Europe South Asia Asia Pacific Americas Middle East Africa BBC Homepage World Service Education



Front Page

World

UK

UK Politics

Business

Sci/Tech

Health

Education

Sport

Entertainment

Talking Point

In Depth

On Air

Archive
Feedback
Low Graphics
Help

Monday, March 8, 1999 Published at 13:57 GMT


Sci/Tech

Best ever view of Ganymede

If it were on its own it would be a planet

By BBC News Online Science Editor Dr David Whitehouse

If it orbited the Sun on its own then it would undoubtedly be a planet. The ice world of Ganymede is the largest moon in the solar system. In fact, it is larger than some planets.

With a diameter of 5,260 kilometres, it is larger than the planets Mercury and Pluto and just over three quarters the size of Mars.

The most-detailed ever view of Ganymede as a whole body has just been compiled from images obtained by the Galileo spacecraft that has been orbiting Jupiter since December 1995.

The image shows the trailing hemisphere of the moon. It is speckled with bright young craters.

Ganymede's craters are remarkably smooth. They seem to have become flattened as the moon's icy surface slowly relaxes.

Frost particles

Its surface shows a mixture of old, dark, cratered terrain and lighter, younger, regions streaked with grooves and ridges.

In reality, Ganymede's colours are subtle browns and greys, but the colours in the image on this page have been enhanced to increase surface contrasts.

The violet shades extending from the top and bottom are likely to be due to frost particles in Ganymede's polar regions.

Another moon of Jupiter, Europa, has captured most of the attention in recent years. This is because of the possibility of an ocean beneath its frozen surface.

New observations of Ganymede suggest that Europa may not be alone in having an under-ice ocean - a possible abode for life.





Advanced options | Search tips




Back to top | BBC News Home | BBC Homepage | ©


Sci/Tech Contents


Relevant Stories

17 Sep 98 | Sci/Tech
Jupiter's ring riddle solved

15 Jun 98 | Sci/Tech
Galileo finds ghostly ring on Jupiter

13 May 98 | Sci/Tech
Getting close to Europa





Internet Links


Galileo homepage


The BBC is not responsible for the content of external internet sites.




In this section

World's smallest transistor

Scientists join forces to study Arctic ozone

Mathematicians crack big puzzle

From Business
The growing threat of internet fraud

Who watches the pilots?

From Health
Cold 'cure' comes one step closer