Martian Carbonates Suggest Past Life on Mars

A research team has found evidence of a long-sought carbonates that shows Mars was home to a variety of watery environments, including regional pockets of neutral or alkaline water.

Recent observations from the Mars Phoenix lander has pointed to a period when clay-rich minerals were formed by water, followed by a drier time, when salt-rich, acidic water affected much of the planet. The presence of carbonates indicates that Mars had neutral to alkaline waters when the minerals formed in the midlatitude region more than 3.6 billion years ago.

“Primitive life would have liked it,” said Bethany Ehlmann, “It’s not too hot or too cold. It’s not too acidic. It's a ‘just right’ place.’

The carbonates showed up in the most detail in two-dozen images beamed back by the Compact Reconnaissance Imaging Spectrometer for Mars, an instrument aboard the NASA Mars Reconnaissance Orbiter. Scientists found the mineral near a trough system called Nili Fossae, which is 667 km long, at the edge of the Isidis impact basin. Carbonates were seen in a variety of terrains, including the sides of eroded mesas, sedimentary rocks within Jezero crater and rocks exposed on the sides of valleys in the crater’s watershed. The researchers also found traces of carbonates in Terra Tyrrhena and in Libya Montes.

The carbonates may have been formed by slightly heated groundwater percolating through fractures in olivine-rich rocks. Or, they may have been formed at the surface when olivine-rich rocks were exposed and altered by running water. Yet another theory is the carbonates precipitated in small, shallow lakes. Either way, such environments would have boded well for primitive life forms to emerge.

“We know there’s been water all over the place, but how frequently have the conditions been hospitable for life?” Mustard said. “We can say pretty confidently that when water was present in the places we looked at, it would have been a happy, pleasant environment for life.” press release

Ref: Orbital Identification of Carbonate-Bearing Rocks on Mars. 2008. Bethany L. Ehlmann, et al. Science 322: 1828 - 1832

Dragonella by Wally Wood

CLICK TO ENLARGE

Heroes, Inc. (Presents Cannon) was self published by Wally Wood in 1969. Working with Steve Ditko and Ralph Reese, Wood produced three new strips for the book including the first appearance of “Cannon”. This is Dragonella’s first and only adventure. It’s notable for letting Wally indulge in some medieval scenery including a riff on Prince Valiant.

Dragonella by Ron Whyte & Wally Wood, 1969. © estate of Wally Wood

The Evolution of Superstition

Both Images from The Horror of It All

Abstract: Superstitious behaviours, which arise through the incorrect assignment of cause and effect, receive considerable attention in psychology and popular culture. Perhaps owing to their seeming irrationality, however, they receive little attention in evolutionary biology.

Here we develop a simple model to define the condition under which natural selection will favour assigning causality between two events. This leads to an intuitive inequality—akin to an amalgam of Hamilton's rule and Pascal's wager—-that shows that natural selection can favour strategies that lead to frequent errors in assessment as long as the occasional correct response carries a large fitness benefit.

It follows that incorrect responses are the most common when the probability that two events are really associated is low to moderate: very strong associations are rarely incorrect, while natural selection will rarely favour making very weak associations.

CLICK TO ENLARGE

Extending the model to include multiple events identifies conditions under which natural selection can favour associating events that are never causally related. Specifically, limitations on assigning causal probabilities to pairs of events can favour strategies that lump non-causal associations with causal ones.

We conclude that behaviours which are, or appear, superstitious are an inevitable feature of adaptive behaviour in all organisms, including ourselves.

Article: The evolution of superstitious and superstition-like behaviour.2008. K. Foster and H. Kokko. Proceedings of the Royal Society B 276: 1654.

The Vanguard by Alex Toth

CLICK TO ENLARGE

The Vanguard © The estate of Alex Toth
Originally printed in Hot Stuff #4, 1977

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

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":

Bite Force of The Great White Shark

image

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.

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