Transits of Venus occur in a pattern, with pairs of transits 8 years apart separated by much longer gaps, that repeats every how many years?
Result - 243
Viewed from Earth, Venus crosses the sun twice every 100 to 120 years or so, about 8 years apart. The next is on 10-11 December 2117. When was the last?
Interference patterns produced when an opaque ruled pattern with transparent gaps is overlaid on another similar pattern, are called what?
