Researchers may have gotten a step closer to solving some of Venus' mysteries by putting a new twist on data collected two decades ago.
Venus' surface is hidden beneath a hot, dense atmosphere. The Magellan spacecraft made the most recent trip to the planet 20 years ago; during this mission scientists noticed radio waves reflected at different altitudes and radio dark spots at higher elevations, the Geological Society of America reported. Neither of the observed phenomenon have been explained, but researchers may have gotten just a little bit closer by looking at the decades-old radar data.
"There is general brightening upward trend in the highlands and then dark spots at the highest locations," said Elise Harrington, an Earth sciences undergraduate at Simon Fraser University, in British Columbia. "Like on Earth, the temperature changes with elevation. Among the possibilities on Venus are a temperature dependent chemical weathering process or heavy metal compound precipitating from the air - a heavy metal frost."
To make their findings Harrington and her internship instructor Allan Treiman of the Lunar and Planetary Institute looked at data from the Magellan spacecraft, but thorugh a new approach. The duo used recently-available stereo radar elevation data instead of lower resolution radar altimetry, which allowed them to look at the surface of Venus in a higher resolution. They also used Magellan's Synthetic Aperture Radar (SAR) to look at radio reflectance, rather than the data on radio emissions from the surface.
The study confirmed the same patterns of radio reflection as low in the atmosphere as 7,900 feet and as high as 14,700 feet, but they also noticed a great deal more of those mysterious black spots. The black spots occur when radio waves are not reflected.
"The previous author saw a few dark spots," Harrington said. "But we see hundreds of them."
In the past researchers have suggested a ferro-electric compound could be the phenomenon behind the dark spots, but have never been able to find evidence.
"No one knows what explains the sudden darkness," said Harrington, who will be presenting the work at the meeting of the Geological Society of America in Vancouver, B.C., on Monday, Oct. 20. "We think this might spur some more interest in Venus."
