The tentative detection of low frequency radio waves on Saturn's icy moon, Titan, could signal an underground ocean of liquid water, a new study says. If so, it would be good news for the possibility of life beneath the surface of this bizarre world.
Titan's crust is thought to be made largely of water ice, kept rock hard by the prevailing surface temperature of -178° Celsius. But theoretical models of the moon's interior suggest that ammonia-rich water deep beneath the surface could stay liquid, perhaps forming a global ocean.
Science & Technology
The strongest evidence yet that ancient Mars was much wetter than it is now has been unearthed by NASA's Spirit rover.
A patch of Martian soil kicked up and analyzed by Spirit appears to be rich in silica, which suggests it would have required water to produce.
A patch of Martian soil kicked up and analyzed by Spirit appears to be rich in silica, which suggests it would have required water to produce.
|
| ©AP photo/HO/NASA |
| A photo released by NASA ,shows a patch of bright-toned soil found by the Mars Rover Spirit so rich in silica that scientists propose water must have been involved in concentrating it. The silica-rich patch, informally named 'Gertrude Weise' after a player in the All-American Girls Professional Baseball League, was exposed when Spirit drove over it during the 1,150th Martian day, or sol, of Spirit's Mars surface mission (March 29, 2007). One of Spirit's six wheels no longer rotates, so it leaves a deep track as it drags through soil. Most patches of disturbed, bright soil that Spirit had investigated previously are rich in sulfur, but this one has very little sulfur and is about 90 percent silica. |
A new analysis of pictures taken by the exploration rover Opportunity reveals what appear to be small ponds of liquid water on the surface of Mars.
The report identifies specific spots that appear to have contained liquid water two years ago, when Opportunity was exploring a crater called Endurance. It is a highly controversial claim, as many scientists believe that liquid water cannot exist on the surface of Mars today because of the planet's thin atmosphere.
The report identifies specific spots that appear to have contained liquid water two years ago, when Opportunity was exploring a crater called Endurance. It is a highly controversial claim, as many scientists believe that liquid water cannot exist on the surface of Mars today because of the planet's thin atmosphere.
|
| ©Ron Levin |
| Smooth bluish areas on a Martian crater floor could be ponds, according to two scientists. The area is approximately 1 square metre. |
Following launching of Ofek-7 into space, officials say more advanced satellites will be launched in coming years
|
| ©Defense Ministry |
| Ofek-7 being launched |
When ice ages held Europe in their grip, Africa also felt the pinch - though in a different way.
It has long been suspected that there is a connection between the west African monsoon and climate at higher latitudes - especially over geological timescales, says David Lea at the University of California, Santa Barbara. "But until now, there hasn't been enough supporting evidence." Now Lea, with team leader Syee Weldeab and colleagues, has reconstructed the most detailed history of the monsoon yet, spanning 155,000 years and two ice ages.
It has long been suspected that there is a connection between the west African monsoon and climate at higher latitudes - especially over geological timescales, says David Lea at the University of California, Santa Barbara. "But until now, there hasn't been enough supporting evidence." Now Lea, with team leader Syee Weldeab and colleagues, has reconstructed the most detailed history of the monsoon yet, spanning 155,000 years and two ice ages.
Paper cuts are actually pretty subtle phenomena and, as you point out, sometimes you get them and sometimes you don't.
The first thing that's needed to break skin is pressure. Pressure is force per unit area. To get an idea of why it's pressure that matters more than force, think of what's worse -- someone standing on your hand with a stiletto heel (small area in contact) or a flat shoe (large area).
With paper, the area of the edge that cuts you is tiny, so even a small force will give a large pressure. This is not the whole story, however, since paper is floppy and can buckle before it manages to cut through skin. To get a paper cut you need to have the paper supported in such a way that it tends not to bend easily. This can happen when you have a book or a ream of paper where one page can easily slide out a little from the rest and present a cutting edge, but still be held tightly against bending.
The first thing that's needed to break skin is pressure. Pressure is force per unit area. To get an idea of why it's pressure that matters more than force, think of what's worse -- someone standing on your hand with a stiletto heel (small area in contact) or a flat shoe (large area).
With paper, the area of the edge that cuts you is tiny, so even a small force will give a large pressure. This is not the whole story, however, since paper is floppy and can buckle before it manages to cut through skin. To get a paper cut you need to have the paper supported in such a way that it tends not to bend easily. This can happen when you have a book or a ream of paper where one page can easily slide out a little from the rest and present a cutting edge, but still be held tightly against bending.
Despite overwhelming military superiority, the world's most powerful nations failed to achieve their objectives in 39 percent of their military operations since World War II, according to a new University of Georgia study.
The study, by assistant professor Patricia L. Sullivan in the UGA School of Public and International Affairs, explains the circumstances under which more powerful nations are likely to fail and creates a model that allows policymakers to calculate the probability of success in current and future conflicts.
"If you know some key variables - like the major objective, the nature of the target, whether there's going to be another strong state that will intervene on the side of the target and whether you'll have an ally - you can get a sense of your probability of victory," said Sullivan, whose study appears in the June issue of the Journal of Conflict Resolution.
Sullivan said the most important factor influencing whether the more powerful nation is successful is whether its strategic objective can be accomplished with brute force alone or requires the cooperation of the adversary.
The study, by assistant professor Patricia L. Sullivan in the UGA School of Public and International Affairs, explains the circumstances under which more powerful nations are likely to fail and creates a model that allows policymakers to calculate the probability of success in current and future conflicts.
"If you know some key variables - like the major objective, the nature of the target, whether there's going to be another strong state that will intervene on the side of the target and whether you'll have an ally - you can get a sense of your probability of victory," said Sullivan, whose study appears in the June issue of the Journal of Conflict Resolution.
Sullivan said the most important factor influencing whether the more powerful nation is successful is whether its strategic objective can be accomplished with brute force alone or requires the cooperation of the adversary.
Humans might have finished off the woolly mammoths, but the genetics of the giants apparently helped them decline well beforehand, scientists now find.
The woolly mammoth (Mammuthus primigenius) was coated in hair up to 20 inches long and possessed extremely long, curved tusks up to 16 feet in length. The giants lived for tens of thousands of years, apparently going extinct roughly 12,000 years ago, around the end of the last ice age.
For years, scientists suspected that ancient human tribes hunted the mammoths and other ice age giants to oblivion. Recent research seems to contradict this notion, however - for instance, a comet or tuberculosis may have helped kill off the American mastodons (Mammut americanum), closely related to mammoths.
The woolly mammoth (Mammuthus primigenius) was coated in hair up to 20 inches long and possessed extremely long, curved tusks up to 16 feet in length. The giants lived for tens of thousands of years, apparently going extinct roughly 12,000 years ago, around the end of the last ice age.
For years, scientists suspected that ancient human tribes hunted the mammoths and other ice age giants to oblivion. Recent research seems to contradict this notion, however - for instance, a comet or tuberculosis may have helped kill off the American mastodons (Mammut americanum), closely related to mammoths.
Although stars with masses reaching up to 150 times the mass of the Sun are expected in the local Universe, no one has reliably found a star exceeding 83 solar masses so far. Until now that is. A team of astronomers from Universite de Montreal has identified the most massive star ever weighed. The details are being presented today by Professor Anthony Moffat at the annual meeting of the Canadian Astronomical Society (CASCA) held at the Royal Military College of Canada in Kingston (ON).
Anti-death penalty forces have gained momentum in the past few years, with a moratorium in Illinois, court disputes over lethal injection in more than a half-dozen states and progress toward outright abolishment in New Jersey.
