Venus, once billed as Earth's twin, is a hothouse (and a tantalizing target in the search for life)

Sep 15, 2020
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I don't believe you are correct that NASA's Viking spacecraft flew by Venus. Both Mariner 10 and MESSENGER did, however, on their way to Mercury. I believe Galileo did on its way to Jupiter and Cassini did on its way to Saturn.
- John Sheff