Massive Meteorite Crater Found in Canadian Arctic

Researchers in Canada's western Arctic have found evidence of a crater that formed when a huge meteorite slammed into Earth millions of years ago.

Measuring about 15 miles (25 kilometers) across, the formation was named the Prince Albert impact crater after the peninsula where it was discovered. Researchers don't know exactly when it was created, but evidence suggests the crater is between 130 million and 350 million years old, according to a statement from the University of Saskatchewan.

Meteors are fragments of asteroids or comets that enter Earth's atmosphere at high speeds; most are small, some as tiny as a grain of sand, so they discintegrate in the air, and only rarely are they large enough to make it to Earth's surface. When meteors slam into Earth, they are called meteorites.

A team of geologists spotted this newly identified meteorite crater while surveying the region for possible energy and mineral resources. They were initially intrigued by steeply tilted strata visible in river gorges and other features in the flat tundra of northwestern Victoria Island. [Photos: Prince Albert Impact Crater]

"Unless you recognized the telltale clues, you wouldn't know what you were looking at," researcher Brian Pratt explained in the statement. "You might see a bunch of broken rocks and wonder how they got there, but we found abundant shatter cones."

Shatter cones are surface features with distinctive wavy patterns that are known to be created only by the tremendous force of a meteorite impact or an underground nuclear explosion. What's more, Pratt said his map showed that the feature is circular, which is characteristic of impact craters.

"Impact craters like this give us clues into how the Earth's crust is recycled and the speed of erosion, and may be implicated in episodes of widespread extinction of animals in the geological past," Pratt said. "It's an exciting discovery."

There are about 180 known impact craters on Earth. Geologists think they would find countless more if plate shifting, volcanic activity and erosion didn't hide the evidence of most ancient impacts.

Earlier this summer, researchers in Greenland documented possibly the oldest and largest meteorite crater ever found on Earth. The crater, estimated to be 3 billion years old, currently measures about 62 miles (100 km) across. But the researchers believe its width before erosion was likely more than 310 miles (500 km) — much bigger than the largest visible crater, the 2-billion-year-old Vredefort crater in South Africa, which measures 186 miles (300 km) across.

NASA's Curiosity Rover Caught in the Act of Landing

PASADENA, Calif. - An image from the High Resolution Imaging Science Experiment (HiRISE) camera aboard NASA's Mars Reconnaissance Orbiter captured the Curiosity rover still connected to its 51-foot-wide (almost 16 meter) parachute as it descended towards its landing site at Gale Crater. 

"If HiRISE took the image one second before or one second after, we probably would be looking at an empty Martian landscape," said Sarah Milkovich, HiRISE investigation scientist at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "When you consider that we have been working on this sequence since March and had to upload commands to the spacecraft about 72 hours prior to the image being taken, you begin to realize how challenging this picture was to obtain." 

The image of Curiosity on its parachute can be found at:http://www.nasa.gov/mission_pages/msl/multimedia/pia15978b.html 

The image was taken while MRO was 211 miles (340 kilometers) away from the parachuting rover. Curiosity and its rocket-propelled backpack, contained within the conical-shaped back shell, had yet to be deployed. At the time, Curiosity was about two miles (three kilometers) above the Martian surface. 

"Guess you could consider us the closest thing to paparazzi on Mars," said Milkovich. "We definitely caught NASA's newest celebrity in the act." 

Curiosity, NASA's latest contribution to the Martian landscape, landed at 10:32 p.m. Aug. 5, PDT, (1:32 on Aug. 6, EDT) near the foot of a mountain three miles tall inside Gale Crater, 96 miles in diameter. 

In other Curiosity news, one part of the rover team at the JPL continues to analyze the data from last night's landing while another continues to prepare the one-ton mobile laboratory for its future explorations of Gale Crater. One key assignment given to Curiosity for its first full day on Mars is to raise its high-gain antenna. Using this antenna will increase the data rate at which the rover can communicate directly with Earth. The mission will use relays to orbiters as the primary method for sending data home, because that method is much more energy-efficient for the rover. 

Curiosity carries 10 science instruments with a total mass 15 times as large as the science payloads on the Mars rovers Spirit and Opportunity. Some of the tools are the first of their kind on Mars, such as a laser-firing instrument for checking rocks' elemental composition from a distance. Later in the mission, the rover will use a drill and scoop at the end of its robotic arm to gather soil and powdered samples of rock interiors, then sieve and parcel out these samples into analytical laboratory instruments inside the rover. 

To handle this science toolkit, Curiosity is twice as long and five times as heavy as Spirit or Opportunity. The Gale Crater landing site places the rover within driving distance to layers of the crater's interior mountain. Observations from orbit have identified clay and sulfate minerals in the lower layers, indicating a wet history. 

NASA's New Mars Rover Sends Higher-Resolution Image

About two hours after landing on Mars and beaming back its first image, NASA's Curiosity rover transmitted a higher-resolution image of its new Martian home, Gale Crater. Mission Control at NASA's Jet Propulsion Laboratory in Pasadena, Calif., received the image, taken by one of the vehicle's lower-fidelity, black-and-white Hazard Avoidance Cameras - or Hazcams. 

"Curiosity's landing site is beginning to come into focus," said John Grotzinger, project manager of NASA's Mars Science Laboratory mission, at the California Institute of Technology in Pasadena. "In the image, we are looking to the northwest. What you see on the horizon is the rim of Gale Crater. In the foreground, you can see a gravel field. The question is, where does this gravel come from?  It is the first of what will be many scientific questions to come from our new home on Mars."  

While the image is twice as big in pixel size as the first images beamed down from the rover, they are only half the size of full-resolution Hazcam images. During future mission operations, these images will be used by the mission's navigators and rover drivers to help plan the vehicle's next drive. Other cameras aboard Curiosity, with color capability and much higher resolution, are expected to be sent back to Earth over the next several days. 

Curiosity landed at 10:32 p.m. Aug. 5, PDT, (1:32 a.m. EDT, Aug. 6) near the foot of a mountain three miles (about five kilometers) tall inside Gale Crater, 96 miles (nearly 155 kilometers) 7in diameter. During a nearly two-year prime mission, the rover will investigate whether the region has ever offered conditions favorable for microbial life, including the chemical ingredients for life. 

The mission is managed by JPL for NASA's Science Mission Directorate in Washington. The rover was designed, developed and assembled at JPL, a division of Caltech.