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aamukherjee A Slice of Entropie -
alchymista Alchymista -
crownedrose Fading Like A Dead Star -
expose-the-light Quarks to Quasars -
ikenbot CWL -
abluegirl A Blue Girl -
perscientiamlibertas A Matter of the Most Pleasant Fraternal Confidence
Moqui Marbles and Martian Blueberries
The photo above shows Moqui Marbles in their native habitat of southern Utah. These curious rocks are actually concretions having iron (hematite) rinds.
Very similar rocks, called blueberries, have been observed repeatedly on Mars by the rovers. Click here to see an image taken by the Opportunity rover of the blueberries. Some scientific papers implicate the possibility of life on Mars playing a role in their formation while others do not.
Discussions about the pros and cons of their formation have been quite lively at times. However, the consensus seems to be that both the marbles and the blueberries were created beneath the surface as naturally occurring substances, most likely minerals, precipitated from flowing groundwater. Pictured with the marbles is a Devil’s-Claw cactus (Sclerocactus parviflorus). — Bret Webster
ikenbot
Small Scale von Karman Vortices
The photo above shows von Karman vortices observed in a muddy puddle near Eger, Hungary. A pebble caused the saber-shaped perturbations in this approximately 12 by 16 in (30 by 40 cm) puddle — the result of melting snow flowing through a tire track.
The direction of flow here is from right to left. In a fluid, be it air or liquid, an object large enough to interfere with the movement of the fluid often leads to the formation of von Karman vortices on the leeside of the flow.
Yellowstone National Park’s Prismatic Pool
The photo above shows the brightly colored Grand Prismatic Spring in Yellowstone National Park, Wyoming. The red and yellow colors of the pool in the foreground contrast sharply with the azure blue color in the mid-ground and with the greens and tans of the slope in the background.
Red and yellow colors are caused by pigmented bacteria and thermophiles (heat-loving algae) inhabiting the hot spring. Specific colors of the thermophiles correspond to a particular temperature range of the naturally heated springs – temperatures are 160 F (70 C) at the spring’s source.
Colors are also a result of the ratio of chlorophyll to carotenoids – red/orange is observed during summer but typically, dark green is favored during the colder months. The inset photo shows a close up of a thermophile colony.
As shown above, the monarch butterfly population is so dense in their mountainous, winter residence of central Mexico that they cover the trees like leaves.
Some branches noticeably sway from the weight of the myriad monarchs even though they each weigh less than a gram. Many of the butterflies on this tree have journeyed 3,000 mi (5,000 km) or further to get to this several-hundred-acre colony, near the village of Michoacan. They overwinter until March before winging their way north to the U.S. and Canada, where they’ll feed, most often on milkweed, until late summer.
They begin their southern migration in early fall, and by the first few days of November, virtually all of them have arrived in Michoacan. The butterflies that make this arduous circuit are the great-great-grand-butterflies of the ones that left the subtropics the previous spring! Genetic programming related to the monarchs’ internal circadian clock guides them, likely using the Sun as a navigation aid, to their winter destination. — Steve Spiegel / Jim Foster
Francis Crick, writing in Nature (April 26, 1974) on the 21st birthday of the original Nature paper (April 25, 1953) proposing the Watson-Crick structure of DNA
21st Birthday Rites for Double Helix
Chemical & Engineering News, May 27, 1974
(via cenwatchglass)
abluegirlThe Acorn Woodpecker stores acorns in oak trees for food. They’re constantly pecking holes in trees and have a system where as the acorn dries and shrinks they move it to a smaller hole higher up the tree.
On our visit to Hastings Natural Reserve one of the things that we noticed is that our cabin had metal plates on it and this was to protect the structure from damage from these birds.
We met researchers there who have been studying these woodpeckers as part of a multi-decade study that focuses on their cooperative breeding habits. They had setup posts on trees to track the acorns since this is an important food source and plays a role in the bird’s ability to find mates.
ucresearch
Scientists say it is possible that there have never been fewer butterflies in Britain since it was first inhabited by humans due, in part, to the miserable weather of 2012. The orange-tip population (above) dropped by 34%. Habit loss and agricultural intensification mean that many species live in isolated colonies in small nature reserves, making them particularly vulnerable to extinction after adverse weather. Photograph: Butterfly Conservation
A total of 380 Yangtze finless porpoise have been visually identified during a survey of the Yangtze River, marking a significant decline from 2006 numbers.
