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March 8 (UPI) -- Thanks to a new study, scientists are beginning to understand why and how meteor showers shift from night to night. As the latest analysis shows, the angles at which meteors enter the upper atmosphere change from meteor to meteor. The study's revelations -- detailed in the journal Planetary and Space Science -- also explain why meteor showers can last several weeks, or even months.
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"I was most surprised by some showers that were initially seen close to the plane of the planets, but then moved up towards the pole over the course of weeks," Peter Jenniskens, an astronomer and meteor researcher at the SETI Institute and NASA Ames Research Center, said in a news release.
The study utilized data collected by the Cameras for Allsky Meteor Surveillance system, a collection of more than 60 low-light video cameras which watch the night sky above the San Francisco Bay. The system has successfully tracked the trajectories of more than 300,000 meteors since 2010, revealing the movement of meteor showers from night to night.
Most meteor showers are the result of the collision between Earth's atmosphere and the string of debris left behind by the tails of comets. But these orbital rivers of space rock have a variety of kinetic subtleties, both big and small.
"The small daily drift of the Perseids is mostly due to Earth's motion around the Sun," said Jenniskens. "But after taking that into account, 18 short-period and 27 long-period showers are still seen to wander from night to night."
Jenniskens mapped the orbits of all known meteor trails to reveal each shower's broader movements.
"Jupiter's gravity is likely responsible for warping these meteoroid streams by causing both the orientation of the orbital plane and the distance of closest approach to the sun to change," said Jenniskens. "The combination of the two creates conditions suitable for hitting Earth over weeks or months."
