Thursday, January 31, 2013

Mount Fuji, Japan

This is a cool image of a cloud hanging around over Japan’s Mount Fuji.

The cloud is in fact a lenticular cloud. Lenticular clouds, also known as; altocumular standing lenticularis clouds, are formed when a current of moist air is forced upwards as it travels over elevated land. This elevation and subsequent decrease in temperature causes the moisture in the air to condense and form a cloud.

Lenticular clouds appear to be perfectly stationary, but in fact, this is not the case. These clouds only appear stationary because the flow of moist air continually resupplies the cloud from the windward side even as water evaporates and vanishes from the leeward side. Lenticular clouds can look like they are hovering for hours or days, until the wind or weather changes and the clouds disperse.

This particular cloud also looks really like a piece of cotton wool!

The imaged was snapped by the DigitalGlobes’s Worldview satellite on the 20th of September 2012.

Implications of Sudden Aspen Death

Ever since the severe droughts in the early 2000’s, aspen trees have been experiencing “sudden aspen death.” Research now suggests that droughts may have weakened past and current trees through a process known as cavitation. Cavitation is a physiological byproduct of a plants response to drought, where they attempt to draw more water through their roots, as water loss through transpiration increases. The added suction can pull air bubbles into the xylem (water-moving pipes) of the tree, disrupting water flow. Trees respond to cavitation by creating bypasses within the xylem, allowing water to move around the air pocket. However, after years of stress, trees will exhibit cavitation-fatigue: where the xylem will tear at the seams, allowing increased incidences of cavitation.

While this process is devastating Aspen trees throughout the United States, the implications for forests around the world are more frightening. Climate change is expected to increase incidences of severe weather and climate events, including drought. If we experience severe droughts over the next few decades, we may be decreasing forest resilience, and ultimately decreasing its biodiversity. While this is difficult to accurately predict, the story our Aspen trees share is one of caution, and hopefully of preemptive action.

Further Reading

Photo - Aspen Forests


You would be forgiven for thinking that this was a photo of an ice shelf. But it's not. It is a sprawling limestone formation called “Pamukkale” or “cotton Castle” in southwest Turkey.

Over the past 400,000 years, a complex of seventeen separate hot springs has been depositing snow white travertine limestone in a series of terraces and waterfalls. The formation is over 2,700 metres long, 600 metres wide and 160 metres high. The springs are present due to the many cracks and fissures in the earth’s surface due to high tectonic activity. The temperature of the spring water as it emerges at the surface ranges between 35–56°C (95–133°F).

Flowing at a rate of 510 litres per second, the water is saturated with calcium carbonate, and as it reaches the surface carbon dioxide is released into the air, allowing the water to deposit the calcium carbonate until its carbon dioxide levels are balanced with those in the air. Initially deposited as a jelly-like substance, the calcium carbonate eventually hardens into travertine. The result is this beautiful landscape which is one of the major tourist attractions in Turkey.

For more photos; follow link:

Image Courtesy of Vasily Goizhevskiy.

Lake Effect Snow

If you live in the Great Lakes region of the United States, you are undoubtedly familiar with the products of lake effect snow (LES). Very simply, LES storms are localized precipitation events that occur as a result of cold air passing over relatively warm waters. However, that explanation does not do justice to the fascinating intricacies that lead to these weather events.

Large bodies of water such as the Great Lakes take longer to warm up than the air (due to waters higher specific heat). As a result, the temperature of the lakes are still warm during fall and some of winter. When cold air moves down from Canada, the warmth of the lakes heats up the bottom layers of the cold air mass, evaporating moisture from the lake into the air. The warm air below begins to rise (since it is less dense), begins to cool, and condenses the evaporated moisture, forming clouds. These clouds cause severe localized snow storms (and sometimes thunder and lightning as well) often exceeding 5 inches (12.7 cm) per hour. The storm bands typically range from 1-25 miles (1.6-40.2 km) wide, appearing as a thin strip on a radar map.

While those who live in LES regions have to adapt to a severe routine weather event, those who don’t can appreciate the power of Earth’s climate under unique geographic circumstances.

Sources/Further Reading

Radar Images/Conceptual Maps

ClarabellafaireStock –

Catch The Granite Wave

You really can ‘ride’ this solid wave. Located near the town Hyden, about 300km east of Perth, Australia, ‘Wave Rock’ is part of the Hyden Wildlife Park and sees around 140,000 visitors each year.

