It was almost exactly a year ago when the naked eye comet named ‘NEOWISE’ graced the morning and evening skies of early summer.
A close up of Comet NEOWISE’s nucleus and coma, along with part of its tail. Photo was taken in July 2020.
Twice this week, I observed with the naked eye what looked like a comet in the partly cloudy western twilight.
Bright object pointing down toward the WNW horizon, about 9:15pm MDT on June 25, 2021.
The object wasn’t a comet, it was an atmospheric event that some refer to as a ‘Venus pillar.’ NASA says Venus pillars are rare occurrences. In fact, the phenomenon is so rare that it doesn’t have an agreed upon name, although ‘Venus pillar’ seems appropriate since it’s similar to a ‘Sun pillar.’
A Sun pillar (a.k.a., light pillar) is light from the Sun, located just above or below the horizon, reflecting off horizontal ice crystals floating in the upper atmosphere. The reflection results in a vertical shaft of light, slightly bulging at the Sun’s position. If the Sun is above the horizon, the Sun pillar can appear above and below the Sun. If the Sun is just below the horizon, the shaft of light will rise vertically above the horizon, from the point directly above the recently set Sun.
A Sun pillar stands over the Jemez Mountains. Photo taken in April 2021.
With this week’s unusually cool, moist weather, ice crystals formed in the upper atmosphere. On two occasions, the planet Venus was close enough to the horizon and bright enough to create a mini-light pillar, above and below the planet.
In the second photograph above (the ‘bright object’ photo), a thick cloud blocked the lower half of the Venus pillar, creating a comet-like effect. The two photos below show the Venus pillar in its entirety.
A Venus pillar seen on June 25th, around 9:30pm MDT. One could argue that this is a Sun pillar since the pillar is created by sunlight reflecting off of ice crystals in Earth’s atmosphere – the sunlight just happened to reflect off of Venus’ cloud tops first!
A second Venus pillar, seen on June 27th, about 9:40pm MDT. Note the gibbous phase of the planet. The pillar bulges a bit in the middle, then appears to taper at the tips like a candle flame.
In all my time watching the sky, I’d never seen a Venus pillar. Now, I’ve seen two in one week.