Strangeness on Jupiter
Jupiter is a strange place. It is unique in so many ways that they are probably uncountable – the largest planet (by far) in our solar system, consisting of a rocky core about the size of the earth enveloped by an immensely thick atmosphere. In that atmosphere is the planet’s signature, the red spot.
Jupiter’s red post has existed for longer than mankind has had telescopes – it was noted by Galileo when he first began pointing his early telescopes at the sky. Astronomers now know what the red spot is: a high-altitude storm. It has stayed in the same place – just south of Jupiter’s equator – and has kept the same rotation rate – it rotates around the planet once ever eight Earth days – since record-keeping began.
But sometimes the red spot does change. Even its color occasionally varies from dark red to orange or to salmon. And lately, it has been getting smaller. The red spot was about three times wider than Earth for a great many years, through the 1920s. Then, it began to slowly shrink. Then, the rate of shrinking accelerated. Now, the red spot is about the same size as the Earth and still shrinking.
Astronomers are beginning to wonder if the red spot might vanish from the face of Jupiter – something that would once have been similar to thinking that Saturn might shed its rings. But the long-raging storm might be winding down.
There is an excellent article about the red spot and how it is changing here: space.about.com.