The wave is part of Hyden Rock, which is a large granite dome and is about 100 meters long and 15 meters tall.

The wave itself is made of 2.63 billion year old granite and forms a flared slope. The flare is formed through a multistage event beginning in the Cretaceous, about 130mya. Various processes, including concentrated underground chemical weathering, joint fracturing, regional tectonic processes, and erosion have created what we see today as the wave.
I Wish all the verts here in the Philippines was like that :D Probably Skaters would amazed at it.


Many theories have been explored over the years as to how the Earth stayed warm during the first two billion years of its development, as even though it was warm enough to support life, it was not from heat provided by the Sun. Earth at that time only received 70 percent of the solar radiation that it receives today and its average temperature was up to 25 °C colder. There is geological evidence that Earth had liquid water at this time, despite the average surface temperature being around -10 °C. Robin Wordsworth and Raymond Pierrehumbert, geologists at the University of Chicago, have suggested in a paper published in the journal Science that it was collisions between hydrogen and nitrogen molecules in the atmosphere that kept early Earth warm.

Previous work had focused on the hypothesis that it was methane released by organisms consuming hydrogen that was acting as a greenhouse gas, trapping the small amount of heat coming from the Sun. In this new study however, Wordsworth and Pierrehumbert suggest that collisions between hydrogen and nitrogen molecules create "dimer" molecules that wobble when hit by infrared light from the Sun. This wobbling would allow for heat capture for Earth’s atmosphere. Evidence for this theory would be indications that there was more hydrogen in Earth’s atmosphere in the past than there is today.

The two researchers reference new work by others which suggests that that is the case: there are some calculations that show that early Earth’s atmosphere may have contained as much as 30 percent hydrogen. According to Wordsworth and Pierrehumbert, if the early Earth had as much as 10 percent more hydrogen in its atmosphere than it does today and nitrogen was present at double or triple today's concentrations, Earth's average surface temperature would have been 10 to 15°C higher.

This research has implications for other planetary bodies, as they too may be experiencing similar warming effects. If these worlds have a lot of hydrogen within their atmosphere, they may be worth further observing as a potentially habitable world if they are within a habitable zone.

Saturn’s largest moon, Titan, has liquid on its surface despite being so far from the Sun. Its atmosphere has high concentrations of hydrogen and nitrogen; these gases are under so much pressure that their molecules constantly collide. These collisions cause a chemical reaction that traps the energy of the Sun.

This new model does not explain fossilized raindrop imprints on Earth that date back to 2.7 billion years ago. The size of these imprints suggests that the raindrops fell quickly to Earth through a thin atmosphere similar to that of the present day, rather than an atmosphere thick with greenhouse gases. Hydrogen is a light gas, so the raindrops would have passed through it more quickly than through an atmosphere rich with CO2 or methane. The concentrations of hydrogen and nitrogen needed by this new model would have slowed the raindrops too much to make them consistent with the imprints.

Wordsworth does admit that there is little geological evidence that hydrogen and nitrogen levels were as high as suggested by this new model, but believes there are other factors that could have created such an atmosphere. It is possible that Earth’s volcanoes of 2 billion years ago emitted more hydrogen than today’s volcanoes. The atmosphere at that time would have been able to hold more hydrogen as oxygen levels were lower; hydrogen would have been less likely to combine with this oxygen to form water. Microbes that consume hydrogen may have been rarer than they are today as there were fewer nutrients.

Though the model itself is good, according to Chris McKay of the NASA Ames Research Center in Moffett Field, California, there will need to be strong evidence of nitrogen and hydrogen levels being that high.

The image shows Earth vs Titan, courtesy Victoria Jaggard of National Geographic News
Hydrogen-Nitrogen Greenhouse Warming in Earth's Early Atmosphere, Science 4 January 2013: Vol. 339 no. 6115 pp. 64-67 DOI: 10.1126/science.1225759

The Earth As Canvas

Lovely designs on a page of sandstone in the desert. No, not petroglyphs or any design from the hand of humankind, but the art of the earth itself.

Some time ago, I wrote a post on Liesegang bands, circular rings of color deposited on a rock by the chemical diffusion of metallic elements in ground waters. This sandstone from the Nevadan desert illustrates this process – the colors show the wandering of various kinds of cations of iron (red to yellow), manganese (purple-blue to black), zinc (white to blue; near maroon when deposited as sphalerite), green (copper) and yellow (barium generally yellow in these circumstances). The white crusty deposits on this sandstone look very much like the kind of crusty carbonates mixed with clays that are associated with hydrothermal (hot spring) systems.

