Jupiter spot changes its colour

Winds in awell-monitored small stormon Jupiterare picking up speed and the storm itself has changed colour, NASA scientist Amy Simon-Miller reports.

Winds in the Little Red Spot, a storm the size of the Earth,have hit 650 kilometresan hour, as fast as those in its older andbigger sibling, the Great Red Spot three times the size of Earth.

"No one has ever seen a storm on Jupiter grow stronger and turn red before," Simon-Miller says.

The faster winds probably caused thesmaller spot to change colour to red from white asthe stormpicked up gaseous material from far below thatreacted when exposed to ultraviolet rays in sunlight, NASA suggested in a release.

NASAhas been monitoring Jupiter the fifth planet from the sun and largest in the solar system for many years. Simon-Miller's report, published in the journal Icarus, is based on observations fromtheHubble telescope.

Winds in the stormsthat later mergedto become the Little Red Spot were only going about 430 km/h in 1979, and hadn't changed by the late 1990s, when the Galileo orbiter revealed that top wind speeds in the Great Red Spot were hitting 650 km/h.

The NASA team used Hubble'sadvanced camera for surveys to measure the wind speeds.

"This instrument has enough resolution to track small features in these storms, revealing their wind speeds," NASA said.

The NASA team could determine precisely why the little spot changed colour using a technique called spectroscopy, which analyzesthe unique light given off by each chemical element.

Butspectroscopy of Jupiter's atmosphere ishard because it has many chemicals that could turn red.

"We need to simulate different possible Jupiter atmospheres in a lab so we can discover what spectrometric signals they give. We will then have something to compare with the actual spectrometric signal," said Simon-Miller.