Halloween's origin is ancient and astronomical. Since the fifth century BC,
Halloween has been celebrated as a
cross-quarter day, a day halfway between an
equinox (equal day / equal night) and a
solstice (minimum day / maximum night in the northern hemisphere). With our
modern calendar, however, the real
cross-quarter day will occur next week. Another cross-quarter day is Groundhog's Day. Halloween's modern celebration retains historic roots in dressing to scare away the spirits of the dead. A perhaps-fitting modern tribute to this ancient holiday is the above-pictured Ghost Head Nebula taken with the
Hubble Space Telescope. Appearing similar to the icon of a fictional ghost, NGC 2080 is actually a
star forming region in the
Large Magellanic Cloud, a satellite galaxy of our own
Milky Way Galaxy. The Ghost Head Nebula spans about 50
light-years and is shown in representative colors.