Sunday, December 14, 2008
Saturday, December 13, 2008
New Region of Earth's Magnetosphere Discovered
Scientists have discovered a new region of the magnetosphere, the invisible shield of magnetic fields and electrically charged particles that surround and protect Earth from the onslaught of the solar wind.The northern and southern polar lights – aurora borealis and aurora australis – are the only parts of the magnetosphere that are visible, but it is a critical part of Earth's space environment.
"Although it is invisible, the magnetosphere has an impact on our everyday lives," Chappell said. "For example, solar storms agitate the magnetosphere in ways that can induce power surges in the electrical grid that trigger black outs, interfere with radio transmissions and mess up GPS signals. Charged particles in the magnetosphere can also damage the electronics in satellites and affect the temperature and motion of the upper atmosphere."
The other regions of the magnetosphere have been known for some time. Chappell and his colleagues pieced together a "natural cycle of energization" that accelerates the low-energy ions that originate from Earth's atmosphere up to the higher energy levels characteristic of the different regions in the magnetosphere.
The warm plasma cloak is a tenuous region that starts on the night side of the planet and wraps around the dayside but then gradually fades away on the afternoon side. As a result, it only reaches about three-quarters of the way around the planet. It is fed by low-energy charged particles that are lifted into space over Earth's poles, carried behind the Earth in its magnetic tail but then jerked around 180 degrees by a kink in the magnetic fields that boosts the particles back toward Earth in a region called the plasma sheet. link
Friday, December 12, 2008
Bettie Page: 1923-2008
Legendary ‘50’s pin-up model, Bettie Page, passed away yesterday at 85. Her obituary in the NY Times is here. Mark Evanier has some comments here.
Out of the public eye and largely forgotten by a generation, she came back to notoriety after 30 years when artist and Rocketeer creator, Dave Stevens, “cast” her as the hero’s girlfriend in his laviously illustrated series of Rocketeer stories.
There are still lots of books and video compilations about her that you can pick up.
Dave passed away recently as well but a great new book about him is out now.
A few years ago they made a film about Bettie's life. Here's the trailer from "The Notorious Bettie Page":
Out of the public eye and largely forgotten by a generation, she came back to notoriety after 30 years when artist and Rocketeer creator, Dave Stevens, “cast” her as the hero’s girlfriend in his laviously illustrated series of Rocketeer stories.
There are still lots of books and video compilations about her that you can pick up.
Dave passed away recently as well but a great new book about him is out now.
A few years ago they made a film about Bettie's life. Here's the trailer from "The Notorious Bettie Page":
Sunday, December 7, 2008
Bite Force of The Great White Shark
ABSTRACT: The notorious jaws of the white shark Carcharodon carcharias are widely feared, yet poorly understood. Neither its bite force, nor how such force might be delivered using relatively elastic cartilaginous jaws, have been quantified or described. We have digitally reconstructed the jaws of a white shark to estimate maximum bite force and examine relationships among their three-dimensional geometry, material properties and function.
We predict that bite force in large white sharks may exceed c. 1.8 tonnes, the highest known for any living species, and suggest that forces may have been an order of magnitude greater still in the gigantic fossil species Carcharodon megalodon.
However, jaw adductor-generated force in Carcharodon appears unremarkable when the predator's body mass is considered. Although the shark's cartilaginous jaws undergo considerably greater deformation than would jaws constructed of bone, effective bite force is not greatly diminished.
Carcharodon was found that the largest great whites have a bite force of up to 1.8 tonnes. By comparison, a large African lion can produce around 560 kg of bite force and a human approximately 80 kg - making the great white's bite more than 20 times harder than that of a human.
UNSW's Dr Steve Wroe, the study's lead author, says the great white is without a doubt one of the hardest biting creatures alive, possibly the hardest.
"Nature has endowed this carnivore with more than enough bite force to kill and eat large and potentially dangerous prey," he says.
"Pound for pound the great white's bite is not particularly impressive, but the sheer size of the animal means that in absolute terms it tops the scales". From the press release.
We predict that bite force in large white sharks may exceed c. 1.8 tonnes, the highest known for any living species, and suggest that forces may have been an order of magnitude greater still in the gigantic fossil species Carcharodon megalodon.
However, jaw adductor-generated force in Carcharodon appears unremarkable when the predator's body mass is considered. Although the shark's cartilaginous jaws undergo considerably greater deformation than would jaws constructed of bone, effective bite force is not greatly diminished.
Carcharodon was found that the largest great whites have a bite force of up to 1.8 tonnes. By comparison, a large African lion can produce around 560 kg of bite force and a human approximately 80 kg - making the great white's bite more than 20 times harder than that of a human.