In addition to just being a lovely but superfluous addition onto the rock, these colors show the mineral explorationist a view of what is (or was) carried in the hydrothermal system: cooler waters carry the more mobile elements like manganese and can include deposits of gold and silver; warmer waters carry the less mobile zinc and copper. A lovely rock surface like this one is like part of a halo of fluids surrounding the core of a hydrothermal mineral deposit.

All the colors on the rock of this photo essentially shout to the geologist that somewhere nearby is a deposit of sulphide minerals, and thus could lead to a discovery of copper, silver, or even gold. How near? Where? Feel a sudden urge to do a bit of exploring?

With such lovely indications as this, mineral exploration and art exploration can go hand in hand. The Earth – we love it for the science, we love the science because it can be so damned beautiful!

Photo used with thanks by Doyle Wayman from his Facebook page 321go explore.

My older post:

Bushfires in Australia, Wildfires in America

Australia’s heat wave has caused temperatures to soar and the risk of bushfires to increase dramatically ( Bushfires surged through New South Wales and Tasmania in recent days, destroying properties and forcing many people to flee their homes. The fires are fuelled by the soaring temperatures of the heat wave as well as powerfulwinds. Hundreds of firefighters have been battling the blazes across Australia, which have been fanned by winds over 70 km/h (~44 miles/h).

Monday 7 January saw a nationwide average maximum temperature of 40.3°C (104.5°F), setting a new record for Australia's hottest day on record and beating the previous record of 40.2°C set on 21 December 1972. The national maximum temperature had also averaged above 39°C (102.2°F) for six consecutive days. There is a ‘dome of heat’ over the centre-east of the continent, and the Australian Bureau of Meteorology has had to extend its temperature scale to include temperatures up to 54°C (129.4°F; Australia is 7,618,000 km²; for comparison, here is a visual of the size of Australia compared to North America:

Firefighters in NSW (New South Wales) have been battling 135 blazes in temperatures above 40°C and a fast-moving fire in Victoria has destroyed two properties. 40 fires in NSW remain uncontained but fortunately there were no reports of loss of life or homes; the fires have burned more than 26,000 hectares (~65,000 acres) of grass, scrub and bushland. Up to 90 percent of NSW was in severe danger and a total fire ban is in place and there is a total fire ban in place in ACT (Australian Capital Territory) as well. The fire in Victoria was about 500 hectares in size (~1235 acres) and created spot fires one kilometre ahead.

In Tasmania, communities that are in the path of a destructive bushfire in the state's southeast have been told it was too late for people to leave. The Tasmania Fire Service (TFS) has advised people that they should head to the Eaglehawk Neck jetty or beach. More than 100 properties have been destroyed in the state already. About 110,000 hectares (~271,000 acres) have now burnt out across the state.

Australia’s vegetation has evolved with fire and has characteristics that promote the spread of fire. Eucalypt is coarse and decays slowly; the bark of many other species is flammable; and green leaves contain highly flammable oils and resins that promote combustion. When weather patterns occur that enable hot and dry winds to blow from the centre of the continent combine with previous drought, bushfires are sparked.

It is not just Australia that is affected by increasing temperatures. 2012 was the hottest year on record for the USA. The average temperature of 13°C (55.3°F) was about half a degree warmer than the 12.4°C (54.32°F) reading in 1998 and the 12.39°C (54.31°F) average in 2006. The temperature went above normal every month from June of 2011 to September of 2012, which had never been seen before in 118 years of record-keeping. Around 100 million Americans experienced 10 or more days of temperatures exceeding ~38°C (100°F). Among the cities experiencing their hottest years on record were Chicago, New York, Boston, Washington, D.C., Milwaukee, St. Louis, Denver and Des Moines.

August 2012 saw many large fires spark across the western and central U.S. regions as they experienced dryness, low humidity, and windy conditions. This resulted in a year-to-date average fire size of 70 ha (173.5 acres), the most since 2000. August’s total of ~1.5 million ha (3.64 million acres) burned by wildfires was the highest for any August since 2000.

While Australian bushfires and American wildfires require hot and dry conditions with preceding drought, American wildfires are triggered by lightning strikes and thunderstorms in some areas. Another cause is the build-up of grass, leaves and twigs in a pile: this collection of dead matter can create enough heat at times to spontaneously combust and ignite the surrounding area.

