Astronomy at a distance: Meteors
Shooting stars – or meteors - are some of the most magical features of the night sky. Seeing a shooting star is a special experience. Seeing many in quick succession – a meteor shower – and you are treated to a spectacular natural firework display. Meteor showers are seasonal and occur at certain times of year. Professor Tom Marsh from the University of Warwick’s astrophysics team explains exactly what shooting stars are and the best way to see them.
When the Sun and planets formed to make our Solar system 4.5 billion years ago, many bits and pieces were left over. They are still around today in the form of asteroids and comets. Such debris comes in all sizes with objects of over a thousand kilometres in diameter right down to millimetre-sized grains of material and smaller.
The smallest objects are also the most common, and they can be seen on any clear night as shooting stars (also called meteors). Meteors are not stars at all, but small pieces of Solar system debris that move at such high speeds (around 50 kilometres per second, or 110,000 miles per hour) that they heat up and vaporise as they enter Earth's atmosphere. Sometimes if you are lucky you might see particularly bright "fireballs" which glow for a few seconds, or even meteors which break apart into several pieces, each with their own glowing trail.
At any time or year there are usually a few meteors every hour, but the rate can jump up around particular dates during meteor ‘showers’ when Earth passes through dust that lies along the orbits of comets. Meteor showers are named after the constellation the meteors appear to come from, but their meteors are still seen all over the sky, so you just need to look up and keep alert.
If a meteor makes it to the ground, it is called a "meteorite". Meteorites can tell us about how our Solar system formed.
Look up to the skies this evening and you may be lucky enough to see part of the Lyrids meteor shower which occurs in April. These are bright fast meteors, some with trails. A maximum of about 18-20 per hour is forecast for around April 21 and 22. After the Lyrids come the Eta Aquariids which are associated with the tail of Halley’s Comet. These appear low in the sky and a maximum of about 35 per hour is forecast for the 5 or 6 May - perfect for the week of the May Bank holiday.
Tips for seeing meteors:
1) Find a place to look for them with as wide a view of the sky as you can. It needs to be a clear, starry night, preferably without a full Moon and away from nearby lights.
2) Wear something warm; you will need to get your eye in and that takes time; plan to spend at least 30 minutes looking. As your eyes adjust you can start spotting dim meteors that you would have missed at the start. Lie down if you can. A sleeping bag or blanket can help.
3) If you can go out past midnight, you will have a better chance because then you will be looking forwards in the direction of Earth's orbit (just like more rain drops hit the front of a car than its rear), but don’t worry if you can’t: meteors can be seen any time when its dark, you just might have to look for longer.
4) You don't need binoculars or a telescope; they don't help at all for looking for meteors. Just use your eyes and try to keep as wide a view as possible. Don't concentrate on one part of the sky, instead try to look everywhere, all at once.
5) Try particularly to observe during meteor showers. The next shower are the meteors of the Lyrids (April 20-21) when you might see around 20 meteors per hour. Best of all perhaps are the Perseids which will peak on August 12-13 this year. The Perseids come when it’s warm and usually produce many bright meteors.
6) Meteors move fast, and can cross a large fraction of the sky in less than a second. If you see instead an object that moves slowly and steadily and can be seen for many seconds, you might just have seen an artificial satellite. They are fun to spot too.
Challenge: If you are lucky enough to see lots of meteors, try to remember the directions in which they travelled, to see if they are similar. If they are, see if you can work out the constellation that they seem to have come from.
Published:
16 April 2020
About:
The Astronomy and Astrophysics group at Warwick is interested in a huge range of scales across the Universe: planetary systems, how they form, live and die; stars, stellar binaries and and the exotic physical processes that they allow us to explore; as well as the transient events which mark the end of stellar lifetimes and the galaxies stars inhabit across the Universe. The group started in September 2003 and is both an observational and theoretical group. The group makes use of a wide range of ground-based telescopes, such as ESO's Very Large Telescope (VLT) in Chile and the Isaac Newton Group of telescopes (ING) in the Canary Islands, or the Atacama Large Millimetre Array (ALMA), as well as space telescopes such as NASA's Chandra and ESA's XMM-Newton X-ray observatories and the Hubble Space Telescope. The Warwick astro group partners in the four large spectroscopic surveys (DESI, SDSS-V, WEAVE, and 4MOST) that will start operations throughout 2020-2021.
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