The study focuses on a process called dissociative recombination, where hydrogen atoms are lost from Venus's atmosphere into space. This phenomenon contributes to Venus losing about twice as much water daily as previously thought.

"Water is really important for life," said Eryn Cangi, a research scientist at the Laboratory for Atmospheric and Space Physics (LASP) and co-lead author of the new paper. "We need to understand the conditions that support liquid water in the universe, and that may have produced the very dry state of Venus today."

Comparing Earth and Venus, "Venus has 100,000 times less water than the Earth, even though it's basically the same size and mass," said Michael Chaffin, co-lead author of the study and a research scientist at LASP.

The team used computer simulations to explore chemical reactions in Venus's atmosphere, identifying a molecule called HCO+ as a key player in the water loss. This molecule, primarily composed of hydrogen, carbon, and oxygen, breaks down in the atmosphere, releasing hydrogen atoms that escape into space.

"Venus wasn't always such a desert," said Cangi.

Despite the discovery, HCO+ has not been directly observed around Venus, a gap attributed to the lack of appropriate instruments on missions to the planet. Michael Chaffin, another co-lead author, highlighted that while many missions have explored Mars, Venus has been relatively neglected.

However, interest in Venus is growing, with NASA's upcoming DAVINCI mission set to delve deep into its atmosphere, although it won't detect HCO+. The researchers are optimistic that future missions will eventually confirm their findings and offer more details on Venus's atmospheric composition.

Research Report:Venus water loss is dominated by HCO+ dissociative recombination

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