if this year has been a bit troublesome and you want to express some wishes for the upcoming one, why not do that with the last meteor shower of 2020?
In today Fact Friday we talk about the Geminids and the Ursids.
A meteor shower consists of a stream of particles of variable sizes and composition that reach Earth at high velocity and burn in the atmosphere. Typical dimensions for these objects go from dust-size to boulder-size. How are we able to see such small particles? The main part of the light that we see doesn’t directly derive from the burning debris but rather from the glowing gas surrounding it.
Meteors in a meteor shower usually reach Earth with parallel trajectories and equal velocity but because of perspective, they seem to originate from a point in the sky called a radiant. Meteor showers are usually named after the constellation from which the meteors appear to originate. For example, you see the Geminidis coming from the Gemini constellation while you see the Ursides coming from the Ursa Minor constellation.
Meteor showers often come from an active comet travelling near the Sun but sometimes can birth from the intermittent disintegration of dormant comets, as in the case of the Geminids. The Gemeids originate from an asteroid called 3200 Phaethon. It is an active asteroid, meaning that it follows a normal asteroidal orbit, but interestingly behaves like a comet when approaching the sun. The Ursids, however, originate from the 8P/Tuttle comet and their maximum is not seen when the comet is at the closest point to the Sun (perigee) as expected but, instead, appear when it is at the farthest point (apogee). This is explained through the resonance phenomenon.
The Gemeids were visible at night between the 4th and 17th of December, with a peak of 60 meteors per hour at night between the 13th and the 14th.
The Urisids will be visible from the 17th and the 26th of December with an expected peak of 100 meteors per hour.