Unfortunately Australia is likely to be at risk of further bushfires and record-breaking heat in the future due to climate change. There is also likely to be an increase in fire risk across the U.S. by 2050. ‘‘Clearly, the climate system is responding to the background warming trend. Everything that happens in the climate system now is taking place on a planet which is a degree hotter than it used to be’’ Australian Bureau of Meteorology’s manager of climate monitoring and prediction, David Jones, said. Record-breaking heat will become more and more common. Though there is some natural variation, there are many more hot records than there are cold records.

The image show flames from the Deans Gap bushfire glow through the smoke covering Princes Highway at Shoalhaven on the NSW south coast on January 8, 2013.

Australian resources:

American resources:

Image courtesy

Climate Changes

Climate change is correctly regarded as one of the greatest threats to humanity in the 21st century and with many of the world’s governments reluctant to reduce greenhouse gas emissions it looks unlikely that we will be able to stop global temperature rises over the coming decades by reduction and substitution alone.

Geoengineering may offer another route to preventing excessive global temperature rise; geoengineering is a branch of engineering that intentionally manipulates earth system processes. A promising technique known as stratospheric aerosol injection (SAI) would reflect incoming solar radiation thereby lowering surface temperatures, in other words it would create global dimming to counter balance global warming.

SAI would inject sulfide gases such as sulfuric acid, hydrogen sulfide or sulfur dioxide by highflying artillery aircraft into the stratosphere. Estimations by the Council of Foreign Relations state, “one kilogram of well placed sulfur in the stratosphere would roughly offset the warming effect of several hundred thousand kilograms of carbon dioxide”.

There are both many positives and many negatives to SAI.
Possible positives include:

- Cost, estimated at costing between $25-50 billion a year it works out over a 100 times cheaper than producing the same temperature change by reducing CO2 emissions.
- Technological feasibility, all the technology for this to work exists.
- Natural process, volcanoes naturally do this same process.
- Speed of action, temperatures would change quickly after the sulfur is injected as the solar radiation is reflected back into space.
- Efficacy, SAI has the potential to completely control the temperature change by adding more or less as required. Factors such as delivery, distribution and lifespan of the aerosols do still need more research to be fully addressed.

Possible negatives include:

- If stopped after many years of use the short lived aerosols would no longer work after a few years leaving the world to heat very quickly as all the longer-lived carbon that it had been offsetting would take effect heating the world very quickly.
- Drought, as risk of monsoon failure in Asia/ Africa.
- Ozone depletion
- Tarnishing the sky, the potential to affect the appearance of the sky resulting in a whitening effect.
- Ecosystems, plant growth may be affected and an increase in ocean acidification due to acid rain.

As the results of climate change are increasingly felt around the world, SAI may provide a get out of jail free card but the cost in doing so could trigger many other problems in the process. More research and modeling is needed before SAI is seriously considered.

More info:


Pollutant Levels Increase Around Tar Sands Mine

Levels of pollution in lakes around the Athabasca Oil Sands mines in Alberta Canada are increasing due to the mining activities. According to Queen’s University’s John Smol, the levels of polycyclic aromatic hydrocarbons (PAHs) have increased up to 23 times in sediment.

PAHs are a known human carcinogen. Smol and his colleagues took sediment core samples from 6 lakes around the mines, even as far away as 90km, for this study. “We show clearly the timing of the change and the type of contamination, and the ones increasing are ones closely related to the tar sands industry.”

The sediment cores date back as far as 1960, 20 years before the mining activities began. Though the levels of PAHs are increasing they have not yet reached the levels found in more urban streams and lakes. The study also shows that there have been no noticeable impacts to the fish or other aquatic life in the lakes.

Photo Credit: Peter Essick (National Geographic)

Further Reading:

Lake Retba

Lake Retba, or Lac Rose, is a stunning pink lake in Senegal, Africa, located to the North of the Cap Vert peninsula.

The lake is obviously named for its bright pink waters, which are caused by the algae Dunaliella salina. The colour appears to be more vivid during the dry season, and as well as being pink, the lake also has a high salinity, similar to that of the Dead Sea, which allow
s people to float with little effort. Because of the high salinity, little else but Dunaliella salina can live in the lake, and the water is no good as a drinking source. The lake does however serve as a tourist spot and as a salt collection spot- enhancing the local economy.

