What causes meteor showers?

Question posed by Jenstie.


Meteor showers are, as the name suggests, events marked by an increased number of meteors visible in the sky. These meteors all appear to come from the same point in the sky (not necessarily the same point for each shower) and are usually named after the constellation in which they (apparently) originate.


What causes them?
When a comet passes through the inner solar system and the sun begins to have an effect and warms some of the ice that makes up any comet. As this ice sublimates* it takes some of the more solid material with it, and, through this and other processes, the comet leaves behind a 'dust trail' which spreads out all along the comet's orbit.

This trail is made up of small pieces of comet of various sizes, from dust particles up to small boulders. The trails left behind by different comets evolve over time. Occasionally, in its orbit, Earth travels through or near to a comet trail (and/or the comet trail evolves to cross the path of the Earth), and some of the debris falls into its atmosphere. The meteoroids then burn up in the planet's atmosphere, and we see them as meteors flying across the sky.

Some meteor showers have different origins: the fragmentation or break-up of a comet or asteroid can produce a similar stream of meteoroids which then may interact with the Earth in the same way.


Famous meteor showers
Arguably the most well-known meteor showers of recent years are the Perseids, which peak on or around the 12th August each year, and the Leonids, which peak around the 17th November. The Geminids, peaking in mid-December, are an example of a meteor shower thought to have originated from the break-up of a body named 3200 Phaethon, thought to be an extinct comet. Many astronomers believe that the Geminid showers are becoming stronger as time goes on, and are one of the most recent meteor shower discoveries, being first observed only about 150 years ago.


Interesting info

  • Any other body with a more-or-less transparent atmosphere can have meteor showers, though these are necessarily different to those observed on Earth due to different interactions with different meteoroid streams.
  • Details of a selection of annual meteor showers that can be viewed from the UK are available here.





Have a question about this topic? Comment below! Got an astronomy related question of your own? Ask it here.








*Turns from a solid into a gas without passing the liquid phase in between.

Comments

  1. Fabulous. Thanx TK. Just followed the link to when the various showers can be seen and on that it says that all meteor showers are best seen between midnight and dawn. That will be very unwelcome news to my other half who normally gives up looking after half an hour at about eleven o clock, while I sit and sit and sit, just hoping to see one more. If next time I'm out there til dawn I will blame you!!!

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  2. Hah! If you want to see astronomical phenomena, night time's generally the best time... Now I've got my snazzy camera, I'm looking at a getting a decent telescope and an attachment so I can take my own spacey pics!

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  3. It'll be a while yet- no money and no space! Need to buy a house with a garden big enough for Emma's veggie plot and my observatory first!

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  4. Good luck with that one!Just promise me a visitor's pass when you get it!

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  5. Lol, you won't need a visitor's pass for my house...

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