It occurred days after the Jupiter impact

Jul 31, 2009 19:01 GMT  ·  By
A montage of ultraviolet images taken during several Venus Express orbits with the Venus Monitoring Camera (VMC)
   A montage of ultraviolet images taken during several Venus Express orbits with the Venus Monitoring Camera (VMC)

On July 19th, while looking through his amateur telescope at Venus, astronomer Frank Melillo, from Holtsville, NY, caught sight of what appeared to be a bright spot on the surface of the planet. The bright phenomenon suddenly appeared in the atmospheric clouds, and its origin left scientists completely in the dark. Expert Sanjay Limaye, a planetary scientist at the University of Wisconsin-Madison, says that this is not the first time the unusual phenomenon has been noticed on our neighbor, but that the source is still a mystery.

After the amateur astronomer discovered the bright spot, the find was confirmed by other members of the community, as well as by the Venus Express spacecraft, operated by the European Space Agency (ESA). Limaye said in an e-mail for Space that its appearance was gaining so much attention precisely because it had occurred just days after Jupiter developed a new dark spot of its own, most likely due to a comet hitting it. The gas giant now sports a darkened scar the size of the Pacific Ocean.

Venus Express measurements of the region determined that the spot actually grew on Venus four days before Melillo saw it, and that it since spread throughout the thick atmosphere, via strong air movements. At this point, there are several theories as to why the spot appeared. Some astronomers believe that it is the result of a massive volcanic eruption, whereas others think that solar winds interacting with the upper layers of the atmosphere may be the root cause.

Limaye believes that another cause may consist of internal changes within Venus' atmosphere. Such modifications could, at least theoretically, have the ability to change the properties of the particles making it up, which could become more reflective. As viewed from outside the planet, they would look brighter. “Clearly something in the cloud properties changed,” the expert says. “Right now, I think it's anybody's guess,” he added, speaking of the possible explanations for the bright spot on Venus.