astralavista

Late in October, the Cassini probe exploring Saturn and it's immediate cosmic neighborhood snapped a beautiful image of Saturn's rings wrapping the planet's cloudy surface in a curved, striped sash of shadow and light. The resulting effect brings to mind a modernist lampshade, even a flying saucer. Note that some of the rings let some sunglight through, lending their shadow smoky translucency.
According to NASA, the three thin and bright arcs in this scene represent three well-known gaps in the immense ring system. From bottom to top here (and widest to thinnest) they are the Cassini Division, the Encke Gap and the Keeler Gap.
NASA said that the image was taken in infrared light (752 nanometers) using the Cassini spacecraft wide-angle camera on Oct. 29, 2005, at a distance of approximately 446,000 kilometers (277,000 miles) from Saturn. The image scale is 23 kilometers (14 miles) per pixel. The image was contrast enhanced to improve visibility of features in the atmosphere.

In May 2004, an east Texas logger died after being stung hundreds of times by a swarm of bees. The Beekeepers' Association newsletter cited data from Texas A&M University, saying that bees have killed 15 Texans since 1991. But what if these deaths weren't just accidents? What if the bees had it in for the victims?
A team of European and Australian biologists just reported in the Journal of Experimental Biology that honeybees "can discriminate and recognize images of human faces."
The researchers were curious whether the ability to recognize faces was something only mammals could do. "There is evidence that the mammalian brain may have specialised neural circuitry for face recognition tasks, although some recent work questions these findings," they wrote in the abstract of their paper. "Thus, to understand if recognising human faces does require species-specific neural processing, it is important to know if non-human animals might be able to solve this difficult spatial task."
Apparently they do. They tested honeybees (Apis mellifera) to "evaluate whether an animal with no evolutionary history for discriminating between humanoid faces may be able to learn this task."
Here's what the team found out: "Using differential conditioning, individual bees were trained to visit target face stimuli and to avoid similar distractor stimuli from a standard face recognition test used in human psychology. Performance was evaluated in non-rewarded trials and bees discriminated the target face from a similar distractor with greater than 80% accuracy. When novel distractors were used, bees also demonstrated a high level of choices for the target face, indicating an ability for face recognition. When the stimuli were rotated by 180° there was a large drop in performance, indicating a possible disruption to configural type visual processing."

Image Credit: Smoky River Express, Caption: Area beekeepers (from left) Paul Benoit and Fernando Sanchez were brave during the Bee Beard Contest in last year's Honey Festival.

Astronomers from Johns Hopkins University and the Space Telescope Science Institute in Baltimore, Md. have come up with the first detailed map of the mysterious dark matter, albeit one covering only a tiny patch of the sky.
Myungkook James Jee, Johns Hopkins researcher and co-author of the project, said that the team came up with the map by measuring the effects of gravitational lensing by dark matter on the images of two galaxy clusters taken by the Hubble Space Telescope.
Gravitational lensing is a visual effect postulated by Einstein's general theory of relativity. Any sufficiently massive body will cause a dimple in space-time and shift, distort, even multiply images of stars and galaxies hiding behind it like a fun-house mirror.
"The images we took show clearly that the cluster galaxies are located at the densest regions of the dark matter haloes, which are rendered in purple in our images," Jee said.
The astronomers also reported that dark matter has a ghost-like character where dark matter particles can pass through each other rather than bounce off and scatter like billiard balls as is common with ordinary matter. "Collision-less particles do not bombard one another, the way two hydrogen atoms do," said Jee. "If dark matter particles were collisional, we would observe a much smoother distribution of dark matter, without any small-scale clumpy structures."
The map appears in the December edition of the Astrophysical Journal.

Image: Snapshot of the computer simulation of the dark matter Universe. These filamentary structures are called "cosmic webs" of dark matter. Credit: Johns Hopkins University.

