Europa as seen from New Horizons.<br /><br />LORRI camera.<br /><br />Wednesday 28th February 2007, from 3 million kilometres.<br /><br />Image taken from Anthmartian's website:<br /><br />
http://anthmartian.googlepages.com/thisislandearth <br /><br />Europa has a diameter of: 3,126 kilometres, with an average global density of: 3.04 gm/cm3, with a surface gravity of 13.5% that of Earth.<br /><br />Europa orbits Jupiter at an average distance of: 670,900 km, once about every: 3 days, 13 hours & 12 minutes.<br /><br />Europa is covered in a surface of ice, on average reflecting 64% of the sunlight striking it. The surface is cold, averaging about minus 153 Celsius.<br /><br />However, the globe of Europa is not made from water, as the density as just over 3 x too great. During the repeated encounters with Europa, using the Galileo orbiter, Europa appears to have a metallic core probably iron (maybe iron sulphide), then a mantle of silicate rock then either:<br /><br />1) an ice layer on top of liquid water, <br /><br />or <br /><br />2): a frozen crust of ice.<br /><br />or<br /><br />3). A brittle hard ice crust, overlaying a layer of softer warmer convecting ice.<br /><br />Impact cratering on Europa is fairly light, crater counts suggesting that much of the current surface is less than 30 million years old. Considering Europa is about 4.6 billion years old, suggests that Europa is active. <br /><br />One area in particular, looks like ice rafts that have jostled & tilted, there are ice hills & valleys, long triple banded ridges, ice boulders, smooth features & lateral faulting. Europa's surface is also contaminated by sulpher from neighbouring Io's volcanoes.<br /><br />Another indication is that the surface of Europa does not appear to be directly in contact with the silicate mantle, completing an extra rotation, once every half a million years, which means that every 250,000 years, alternate hemisph <div class="Discussion_UserSignature"> <p><font color="#000080">"I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before".</font> <em><strong><font color="#000000">Linda Morabito </font></strong><font color="#800000">on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.</font></em></p><p>
<font size="1" color="#000080">http://www.launchphotography.com/</font><br /><br />
<font size="1" color="#000080">http://anthmartian.googlepages.com/thisislandearth</font></p><p>
<font size="1" color="#000080">http://web.me.com/meridianijournal</font></p> </div>