The Orionids reached its peak on Oct. 21st when up to 20 meteors an hour could be seen in the night sky. Nevertheless, the annual celestial event takes place for almost five weeks between October 2 and November 7, giving stargazers plenty of opportunities to observe one of winter’s best meteor showers.
These heavenly fireworks will appear to emerge from Orion’s belt, which is how they got their name. In order to get the best view possible of the spectacle, observers need to make sure that they avoid any light pollution caused by cities or street lights. Ideally, you want to be out in the country under a clear sky with a comfy seat, which should allow you to appreciate in greater detail the persistent ionized gas trails left by around half of the Orionid meteors. Occasionally, an Orionid meteor can appear exceptionally bright, and delight observers by breaking up into fragments above their heads. The debris that generates this shower is extremely small, though, so no need to worry about anything hitting the ground as everything will burn up in the atmosphere.
The Orionid meteor shower actually consists of debris from Halley’s Comet, which last passed through our solar system in the 1980s. Although the comet leaves us for over 70 years, remnants of its tail remain in large clouds inside the solar system which cover the previous path of the comet. Earth passes through this cloud each year, and due to its variation in density, some years it appears that no meteors emerge from it, while at other times we get to see thousands. We pass through this cloud from October 2nd to November 7th. It’s pretty amazing to think that pieces of this very distant and enchanting comet are raining down on us, but why is Haley’s comet disintegrating?
Halley’s comet has a highly elliptical orbit, meaning its distance to the Sun varies greatly. It spends most of its time in the outer reaches of the solar system, past the orbits of Saturn, Uranus, and partially even Neptune. It is extremely cold at these distances, and water is turned into rock, and carbon dioxide sublimes to the surface. As the comet begins hurtling back towards the Sun, it begins to heat up; carbon dioxide and water then begin to evaporate and are ejected behind, carrying rock and dust with it.
This actually forms two separate tails behind the comet, the gas tail and the dust tail. The dust tail is always following the path of the comet, mainly consisting of rocks and debris, and this is what actually rains down on the Earth during the shower. Meanwhile, the gas tail consists of vaporized water and carbon dioxide, which are influenced and carried away by the solar wind which is constantly emerging from the Sun. This means that the tail is always pointing away from our nearest star, even when the Sun is behind the comet, which is why comets may appear to have two separate tails at times.
Although Haley’s comet is losing massive amounts of material every time it heats up, we don’t need to worry about it disappearing anytime soon. It has the mass of about two and a half million aircraft carriers! This will ensure Haley’s comet, and the Orionid meteor shower will visit us for many generations to come. If you were lucky enough to have seen the meteor shower yesterday, or over the coming days, its fun to remind yourself that this spectacle is actually a portion of Haley’s comet finally reaching out and touching us here on Earth.