Moon may outshine annual meteor shower.
BEIRUT: This weekend's night sky will -- to the naked, Earth-bound eye -- be filled with shooting stars for annual Perseid meteor shower, however only half the usual number of shooting stars will be seen during the peak.
Most years, between 80 to 120 meteors can be seen every hour during the shower. But this year, they will be outshined by a celestial competitor, Marwan Gebran, associate professor at the Department of Physics and Astronomy at the Notre Dame University-Louaize, told The Daily Star.
"The moon is very bright this year -- it will be in its third phase [more than half full], and we need [to observe from] a place without light pollution" to view the meteor shower, Gebran said.
Light pollution is caused by bright sources of light "polluting" the dark sky, which is far less bright to viewers on Earth compared to the light of the moon or most big cities.
Organizers of various stargazing tours are bracing themselves for the moon's interference in the visibility of the shooting stars.
"We have low expectations [of seeing] as many falling stars as last year. The moon [will be] so bright, nearly full," Hady Assaf, manager at the Cedars Ground Campsite in the Chouf mountains, which hosts a stargazing event, said.
The meteor shower -- which is named after the point it appears to emerge from in the night sky, the Perseus constellation -- is a recurring phenomenon. Each year, the Swift-Tuttle Comet passes the sun. Chunks of the comet's ice and other materials break off, floating through space until they come crashing through the Earth's atmosphere as it enters their path in the summer.
This happens each year, from roughly July 17 until Sept. 1, peaking in August.
The pieces of celestial debris appear to Earth-bound viewers as brilliant streaks of light passing through the sky.
"These objects are very small but travel at 50 km per second. They become heated from the friction and then they ignite," Gebran explained.
The light created by this ignition is what we see as a shooting star.
"[Seeing one] is a rare event for many people. Some might see it once a year -- some have never seen a shooting star [in their life]. When you see it, it's very interesting," Gebran said.
The number of people in Lebanon interested in viewing the Perseid meteor shower is slowly growing, according to organizers of stargazing events. "We do this every year [and the number of attendees] is increasing every year," Najat Fadlallah, organizer of the Lebanese American University Astronomy Club's meteor shower trip, told The Daily Star.
"[At] the first event we went out with 200 [people]," she said. "This year maybe 300 or more students [will] show up."
Fadlallah said she was well aware of the potential problems with the brighter-than-desired moon, but said she wasn't too worried. The group is going to the popular ski resort area of Mzaar-Kfar Zebian, where the natural geography will help to give them a clearer view.
"[The moon is] going to affect [the view] negatively but it won't be as much after midnight, [after] the moonset," she said. "It will be behind a mountain."
For the best chance of getting a good view of the shower, it's important to get up in the mountains, NDU's Gebran explained.
"When you go up, there's less pollution, both light and atmospheric. You see [the shooting stars] clearer because there's less variation in temperature," he said, adding, "That's why telescopes are built up high."
Higher temperatures can obscure light and make it "blink" or "shimmer," as when one looks on a hot summer evening and the lights from cities seem to be flickering.
Not surprisingly, the most recommended spot for Lebanese stargazers to get a pellucid view of the night sky is Qornet al-Sawda -- which is forecast to be a cool 14 to 16 degrees Celsius Saturday night.
But even if the radiant moon happens to block some of the Perseid glory, the celestial event will still be worth a look, according to Cedars Ground Campsite's Assaf.
"This year, very serious stuff is happening in the sky," he said.
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