Green Man Blog - Earth's Wonders

Earth: Biggest Hits in History

nospam@example.com (Green Man) — Wed, 10 Mar 2010 07:56:55 -0700

The animation at right, from the University of Arizona, depicts the impact that formed the Chicxulub crater in Yucatan, Mexico.

The crater measures 180 kilometers across and the impacting meteorite is estimated to be 10 kilometers wide.

The impact was so great it caused the mass extinction of the dinosaurs.

As big as it is, however, there are other craters even bigger.

Vredefort crater

The Sudbury crater in Ontario, Canada, measures 250 kilometers across. Occurring 1.85 billion years ago, the crater was formed when a comet hit the Earth.

But the largest crater is known as the Vredefort crater, located in South Africa. It measures 300 kilometers across, and the impact occurred about 2 billion years ago.

Impact craters are still being discovered; the latest may be the 36-46 kilometer wide crater found in the Congo.

This crater was revealed only after deforestation occurred in the area, and if confirmed would be one of the 25 largest impact craters in the world.

The Earth Impact Database has more information on craters around the world.

Meteor Crater, Arizona.

Avalanches Around the World

nospam@example.com (Green Man) — Wed, 10 Feb 2010 06:43:28 -0700

Recent avalanches in the Salang Pass of Afghanistan have killed over 150 people, and many more remain buried alive. This tragedy is a reminder of the power and danger avalanches present.

Nearly a hundred years ago, during World War I, Austrian and Italian troops fighting in the Alps faced the prospect of catastrophic avalanches that some believe were caused by artillery fire. The number of troops killed is staggering. During December of 1916, for example, over 10,000 Austrian and Italian soldiers were killed by a deadly series of avalanches, including one avalanche on December 13 that buried an Austrian barracks and killed several hundred soldiers.

In 1951-1952, during what was called the Winter of Terror, over 650 avalanches were recorded in the Alps, killing 265 people.

In 1999, an avalanche in Montroc, France, hit speeds of 60 mph and moved over 310,00 cubic yards of snow as it buried chalets and killed 12 people. The same year 31 people died in the Austrian town of Galtur as the worst avalanche in 40 years hit the village.

The Salang Pass in summer. The steep sides mean winter travelers face a constant threat of avalanches.

World's Smallest Gears

nospam@example.com (Green Man) — Mon, 01 Feb 2010 05:14:26 -0700

The video at right shows two gears being turned by, of all things, common bacteria.

The gears are tiny, only 380 microns wide, which is about 8 times thicker than a human hair. They are turned by a swarm of bacteria randomly colliding into them.

It only takes a few hundred bacteria to start the gears turning, and the gears can be stopped and started by decreasing or increasing oxygen to the bacteria. Researchers at Argonne Labs, who pioneered the process, hope this is the beginning of hybrid biological machines than can work on microscopic levels.

A Giant Coming Down At Last

nospam@example.com (Green Man) — Thu, 21 Jan 2010 15:07:16 -0700

Photograph by Robert F. Bukaty

In Yarmouth, Maine, a towering elm tree is coming down.

It’s no ordinary tree.

Scientists say the massive elm was standing in the days of the American Revolution. It may be over 240 years old, but the exact age won't be known until the tree rings are counted.

But Dutch elm disease has finally killed the great tree.

Surprisingly, the tree has withstood 14 bouts with Dutch elm disease before. Over the last fifty years the tree was lovingly cared for by Frank Knight, who is now 101 years old himself.

Wood from the tree will be given to craftsmen and artisans who will make furniture and other products with it.

Would Hemingway Recognize It Now?

nospam@example.com (Green Man) — Wed, 13 Jan 2010 01:05:00 -0700

Kilimanjaro is a snow-covered mountain 19,710 feet high, and is said to be the highest mountain in Africa. Its western summit is called the Masai "Ngaje Ngai," the House of God. Close to the western summit there is the dried and frozen carcass of a leopard. No one has explained what the leopard was seeking at that altitude.

-Ernest Hemingway, preface to the short story, "The Snows of Kilimanjaro."

The Green Man Blog is written to spread environmental awareness and appreciation of the natural world around us. Thank you for visiting! Stay green, support the organic movement, and be sure to visit www.greenmantshirts.com or www.robjuszak.com for the best in organic cotton and bamboo t shirts!

