Skywatchers beware: the moon will try to visit the Perseids, typically one of the best meteor screens of the year.
For northern hemisphere observers, August is simply considered “meteor moon”, with one of the best displays of the year reaching its peak mid-moon. Rolling a sleeping bag in the open air is an easy way to enjoy summer meteor showers, especially the annual Perseid meteor shower, which is favorite by everyone from veteran meteor enthusiasts to summer campers.
Unfortunately, 2020 will see a night in the night of August 11 last quarter month, coinciding with the peak of the Perseids, which is predicted to happen in the night hours of August 11-12. From the mid-northern latitudes, moon rises at 12.15 local daylight on Wednesday (August 12). The moon will be about 8 degrees below the Pleiades star cluster and not all so far from the constellation Perseus, where the meteors appear to originate (hence the name “Perseid”).
Related: Best Night Sky Events of August 2020 (stargazing maps)
Most of these “shooting stars” could identify as Perseids, because their paths, extending backwards along the flight line, intersect at a point on the border of Perseid-Cassiopeia.
Perseus himself does not begin to climb high into the northeastern sky until after 11 o’clock local time; by morning it is almost overhead. If you plan to spend a night out, your best acting platform would be a reclining lawn chair that allows you to concentrate above and to the northeastern part of the sky.
The moon muscles in
Skywatchers may have caught a Perseid or two since the meteor shower began on July 17. But a noticeable rise in Perseid activity traditionally begins in the second week of August, leading to its peak.
Persistent meteors are typically fast and clear and sometimes show sustained trains. Every now and then a brilliant one Perseid fireball will blow forward, bright enough to be quite spectacular, even maybe it seems to end in a strobe flash. Such an outlier would be more than capable of attracting attention, even in bright moonlight.
Unfortunately, the moon will always be above the horizon during the preceding mornings, when viewing Perseid is always at its best. That timing means that the moon glory will be very difficult in the second week of August; the moon will be in a fairly bright, diminishing fifth phase and taking the Perseids’ build-up seriously. That even the slow rise of the shower will be obscured by moonlight.
Under normal circumstances, a single observer would be able to see anywhere from 45 to 90 meteors per hour on the night of maximum Perseid activity. This year, the display will not come close to that number, but the Perseids may still be able to put on an entertaining show despite the interference moonlight.
Comet crawls
These meteors are the dross of the Comet Swift-Tuttle, which was discovered in 1862 and takes about 135 years to orbit the sun. In much the same way as the comet Temple-Tuttle left a trace of pun along its orbit that produces the spectacular Leonid meteors of November, the comet Swift-Tuttle produces a similar orbital route, causing the Perseids. Every year in mid-August, as the Earth orbits near the orbit of Swift-Tuttle, the material left behind by the comet from its previous visits hits our atmosphere at a speed of about 37 miles (60 kilometers) per second, and makes fast-moving bright streaks of light in our afternoon skies.
The Perseids were primarily productive, producing meteors in the hundreds per hour, the last time Swift-Tuttle passed through the inner part of our solar system was in 1992. Interestingly, the next two times the comet will float around the sun, in 2126 and 2261, it will pass within about 14 million miles (22 , 5 million km)) of Earth, which probably appears very large and clear in our air and also produces spectacular eruptions of Perseid, again in the hundreds per hour.
In his book, “Impact! The Threat of Comets and Asteroids” (Oxford University Press, 1997), astronaut Gerrit L. Verschuur described the comet Swift-Tuttle as “the single most dangerous object known to man.” That point will be driven home primarily in the year 3044, when the comet is expected to pass only 1 million miles (1.6 million km) from Earth!
But despite the comet’s superlative, the Perseid “shooting stars” themselves are harmless, no larger than grains of sand or pebbles. With the consistency of cigarettes, the pound of comet scores of miles above our heads is consumed.
Another shower from August to see
As August progressed, with both the moon and the Perseids on the way, a different meteor shower will take to the skies, the Kappa Cygnid shower. According to forecasts by the International Meteorological Organization (IMO), these meteors will peak on August 17, although they started on August 3 and will continue through August 25.
The Kappa Cygnids were juicy in 2007 and 2014. Juicy. But for 2020, however, there are no available forecasts suggesting that further peculiarities may occur.
Although this shower produces only a handful of meteors (two to four) every hour, some of these fireballs are firebeams. Best view is in the early evening, when the radiance in northwestern Cygnus is almost overhead. Unlike many other storms, the Kappa Cygnids are associated with no known comet.
Joe Rao serves as an instructor and guest lecturer at Hayden Planetarium in New York. He writes on astronomy for Natural History magazine, the Farmers’ Almanac and other publications. Follow us on Twitter @Spacedotcom and on Facebook.
