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Eroding Layers in an Impact Crater February 13, 2010

Posted by jtintle in Planets, Space Fotos.
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Eroding Layers in an Impact Crater

Credit:

NASA/JPL/University of Arizona, Colin Dundas

Description:

This image shows a stack of layers on the floor of an impact crater roughly 30 kilometers across. Many of the layers appear to be extremely thin, and barely resolved.

In broad view, it is clear that the deposit is eroding into a series of ridges, likely due to the wind. Below the ridges, additional dark-toned layered deposits crop out. These exhibit a variety of textures, some of which may be due to transport of material.

The light ridges are often capped by thin dark layers, and similar layers are exposed on the flanks of the ridges. These layers are likely harder than the rest of the material, and so armor the surface against erosion. They are shedding boulders which roll down the slope, as shown in the subimage. Although these cap layers are relatively resistant, the boulders do not seem to accumulate at the base of the slope, so it is likely that they also disintegrate relatively quickly.

The subimage itself is 250 meters wide. The light is from the left. Boulders are visible on the slopes of the ridges along with thin dark layers including the cap layer, but they are absent on the spurs where the resistant cover has been eroded. This demonstrates that the boulders come only from the dark layers, and are not embedded in the rest of the deposit.

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Orion in a New Light February 12, 2010

Posted by jtintle in Deep Space, Space Fotos.
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Description:

The Orion Nebula reveals many of its hidden secrets in a dramatic image taken by ESO’s new VISTA survey telescope. The telescope’s huge field of view can show the full splendour of the whole nebula and VISTA’s infrared vision also allows it to peer deeply into dusty regions that are normally hidden and expose the curious behaviour of the very active young stars buried there.

VISTA — the Visible and Infrared Survey Telescope for Astronomy — is the latest addition to ESO’s Paranal Observatory (eso0949). It is the largest survey telescope in the world and is dedicated to mapping the sky at infrared wavelengths. The large (4.1-metre) mirror, wide field of view and very sensitive detectors make VISTA a unique instrument. This dramatic new image of the Orion Nebula illustrates VISTA’s remarkable powers.

The Orion Nebula is a vast stellar nursery lying about 1350 light-years from Earth. Although the nebula is spectacular when seen through an ordinary telescope, what can be seen using visible light is only a small part of a cloud of gas in which stars are forming. Most of the action is deeply embedded in dust clouds and to see what is really happening astronomers need to use telescopes with detectors sensitive to the longer wavelength radiation that can penetrate the dust. VISTA has imaged the Orion Nebula at wavelengths about twice as long as can be detected by the human eye.

As in the many visible light pictures of this object, the new wide field VISTA image shows the familiar bat-like form of the nebula in the centre of the picture as well as the fascinating surrounding area. At the very heart of this region lie the four bright stars forming the Trapezium, a group of very hot young stars pumping out fierce ultraviolet radiation that is clearing the surrounding region and making the gas glow. However, observing in the infrared allows VISTA to reveal many other young stars in this central region that cannot be seen in visible light.

Looking to the region above the centre of the picture, curious red features appear that are completely invisible except in the infrared. Many of these are very young stars that are still growing and are seen through the dusty clouds from which they form. These youthful stars eject streams of gas with typical speeds of 700 000 km/hour and many of the red features highlight the places where these gas streams collide with the surrounding gas, causing emission from excited molecules and atoms in the gas. There are also a few faint, red features below the Orion Nebula in the image, showing that stars form there too, but with much less vigour. These strange features are of great interest to astronomers studying the birth and youth of stars.

This new image shows the power of the VISTA telescope to image wide areas of sky quickly and deeply in the near-infrared part of the spectrum. The telescope is just starting to survey the sky and astronomers are anticipating a rich harvest of science from this unique ESO facility.

Credits:

European Southern Observatory, Paranal Observatory

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The Changing Faces of Pluto February 10, 2010

Posted by jtintle in Planets, Space Fotos.
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Credit:

NASA, ESA, and M. Buie (Southwest Research Institute)

Explanation:

This is the most detailed view to date of the entire surface of the dwarf planet Pluto, as constructed from multiple NASA Hubble Space Telescope photographs taken from 2002 to 2003.

Hubble’s view isn’t sharp enough to see craters or mountains, if they exist on the surface, but Hubble reveals a complex-looking and variegated world with white, dark-orange, and charcoal-black terrain. The overall color is believed to be a result of ultraviolet radiation from the distant Sun breaking up methane that is present on Pluto’s surface, leaving behind a dark, molasses-colored, carbon-rich residue.

The center disk (180 degrees) has a mysterious bright spot that is unusually rich in carbon monoxide frost. This region will be photographed in the highest possible detail when NASA’s New Horizons probe flies by Pluto in 2015.

The Hubble images are a few pixels wide. But through a technique called dithering, multiple, slightly offset pictures can be combined through computer-image processing to synthesize a higher-resolution view than could be seen in a single exposure. This series of pictures took four years and 20 computers operating continuously and simultaneously to accomplish.

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Night Launch of the Space Shuttle Endeavour February 9, 2010

Posted by jtintle in Planets, Space Fotos.
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See Explanation.  Clicking on the picture will download  the highest resolution version available.
Credit:

NASA

Explanation:

Sometimes, the space shuttle launches at night. Pictured above, the space shuttle Endeavour lifted off in yesterday’s early morning hours from Launch Pad 39A in Kennedy Space Center, Florida, USA, bound for the International Space Station (ISS). A night launch, useful for reaching the space station easily during some times of the year, frequently creates vivid launch imagery. The shuttle, as pictured above, is framed by an enormous but typical exhaust plume ejected as the shuttle’s powerful rockets began lifting the two million kilogram space bus into Earth orbit. Endeavour’s mission, labeled STS-130, includes the delivery of the Tranquility module to the space station. Tranquility will provide extra room for space station astronauts and includes a large circular set of windows designed to bestow vastly improved views of the Earth, the night sky, and the space station itself.

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