Image; Tumblr


The pre-Cambrian is the name given to all of geological time before the Cambrian period, and is itself divided into three eras of Geological time, the Hadean, the Archean and the Proterozoic. The time frame encompassed by the “Pre-Cambrian” includes everything from the formation of the Earth 4600 million years ago, to the start of the Cambrian period 542 million years ago.

The Hadean era is the eldest era, and spans from the formation of the Earth (4600ma) to the beginning of the Archean era 3800ma. No rocks survive from the Hadean era, but it is theorised that at this time the surface of the Earth was a giant sea of lava with huge volcanoes, and a highly toxic (to us) atmosphere made of carbon dioxide and water vapour. Any rocks that did manage to form on the surface would have been quickly covered by new lava flows, or blasted away by impacts from space. It is believed that during the Hadean era an asteroid as large as the planet Mars smashed into the Earth and in the process created the moon as part of the “splash”! Rocks that have a date from this era are rocks that have fallen from Space and Moon Rocks.

Links for the Hadean era:

Image Credit; (

Sunrise over Bryce Canyon

The stunning image below shows the sun rising over Bryce Canyon, located in Utah, USA. Bryce Canyon is famous for its spectacular rock outcrops showing many different colours.

The rocks were deposited in differing environments which included marine shale, lake limestone and delta plain sandstone over a time span from the late Mesozoic to the middle Cenozoic.

The unique outcrop pattern comes from a combination of uplift - two events: the Laramide orogeny (70-50ma) and the uplift of the Colorado Plateau (during the Miocene, around 20-16ma) - and erosion.

The uplift caused vertical joints to appear, and the rock was preferentially eroded along these joints creating the columns seen in the image. The columns are known as hoodoos, and Bryce Canyon has the highest concentration of hoodoo features of anywhere on Earth.

The colours in the hoodoos are from different concentrations of minerals; the reds, browns and pinks are from hematite, the yellows from limonite and the purples from pyrolusite.

Image: Munish Singla


The Bourke's Luck Potholes are found within the Mpumalanga province of South Africa and are a natural water feature, formed over thousands of years of water erosion. They mark the beginning of the Blyde River Canyon, one of the largest canyons in the world.

The Bourke's Luck Potholes occur at the confluence of the Treur and the Blyde rivers, about 35km north of Graskop on the R532. The potholes were formed by the waterborne sand and pebbles within the Treur river, grinding huge cylindrical potholes as they swept over the bedrock. The colours of the bedrock vary from white to yellow to reddish brown.

The potholes are named for a prospector named Tom Bourke, who discovered signs of alluvial gold in the canyon in the late 1880s. He staked a claim and started panning for gold – to no avail. Other prospectors in the area did however strike it rich. Bourke's Luck Potholes have been referred to as 'nature's wishing well' by some and many a tourist has dropped coins into the well.

Harnessing Tornados For Energy

Sounds like a poorly written script for a cheap disaster movie right?

Well this is the idea behind the Canadian company AVEtec founded by engineer Louis Michaud. He isn’t the only one who believes it’s possible however, eccentric billionaire Peter Thiel the co-founder of Paypal and early investor in Facebook is planning to fund the idea with an initial grant of $350,000 through his foundation. Thiel has a strong track record for spotting the crazy genius in the just damn right crazy.

Atmospheric Vortex Engine (AVE) works by introducing warm air into a circular station, taking the form of a rising vortex through convection. The rising vortex is essentially a fixed and controlled tornado, capable of being stopped simply by turning off the warm air. The work done by the convection is captured with turbines located at ground level around the periphery of the arena. The heat source to create the warm air can be warm water (tropical oceans), waste heat or solar energy.

AVE is a clean energy source that doesn’t produce carbon emissions and doesn’t need energy storage. Another advantage is the low cost; at an estimated 3 cents per kilowatt-hour AVE would be one of the least expensive forms of energy production. A 100m diameter AVE power station would generate 200 megawatts of electrical power, which is about the same as a conventional coal power station.

Latent heat of water vapor in the bottom kilometer of the atmosphere has almost twice the energy (13x10 21J) of the remaining oil (7.3x 10 21J) reserves and can be fully replenished in 10 days through solar radiation compared to 100s of millions of years for natural oil.

Currently AVEtec is building a prototype in partnership with Lambton College to demonstrate the feasibility and safety of the atmospheric vortex engine.

