Σάββατο 26 Μαρτίου 2016
Secretary Kerry, With Belgian Prime Minister Michel and Foreign Minister Reynders, Delivers a Statement to the Media in Brussels
Unmanned Undersea Vehicles Can Wander the Oceans for 6 Months
Unmanned Undersea Vehicles Can Wander the Oceans for 6 Months
Photo: Boeing
As far as locales go, the bottom of the ocean is a particularly exasperating place to explore. Anyone or anything you send down there has to contend with the dark, with thousands of pounds of pressure on every square inch, with the inability to replenish fuel supplies without returning to the mother ship.
In recent years, unmanned undersea vehicles (UUVs) have improved the situation, eliminating the need to send a human down below, or to attach an unmanned vessel to a surface ship with a long umbilical cord. Those include Boeing’s Echo Ranger and Echo Seeker underwater robots, which can spend a few days at at time below the surface, with ranges measured in the tens or hundreds of miles. That’s progress, but it’s not enough to emancipate the UUV from the need for a nearby surface ship with a human crew, which piles on costs.
Japan Killed More Than 300 Whales in the Southern Ocean
Japan Killed More Than 300 Whales in the Southern Ocean
Photo: Customs and Border Protection, Commonwealth of Australia
Japan has confirmed that more than 300 whales, including 200 pregnant females, were slaughtered in the country’s latest whaling mission in the Southern Ocean.
The kill was confirmed by Japan’s Institute of Cetacean Research as its ships returned from their “scientific” expedition in the Antarctic region on Thursday.
Four ships were sent to the Antarctic region over a period of 115 days from 1 December last year and killed 333 minke whales.
Japan’s actions are in defiance of international criticism and despite a 2014 UN legal decision that ruled so-called scientific whaling activity in the Southern Ocean was a front for commercial hunts.
Darren Kindleysides, the director of the Australian Marine Conservation Society, said the 2014/15 summer was the first time in 70 years Japan had stopped its whaling program – but the break was short-lived.
He said Australia’s leading international experts had examined Japan’s new so-called scientific research program this year and found it was also a guise for killing whales and a breach of international law.
Παρασκευή 25 Μαρτίου 2016
How the Moon Moved (βρισκομαστε σε πορεια συγκρουσης με την σεληνη;)
How the Moon Moved: Lunar Poles Have Wandered
By Mike Wall, Space.com Senior Writer | March 23, 2016 02:01pm ET
The moon's poles have shifted over the eons, likely as a result of geological activity beneath the lunar crust, a new study suggests.
This finding — which is based on an analysis of the distribution of water ice near the lunar north and south poles — sheds light on the structure and evolution of the moon, and also provides clues about where Earth's water came from, researchers said.
"The ice at the poles of the moon records the interior evolution of the moon, which seems crazy — that is the last place you would think to look," said study lead author Matt Siegler, of the Planetary Science Institute in Tucson, Arizona, and Southern Methodist University in Dallas. [Video: The Moon's Axis Shifted 6 Degrees Over 1 Billion Years]
"Also, that means the ice has to be really old, and therefore may record the ancient delivery of ice to the inner solar system," Siegler told Space.com via email.
A cross section through the moon showing lunar polar volatiles (in cyan) and how they trace an ancient spin pole (green arrow). The re-orientation from that ancient spin pole to the present-day spin pole (blue arrow) was driven by the formation and evolution of the Procellarum, a region on the lunar nearside associated with a high abundance of radiogenic heat-producing elements, high heat flow and ancient volcanic activity.Credit: James Tuttle Keane
Water on the moon
Observations made by a variety of spacecraft over the past few decades suggest that the moon harbors a lot of water ice in permanently shadowed craters near the poles, which are some of the coldest locales in the solar system.
Siegler and his colleagues studied measurements made by two of these probes: NASA's pioneering Lunar Prospector (LP) spacecraft, which circledthe moon from January 1998 through July 1999, and the agency's Lunar Reconnaissance Orbiter (LRO), which is still in operation.
The orbiters' data revealed ice deposits at both poles, as expected. But there was a surprise as well: A large patch of ice exists near each pole, in a spot offset from the true pole by 5.5 degrees. Moreover, these "displaced" deposits are positioned such that a straight line drawn through the center of the moonwould connect them.
Siegler and his team have an explanation for this finding, which they report online today (March 23) in the journal Nature: The moon's rotational axis has shifted by 5.5 degrees over the ages, and the offset ice patches mark the "paleopoles."
