An intense bright spot has appeared in the clouds of Venus. Could it be associated with volcanic activity on the surface?

The Solar System is breaking out in spots. First Jupiter took a smack from a passing asteroid or comet, manifesting as a dark scar in the Jovian atmosphere, and now Venus is sporting a brilliant white spot in its southern polar region.

In an alert to fellow amateur astronomers, Venus observer Frank Melillo reports on his images captured on 19 July: "I have seen bright spots before but this one is an exceptional bright and quite intense area."

He suggests that it could be explained as an atmospheric effect, but could it be a sign of volcanic activity at the planet's surface? Venus is covered in a thick cloak of clouds which prevents any visible observation of the surface. Instead, radar is used to map the surface, but volcanic activity has never been observed directly.

"A volcanic eruption would be nice, but let's wait and find out!" says Venus specialist Dr Sanjay Limaye of the University of Wisconsin. "An eruption would have to be quite energetic to get a cloud this high." Furthermore, at a latitude of 50 degrees south, the spot lies outside the region of known volcanoes on Venus.

Melillo comments that the spot will not be seen again as intense as it is now, thanks to the rapid rotation of the planet's atmosphere. "I hope that someone will image Venus on Thursday when this part of the atmosphere is facing us again," he says.

Further observations will help shed light on the genesis of the bright spot and how it evolves as the atmosphere churns over.