The Perseids Meteor Shower
What causes the Perseid meteor shower?
The comet Swift-Tuttle orbits the sun once every 130 years, it last swept through the inner Solar system in 1992. As it passed near the sun it left behind fragments of rock and dust – it is these rock and dust fragments that cause the Perseid meteor shower. As the Earth passes through this gritty debris, the rock and dust fragments cause the Perseid meteor shower. This debris field was left behind by Comet Swift-Tuttle when it last came near the Sun.
The debris burns up in the Earth’s atmosphere, most of the meteoroids are smaller than a grain of sand, yet they produce an impressive display. Any fragments that do reach the Earth’s surface are then called meteorites.
How did the Perseid’s get their name?
The Perseids are named because they appear to come from an area inside the Perseus constellation. Much of the debris that the Earth will pass through is about 1000 years old, but the Perseids have been seen for over 2000 years. The first know observations of the Perseids came from the Far East, in early medieval Europe they were known as the “Tears of St Lawrence.”
When and where can they be seen?
The Perseid meteor shower can be seen from mid-July each year, but the most obvious activity is between August 8 and 14, and usually peaks about August 12. During the showers peak, the rate of meteors can reach between 60-80 meteors or more per hour. The meteors can be seen all across the sky, but because of the path of Swift-Tuttle's orbit, the Perseids are more easily visible in the northern hemisphere.
In 2009 the National Trust produced a list of the seven best places to observe the Perseid meteor shower in the UK, these were:
- · Black Down in Sussex
- · Teign Valley in Devon
- · Penbryn Beach in Wales
- · Stonehenge Landscape in Wiltshire
- · Wicken Fen National Nature Reserve in Cambridgeshire
- · Mam Tor in Derbyshire
- · Friar's Crag in Cumbria
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