Science & Technology
An enormous plume of dust and water spurts violently into space from the south pole of Enceladus, Saturn's sixth-largest moon. This raging eruption has intrigued scientists ever since the Cassini spacecraft provided dramatic images of the phenomenon.
Now, physicist Nikolai Brilliantov, at the University of Leicester, and colleagues in Germany, have revealed why the dust particles in the plume emerge more slowly than the water vapour escaping from the moon's icy crust.
|©Michael Carroll, www.stock-space-images.com
|Geyser on Enceladus.
Enceladus orbits in Saturn's outermost "E" ring. It is one of only three outer solar system bodies that produce active eruptions of dust and water vapour. Moreover, aside from the Earth, Mars, and Jupiter's moon Europa, it is one of the only places in the solar system for which astronomers have direct evidence of the presence of water.
Wed, 20 Feb 2008 15:43 CST
The secret of the Universe is not 42, according to a new theory, but the unimaginably larger number 10122. Scott Funkhouser of the Military College of South Carolina (called The Citadel) in Charleston has shown how this number - which is bigger than the number of particles in the Universe - keeps popping up when several of the physical constants and parameters of the Universe are combined1. This 'coincidence', he says, is surely significant, hinting at some common principle at work behind the scenes.
The number first turned up when, more than a decade ago, physicists discovered that the expanding Universe is accelerating. This implies that there is a force that opposes gravity on very large scales, which physicists call dark energy. It is quantified by a parameter called the cosmological constant.
One interpretation of dark energy is that it results from the energy of empty space, called vacuum energy. The laws of quantum physics imply that empty space is not empty at all, but filled with particles popping in and out of existence. This particle 'fizz' should push objects apart, just as dark energy seems to require. But the theoretical value of this energy is immense - so huge that it should blow atoms apart, rather than just causing the Universe to accelerate.
Fri, 22 Feb 2008 14:29 CST
Geologists have found a buried volcano inside Panmure Basin, which is the mouth of a volcano that erupted about 28,000 years ago. It is extremely rare for two eruptions to have occurred at the same site in the Auckland Volcanic Field.
The discovery was made by a group of geologists from government-owned research and consultancy company GNS Science and The University of Auckland as they drilled into the basin from a barge this week to find out more about the volcanic history of volcanoes in the upper North Island.
The FBI has developed sophisticated new software for reconstructing a person's face from their skull. The software is designed to help police identify partially decomposed or burned bodies.
At present, reconstructing a face from a skull takes a specialist artist up to two weeks and can cost up to $2,000 (£1,020).
Meteorites from the Moon and Mars give earthbound scientists free rock samples from other worlds. Now Brett Gladman and Jaime Coffey (University of British Columbia, Vancouver) say we should expect a few meteorites from Mercury too.
Gladman and Coffey conducted computer simulations of what happens after asteroids and comets slam into the innermost planet and kick debris into space. Past studies assumed that rocks knocked off Mercury weren't getting away with much more than its escape velocity of 2.6 miles (4.2 km) per second. That's too slow to climb away from the Sun and make it out to Earth.
|©NASA / JHU-APL / Carnegie Inst. of Washington
|Taken by Messenger on January 14, 2008, from about 17,000 miles away, this view of a gibbous Mercury shows about half of the area not photographed by Mariner 10 in 1974 - 75. The heavily cratered landscape is reminiscent of other areas previously seen. The broad circular plain toward upper right, appearing brighter than its surroundings in this red-light view, marks the interior of Caloris basin, a huge impact scar more than 800 miles across.
The space around Earth is a busy place, as teeming with traffic as a roundabout. More than 500 active satellites are bustling about up there right now. Some are transmitting radio, television, and telephone signals; others are gathering information about Earth's atmosphere and weather; still others are helping people navigate down here; and the rest are conducting space research.
The first direct evidence of how and when tectonic plates move into the deepest reaches of the Earth is published in Nature today. Scientists hope their description of how plates collide with one sliding below the other into the rocky mantle could potentially improve their ability to assess earthquake risks.
Venus Express has revealed a planet of extraordinarily changeable and extremely large-scale weather. Bright hazes appear in a matter of days, reaching from the south pole to the low southern latitudes and disappearing just as quickly. Such 'global weather', unlike anything on Earth, has given scientists a new mystery to solve.
A team of academic, industry and independent researchers has demonstrated a new class of computer attacks that compromise the contents of "secure" memory systems, particularly in laptops.
The attacks overcome a broad set of security measures called "disk encryption," which are meant to secure information stored in a computer's permanent memory. The researchers cracked several widely used technologies, including Microsoft's BitLocker, Apple's FileVault and Linux's dm-crypt, and described the attacks in a paper and video published on the Web Feb. 21.
Preparing groundwork for an exascale computer is the mission of the new Institute for Advanced Architectures, launched jointly at Sandia and Oak Ridge national laboratories.
An exaflop is a thousand times faster than a petaflop, itself a thousand times faster than a teraflop. Teraflop computers - the first was developed 10 years ago at Sandia - currently are the state of the art. They do trillions of calculations a second. Exaflop computers would perform a million trillion calculations per second.