When the Moon Was Young

Remember when the Moon was young? It was just last Monday. On May 9th, this slender
crescent Moon was recorded at a tender age of 34 hours and 18 minutes. Well, OK ...
when calculating the lunar age during a lunation or complete cycle of phases - from
New Moon to Full Moon and back to New Moon again - the Moon never gets more than 29.5
days old. Still, a young Moon can be a rewarding sight, even for casual skygazers,
though the slim crescent is relatively faint and only easy to see low in the west as
the sky grows dark after sunset. Sighting this young Moon last Monday, lucky astronomer
Stefan Seip was also treated to a very dramatic telescopic view of an airliner flying in
front of the distant sunlit crescent. At a high altitude, the jet's stunning contrails
reflect the strongly reddened light of the Sun setting below the western horizon.