More info:

Image of how it works:


Noctilucent Clouds

These rare, mystifying clouds are referred to as “night-shining” clouds, or noctilucent clouds. They are formed under very restrictive conditions and are only seen in the summer, at latitudes north of 50 degrees.They originate in the layer called the mesosphere; making them the highest cloud formations in our atmosphere.

Normally, they are far too faint to be seen, but they can be visible when illuminated by sunlight below the horizon. As with normal clouds, ice crystals within noctilucent cloud systems need two things to grow; water and something for the water to adhere to, usually dust. While ordinary tropospheric clouds get their source of dust from things like desert storms, this is not a viable medium in the mesosphere where this dust simply cannot reach. Accordingly, it is speculated that these cloud formations utilise dust particles from outer space.

As for the source of the water vapor necessary to produce clouds at such extreme altitudes, upward winds during the summertime are capable of carrying water droplets from the moist lower atmosphere toward the mesosphere. That's why noctilucent clouds only appear during the warm summer months.

For more information see:

Picture courtesy of Science Photo Library.

Ice Fracturing

Cold enough for you? If it’s frosty where you live, a visit to any rocky outcrop can demonstrate one of the earth’s most active geologic processes.

Rocks may look solid, but there are enough cracks and voids in them so that with a good rain, they fill with water like a sponge. An odd property of water is that it is one of the rare substances that gains volume (about 9%) when it changes to a solid state. Thus, when water seeps into small fractures and voids, then freezes during a cold night or winter, its volume increases so that the ice in a fracture acts like a wedge, pushing and shoving apart the surrounding rocks.

The wedging action of a single freeze may not alone be capable of cracking open a “solid” rock. But over even a short geologic period of several thousands of years, the freezing wedge can be repeated thousands of times. A state of constant freeze, such as in the Antarctic, is not as effective as in a climate of rapidly fluctuating conditions between freezing and melting. Such conditions of repetitive hard freezes are common in Alpine and periglacial regions. Many of the mountains we view today bear the scars of ice fracturing from the repetitive hard freezes dating from the latest days of the latest ice age.

The effects of ice fracturing can be seen everywhere in the mountains of more temperate zones. It aids processes of surficial rock exfoliation, and can even be the cause of splitting off sides of mountains hundreds of meters in size. Yet is it a commonly overlooked geologic process within rocks examined by geologists in the hot summer months. In the winter, look out: rock falls are often the result of ice fracturing.

Photo by Anna Batsi

Read more:
Rassios, Ghikas, Batsi, 2013. The Birth of Meteora.

Fallstreak Holes AKA Hole-Puch Clouds

Fallstreak holes are a cloud formation that occurs as gaps in mid or high level cloud layers; below them trails of ice crystals dangle. In order for a fallstreak hole to form, the cloud layer must be composed of supercooled droplets (liquid water), despite the temperatures at cloud level being well below 0°C. When one region of the cloud begins to freeze, the fallstreak hole forms. This begins a chain reaction whereby all the moisture from the supercooled droplets in the nearby area is drawn in and joins the ice crystals. These then grow big enough to fall beneath the hole; fallstreak holes have been known to reach 50 kilometres across just an hour after the hole began to form.

Though these cloud formations have been known about for some time, scientists were unclear as to why the freezing began in one area of a cloud layer and how it grew in size. Research published in Science magazine in July 2011 sought to answer these questions.

The research was performed by Andy Heymsfield and his colleagues at the National Center for Atmospheric Research in Boulder, Colorado. The team used a satellite called GOES to track 92 cloud holes over Texas over 4 hours in January 2007. The holes grew a considerable amount within an hour and then slowly began to shrink. Most of the holes had a diameter between 10 and 50 kilometres. Heymsfield theorised that a side effect was at play, creating the ice that caused the holes to grow.

To test this theory, Heymsfield ran a detailed computer model of the internal workings of a cloud, introducing a line of ice crystals like those produced by an aircraft. The simulation showed a hole that grew to a diameter of 4.4 kilometres in 90 minutes. If the heating effect of creating ice in the simulation was turned off, the hole grew slowly; if the effects of evaporation were also removed, the hole didn't grow at all.

The research confirmed that aircraft flying through the cloud could be what is setting off the freezing process. The air expands as it passes over the aircraft wings and over the blades of its propellers. This causes the air to cool; this cooling can be long enough to decrease the temperature enough for the droplets to start to freeze. When these droplets change into solid particles, they emit a small amount of heat, which causes the air around them to expand and rise somewhat. This rising current causes the surrounding air to sink slightly.

