Scientists find surprising clue about Venus' past in its atmosphere 

 Scientists found an unexpected ratio of hydrogen to deuterium in Venus' atmosphere, offering clues about the world's past. 

https://cdn.mos.cms.futurecdn.net/DFWZg6vmm7kFMwrBBna5vG.jpg

https://www.space.com/venus-atmosphere-deuterium-water-ratio