The Perseid Meteor Shower
Next Friday night, August 11, 2023, the peak of the Perseid Meteor Shower will begin. Bringing with it an increase in regular meteor activity by upwards of 100 meteors per hour overnight Saturday, August 12-13. As we have stated in the past, observing a meteor shower is highly dependent on local conditions as well as celestial conditions. Most importantly, the sky needs to be as clear as possible, no clouds, no haze, and the Moon cannot be present. Timings are critical as well because the radiant point of the shower needs to be well above the horizon to see the most meteors. In 2023, we certainly have great conditions in regards to the Moon, but August is wildfire season, and 2023 has been a very smokey year. Sadly, smoke from wildfires usually obscures the yearly meteor display over Southern New England. Can 2023 work to our advantage? It’s still too early to tell, but the shower is lined up to impress, and we are hopeful that we may get a break.
The Perseid shower is a product of a comet named 109P/Swift-Tuttle. A periodic comet with an orbital period of 133 years, Swift-Tuttle will cross Earth’s orbit during perihelion passage (closest to the Sun). When this happens the increasing bombardment of the solar wind against the comet causes the nucleus to heat up, resulting in the melting of ices on the comet. This process will cause particles of ice and rock to be released into a debris field along the orbital path of the comet. Most of these particles are between dust-sized to rice-sized. When Earth orbits through the debris field every August, these small particles get caught in Earth’s gravity and enter the atmosphere at rates of 37 miles per second. Once encountering the mass of Earth’s atmosphere, these particles burn up leaving a visible streak across the sky. Occasionally larger particles will enter the atmosphere, these are what creates a fireball meteor or a bolide, which can be defined as very bright, longer lasting meteors that may fragment and result in a delayed concussive sound. Because Earth passes through this stream of meteor fragments every August, meteors will appear to radiate, in the sky, from the star Miram in the constellation Perseus. This is where the meteor shower gets its name from – the constellation of the radiant point.
Comet Swift-Tuttle is rather large, with a nucleus measuring 16 miles in diameter. The comet passes quite close to Earth during perihelion passage and was once considered a significant impact threat. During the last perihelion passage in 1992, we were able to learn a lot about the comet and refine our understanding of the comet’s orbit, removing any such threats. Though the comet will still pass VERY close to Earth during future passes, specifically in 3044 when the comet passes Earth at a distance of 994,194 miles distant. The next close approach of Swift-Tuttle to Earth will occur on August 5, 2126 at a distance of 14.2 million miles.
So how should one observe the Perseid peak? Depending on your location there are a few things to keep in mind. Considering that the 6% waning crescent Moon will rise at 2:45 am on the morning of the 13th, the Moon will not significantly interfere with your view, so you will certainly want to get out of the city and find a super dark spot, free of light pollution, with a wide open view of the sky. The best times to be out will be after 11:00 pm, and during the morning hours of August 13th. The Perseid radiant point is circumpolar from our latitude in Southern New England, which means that it never rises or sets, and is always above the horizon. Though it does sit rather low on the horizon at sunset and will reach 30° in altitude by midnight, becoming nearly overhead at sunrise. Looking towards the radiant point will reduce the number of meteors you see because they enter the atmosphere near that location and will brighten as they streak away from that spot. Laying on your back, so you have a comfortable view of the zenith (top of sky), will be key. When laying down, orientate your feet towards the S - SW, and keep an eye to the zenith.
Frosty Drew Observatory and Science Center will host a special event for the Perseid Peak that starts at 8:30 pm on August 12th. The event is dependent on weather, which is still uncertain at this point. Keep checking our event page for updates. It’s been years since we have had a good Perseid peak that was visible at Frosty Drew, with the last time being in 2015. Check out this composite of the Perseid shower we captured at Frosty Drew in 2015. Perhaps 2023 will bring the next amazing view, and on a Saturday night!