NASA’s Cassini beams back stunning pictures of Saturn, Earth

Per CBS News and NASA

 

NASA’s Cassini spacecraft has beamed back spectacular pictures of Saturn, its rings and distant Earth, a “pale blue dot” nearly a billion miles away, as the robot passed behind the ringed planet last Friday.

Following Cassini’s lead, NASA’s Messenger spacecraft, in orbit around Mercury, also trained its camera on Earth during a search for undiscovered moons.

 

Passing behind Saturn last Friday, NASA’s Cassini spacecraft snapped a series of pictures showing the planet and its rings, including planet Earth as a “pale blue dot” 898 million miles away. A mosaic of all the images will be released in six weeks or so showing Earth, Saturn and its complete ring system.

/ NASA

 

 

“That images of our planet have been acquired on a single day from two distant solar system outposts reminds us of this nation’s stunning technical accomplishments in planetary exploration,” Sean Solomon, the principal investigator with the Mercury mission, said in a NASA statement.

“And because Mercury and Saturn are such different outcomes of planetary formation and evolution, these two images also highlight what is special about Earth. There’s no place like home.”

The Cassini images were the brainchild of Carolyn Porco, leader of the spacecraft imaging team at the Space Science Institute in Boulder, Colo. Porco launched a pair of contests inviting the public to submit music and photos that captured the moment of the cosmic encounter and urged people to step outside and wave at Cassini.

A zoomed-in view from Cassini’s narrow-angle camera shows humanity’s home and its moon as small points of light in the blackness of space, an image intended to spark wonder “in a way we only rarely get to see, from the most distant robotic outpost we have ever established around another planet,” Porco said on her web page.

 

This shot from Cassini’s narrow-angle camera shows a magnified image of the Earth, left, and its moon from the vantage point of Saturn.

/ NASA

 

 

“From the U.S. to New Zealand, England to South Africa, we used the opportunity to contemplate our cosmic whereabouts, the uniqueness of our lush, life-giving planet, and the significance of our own existence,” she wrote.

Cassini snapped the images from a distance of about 898 million miles while the spacecraft was passing behind Saturn, in eclipse and out of the direct glare of the sun.

A series of wide-angle shots will be assembled into a mosaic over the next six weeks or so, showing Saturn and its entire ring system in natural colors, as an astronaut passing behind Saturn might see it.

 

Earth and its moon as viewed from the Messenger spacecraft in orbit around Mercury, 61 million miles away.

/ NASA

 

 

A similar mosaic captured by Cassini in 2006 also showed Earth, but the image was captured as part of a science campaign. It was not optimized to show Saturn in natural color and the narrow-angle camera was not used to zoom in on Earth.

This time around, Porco wanted a mosaic that would appeal to the public, showing the glory of Saturn as well as the tiny point of light that is humanity’s home in space.

One segment of the eventual mosaic was released Monday, showing Earth as a star-like point of light just below the rings. The zoomed-in view also was released, clearly showing both Earth and moon. At Cassini’s distance, the image scale was 53,820 miles per pixel.

The Voyager 1 spacecraft imaged Earth from an even greater distance in 1990 as it neared the edge of the solar system. It was that image that prompted Carl Sagan to dub Earth a “pale blue dot” in space.

 

Play VIDEO

A view of Earth, from Saturn

 

Even though Cassini is much closer than Voyager 1 was in 1990, the scale was still daunting — 53,820 miles per pixel.

“The illuminated areas of neither the Earth nor the Moon are resolved here,” NASA said in a statement. “Consequently, the size of each `dot’ is the same size that a point of light of comparable brightness would have in the wide angle camera.”

While no surface detail is visible, “this pale blue dot is a succinct summary of who we were on July 19,” Linda Spilker,the Cassini project scientist, said in NASA’s statement. “Cassini’s picture reminds us how tiny our home planet is in the vastness of space, and also testifies to the ingenuity of the citizens of this tiny planet to send a robotic spacecraft so far away from home to study Saturn and take a look-back photo of Earth.”

Seismic ‘scream’ portends violent volcanic eruption

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By Monte MorinJuly 15, 2013, 5:04 p.m.

It began as series of small shuddering earthquakes beneath Alaska’s Mt. Redoubt that gradually coalesced into a high-frequency “scream,” according to seismologists.

While scientists could only guess as to what triggered the vibrations, there was no question about what happened next: The seismic scream was followed by 30 seconds of silence, and then a series of volcanic eruptions — 20 over a two-week period — that launched an enormous plume of ash resembling a mushroom cloud.

In a study published recently in Nature Geoscience, researchers examined data from the 2009 eruption and concluded that the sustained vibrations were caused by numerous so-called stick-slip movements on faults more than a mile beneath the volcano.

While researchers said it was beyond the scope of their study to determine the cause of the quake, they theorized that it was the result of pressure building in blocked magma conduits underground.

“Blockage of conduit flow increases magma pressure, driving increasingly rapid deformation until the obstruction is breached and an explosion commences,” wrote lead study author Ksenia Dmitrieva, a graduate student in the department of geophysics at Stanford University, and colleagues.

High-frequency harmonic tremors have been recorded before other volcanic eruptions, as well as in the collision of icebergs. Usually, these tremors cannot be heard by people. In the case of the Redoubt eruption, however, the shaking was just barely audible as a hum, according to study authors.

“Although this is a rare and extreme example, if you ever happen to be near an active volcano and feel the ground humming, you might want to take cover,” wrote study co-author Alicia Hotovec-Ellis, a graduate student in the Department of Earth and Space Sciences at the University of Washington, in Seattle.

Click here to read more and listen to a recording of the scream.

Villagers flee as Indonesian volcano spews ash

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A resident of Cangkringan district in Indonesia's Central Java province wears mask to protect himself against volcanic ash from Mount Merapi (background) after spewing volcanic ash.Photo / AFP

A resident of Cangkringan district in Indonesia’s Central Java province wears mask to protect himself against volcanic ash from Mount Merapi (background) after spewing volcanic ash.Photo / AFP

Indonesia’s most volatile volcano spewed smoke and ash Monday, forcing hundreds of people to flee their villages along its slopes, a disaster official said.

Mount Merapi on the main island of Java rumbled as heavy rain fell around its cloud-covered crater, said Sutopo Purwo Nugroho, disaster mitigation agency spokesman.

The volcano unleashed a column of dark red volcanic material 1,000 meters into the air, and the ash made the rain thick and muddy in several villages as terrified residents fled to safety, he said.

The sound was heard 30 kilometers away, but an eruption did not occur and the volcano’s alert level was not raised, Nugroho said.

The 2,968-meter mountain is the most active of 500 Indonesian volcanoes. Its last major eruption in 2010 killed 347 people.

Indonesia, an archipelago of 240 million people, is prone to earthquakes and volcanic activity because it sits along the Pacific “Ring of Fire,” a horseshoe-shaped series of fault lines.

– AP

 

http://www.nzherald.co.nz/world/news/article.cfm?c_id=2&objectid=10901602

A History of Destruction: 8 Great Hurricanes

This is a neat list, and one that I’d agree with totally. Camille, while before I was born, will always be considered the strongest in my mind. Hard to argue with 200mph winds in an hurricane.

A History of Destruction: 8 Great Hurricanes