The Geminids should also be active at lesser levels for several nights before and after the peak. The difference attests to the changing profile of the debris stream that Earth crosses each December 13th or 14th. The change is due to the stream's slow drift with respect to Earth's orbit. A close look at the Geminids for 1996 should help observers predict how they might fare this year. This graph incorporates 19,604 Geminids that 119 observers counted and reported to the International Meteor Organization.
Vertical bars show the range of statistical uncertainty for each point .
Astronomers have yet to convincingly explain Phaeton's orbital and physical properties. Decades of careful visual counts have enabled researchers to map out the complex structure of the Geminid debris stream, while two-station photography of individual meteors has shed light on the particles' trajectories and densities. According to meteor specialist Neil Bone, at 2 grams per cubic centimeter on average, Geminid meteoroids are several times denser than the cometary dust flakes that supply most meteor showers. Sky Publishing Corp. All rights reserved. Please read our copyright and permissions policy .