Less than 250 years ago, the brightest minds of the Enlightenment were stumped over how far the Earth is from the sun. The transits of the 1760s helped answer that question, providing a virtual yardstick for the universe.
A rare astronomical event will take place Tuesday evening: The planet Venus will pass between Earth and the sun, appearing as a small black dot moving across the sun's bright disk. It's known as the transit of Venus, and it won't happen again for more than 100 years.
The early word is that it could have been worse. The steel and aluminum dome atop the Mount Evans observatory was destroyed by high winds over the winter. But damage to the telescope inside may not be as bad as first thought.