Friday, March 18, 2011

APOD 3.8

In this photo taken at Lorry State Park in Colorado, the seasonal constellations for this time of year are labelled and easily identified.  Along with constellations such as Draco and Canis Major, the orbital paths of the International Space Station (which is currently orbiting around Earth at this moment) and Discovery Space Shuttle (that landed back on Earth on March 9th this year) are indicated.  It is astounding to be able to see many of the lower magnitude stars, such as the full visibility of all of the stars in the typically faint constellation Ursa Minor, due to the remoteness and high elevation of this location.  As a future student of University of Colorado at Boulder, I am super excited to be able to star gaze and see clear skies with high visibility of the stars in the night sky.       

Friday, March 4, 2011

APOD 3.7

This image of Hyperion, Saturn's irregularly shaped moon was taken by the Cassini spacecraft in 2005  Typically Hyperion appears to have a reddish tint when viewed in natural color, but here it appears to have a grayish tint because the image was enhanced using false color imaging techniques. The reason behind this bizarre shape is that although Hyperion is quite large, its gravitational force is not sufficient to eliminate the gaps and hold the object together as a sphere. Scientists suspect that Hyperion was originally apart of a larger moon, but broke away after a major impact from an asteroid.  Hyperion has little gravitational force due to the fact that it has a surprisingly low density Hyperion's rotation is also unusual, because it has no fixed spin axis (as revealed by the Voyager 2 mission) and since Titan orbits Saturn 3 times for every 4 times that Hyperion orbits Saturn, Hyperion experiences strong pulls from Titan's massive gravitational force as there orbits match up.  The sponge-like cratered surface is likely a result of the fact that Hyperion orbits Saturn at a relatively far distance compared to Saturn's other moons and therefore experiences little tidal forces that would help blur these bizarre features. One of the most interesting aspects of Hyperion's composition is that it has bright crater walls, which are likely to be forms of condensed water ice and it is a future goal of scientists to further investigate the surface and its potential to contain water.