Where’d they go? Why June’s meteor showers often vanish

As Earth nears its June solstice, communities across the Northern Hemisphere experience the most sunlight of the year, effectively washing out the chances of seeing planets, stars, auroras and meteor showers, but that doesn’t stop galvanized stargazers from attempting to catch a glimpse of what passes through the night sky.

On rare occasions, nighttime sky conditions can produce what can only be described as a celestial wonder - events that are statistically less likely to happen than being in a car crash or getting audited by the IRS – and June’s Bootids is one of those.

The June Bootids meteor shower, produced by debris from Comet 7P/Pons-Winnecke, was originally discovered during the summer of 1916, and, since then, there have been fewer than a handful of significant appearances, with noteworthy sightings reported in 1921, 1927 and 1998.

DON’T LOOK UP: WHY SOME CONSIDER JUNE'S METEOR SHOWERS TO BE INVISIBLE

While the Sun contributes to masking the annual event, what’s known as the Zenithal Hourly Rate, or what is commonly referred to as the ZHR, may play a big role in how frequently the event is observed.

According to the American Meteor Society, the ZHR is a measure used to estimate the number of meteors an observer can see under ideal conditions.

Meteor showers with high ZHR values are more likely to be spotted than those with a ZHR of just 1 or 2.

During most years, the Bootids have a ZHR value of only 1 or 2, but occasionally, the shower has peaked closer to 100.

Comets tend to produce stronger meteor showers when they approach the Sun, as gases and ice break down and vaporize, but astronomers have not yet identified a reliable pattern for Comet 7P/Pons-Winnecke’s outbursts.

Its short orbital cycle means it approaches the Sun roughly every six to seven years, but it only lights up Earth’s sky a few times each century as our planet crosses through its dusty trail.

SEE THE OBJECTS HUMANS LEFT BEHIND ON THE MOON

Due to its unpredictable nature, the American Meteor Society has the June Bootids listed in its Class III category, with dozens of other annual meteor showers ranking as either Class I or Class II. 

Since no activity has been observed in recent years, it is not enough to completely write off the event, but it is also not significant enough to stay up for and circle on your calendar.

The current ZHR for this year's event remains unknown, unlike more than two dozen other meteor showers whose values have been calculated and can be planned around, if viewing weather cooperates.

According to NASA, the Perseids in mid-August and the Geminids in December are the best opportunities for meteor viewing, while lesser events such as the Southern Delta Aquariids, Orionids, and Leonids occur in July, October and November, respectively.