Solar Eclipse visible in the western US in May 2012

Jan 16, 2012; 3:31 PM ET

A little tough to understand, but this diagram shows where the solar eclipse in May of 2012 can be experienced

An annular solar eclipse will take place on May 20, 2012 with a magnitude of 0.9439. For more about what the magnitude of a solar eclipse is, please click here. A solar eclipse occurs when the Moon passes between Earth and the Sun, thereby totally or partially obscuring the image of the Sun for a viewer on Earth. An annular solar eclipse occurs when the Moon’s apparent diameter is smaller than the Sun, causing the sun to look like an annulus (ring), blocking most but not all of the Sun’s light. An annular eclipse appears as a partial eclipse over a region thousands of kilometres wide.

The annular phase will be visible from the Chinese coast, the south of Japan, and the western part of the United States and Canada. Cities such as Albuquerque, New Mexico and Redding, Ca. will see this eclipse. Guangzhou, China, Tokyo and Albuquerque will be on the central path. Its maximum will occur in the North Pacific, south of the Aleutian islands for 5 min and 46.3 s, and finish in the western United States.

It will be the first central eclipse of the 21st century in the Lower 48, and also the first annular eclipse visible here since the solar eclipse of May 10, 1994. – Astronomy | Solar Eclipse visible in the western US in May.


Twin NASA Spacecrafts Begin to Orbit the Moon

Jan 1, 2012; 12:07 AM ET

An artist’s rendition of the twin GRAIL spacecraft in Moon’s orbit

NASA’s twin spacecraft to study the Moon while in lunar orbit will both enter orbit soon.

Named Gravity Recovery And Interior Laboratory (GRAIL), GRAIL-A was put in orbit at 4:21 p.m. EST Dec. 31, and GRAIL-B will settle into orbit at 5:05 p.m. EST on New Year’s Day.

NASA’s Apollo crews took about three days to travel to the Moon. In contrast, these spacecraft were launched from Cape Canaveral Air Force Station on Sept. 10, 2011, the GRAIL spacecraft are taking about 30 times that long to cover the more than 2.5 million miles to get there.

Over the following weeks, the GRAIL team will execute a series of burns to each spacecraft to reduce their orbital period from 11.5 hours down to just under two hours. At the start of the science phase in March 2012, the two GRAILs will be in a near-polar, near-circular orbit with an altitude of about 34 miles.

When science collection begins, the spacecraft will transmit radio signals to figure out exactly the distance between them as they orbit the Moon. As they fly over areas of greater and lesser gravity, caused both by visible features such as mountains and craters and by masses hidden beneath the lunar surface, they will move slightly toward and away from each other. An instrument aboard each spacecraft will measure the changes in their relative velocity very precisely, and scientists will translate this information into a high-resolution map of the Moon’s gravitational field. The data will allow mission scientists to understand what goes on below the surface of the Moon. This information will increase our knowledge of how Earth and its rocky neighbors in the inner solar system developed into the diverse worlds we see today.

via – Astronomy | Twin NASA Spacecrafts Begin to Orbit the Moon.

Ice cavern ‘could support life’ on Jupiter’s moon Europa

7:30AM GMT 17 Nov 2011

An ice cavern containing as much water as the North American Great Lakes may provide a potential habitat for life on Jupiter’s moon Europa, scientists believe.

The salty “lake” is thought to be locked within Europa’s icy outer shell a few kilometres from the surface.

Other large pockets of liquid water are also likely to exist on the moon, it is claimed.

Scientists are excited by the discovery, which offers one of the best hopes yet of finding life beyond the Earth.

Evidence for the ice-covered lake in Europa’s Thera Macula region is seen in the shape of the terrain above it. The site appears to be marked by a fractured and collapsing “lid” of floating ice.

On Earth, similar features in the Antarctic are caused by briny seawater penetrating and weakening ice shelves. They are also present in Iceland, where glaciers are heated from below by volcanic activity.

Scientists have long suspected that a liquid or slushy ocean exists under Europa’s surface, warmed by the tidal forces of Jupiter’s powerful gravity.

Theoretically, a liquid water ocean could provide a suitable habitat for life – but only if it was not too far from the surface.

Experts disagree about how thick the layer of covering ice is. The new research, based on images from the Galileo probe, suggests that water “lenses” could lie as little as three kilometres below the bottom of the surface crust.

Lead scientist Dr Britney Schmidt, from the University of Texas, said: “One opinion in the scientific community has been, ‘If the ice shell is thick, that’s bad for biology – that it might mean the surface isn’t communicating with the underlying ocean’.

“Now we see evidence that even though the ice shell is thick, it can mix vigorously. That could make Europa and its ocean more habitable.”

The research, published today in the journal Nature, involved computer simulations based on observations of Europa and Earth.

Dr Schmidt’s team focused on two circular bumpy regions on Europa’s surface called “chaos terrains” .

The scientists produced a four-step model to explain the features which resolves several conflicting observations.

However, it can only infer the presence of the hidden lakes. Their existence will only be confirmed by a new space mission designed to probe Europa’s ice shell.

Such a mission, likely to employ ground-penetrating radar, is now under consideration by American space agency Nasa.

Commenting on the study, Dr Robert Pappalardo, senior research scientist at Nasa’s planetary science section, said: “It’s the only convincing model that fits the full range of observations. To me, that says ‘yes, that’s the right answer’.”

via Ice cavern ‘could support life’ on Jupiter’s moon Europa – Telegraph.