Category: Earth

It could be the scene from a movie: huge plumes of ash and gas rising during a ferocious volcanic eruption, sparking off a dazzling lightning storm; lightning bolts thundering to life inside and out of the hot cloud. However, this is the reality down on the ground for the people living near the Chaiten Volcano, southern Chile, who have been evacuated since the volcano erupted on Friday. Activity continues to increase, producing these terrifying, yet mesmerizing scenes…

Lightning can happen as a result of a volcanic eruption. As the hot ash rises through the cooler atmosphere, transfer of charge occurs. This excess of electrons within the cloud makes it act like a capacitor, and should the conditions be correct, huge electrical discharges may be observed as bolts of lightning during volcanic eruptions. It seems that the Chaiten volcano’s recent activity has created the perfect conditions for such a show, allowing photographers in the region to capture some stunning images.

I actually saw the picture shown at the top of this article in a double page spread in today’s edition of the UK’s Daily Mail. At first I couldn’t work out what I was seeing but on reading the caption I soon realized it was connected with the recent eruption in Chile. Fortunately the Daily Mail also posted the article on their website, giving me the opportunity to share these incredible images on the Universe Today.

This region of South America has some very active plate tectonics and has been dubbed “Andean Arc” region of Chile, Peru, Ecuador and Columbia containing around 200 to 300 volcanoes. Volcanologists are highly concerned as many of these volcanoes are located in densely populated areas, so they are studying the Chaiten eruption very carefully. The small town of Chaiten is being threatened by this particular eruption, but fortunately the surrounding area is otherwise unpopulated.

Sources: Physorg.com, Daily Mail

Can a planet like Earth be considered a single living organism? After all, the human body is composed of hundreds of billions of bacteria, and yet we consider the human body to be a single organism. The Gaia Hypothesis (or popularly known as “Gaia Theory”) goes beyond the individual organisms living on Earth, it encompasses all the living and non-living components of Earth’s biosphere and proposes that the complex interacting systems regulate the environment to a very high degree (here’s a biosphere definition). So much so, that the planet may be viewed as a single organism in its own right. What’s more this hypothesis was developed by a NASA scientist who was looking for life on Mars…

When you stop to think about it, our planet does act like a huge organism. If you look at the interrelationship between plants and atmospherics, animals and humans, rocks and water, a complex pattern of symbiotic processes seem to complement each other perfectly. Should one system be pushed out of balance by some external force (such as a massive injection of atmospheric carbon dioxide after a volcanic event), other processes are stimulated to counteract the instability (more phytoplankton appear in the oceans to absorb the carbon dioxide in the water). Many of these processes could be interpreted as a “global immune system”.

The hypothesis that our planet could be a huge organism was the brain child of British scientist Dr James Lovelock. In the 1960’s when Lovelock was working with NASA on methods to detect life on the surface of Mars, his hypothesis came about when trying to explain why Earth has such high levels of carbon dioxide and nitrogen. Lovelock recently defined Gaia as:

“…organisms and their material environment evolve as a single coupled system, from which emerges the sustained self-regulation of climate and chemistry at a habitable state for whatever is the current biota.” – Lovelock J. (2003) The living Earth. Nature 426, 769-770.

So, Lovelock’s work points to interwoven ecological systems that promote the development of life currently living on Earth. Naturally, the statement that Earth itself is actually one living organism encompassing the small-scale mechanisms we experience within our biosphere is a highly controversial one, but there are some experiments and tests that have been carried out to support his theory. Probably the most famous model of the Gaia hypothesis is the development of the “Daisyworld” simulation. Daisyworld is an imaginary planet whose surface is either covered in white daisies, black daisies or nothing at all. This imaginary world orbits a sun, providing the only source of energy for the daisies to grow. Black daisies have a very low albedo (i.e. they do not reflect the sun’s light), thereby getting hot and heating up the atmosphere surrounding them. White daisies have a high albedo, reflecting all the light back out of the atmosphere. The White daisies stay cool and do not contribute to atmospheric warming.
Java applet of the Daisyworld simulation »

When this basic computer simulation runs, a rather complex picture emerges. In the aim of optimizing the growth of daisies on Daisyworld, the populations of white and black daisies fluctuate, regulating the atmospheric temperatures. When the simulation starts, there are huge changes in population and temperature, but the system quickly stabilizes. Should the solar irradiance suddenly change, the white:black daisy ratio compensates to stabilize atmospheric temperatures once more. The simulated Daisyworld plants are self-regulating atmospheric temperature, optimizing their growth.