13 Billion Years Ago

nospam@example.com (Green Man) — Wed, 06 Jan 2010 03:04:00 -0700

The photo at right is the earliest image ever taken of our universe.

It represents looking back in time 13 billion years. The picture was taken by the Hubble telescope.

The universe is about 13.7 billion years old, and scientists want to see far enough out in space to catch images of the first galaxies and stars formed after the Big Bang. To achieve this, a new telescope—the $4.5 billion James Webb telescope—will be launched in about 4 years.

If successful, the James Webb telescope will be able to see across time to the very earliest years of the universe, perhaps within a few million years of its creation.

Our question is: what existed before the Big Bang?

Ice Ahead!

nospam@example.com (Green Man) — Wed, 23 Dec 2009 11:38:00 -0700

We all know something about icebergs: only about 1/10 of an iceberg is above water, and ships do best to avoid them.

But here are a few more bits about these pieces of ice: they generally range from 1 to 80 yards above sea level and weigh from 100,000 to 200,000 tons. They can float along at 10 miles per day. The tallest iceberg on record was 550 feet above sea level.

The overall biggest, however, was the one that broke off the Ross Ice Shelf back in 2000. It was over 180 miles long and 23 miles wide. The scientists gave it the rather dull name of B-15, and estimated it to weigh over 3 billion tons.

After 10 years it still hasn’t melted, although it has fractured into several smaller sized chunks.

Snow, And Lots Of It!

nospam@example.com (Green Man) — Tue, 22 Dec 2009 20:52:00 -0700

The first day of winter was yesterday, December 21, and it’s only fitting to talk about snow.

Here in San Diego we don’t think much about it, though. We have a Mediterranean climate that gives warm sunshine all year. But other parts of the country, of course, get snow; lots of snow.

Snow records have only been kept about a hundred years, but there are still some amazing snowfalls on record.

In 1921, Silver Lake, Colorado, received 76 inches of snow in only 24 hours.

In 1955, a five-day storm dropped 175 inches of snow over parts of Alaska. That’s nearly 15 feet of snow in less than a week.

And in a year’s period, 1,224 inches of snow fell on Mt. Rainer in Washington state, making that the heaviest recorded annual snow.

Snow can be such a pain, especially if you have to drive in it or shovel out your walkway each day. But individual snowflakes are beautiful, as these pictures from SnowFlakes.com illustrate.

VISTA Now Online

nospam@example.com (Green Man) — Sun, 13 Dec 2009 08:31:26 -0700

This image is the first one released from VISTA. It shows the clearest picture ever attained of the Flame Nebula, in the constellation of Orion, and its surroundings.

A new telescope has just gone online down in Chile. Called VISTA (the Visible and Infrared Survey Telescope for Astronomy), the infrared telescope features a 4.1 meter mirror of the highest quality ever achieved.

The mirror is so perfectly polished that its only deviations are less than a few thousandths of the thickness of a human hair.

VISTA sits on a peak in the Atacama Desert, which has some of the best night viewing conditions on the planet. Its infrared technology allows it to “see through” dust clouds that block the view of normal telescopes.

Inside VISTA is a special 3 ton camera that records the images, and the camera has to be cooled to -200 degrees Celsius so its own heat won’t interfere with the faint infrared radiation the mirror picks up from space.

The VISTA camera was a team project built by the Rutherford Appleton Laboratory, the UK ATC and the University of Durham in the United Kingdom.

http://www.eso.org/public/

The Eyes Have It

nospam@example.com (Green Man) — Sat, 12 Dec 2009 03:35:00 -0700

You wouldn’t think a shark like a Hammerhead could see well, would you?

Come on, look at the thing. With that distinctive head shape and one eye poking out each side, how can it possibly have binocular vision the way humans and other animals do?

Turns out it does, though.

When scientists got around to studying the issue and measured the visual fields, it turned out that Hammerhead sharks have a 182 degree field of view from each eye. This means their fields of view overlap, and in some types of hammerhead that overlap can be to 32 degrees.

This gives these sharks outstanding binocular vision, meaning excellent depth perception.

So as ugly as the Hammerhead shark looks, it has no trouble looking out for itself, so to speak.