万圣节与巫师星云

2023年10月31日

Halloween and the Wizard Nebula
Image Credit & Copyright: Richard McInnis

Explanation: 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 a modern calendar however, even though Halloween occurs today, the real cross-quarter day will occur next week. Another cross-quarter day is Groundhog Day. Halloween’s modern celebration retains historic roots in dressing to scare away the spirits of the dead. Perhaps a fitting tribute to this ancient holiday is this closeup view of the Wizard Nebula (NGC 7380). Visually, the interplay of stars, gas, and dust has created a shape that appears to some like a fictional ancient sorcerer. Although the nebula may last only a few million years, some of the stars being conjured from the gas by the great gravitational powers may outlive our Sun.

Tomorrow’s picture: sun block

万圣节与巫师星云
影像提供与版权: Richard McInnis

说明: 万圣节的起源很古老而且与天文学有关。从西元前五世纪起，万圣节是越区节的一个庆典，这种节日恰好介于北半球日夜等长的春/秋分，及昼夜差异最大的夏/冬至之间。不过在现代历法里，纵然今天是万圣节，但真正的越区节是在下星期。另一个越区节则是土拨鼠日。现代庆祝万圣节的服饰，是另一项古代遗留下来的习俗，目的是要吓走在人间游荡的鬼魂。所以上面这幅巫师星云（NGC 7380）的特写影像，对这个古老节日是一项很适当的献礼。在视觉上，恒星、气体和尘埃交互作用所成就的形状，有人认为看起来像是一个虚构的古代巫师。虽然这个星云或许只能存续数百万年，但在强大引力的作用下它所形成的部分恒星，可能会比太阳还要长寿。

明日的图片: sun block