Acoustic equipment identified 172 finless porpoise during an expedition. Also known locally as the river pig, a 2011 survey revealed that the porpoise population currently stands at 1,000 in the Yangtze River, and is decreasing by 6.4 percent annually.
These porpoises are being scattered and isolated which is not good for their reproduction. The scattered distribution pattern could be the result of shipping traffic that made migration harder, projects that altered hydrological conditions in the middle and lower reaches, and habit loss. Illegal fishing practices are affecting the finless porpoise populations as well.
I just really hope China steps it up and helps them out. Haven’t they already learned from the extinction of the Baiji dolphin?
This is such a shame. The article linked above was from December 2012, so I found a more recent article from the BBC in February (2013) for anyone curious on what’s happening now:
From 2013 BBC article: “Protection for highly threatened Yangtze finless porpoises in China is “insufficient”, researchers say.
The mammals have suffered a dramatic decline and are now threatened with extinction.
Researchers carried out a survey to the establish how the animals are distributed in the Yangtze river.
They found current protected sections of the Yangtze do not cover all the areas where most porpoises were found.
Details of the findings are published in the journal Animal Conservation.”
You can read further at: http://www.bbc.co.uk/nature/21261583
crownedrose
Bull Valley Slot Canyon and Truck Wreck
Over the years many Earth Science Pictures of the Day have featured slot canyons, remarkable landforms of the Southwestern United States and elsewhere. The slot canyon shown above is unique. In 1954, a highway accident claimed three lives when a pick-up truck tumbled off the road and into Bull Valley Slot Canyon in southern Utah. The arrows on the image point to the truck’s wheels that can still be seen high above the canyon floor.
Skutumpah Road crosses this slot canyon. The canyon is so narrow that boulders were wedged into the top of the canyon to support the rock-fill bridge seen from above in the second photo.
You might find it unusual that a bridge needs to be pointed out when photographed from only a few meters away. To show the location my wife Elaine is standing at the middle of the bridge and nearly 200 ft (60 m) directly above Bull Valley Slot’s deep floor. — Thomas McGuire
Heart-Shaped Glomerocryst Photomicrograph
While studying samples of lavas from the Aeolian Islands off the west coast of Italy, I came across an interesting aggregate of crystals (glomerocryst).
A photomicrograph thin section of the aggregate is featured above. Aeolian lava is studied to understand how magma forms at depth and the level of risk of its eruption. This particular glomerocryst is made of two minerals; plagioclase and pyroxene, whose chemical compositions, textures and melt inclusions help decipher just what happens in a magma chamber.
But, if you look closely at its shape, you might learn something more — that even something as hard as a rock has a heart. — Bernardo Cesare
Double Pink Rainbow Over Glen Ashley, South Africa
The photo above showing a high-arching pink rainbow was captured at sunset near Durban, South Africa.
The camera is facing toward the anti-solar point. Like the setting Sun, the rainbow colors we’re familiar with acquire red or pink hues once the Sun dips close to the horizon. This is because as the Sun sets (or rises) the increased path length sunlight takes through the atmosphere acts to scatter out the green, blue and violet colors from our view. — Photo Jacques Joubert Summary Jim Foster
The point on the celestial sphere that lies directly opposite the sun from the observer, that is, on the line from the sun through the observer.
Colors in Pond Ice Using a Polarizer Lens
The photo above showing meltwater on ice, imaged using a circular polarizer lens, was taken on a pond near Rimavska Sobota, Slovakia.
The refractive index of ice crystals depends upon the polarization and propagation direction of a beam of light. This property is known as birefringence (sometimes called double refraction). The colored light seen when looking through the sides of an airplane window is an example of birefringence. When a beam of light propagates through ice crystals, two distinct rays result, depending upon the direction of propagation.
A polarizer filter or lens acts to recombine the rays. However, due to the fact that these rays were out of phase when recombined, the new polarized rays are composed of various wavelengths of visible light, which as shown here result in especially vibrant colors. Note that colors in pond ice may also be due to interference in narrow fissures and from refraction by trapped air bubbles. — Photography: Daniela Rapava Summary: Jim Foster & Daniela Rapava
