Fig. 1

The growing corpus of scientific literature on the topic (Smithsonian-ADS refereed paper search 9/28/2017). Search keywords “Venus” and “Lightning” were both required in the title or the abstract; the abstract search turns up more general papers as well as Venus-lightning-specific articles. The curves have a plateau in the 1995–2007 period as the Pioneer Venus interpretation debate fizzles out; the pace of papers increases a little after Venus Express data begin to emerge