You may have heard about the Geminids meteor shower that appeared in the night sky in December 2015. If you were like me and missed out, never fear – there is always a chance of observing these beauties this year!
Despite being known as ‘shooting stars’, meteors are in fact space debris – a rocky or metallic body of sizes ranging between a grain of sand to a boulder. When a meteor enters the Earth’s atmosphere, it heats up due to the air resistance on the meteor. This causes the meteor and the air around it to glow, displaying a bright streak in the sky. The glow lasts only for a short amount of time, with most meteors disintegrating while passing through Earth’s atmosphere.
Meteor showers usually occur when a comet passes close to the Sun and produces a debris trail which is strewn around the comet’s orbit. Every time Earth passes through this region of the comet’s orbit it experiences a meteor shower. The brightness and frequency of the meteors depends on how dense the debris trail is; how deeply into the trail the Earth passes; and whether the Earth passes through more than one trail. The meteors in each shower all move on a parallel path at the same velocity, so from our point of view they seem to radiate from a single point, called a radiant, in the sky. Some meteor showers occur at the same time every year and by convention, these are named after the constellation in which the radiant is located.
Below is the list of regular meteor showers that can be viewed in Sydney. The best time for viewing any meteor shower is after midnight and they are best seen under dark skies, away from city lights.
- Lyrids, 22nd April between midnight and 5 am
- eta-Aquarids, 5th May between 2 am and 6 am
- Southern delta-Aquarids, late July to early August (maximum 28th – 30th July, an hour or two before dawn)
- Orionids, 21st October between 1 am and 5 am
- Leonids, 18th November between 3 am and 5 am
- Geminids, 14th December between 11 pm and 5 am