After some 400 years of relative stability, Earth's North Magnetic Pole has moved nearly 1,100 kilometers out into the Arctic Ocean during the last century, scientists from Oregon State University reported. If it keeps going at the present clip, it will move from northern Canada to Siberia within the next half-century.
Besides the possibility that Alaskans, the Inuit and other natives of northern Norh America may loose the sight of the Northern Lights for many generations, the shift has implications for international travel and communications. The scientists said that radiation influx associated with our planet's magnetic field affects charged particles streaming down through the atmosphere can impact airplane flights and telecommunications.
"This may be part of a normal oscillation and it will eventually migrate back toward Canada," said Joseph Stoner, assistant professor at the university' s College of Oceanic and Atmospheric Sciences. "There is a lot of variability in the polar motion, but it isn't something that occurs often. There appears to be a 'jerk' of the magnetic field that takes place every 500 years or so. The bottom line is that geomagnetic changes can be a lot more abrupt than we ever thought."
The scientists said in a press release that calculations of the North Magnetic Pole's location from historical records goes back only about 400 years, while polar observations trace back to John Ross in 1838 at the west coast of Boothia Peninsula.
To look deeper in the past, the scientists drilled 5-meter core samples from the ice and 5,000 year old sediments deposited on the bottom of frozen Arctic lakes.
These sediments contain magnetic particles called magnetite, the scientists said. Much like a classroom experiment with magnets and iron filings, they record the the orientation of Earth's magnetic field at the time they were deposited. The team then used carbon dating and layer counting to determine approximately when the sediments were deposited and track changes in the magnetic field.
The Oregon team reported that "Earth last went through a magnetic reversal some 780,000 years ago. These episodic reversals, in which south becomes north and vice versa, take thousands of years and are the result of complex changes in the Earth's outer core. Liquid iron within the core generates the magnetic field that blankets the planet."
Because of that field, a compass reading of north in Oregon will be approximately 17 degrees east from 'true geographic north.' In Florida, farther away and more in line with the poles, the declination is only 4-5 degrees west."
The Northern Lights, which are triggered by the sun and fixed in position by the magnetic field, drift with the movement of the North Magnetic Pole and may soon be visible in more southerly parts of Siberia and Europe - and less so in northern Canada and Alaska."
No word on whether the southern magnetic pole is undergoing silimar shift.
One beguiling question also remains unaswered. Could it be the movement of Earth's crust that's actually sped up? After all, it was magnetite crystals recovered from basalts in Greenland in the 1960s that proved the movement of plate tectonics and pointed to the existence of Pangea, the mother of all continents.

Image Credit: University of Northern British Columbia

Call it the cosmic Katrina. The Perseus Cluster, some 250 million light years away from Earth, is a giant bundle of destruction shredding its cosmic neighborhood to gauzy wisps of interstellar dust.
The cluster has been wracked by some nasty cosmic "weather" for hundreds of millions of years. Now scientists from Harvard and NASA have trained their orbital Chandra X-ray observatory at the cluster for 270 hours for detailed observations.
They've reported that the cluster, which is one of the most massive objects in the universe, "contains thousands of galaxies immersed in a vast cloud of multimillion degree gas with the mass equivalent of trillions of suns." They also observed an entire galaxy that's being torn apart and cannibalized by its giant cousin, called Perseus A, residing at the center of the cluster. (See the dark blue filaments near the center of the image.)
Perseus A itself is spinning around a vicious black hole. Resembling a cosmic hurricane, the scientists spotted huge low pressure regions expanding outward 300,000 light years from the space warping singularity. "The plumes are due to explosive venting from the vicinity of the supermassive black hole," the scientists said.
They said that the venting produces sound waves which heat the gas throughout the inner regions of the cluster and prevent the gas from cooling and making stars at a high rate. "This process has slowed the growth of one of the largest galaxies in the Universe," they said. "It provides a dramatic example of how a relatively tiny, but massive, black hole at the center of a galaxy can control the heating and cooling behavior of gas far beyond the confines of the galaxy."
In the Greek mythology, Perseus was the son Zeus and Danae. Besides riding the winged horse Pegasus and liberating Andromeda, he's perhaps best remembered for chopping off Medusa's slithering head.