Israelis Get Starry-eyed Over Meteor Shower

City-dwellers went to the Negev, where the spectacular Perseid shower featured up to 100 meteors an hour.

Aug 12, 2013

The most spectacular meteor shower of the month is expected to be visible Monday night in Israel. From suitable viewing locations, the meteors should become clearly visible starting at about 10:30 P.M. and into the night early Tuesday until sunrise. Known as the Perseid meteor shower, at its peak, it is expected to feature 100 meteors an hour.

The Perseid meteor shower is visible without any special equipment and use of binoculars could actually hinder the view. Due to the glare of city lights, or "light pollution," as it is called by professionals, the meteor shower is not visible inside the major cities. "If you go from the city to a dark, dry, high desert setting, particularly in the Negev, you can see dozens and even hundreds of meteors at the peak of the night between Monday and Tuesday," said Ilan Manulis, the director of the Weizmann Institute's Kraar observatory.

Meteors visible from Earth are caused by debris from comets whose orbit sometimes crosses the Earth's orbit. "Comets are bodies dozens of kilometers in diameter that are made of 'dirty ice,' ice composed of gases in a frozen coagulated state covered in a thin layer of rock," said Manulis. "When the comet approaches the sun, it heats up and the ice undergoes a physical change that causes the dispersal of the gases inside the comet. The gases escape from the comet through cracks in its surface and fly out with particles of dust that are left to orbit the sun in the comet's original path. When the Earth's orbit intersects that of the dust particles, they enter the [atmosphere] and are visible as a meteor shower."

Unlike relatively large meteorites, which contain metallic substances and sometimes actually land on Earth, as occurred in February in Russia, causing widespread injury and property damage, the dust particles that cause the current meteor shower are small, "between the size of dust particles and pebbles," Manulis explained.

"They move at the original velocity of the comet, which is estimated at dozens of kilometers per second, 3,600 times the velocity of a car speeding on a highway,” he added. “Due to the friction created with the air after they enter atmosphere, they burn up dozens of kilometers above the Earth."

Meteors are visible only after they have entered the atmosphere, when the trail that they leave behind can be seen after the meteors themselves have actually burned up. The meteors should become visible in the night sky near the constellation Perseus, hence the name Perseid meteor shower. The constellation will be rising above the horizon at about 11:15 P.M. Monday night, but even before that, beginning about 10:30 P.M., the long trails of the meteors should be clearly visible from locations where viewing is suitable. As the shower moves higher in the sky into the night, the meteors will appear to be shorter and faster, until sunrise. There were two other meteor showers earlier in August, but the Perseid shower is the largest of them.

A man watches the stars in front of his tent.Credit: AP