June 24, 2018
The light from the farthest visible stars set out on its journey long before your first birthday.
Rocket Plume Shadow Points to the Moon
Birthday · June 24, 2018
A little universe, just for you
Your date.
Ready to give.
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APOD published June 24, 2018. Full image credits are on the original APOD entry below. A publication-date match, not a photo taken on your date. Independent of NASA.
Why would the shadow of a space shuttle launch plume point toward the Moon? In early 2001 during a launch of Atlantis, the Sun, Earth, Moon, and rocket were all properly aligned for this photogenic coincidence. First, for the space shuttle's plume to cast a long shadow, the time of day must be either near sunrise or sunset. Only then will the shadow be its longest and extend all the way to the horizon. Finally, during a Full Moon, the Sun and Moon are on opposite sides of the sky. Just after sunset, for example, the Sun is slightly below the horizon, and, in the other direction, the Moon is slightly above the horizon. Therefore, as Atlantis blasted off, just after sunset, its shadow projected away from the Sun toward the opposite horizon, where the Full Moon happened to be.