UNSW's Dr Steve Wroe, the study's lead author, says the great white is without a doubt one of the hardest biting creatures alive, possibly the hardest.
"Nature has endowed this carnivore with more than enough bite force to kill and eat large and potentially dangerous prey," he says.
"Pound for pound the great white's bite is not particularly impressive, but the sheer size of the animal means that in absolute terms it tops the scales". From the press release.
Three-dimensional computer analysis of white shark jaw mechanics: how hard can a great white bite?. 2008. S. Wroe, et al. J. Zoology 276: 336 – 342.
She Gods of Shark Reef
Saturday, December 6, 2008
I Fought The Tyrannosaurus
From Tales of Suspense #5 (Sept. 1959) comes this story illustrated by Steve Ditko:
Thursday, December 4, 2008
The Perfect Imperfect Body
Having an imperfect body may come with some substantial benefits for some women, according to a new article in the December issue of Current Anthropology.
Women around the world tend to have larger waist-to-hip ratios—more cylindrical rather than hourglass-shaped bodies—than is considered optimal.Medical studies have shown that a curvy waist-to-hip ratio of 0.7 or lower is associated with higher fertility and lower rates of chronic disease. Studies have also shown that men prefer a ratio of 0.7 or lower when looking for a mate.
The preference makes perfect sense, according to evolutionary psychologists, because the low ratio is a reliable signal of a healthy, fertile woman.But in data that Cashdan compiled from 33 non-Western populations and 4 European populations, the average waist-to-hip ratio for women is above 0.8. If 0.7 is the magic number both in terms of health and male mate choice, why are most women significantly higher?
Androgens, a class of hormones that includes testosterone, increase waist-to-hip ratios in women by increasing visceral fat, which is carried around the waist. But on the upside, increased androgen levels are also associated with increased strength, stamina, and competitiveness. Cortisol, a hormone that helps the body deal with stressful situations, also increases fat carried around the waist.
Trading the benefits of a thin waist for better ability to collect resources may be a good deal in certain societies and situations. link
Wednesday, December 3, 2008
The Seed of Life Floats Between The Stars
Astronomers have detected a building block of RNA floating within the hot, compact core of a massive star-forming region in the Milky Way. The molecule appears to have formed with all of the other stuff that makes up planets, suggesting that many other worlds are seeded with some of life's ingredients right from birth.
Using the IRAM radio dish array in France, a team of European astronomers has detected glycolaldehyde--a simple sugar that makes up ribose, one of the constituents of RNA--within the core of what appears to be a coalescing disk of dust and gas in a star-forming region called G31.41+0.31, about 26,000 light-years away. The sugar molecule can apparently form in a simple reaction between carbon monoxide molecules and dust grains.
The discovery is significant for two reasons.
1: G31.41+0.31 lies far away from the radiation-filled center of the Milky Way, so if any biological processes start up there, they will have a chance to establish themselves.
2: The abundance of glycolaldehyde in the G31.41+0.31 cloud suggests that the molecule is "common throughout star-forming regions," says astrophysicist and co-author Serena Viti of University College London. The implication is that wherever there is starmaking and planet formation going on, organic building blocks could be assembling as well.
Astrobiologist Michael Mumma of NASA's Goddard Space Flight Center in Greenbelt, Maryland, says it's possible that life's building blocks arrive on planets after this violent period has passed. Glycolaldehyde, for example, seems to be located in an area of the star-forming region where it could become part of comets. If so, Mumma says, some of those comets could eventually deliver the sugar to young planets. From Science Now
Using the IRAM radio dish array in France, a team of European astronomers has detected glycolaldehyde--a simple sugar that makes up ribose, one of the constituents of RNA--within the core of what appears to be a coalescing disk of dust and gas in a star-forming region called G31.41+0.31, about 26,000 light-years away. The sugar molecule can apparently form in a simple reaction between carbon monoxide molecules and dust grains.
The discovery is significant for two reasons.
1: G31.41+0.31 lies far away from the radiation-filled center of the Milky Way, so if any biological processes start up there, they will have a chance to establish themselves.
2: The abundance of glycolaldehyde in the G31.41+0.31 cloud suggests that the molecule is "common throughout star-forming regions," says astrophysicist and co-author Serena Viti of University College London. The implication is that wherever there is starmaking and planet formation going on, organic building blocks could be assembling as well.
Astrobiologist Michael Mumma of NASA's Goddard Space Flight Center in Greenbelt, Maryland, says it's possible that life's building blocks arrive on planets after this violent period has passed. Glycolaldehyde, for example, seems to be located in an area of the star-forming region where it could become part of comets. If so, Mumma says, some of those comets could eventually deliver the sugar to young planets. From Science Now
First detection of glycolaldehyde outside the Galactic Center. 2008. M.T. Beltran et al. Astrophysics
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