high winds, light grains and geologic timescales, however, they can grow.


Does a Shower of Subatomic Positrons Mean We've Found Dark Matter?

The mysterious stuff known as dark matter may have left a calling card at the edge of the Earth's atmosphere where a space-faring satellite named PAMELA could pick it up. Researchers are reporting that PAMELA detected a high number of the subatomic particles called positrons, the positively-charged counterpoints to electrons, which could have been created by collisions between dark matter particles. "PAMELA found a number of positrons much higher than expected," the mission's principal investigator Piergiorgio Picozza [said]. "Many think this could be a signal from dark matter" [SPACE.com]. But of course, others think there's a more mundane explanation.


Titan's squashed shape hints at soggy interior

© NASA/JPL/Space Science Institute
Titan may look like a sphere, but radar studies by the Cassini probe show it is slightly squashed.
Saturn's moon Titan is surprisingly non-spherical, suggesting it may hide vast reserves of liquid methane beneath its surface, according to a new study.

Titan is 5150 kilometres across, making it larger than Mercury and only slightly smaller than the largest moon in the solar system, Jupiter's Ganymede.

By bouncing radar signals off the moon's smog-enshrouded surface, the Cassini spacecraft has now measured Titan's shape precisely for the first time.

"What we have are the first actual measurements showing that Titan's not an exact sphere - this distorted egg-shaped thing best fits the observed shape," study leader Howard Zebker of Stanford University told New Scientist.


Jupiter's Stormy Great Red Spot is Shrinking

NASA's Cassini spacecraft photographed Jupiter and its Great Red Spot, seen center near the equator, in 2000.
Everything about Jupiter is super-sized, including its colorful, turbulent atmosphere. But there's fresh evidence that one of the planet's most recognizable features, the Great Red Spot, is shrinking.

The spot, which is actually an ancient monster storm that measures about three Earths across, lost 15 percent of its diameter between 1996 and 2006, scientists at the University of California, Berkeley, have found.

It shrank by about 1 kilometer (about 0.6 miles) a day during that time period, said Xylar Asay-Davis, a postdoctoral researcher who was part of the study.


"Type A" Personalities Have the Edge in Procreating

© Rick Gomez / Corbis
Type A family
Throughout most of human history, you didn't get some unless you had some. More precisely: it was wealthy, powerful men who scored the most sexual mates and, therefore, fathered the most offspring. Men with less wealth and low standing, meanwhile, died disproportionately childless. (As for women, they had little choice about sex regardless of status, since men treated them as property.)

Many evolutionary scientists believe that those thousands of years of human behavior are no artifact: modern men still strive for status partly because it is an evolutionary advantage for improving reproductive success. But other researchers have disputed that theory by citing data showing that wealthier, higher-status men do not in fact have more children than their less moneyed, lower-status peers. (See pictures of Barack Obama's family tree.)

Now a new study in the Journal of Personality offers another theory: it is not necessarily wealth that facilitates procreation but a more basic and deeply ingrained evolutionary trait - having a Type A personality. The study finds that adolescents who say they always take charge, tell others what to do, anger quickly, get into fights easily, and walk, talk and eat fast end up having more kids than others when they grow up. That's true regardless of the kids' performance in school.


Hidden Planet Discovered in Old Hubble Data

© NASA, ESA, and G. Bacon (STScI)
This is an artistic illustration of the giant planet HR 8799b. The planet was first discovered in 2007 at the Gemini North observatory. The planet is young and hot, at a temperature of 1500 degrees Fahrenheit. It is slightly larger than Jupiter and may be 10 times more massive.
A new technique has uncovered an extrasolar planet hidden in Hubble Space Telescope images taken 11 years ago. The new strategy may allow researchers to uncover other distant alien worlds potentially lurking in over a decade's worth of Hubble archival data.

The method was used to find an exoplanet that went undetected in Hubble images taken in 1998 with its Near Infrared Camera and Multi-Object Spectrometer (NICMOS). Astronomers knew of the planet's existence from images taken with the Keck and Gemini North telescopes in 2007 and 2008, long after Hubble snapped its first picture of the system.

The planet is estimated to be at least seven times the mass of Jupiter. It is the outermost of three massive planets known to orbit the dusty young star HR 8799, which is 130 light-years away from Earth. NICMOS could not see the other two planets because its coronagraphic spot - a device that blots out the glare of the star - blocked its viewof the two inner planets.

Light Saber

World's largest laser built in California

© Unknown
The U.S. Department of Energy says the National Nuclear Security Administration has certified the completion of the world's largest laser. Located at the Lawrence Livermore National Laboratory's National Ignition Facility in California, the laser is expected to allow scientists to achieve fusion ignition in the laboratory, obtaining more energy from the target than is provided by the laser.

"Completion of the National Ignition Facility is a true milestone that will make America safer and more energy independent by opening new avenues of scientific advancement and discovery," said NNSA Administrator Thomas D'Agostino. "NIF will be a cornerstone of a critical national security mission, ensuring the continuing reliability of the U.S. nuclear stockpile without underground nuclear testing, while also providing a path to explore the frontiers of basic science and potential technologies for energy independence."


ESA space debris conference begins

© Unknown
The European Space Agency is the host for the Fifth European Conference on Space Debris through Thursday at its Space Operations Center in Darmstadt, Germany. The ESA said the conference, which began Monday, is the largest dedicated event on space debris issues. It is co-sponsored by the British, French, German and Italian space agencies, the Committee on Space Research and the International Academy of Astronautics.

"Space debris has recently been attracting increasing attention not only due to the growing recognition of the long-term need to protect the commercially valuable low-Earth and geosynchronous orbital zones but also due to the direct threat that existing debris poses to current and future missions," the ESA said. "While commercial and scientific uses of space have expanded across a wide range of activities, including telecommunications, weather, navigation, Earth observation and science, space debris has continued to accumulate, significantly threatening current and future missions."


What would it look like to fall into a black hole?

Falling into a black hole might not be good for your health, but at least the view would be fine. A new simulation shows what you might see on your way towards the black hole's crushing central singularity. The research could help physicists understand the apparently paradoxical fate of matter and energy in a black hole.

Andrew Hamilton and Gavin Polhemus of the University of Colorado, Boulder, built a computer code based on the equations of Einstein's general theory of relativity, which describes gravity as a distortion of space and time.


Conficker virus could be deadly threat - or April Fool's joke

© Unknown
It could be the biggest April Fool's joke ever played on the internet, or it could be one of the worst days ever for computers connected to the network. Security experts can't work out whether the Conficker virus - which has infected more than 10m Windows PCs worldwide - will wreak havoc on Wednesday , or just let the day pass quietly.

Experts have worked out that from midnight on 1 April, the Conficker program will start scanning thousands of websites for a new set of instructions telling it what to do next. The infected machines thus comprise one of the biggest "botnets" - a network of "robot" computers - in internet history. And if they were all given a target, such as simultaneously sending search queries to Google or trying to connect to a gambling site, they could knock it offline through the sheer volume of connections - a "denial of service". Victims usually discover that they have been locked out of their computers or have very slow-running internet connections.