Prepare for a celestial spectacle! On Friday, September 19th, a unique astronomical event will grace the predawn sky: a triple conjunction featuring Venus, the star Regulus, and a slender crescent Moon. This captivating arrangement, appearing as a celestial smiley face, offers a fascinating glimpse into the vast distances within our solar system and beyond.
The Moon, a mere 5 percent illuminated, will be positioned near Venus, shining brightly at 89 percent illumination, and Regulus, the brightest star in the constellation Leo. While visually close, their actual distances vary dramatically. The Moon is a relatively close 385,000 kilometers away, Venus sits over 12 light-minutes distant, and Regulus resides a staggering 78 light-years away, far beyond our solar system.
This alignment presents a rare opportunity. For a select few in northern Siberia, the Moon will occult, or pass in front of, Regulus. This is part of an ongoing cycle of occultations that will continue until January 24th, 2027. More impressively, the Moon will also occult Venus, visible from the extreme northwestern Canadian Arctic under dark skies and, during the daytime, across the North Atlantic, continental Europe, and parts of northern Africa. Even those outside these areas can attempt to spot the pair during daylight hours, though it will require a keen eye and possibly binoculars or a telescope to help filter out the sun's glare.
A truly exceptional aspect of this event is the double occultation of Venus and Regulus by the Moon – a rare phenomenon likely visible only from a remote area north of Dudinka, Russia, under bright twilight skies. The precise positioning of the celestial bodies will create the illusion of a ‘smile’ with Venus and Regulus as the eyes and the crescent Moon forming the mouth. The effect will be more pronounced in northwestern North America, with the Yukon and Alaska providing optimal viewing conditions.
The rarity of this event stems from the precise alignment required. Considering the five visible planets and four bright stars near the Moon’s path, along with the Moon’s phase and its hourly movement, such a close grouping of celestial objects within a half-degree circle is remarkable. An analysis spanning to 3000 AD revealed only 85 such events, highlighting the significance of this celestial smile. While some similar events have occurred in the past, like the April 23rd, 1998, occultation of Venus and Jupiter, the next comparable event isn't expected until October 15th, 2036. So don’t miss your chance to witness this cosmic spectacle!
This event coincides with the final lunar eclipse of 2025, which will be visible from New Zealand, the South Pacific, and Antarctica on September 21st. For now, enjoy the unique celestial smiley face on September 19th – a testament to the universe's unexpected humor.
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Originally published at: https://www.sciencealert.com/look-up-this-week-to-see-a-rare-triple-conjunction-smiling-down
