Move Over, Mars
After decades away, NASA is sending not one, but two missions to Venus.
In June of 1769, an astronomer named David Rittenhouse prepared to observe a rare cosmic phenomenon, the transit of Venus. Rittenhouse had built an observatory on his farm in Pennsylvania to monitor the planet as it moved across the face of the sun, a small black dot against the glowing orb in the afternoon sky. When the moment arrived, Rittenhouse “became so over-excited that he collapsed and fainted, missing the beginning of the most important event of his scientific life,” writes the historian Andrea Wulf. “When he regained consciousness, he quickly grabbed his telescope to discover that Venus had already entered the sun, but calmed himself sufficiently to
