In March 1610 Galileo pointed his homemade telescope towards Jupiter. He saw 4 stars near Jupiter. A few days later he noticed that Jupiter had moved from its previous location and the 4 stars followed Jupiter. Another astronomer Simon Marius also saw these “stars” and people realized that they were watching the moons of Jupiter.
According to mythology the Greek God Jupiter had several love affairs. Some of them were with Io,daughter of the River,Callisto of Lycaon, Europa of Agenor. Jupiter also had a son Ganymed, who had the shape of an eagle. The four moons were thus named Io, Callisto, Europa and Ganymede. These moons were called Galilean Moons. VERITAS readers, today we will study Europa.
Europa is a mysterious moon. The more we learn about it the more mysteries it opens for us. It is the sixth largest moon in our solar system( Ganymede is the largest). It has a diameter of 3138 Kms.It is much lighter than earth. It orbits Jupiter at a distance of 671000 Kms.
The strange thing about Europa is that it is a VERY smooth moon. From a distance it appears to be as smooth as a billiard ball.
When you get close to it you can see a complex network of lines on its surface. Pictures from the spacecraft Voyager show pale-yellow icy plains with red and brown regions. Long cracks run for thousands of Kilometres.
None of the structures on this moon is more than a few kilometres high which makes it the smoothest body in our solar system. To understand the significance of this lets compare the surfaces of Earth and MOon.
The Moon and the Earth have been hit equally by large meteors. The surface of MOon is filled with craters all over its surface making it a very rough surface. You hardly see any craters on the Earth making it a smooth body. The reason for the disappearance of the craters on the Earth is because there is a huge amount of geological activity going on here( storms , floods, rains, wind, earthquakes etc). These geological activities fill up the impact craters thus making the body smooth. Ganymede and Callisto are very rough and are heavily cratered.
Europa could not have escaped the bombardment of meteors that hit the other moons of Jupiter. The only explanation of its smoothness? There is a huge amount of geological activity going on there!!!!!!!!!!!!!!!!!!!!!!!!!!!
Europa has a surface looks like broken glass which has been repaired by icy glue. What kind of activity goes on in its surface? The surface is covered with ice. In a battle of Huge dimentions each day the ice is pulled in 2 opposite directions: By Jupiter from one side and by the other moons from the other side. The ice stretches and compresses till it cracks after several days. Almost immediately stuff from below the ice comes up and repairs the cracks. It comes up and immedialety freezes to repair the crack! What is this stuff? THis is water! The ice on the surface of Europa covers oceans of water!!!!!!!!!!!!!!!!!!!!!!!!!
These oceans might be as deep as 50 kilometres.
Can life exist in these oceans? We know that liquid water is one of the major ingredients of life. But what about energy( sunlight). We have seen that in Earth’s oceans life can exist even as deep as the Marinas Trench supported by Geothermal Vents(See VERITAS: The Limits of Ocean Depth, 4 Jun 2003). So why not?! It is definitely a possibility. The three bodies( apart from Earth) which might have the possibility of life are Mars, Europa and Saturn’s Moon Titan(a possible subject for VERITAS a few months/years from now??)
How do we know so much about Europa? Most of this information has come to us from the Galileo space probe. Galileo was launched in 1989 and reached close to Jupiter in 1995. It discovered several new satellites of Jupiter bringing the count to 61! The mission wil end when Galileo falls into Jupiter in Sept 2003.
See the attached pictures of Europa and Jupiter with the four Galilean Moons of Jupiter( A family picture). Can you identify Europa in the “family picture”?
Go, wondrous creature! mount where Science guides:
Go, measure earth, weigh air, and state the tides:
Instruct the planets in what orbs to run,
Correct old time and regulate the Sun;