Maps of lunar hydrogen (a proxy for water ice), as measured by NASA's Lunar Prospector spacecraft poleward of 80 degrees N/S. The hydrogen-abundance maxima (white dots) are offset significantly from the present north and south poles, and are inferred to be ancient lunar-spin poles.Credit: James Tuttle Keane
Modeling work suggests these paleopoles were the actual poles about 3 billion years ago, Siegler said.
"Models are models, so you can make the migration happen any time between 1.5-4.5 billion years ago depending on how you tweak parameters (such as the past rigidity of the lunar crust), but it most likely was around 3 billion years ago," he said.
The lunar poles then shifted by about 125 miles (200 kilometers) over the course of one billion years or so — a rate of 1 inch (2.5 centimeters) every 126 years, the researchers think.
"This was such a surprising discovery. We tend to think that objects in the sky have always been the way we view them, but in this case the face that is so familiar to us — the Man on the Moon — changed," Siegler said in a statement. "It would be as if Earth's axis relocated from Antarctica to Australia. As the pole moved, the Man on the Moon turned his nose up at the Earth."
Over the past 4.5 billion years, the moon has changed its orientation with respect to the Earth, revealing many different faces. This tilting of the moon, known as true polar wander, is preserved in the distribution of lunar polar volatiles.Credit: James Tuttle Keane
Lunar mass shift
The moon is Earth's nearest neighbor, but its origins date back to a violent birth billions of years ago. See how the moon was made in this Space.com infographic.Credit: By Karl Tate, Infographics Artist
The most likely driver of this "polar wander" was a shift in the internal distribution of lunar mass, the researchers said.
"Planets can change their orientation if their internal mass distribution changes. Pockets of dense material tend to be close to the equator to minimize the planet's spin energy," Ian Garrick-Bethell, of the University of California, Santa Cruz, explained in an accompanying "News and Views" article published in the same issue of Nature.
"If a huge pile of lead weights suddenly appeared in New York, the city's latitude would eventually shift to a position slightly southward, because of planetary re-orientation," Garrick-Bethell added. "The opposite is also true — if New York suddenly became lower in density, it would shift northward."
Siegler and his team think they have figured out where this mass shift on the moon occurred. Their work points to the Procellarum KREEP Terrane (PKT) region on the lunar nearside, which was volcanically active long ago. Volcanism in the PKT area about 3.5 billion years ago began heating up the mantle there, creating a "low-density thermal anomaly" — hot rocks are less dense than cool ones — that caused the polar shift, the thinking goes.
"This giant blob of hot mantle was lighter than cold mantle elsewhere," Siegler said in the statement. "This change in mass caused Procellarum — and the whole moon — to move."
Study team members think the polar ice predates the moon's axis shift, which suggests that the material is very ancient indeed. So the new results could help scientists get a better handle on the origin of Earth's water.
"The ice may be a time capsule from the same source that supplied the original water to Earth," Siegler said in the statement. "This is a record we don't have on Earth. Earth has reworked itself so many times, there's nothing that old left here. Ancient ice from the moon could provide answers to this deep mystery."
If the interpretation advanced by Siegler and his colleagues is correct, it raises a new question, said Garrick-Bethell.
"The moon's volcanism mostly stopped 3 billion years ago, which means that the PKT has probably been getting colder and denser since then, not hotter," he wrote. "The direction of polar wander during this period would therefore have been in the opposite direction to the wander that produced the ice paleopole."
So researchers do not yet have a full understanding of "true polar wander" (TPW) or the mechanisms that drive it, the researchers said. Indeed, more work is required to achieve this goal, Siegler and his team stressed.
"In situ measurements, sample return and high-resolution orbital geochemistry measurements could differentiate plausible TPW scenarios," the researchers wrote in their Nature paper.
Moon used to spin 'on different axis'
Image copyrightJames Tuttle KeaneImage captionThe scientists suggest volcanic activity generated the "wander"The Moon used to spin on a different axis and show a slightly different face to the Earth, a new study suggests.
Using data collected by Nasa's Lunar Prospector mission in the late 1990s, scientists spotted two hydrogen-rich regions near the Moon's poles, probably indicating the presence of water ice.
The icy patches are opposite each other - the line between them passes through the middle of the Moon - so it appears that this used to be its spin axis.
The work appears in the journal Nature.
It describes a gradual wobble, or "true polar wander", adding up to about a six-degree shift altogether.
