With the Delta Aquarids meteor shower already underway, the 2016 version of the annual Perseid meteor shower is scheduled to peak on the night of August 11 to 12 and promises to be even more impressive than usual. According to astronomers, observers may see double or even triple the number of shooting stars this year.
A meteor shower occurs when the Earth's orbit takes it into the path of a comet. The Perseid meteor shower, so-called because the shooting stars appear to come from the part of the sky occupied by the constellation Perseus, consists of particles of debris that originate with the Swift-Tuttle comet. As the Earth passes through the comet's tail, from about mid-July to mid-August of each year, some of the particles in the cloud of dust and ice ignite as they come into contact with Earth's atmosphere. The streaks of light, or shooting stars, are really bits of dust burning up in our atmosphere, traveling at a rate of 37 miles or 59 kilometers per second.
The source of the debris responsible for the Delta Aquarids meteor shower remains a mystery. As reported in Gizmodo, there are multiple current theories about which comet produced the trail of debris that appears to originate within the constellation Aquarius.
The Delta Aquarids Meteor Shower
The Delta Aquarids meteor shower is smaller in terms of the rate of shooting stars than the Perseids, and it is already underway.
Visible already since July 12, according to Astronomy Magazine, the Delta Aquarids meteor shower will peak tonight, the night of July 29 to 30. The meteor shower should produce between 15 and 20 shooting stars per hour during the prime viewing hours after midnight.
The shooting stars will seem to originate around a star called Delta (d) Aquarii in the constellation Aquarius, which will climb to its highest point in the southern sky at around 3 a.m. From that so-called radiant, the meteor shower will streak throughout the sky. The Delta Aquarids meteor shower will still be visible in the southeastern part of the sky for a day or two after its peak tonight, albeit at lesser rates. Because the radiant is located fairly low in the southern skies, it will be most visible in the Southern Hemisphere.
The Perseid Meteor Shower And The "Outburst"
The Perseid meteor shower will actually be visible from about August 4 to August 15 or 16. According to the CBC News, the peak viewing time will be between midnight and sunrise on the evening of August 11 to 12 after the moon has set and the constellation Perseus has risen in the sky.
This year's display is expected to be even more spectacular than usual because of the influence of Jupiter and Saturn. The orbits of these two large planets are influencing the cloud of dust from the Swift-Tuttle comet, essentially clumping the comet's tail of debris close to earth's orbit.
Bill Cooke, the head of NASA's Meteoroid Environment Office, is quoted in Scientific American as saying, "This year, instead of seeing about 80 Perseids per hour, the rate could top 150 and even approach 200 meteors per hour."
The last time such an "outburst" occurred was in 2009 when it produced about twice the number of shooting stars. However, outbursts in previous years have sometimes resulted in several times the number of shooting stars visible during the Perseid meteor shower.
Even though the Perseid meteors are typically about the size of a grain of sand, they have been known to inflict damage to satellites, particularly during an outburst. In 1993, the Perseid meteor shower outburst actually resulted in permanent damage to the European Space Agency telecommunications satellite known as Olympus. During 2009's outburst, a collision with a Perseid meteor temporarily caused the Landsat 5 satellite managed by NASA and the U.S. Geological Survey to spin out of control.
How To Watch A Meteor Shower
For best viewing of either meteor shower, it is essential to get away from as much artificial light as possible, generally out of the city and into the suburbs or rural areas. The Delta Aquarids will continue until around August 23, overlapping with the Perseid meteor shower, although visibility will vary around the peak periods.
In the Northern Hemisphere, the Delta Aquarids will originate in the southeastern sky, lower to the horizon and dimmer than the Perseids. The Perseid meteor shower will center around the north or northeastern sky. The Perseid meteor shower will still be visible in the Southern Hemisphere but at a rate of about a third of that visible in northern skies. The Perseid meteor shower will be visible between midnight and dawn anywhere in the world.
Moonlight plays a role in how many shooting stars are viewed from the ground. The Delta Aquarids meteor shower will benefit from a waning crescent moon that becomes a new (dark) moon on August 4. The Perseid meteor shower will become less visible after August 14, with a full moon occurring on August 18.
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