Extended Data Fig. 1: Random-like variations in radar echo power are illustrated.

Representative variations in radar echo power (speckles) from observations of Venus with the Goldstone Solar System Radar and Green Bank Telescope at 8560 MHz on 2016 Nov. 26. The GBT echo was shifted in time by 20 s to illustrate the high degree of correlation between the received waveforms when the speckle trajectory is aligned with the antenna baseline.