Monday, July 9, 2012

Enceladus




The Cassini spacecraft has made its lowest pass yet over the south pole of Enceladus, an active moon of Saturn which may harbour a liquid water ocean.
The flyby, at an altitude of 74km (46mi), allowed Cassini to "taste" the jets of ice and water vapour that gush from the moon's polar region.
Several lines of evidence suggest these jets are fed by a liquid water ocean beneath Enceladus' outer icy shell.
The spacecraft's closest approach took place at 1930 GMT on Tuesday.
The scientists are using Cassini's Ion and Neutral Mass Spectrometer instrument to learn more about the composition, density and variability of the plumes from Enceladus.
Scientists previously detected salts in these jets, which suggested the sub-surface liquid water ocean was probably in contact with Enceladus' rocky core.
This makes Enceladus an even more important target in the search for life elsewhere in the Solar System, as rocks could furnish the ocean with the chemical ingredients thought essential for life.
The plumes erupt from fissures at the south pole known as "tiger stripes".
Last week, scientists presented evidence of a connection between the jet activity on Enceladus and the way Saturn's gravity stretches and stresses the fissures.
Theresults were outlinedby Terry Hurford, from Nasa's Jet Propulsion Laboratory (JPL), at theLunar and Planetary Science Conference (LPSC)in The Woodlands, Texas.
However, about 35% of the observations could not be explained by tension in the jets' source regions.
Enceladus moves around Saturn in a distorted, oval-shaped orbit rather than a circular one. This causes the moon to be pulled and squeezed by Saturn's gravity, inducing the heat that enables geological activity on the icy moon.

Article From BBC.
Hillary Maruwa 9Th July, 2012

Friday, February 3, 2012

Stunning Barred Spiral Galaxy Image

 

Hubble snaps stunning barred spiral galaxy image


 
 The Hubble space telescope has captured an image of a "barred spiral" galaxy that could help us better understand our own Milky Way.
Most of the known spiral galaxies fall into this "barred" category - which are defined by the pronounced bar structure across their centres.
The presence of this structure may be an indication of a galaxy's age.
Two-thirds of nearby, younger galaxies have the bar, while only a fifth of older, more distant spirals have it.
The new picture also continues the Hubble space telescope's long heritage of striking astronomical images.
In the upper left of the image is a cluster showing recent star formation that is just visible to Hubble's cameras.
But it is a bright source in X-ray light; astronomers believe that this IXO-5 X-ray source is actually a "binary" system comprising a star and a black hole in mutual orbit.

Article From BBC,
Hillary Maruwa, 3rd February, 2012.