Chandra Movie of Vela Pulsar: Neutron Star Action

The Vela pulsar, a neutron star that was formed when a massive star collapsed. (X-ray: NASA/CXC/Univ of Toronto/M.Durant et al; Optical: DSS/Davide De Martin).

This movie from NASA's Chandra X-ray Observatory shows a fast moving jet of particles produced by a rapidly rotating neutron star, and may provide new insight into the nature of some of the densest matter in the universe.

The star of this movie is the Vela pulsar, a neutron star that was formed when a massive star collapsed.

The Vela pulsar is about 1,000 light years from Earth, spansis about 12 miles in diameter, and makes over 11 complete rotations every second, faster than a helicopter rotor.

As the pulsar whips around, it spews out a jet of charged particles that race out along the pulsar’s rotation axis at about 70% of the speed of light.

In this still image from the movie, the location of the pulsar and the 0.7-light-year-long jet are labeled.

The Chandra data shown in the movie, containing 8 images obtained between June and September 2010, suggest that the pulsar may be slowly wobbling, or precessing, as it spins.

"It's like having an unsecured fire hose and a flow of water at high pressure," said co-author George Pavlov, principal investigator of the Chandra proposal at Pennsylvania State University in University Park. "All you need is a small bend in the hose and violent motion can result."

"We think the Vela pulsar is like a rotating garden sprinkler, except with the water blasting out at over half the speed of light," said Martin Durant of the University of Toronto in Canada, who is the first author of the paper describing these results.

Anomalies amongst Geological Features and Dried Up Lakes on Titan

Radar images from NASA's Cassini spacecraft reveal some new curiosities on the surface of Saturn's mysterious moon Titan, including a nearly circular feature that resembles a giant hot cross bun and shorelines of ancient seas.

The results were presented today at the American Astronomical Society's Division of Planetary Sciences conference in Reno, Nev.

Steam from baking often causes the top of bread to lift and crack. Scientists think some similar process involving heat may be at play on Titan.

The image showing the bun-like mound was obtained on May 22, 2012, by Cassini's radar instrument.

Scientists have seen similar terrain on Venus, where a dome-shaped region about 20 miles (30 kilometers) across has been seen at the summit of a large volcano called Kunapipi Mons.

They theorise that the Titan cross, which is about 40 miles (70 kilometers) long, is also the result of fractures caused by uplift from below, possibly the result of rising magma.

"The 'hot cross bun' is a type of feature we have not seen before on Titan, showing that Titan keeps surprising us even after eight years of observations from Cassini," said Rosaly Lopes, a Cassini radar team scientist based at NASA's Jet Propulsion Laboratory, Pasadena, Calif.

"The 'bun' may be the result of what is known on Earth as a laccolith, an intrusion formed by magma pushing up from below. The Henry Mountains of Utah are well-known examples of this geologic phenomenon."

Another group of Cassini scientists, led by Ellen Stofan, who is based at Proxemy Research, Rectortown, Va., has been scrutinizing radar images of Titan's southern hemisphere.

Titan is the only place other than Earth that has stable liquid on its surface, though the liquids on Titan are hydrocarbon rather than water. So far, vast seas have only been seen in Titan's northern hemisphere.

A new analysis of Cassini images collected from 2008 to 2011 suggests there were once vast, shallow seas at Titan's south pole as well. Stofan and colleagues have found two good candidates for dry or mostly dry seas.

One of these dry seas appears to be about 300 by 170 miles (475 by 280 kilometers) across, and perhaps a few hundred feet (meters) deep.

Ontario Lacus, the largest current lake in the south, sits inside of the dry shorelines, like a shrunken version of a once-mighty sea.

ESA Mars Express spots Wrinkle Ridges and Grabens in Tempe Terra

Tempe Terra is located at the northeastern edge of the Tharsis volcanic region and forms the transition zone between the southern highlands and the northern lowlands.

This area is characterised by a large variety of tectonic structures and is one of the most geologically diverse on Mars.

These images from the High Resolution Stereo Camera (HRSC), operated by the German Aerospace Center (Deutsches Zentrum fur Luft- und Raumfahrt; DLR) on board ESA's Mars Express spacecraft, which were acquired on 17 July 2011, show a large number of interesting geological phenomena.

The effects of different forces can be seen adjacent to one another. These have led to both extension of the Martian crust and crustal compression, which has created 'wrinkle ridges'.

The most striking result of the crustal extension is a linear graben running across the entire image and only broken by misalignment in a few places.

This graben is up to a kilometre wide and is overlaid by a large impact crater some 12 kilometres across and its ejecta; inside the crater, the graben is covered by younger sediments.

The images show a section of the HRSC image strip located at 42 degrees north and 304 degrees east, obtained during orbit 9622 with a resolution of about 18 metres per pixel.

Landscape shaped by water as well as tectonic forces
To the north of the graben, in the right third of the image, the terrain falls away to the lowlands by over 1000 metres. The landscape here is marked by several extensive valley systems.

Upslope, a number of smaller, dendritic valleys partially covered by impact craters can be made out. Many younger craters in the region south of the graben that still have well-preserved contours exhibit lobate, concentric structures in their interior that have been caused by a slow moving plastic material.

These features, referred to by geologists as concentric crater fill, can be found in a number of places on Mars - including Phlegra Montes, the subject of last month's images.

Prominent mesas are visible in the upper left section of the image, to the southwest. They reveal the original terrain level of the Martian southern highlands. Also conspicuous are the clearly structured ejecta of several impact craters. These partially cover the older flow and graben systems and therefore occurred later. Older, large impact craters have been almost completely covered with sediment or filled with ejecta.

Tempe Terra was first described by Greek astronomer Eugenios Antoniadis (1870-1944, later known as Eugene Michel Antoniadi through his work in France).

His observations of the Tempe Terra region with a powerful new telescope at the Paris Observatory in Meudon during the opposition of Mars in 1909 - described in detail in 1930 - disproved the theory circulating among astronomers that the 'canali' observed by Giovanni Schiaparelli in 1877 were artificial canals; Schiaparelli himself had serious doubts about this interpretation.

Spoke-like patterns on Mercury

Rembrandt, the second-largest impact basin on Mercury, was discovered during the Messenger spacecraft's second flyby in October 2008. Researchers are now puzzling over features found near its centre (pictured), which show a spoke-like pattern of ridges and troughs that is reportedly unlike anything else in the solar system (Image: NASA/JHUAPL/Smithsonian/Carnegie Institution of Washington)