Why settle for dusty ol' Mayan calendars and 12/12/12 apocalyptic visions, when 2012 has been offering up so many stellar—and planetary—sightings? We Earthlings have already been treated to nice meteor showers as well as a magnificent supermoon, and this weekend brings an annular solar eclipse. That's not even the best treat: Venus will be ambling between Earth and the sun in a rare (though non-earth-shattering) planetary alignment. Sure, the event might look like a black pimple floating across the face of the sun, but this celestial rarity once guided adventurous astronomers in their quest to determine the size of the solar system and yielded the first-ever global scientific collaboration. Don't blink—Venus doesn't cross our path again until December 2117. An annular solar eclipse and that ring of fire: A solar eclipse happens this Sunday, except for the Eastern seaboard (sorry). It's an "annular" eclipse rather than a total one, which means t...