David Shortt is a physicist who has been a member of the Planetary Society since the early 1980s. A graduate of MIT and Stanford, he directs research at KLA-Tencor, a semiconductor equipment firm in Silicon Valley. He is passionate about science education and teaches occasional courses for the Osher Lifelong Learning Institute at Santa Clara University.
With the recent announcement by NASA that the 36 year-old spacecraft Voyager 1 has officially entered interstellar space at a distance from the sun about four times further than Neptune's orbit, and with Voyager 2 not far behind, it seems worthwhile to explore how humans managed to fling objects so far into space.
The upcoming rare transit of Venus is one step in a long dance among Earth, Venus and the Sun. Transits of Venus follow a peculiar pattern—two transits 8 years apart, then 105.5 years with no transits, then two transits 8 years apart, then 121.5 years with no transits, for a total cycle of 243 years—and thereby hangs a tale.