A likely explanation for this shift, which the researchers suggest took place over several billion years, is volcanic activity in a region called the Procellarum.
This swathe of territory includes most of the Moon's dark patches that are visible from the Earth. Volcanoes and associated geological activity would have made it warmer and lighter than the rest of the Moon.
According to Matt Siegler, from the Planetary Science Institute in Arizona, and his colleagues, that drop in density produced enough wobble to explain the two "palaeopoles" they detected in the Lunar Prospector data.
"The Procellarum region was most geologically active early in lunar history, which implies that polar wander initiated billions of years ago," they write.
Image copyrightJames Tuttle KeaneImage captionThe presumed icy patches are opposite each other, nearby the present lunar polesDr Siegler and his colleagues discovered the hydrogen-rich patches in data from the Lunar Prospector's neutron spectrometer: measuring the neutrons bounced off the Moon's surface by incoming cosmic rays.
That hydrogen signal is taken to indicate the presence of water ice, which can -and does - exist in permanently shaded craters at the Moon's poles.
Precisely why it has persisted in these regions, which have now drifted away from the poles and into sunlight, is a mystery.
The researchers suggest it may have been buried by asteroid impacts, but this will require further investigation.
Previous studies have suggested that the Moon may have wobbled around to an even greater extent - perhaps as much as 35 degrees.
The lead author of one of those earlier papers, Ian Garrick-Bethell from the University of California Santa Cruz, wrote in a comment piece for Nature: "A key goal will be to reconcile these many stories of the changing orientation of the Moon, and to determine what density changes drove it to wander."
Secretary Kerry Meets With Russian President Putin and Russian Foreign Minister Lavrov to Discuss Syria and Ukraine in Moscow
U.S. Secretary of State John Kerry and Russian President Vladimir Putin, accompanied by their respective delegations, discuss Syria and Ukraine during their bilateral meeting at the Kremlin in Moscow, Russia, on March 24, 2016. Also pictured are Chief of Staff Jon Finer, Assistant Secretary of State for European and Eurasian Affairs Toria Nuland, U.S. Ambassador to Russia John Tefft, and Russian Foreign Minister Sergey Lavrov
Secretary Kerry and Russian Foreign Minister Lavrov Address Reporters at a Joint News Conference in Moscow
With U.S. Assistant Secretary and Spokesperson John Kirby and his Russian counterpart looking on, U.S. Secretary of State John Kerry and Russian Foreign Minister Sergey Lavrov address reporters at a joint news conference at the Kremlin in Moscow, Russia, on March 24, 2016
U.S. Secretary of State John Kerry and Russian President Vladimir Putin pose for a photo before their bilateral meeting on March 24, 2016, to discuss Syria and Ukraine at the Kremlin in Moscow, Russia
U.S. Secretary of State John Kerry sits with Sheikh Mohammed bin Zayed, Crown Prince of Abu Dhabi and Deputy Supreme Commander of the Armed Forces, before a bilateral meeting to discuss Syria and other regional issues in Moscow, Russia, on March 24, 2016.
U.S. Secretary of State John Kerry looks towards the U.S. delegation during a bilateral meeting with Russian Foreign Minister Sergey Lavrov and Russian counterparts in Moscow, Russia, on March 24, 2016
Flyby Comet Imaged By Radar
Δημοσιεύτηκε στις 24 Μαρ 2016
Radar data of comet P/2016 BA14 taken over three days (March 21—23, 2016), when the comet was between 2.5 million miles and 2.2 million miles (4.1 million kilometers and 3.6 million kilometers) from Earth.
ΣΤΟ ΕΠΟΜΕΝΟ ΠΕΡΑΣΜΑ ΠΟΥ ΘΑ ΚΑΝΗ ΜΕΤΑ ΤΗΝ ΣΤΡΟΦΗ ΑΠΟ ΤΟΝ ΗΛΙΟ ΤΙ ΓΙΝΕΤΑΙ;
Rocks Rain Down On Bus Passengers
Δημοσιεύτηκε στις 24 Μαρ 2016
Occurred March 19, 2016 / District Kohistan, Northern Pakistan
Bus passengers on the Karakoram Highway face flying boulders! Heavy rainfall lead to the closure of the highway and these rock slides. Luckily, no one was injured.
Bus passengers on the Karakoram Highway face flying boulders! Heavy rainfall lead to the closure of the highway and these rock slides. Luckily, no one was injured.
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