Spectacular Draconid Meteor Shower Drops a Ton of Material on Earth

Meteors may be contributing to Earth more than we thought. Researchers have discovered that about a ton of material that came from comet 21P/Giacobini-Zinner was deposited in our planet's atmosphere in 2011.

The 2011 meteor shower was one of the most intense meteor showers in the last decade. In fact, researchers calculated that more than 400 meteors per hour could be seen in the night sky. This particular shower, though, is somewhat regular. Every 6.6 years, the comet Giacobini-Zinner circulates through the inner solar system and passes through the perihelion, the closest point to the sun in its orbit. This is when the comet heats up, ejecting a large number of particles that are distributed in filaments. The oldest of these particles have formed a swarm which Earth passes through every year in early October, which results in the Draconid meteor shower.

Yet the shower in 2011 was particularly spectacular. Researchers examined the orbits of twenty meteors in the solar system in order to confirm the origin of the particles that caused the meteor outbreak. More specifically, they found a dense region of meteoroids intercepted by Earth that had not been seen before. This particular region actually involves new challenges for theoretical models.

"When a comet approaches the sun, it sublimates part of its superficial ice and the gas pressure drives a huge number of particles that adopt orbits around the sun, forming authentic swarms," said Josep Maria Trigo, researcher from the CSIC Institute of Space Sciences, in a news release. "The study shows that in the evening from October 8^th to 9^th 2011, the Earth intercepted three dense spindles of particles left behind by the comet when it crossed the perihelion."

Two of the dense spindles had been theoretically predicted before and have been identified by scientists. Yet the third dense spindle is a surprise. It shows exactly why the meteor shower in 2011 was so spectacular and bright and may teach researchers a little bit more about this kind of phenomenon.

The findings were published in the Monthly Notices of the Royal Astronomical Society.