This is an oversimplified view of might be happening on Earth, but it demonstrates the principal argument that Gaia is a collection of self-regulating systems. Gaia helps to explain why atmospheric gas quantities have remained fairly constant since life formed on Earth. Before life appeared on our planet 2.5 billion years ago, the atmosphere was dominated by carbon dioxide. Life quickly adapted to absorb this atmospheric gas, generating nitrogen (from bacteria) and oxygen (from photosynthesis). Since then, the atmospheric components have been tightly regulated to optimize conditions for the biomass. Could it also explain why the oceans aren’t too salty? Possibly.

This self-regulatory system is not a conscious process; it is simply a collection of feedback loops, all working to optimize life on Earth. The hypothesis also does not interfere with the evolution of species or does it point to a “creator”. In its moderate form, Gaia is a way of looking on the dynamic processes on our planet, providing an insight to how the seemingly disparate physical and biological processes are actually interlinked. As to whether Gaia exists as an organism in it’s own right, it depends on your definition of “organism” (the fact that Gaia cannot reproduce itself is a major drawback for viewing Earth as an organism), but it certainly makes you think…

Original source: Guardian

In December of 1968, the Apollo 8 capsule had successfully gone into orbit around the moon and the crew was busy taking pictures of the lunar surface. On the fourth orbit, as the Apollo spacecraft was coming around from behind the Moon, the crew saw a breathtaking sight: the Earth rising over the stark lunar horizon. Lunar module pilot Bill Anders looked up up and called out, “Wow! Look at that!”  Commander Frank Borman had a camera with black and white film, and he actually took the first picture of Earth rising over the moon. But Bill Anders managed to get some color film in his camera, and he took the color photo that’s become an icon, known simply as “Earthrise.”

On Earth Day, Bill Anders reflected on the famous picture that’s become one of the most frequently used images ever. Anders said even though it wasn’t in the original flight plan to take pictures of Earth, it didn’t take much time for him to realize how striking this view of the Earth was, and quickly snapped the celebrated image.

“I instantly thought it was ironic; we had come all this way to study the moon, and yet it was this view of the Earth that was one of the most important events for Apollo,” said Anders in an interview on NASA TV.

“There are basically two messages that came to me,” Anders said of the picture. “One of them is that the planet is quite fragile. It reminded me of a Christmas tree ornament. But the other message to me, and I don’t think this one has really sunk in yet, is that the Earth is really small. We’re not the center of the universe; we’re way out in left field on a tiny dust mote, but it is our home and we need to take care of it.”

Anders said it didn’t take long after the crew had returned home for this photograph to become iconic for the environmental movement.

“Back in the 60’s, it gave us a sense that the world was a place we all shared together,” Anders said. “We couldn’t see any boundaries from space.”

In addition to the important pictures of Earth, the Apollo 8 crew also photographed many smaller lunar features, that were previously undiscovered. Those features are located principally on the farside of the Moon in areas that had been photographed only at much greater distances by early robotic spacecraft. The Apollo 8 mission yielded more than 150 photographs of the Earth and more than 700 photographs of the Moon.

Original News Source: NASA TV

If anyone is denial about climate change possibly occuring on Earth, please take a look at this. This animation highlights the rapid loss of ice recently on the Wilkins Ice Shelf in Antarctica. Between February 28 and 29, 2008 an area of about 400 sq km disintegrated into large and small icebergs within 24 hours. As a result of the recent collapse, the remaining shelf, which totals about 14 500 sq km, is now only supported by a 6 km strip of ice. This strip is already rifted, and the remaining strip is in danger of breaking up as well.

The Wilkins Ice Shelf is a broad plate of floating ice south of South America on the Antarctic Peninsula. Since the ice shelf is already floating, this event will not cause a rise in sea level. However, ice shelves on the Antarctic Peninsula are sandwiched by extraordinarily raising surface air temperatures and a warming ocean, making them important indicators for on-going climate change.

Thousands of years of accumulated and compacted snow on the Antarctic central plateau have formed a mighty ice sheet which flows under gravity towards the coastal plane. Along the coast the ice gradually floats on the sea – to form massive ledges known as ice shelves. But as the temperature has increased, several ice shelves have broken up and disintegrated.

The images used for this annimation were taken by the ESA’s Envisat satellite. Within days of its launch, Envisat captured the disintegration of the Larsen-B ice shelf in Antarctica on 18 March 2002. Scientists estimate Larsen-B had been stable since the last ice age 12,000 years ago.

These images were acquired as part of ESA’s support to the International Polar Year (IPY) 2007-2008, a large worldwide science programme focused on the Arctic and Antarctic.

Original News Source: ESA Press Release