When the air around the frozen fallstreak sinks and begins to warm up, the droplets within begin to evaporate. This appears to be why the fallstreak of ice crystals produced by the plane flying through the cloud layer forms a circular hole that looks like it has been ‘punched’ out of the cloud layer. It does not seem to matter whether the plane is ascending or descending through the cloud layer.

Image is over Jay, Florida, USA. Courtesy Vicki Harrison / The cloud collector's handbook

Petrified Forest National Park

When I saw that a new geologic map had been made for the Petrified Forest National Park, my thoughts went back to my first visit there when I was just four-years-old; of all my childhood memories, these are among the most vibrant. It wasn’t until I could read that I could go through the “report” on the park published before I was born (I still have it); and not until I was in second grade that my piece of petrified wood from the souvenir shop was glued to a board and included as part of my first science project.

Petrified wood is rare; petrified wood of the quality in the National Park is very very rare. The existence of petrified wood in the area that would be the park was recognized in 1851, and documented in an early scientific study in 1853. First proposed to become a National Park in 1890, even with the help and study of John Muir, the area was initially declared a National Monument by Teddy Roosevelt in 1906, and finally gained National Park status in 1962.

So why is this an “old” park?

The majority of the park’s terrain consists of the upper Triassic Chinle Formation (~215 million years in age), which comprises geologic deposits from a lowland terrestrial environment with meandering river valleys, swamps and lakes. And forests. And dinosaurs. It is not unusual to encounter a Triassic formation, but so great an expanse of preserved surface lands is exceedingly rare. The Chinle is so little deformed, so mildly metamorphosed, that it is like, well, visiting the planet Earth in the Triassic. This is one of the world’s oldest and best preserved “fossil” ecosystems.

Petrified wood as in the Park is the remnant of trees and other vegetation that have been “fossilized” by replacement of plant material slowly via the penetration of silica-bearing waters which then slowly turn the wood into jasper. This jasper, in itself stunningly colored, frequently retains the original structure and appearance of the parent tree: within the park, you can visit conifer stumps with their roots intact; count the tree rings to see how old a tree was when it died in the Triassic; and even observe the borings of Triassic insects into the trees. In some petrified wood, the jasper has crystallized to from quartz crystals including semi-precious stones of citrine and amethyst.

In addition to the ancient geologic setting, the park has abundant petroglyphs, carvings on stone surfaces by native Americans, some dating back to 13,000 years in age. Much of the area referred to as “The Painted Desert” is contained in the National Park, in itself a desert region deserving its own post here on TES.

Thank you for allowing me, through The Earth Story, to revisit a place that holds a special place in my memory. Perhaps if you take your four-year-old to visit the Park, he/she too may become a geoscientist!

Photo: Courtesy National Parks Service
The new map and report by the park geologists can be downloaded here:
I highly recommend the photo gallery of the National Park Service and USGS:
Link to my first rock-baby:

Moon Dog

Moon Dogs are analogous to Sun Dogs ( except of course they are formed by moonlight. Scientifically called paraselenae, they appear 22 degrees to the left and right of the moon, but show very little color due to the light not being bright enough to activate the human eyes cone cells. This lack of brightness makes them much more rare than sun dogs.

This photo is loaded with extra goodies as well. Just below the moon are noctilucent clouds ( and on the far left there is a faint wisp of aurora borealis (

Photo Credit: David Cartier (


World's oldest fossils

Most of you would have heard of stromatolites, fossilised communities of single celled blue-green algae (also known as cyanobacteria,) but biogeochemist Nora Noffke believes that the organisms that produced stromatolite structures may have produced other structures that are even older than stromatolites, some may date back to being 3.49Ga!

Microbially induced sedimentary structures or MISS as Nora calls them are believed to represent the oldest fossils ever described, and Nora and her team presented their research at a December meeting of the Geological Society of America.

Like stromatolites, MISS also form their shapes by trapping mineral and sand particles in their matrix. When the community dies off the structure turns to solid rock, fossilising the original structure of the community.

The research centres on the Pilbara region of Western Australia, and whilst the team needs to complete additional research to verify the age of the fossils, the could well be evidence of our oldest ancestors!

Image: Paul Harrison "Stromatolites growing in Hamelin Pool Marine Nature Reserve, Shark Bay in Western Australia."