Posts Tagged ‘volcanoes’

Venus: Death of a Planet

Sunday, August 8th, 2010

From the fires of a sun’s birth… twin planets emerged. Venus… and Earth. Two roads diverged in our young solar system. Nature draped one world in the greens and blues of life.

While enveloping the other in acid clouds… high heat… and volcanic flows. Why did Venus take such a disastrous turn?

For as long as we have gazed upon the stars, they have offered few signs… that somewhere out there… are worlds as rich and diverse as our own.

Recently, though, astronomers have found ways to see into the bright lights of nearby stars.

They’ve been discovering planets at a rapid clip… using observatories like NASA’s Kepler space telescope… A French observatory known as Corot … .And an array of ground-based instruments. The count is approaching 500… and rising.

These alien worlds run the gamut… from great gas giants many times the size of our Jupiter… to rocky, charred remnants that burned when their parent star exploded.

Some have wild elliptical orbits… swinging far out into space… then diving into scorching stellar winds. Still others orbit so close to their parent stars that their surfaces are likely bathed in molten rock.

Amid these hostile realms, a few bear tantalizing hints of water or ice… ingredients needed to nurture life as we know it.

The race to find other Earths has raised anew the ancient question… whether, out in the folds of our galaxy, planets like our own are abundant… and life commonplace?

Or whether Earth is a rare Garden of Eden in a barren universe?

With so little direct evidence of these other worlds to go on, we have only the stories of planets within our own solar system to gauge the chances of finding another Earth.

Consider, for example, a world that has long had the look and feel of a life-bearing planet.

Except for the moon, there’s no brighter light in our night skies than the planet Venus… known as both the morning and the evening star.

The ancient Romans named it for their goddess of beauty and love. In time, the master painters transformed this classical symbol into an erotic figure.

It was a scientist, Galileo Galilei, who demystified planet Venus… charting its phases as it moved around the sun, drawing it into the ranks of the other planets.

With a similar size and weight, Venus became known as Earth’s sister planet. But how Earth-like is it?

The Russian scientist Mikkhail Lomonosov caught a tantalizing hint in 1761. As Venus passed in front of the Sun, he witnessed a hair thin luminescence on its edge.

Venus, he found, has an atmosphere. Later observations revealed a thick layer of clouds. Astronomers imagined they were made of water vapor, like those on Earth. Did they obscure stormy, wet conditions below?

And did anyone, or anything, live there? The answer came aboard an unlikely messenger…. an asteroid that crashed into Earth.

That is… according to the classic sci-fi adventure, The First Spaceship on Venus. A mysterious computer disk is found among the rubble.

With anticipation rising on Earth, an international crew sets off to find out who sent it… and why. Approaching Venus, the astronauts translate the contents of the disk. The news is not good.

In a desperate attempt to prevent an interplanetary war… and save their home planet… the crew embarks on a dangerous mission.

They descend to the planet’s dark surface to confront the adversaries.

Duration : 0:22:9

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Planet of Altered States

Friday, July 2nd, 2010

Best viewed full screen 1080p. Natural and human-caused change captured in these extraordinary image sequences covering years and decades of time. Read about the individual sequences on:

http://earthobservatory.nasa.gov/Features/WorldOfChange/index.php

Earth is constantly changing. Some changes are a natural part of the climate system, such as the seasonal expansion and contraction of the Arctic sea ice pack. The responsibility for other changes, such as the Antarctic ozone hole, falls squarely on humanity’s shoulders. NASA’s World of Change series documents how our planet’s land, oceans, atmosphere, and Sun are changing over time.

Mt. St. Helens
The devastation of the May 18, 1980, eruption of Mt. St. Helens and the gradual recovery of the surrounding landscape is documented in this series of satellite images from 1979–2009.

Aral Sea
A massive irrigation project in the Kyzylkum Desert of central Asia has devastated the Aral Sea over the past 50 years. These images show the continued decline of the Southern Aral Sea in the past decade, as well as the first steps of recovery in the Northern Aral Sea in recent years.

Dubai
To expand the possibilities for beachfront tourist development, Dubai, part of the United Arab Emirates, undertook a massive engineering project to create hundreds of artificial islands along its Persian Gulf coastline.

Yellowstone
In 1988, wildfires raced through Yellowstone National Park, consuming hundreds of thousands of acres. This series of Landsat images tracks the landscape’s slow recovery through 2008.

Southeast Australia
Drought has taken a severe toll on croplands in Southeast Australia during many years this decade.

Colorado River
Combined with human demands, a multi-year drought in the Upper Colorado River Basin caused a dramatic drop in the Colorado River’s Lake Powell in the early part of the 2000 decade. The lake began to recover in the latter part of the decade, but as of May 2010, it was still less than 60 percent of capacity.

Antarctica
In the early 1980s, scientists began to realize that CFCs were creating a thin spot—a hole—in the ozone layer over Antarctica every spring. This series of satellite images shows the ozone hole on the day of its maximum depth each year from 1979 through 2008.

Amazon
The state of Rondônia in western Brazil is one of the most deforested parts of the Amazon. This series shows deforestation on the frontier in the northwestern part of the state between 2000 and 2008.

Larsen B Ice Shelf
In early 2002, scientists monitoring daily satellite images of the Antarctic Peninsula watched in amazement as almost the entire Larsen B Ice Shelf splintered and collapsed in just over one month. They had never witnessed such a large area disintegrate so rapidly.

West Virginia
Based on data from NASA’s Landsat 5 satellite, these natural-color (photo-like) images document the growth of the Hobet mine in Boone County, West Virginia, as it expands from ridge to ridge between 1984 to 2009.

Iraq
In the years following the Second Gulf War, Iraqi residents began reclaiming the country’s nearly decimated Mesopotamian marshes. This series of images documents the transformation of the fabled landscape between 2000 and 2009.

Yellow River Delta
Once free to wander up and down the coast of the North China Plain, the Yellow River Delta has been shaped by levees, canals, and jetties in recent decades.

Duration : 0:3:16

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