This annual Springtime shower peaks around the 22nd of April. This year, 2007, it will be after 10pm on Sunday night (22nd) when it will peak for observers in Ireland.


Background

The April Lyrids are the oldest recorded meteor shower, with Chinese records going back as far as c. 687BC. Although most meteor showers are associated with regular periodic comets to keep up annual displays, the April Lyrids are more associated with longterm-periodic comet Thatcher C/1861 G1, which takes around 415 years to travel around the Sun. Prior to this comets’ pass in 1861 (as discovered by Mr. A.E. Thatcher in New York), the Lyrids were still associated with this previously unknown periodic comet, but it would have only passed Earth 5 times in its recorded 2,600 year history.

Any meteor shower gets its name from the constellation in the sky where activity seems greatest. As Earth encounters a dust stream, a rise in meteor activity is called a “shower”. The known constellation closest to that peak as seen in the sky gives its name to that shower. Thus, the Lyrids occur in the constellation of Lyra (the “Lyre”, or “Harp”). There are a couple of showers in a year that occur in this general area, so this shower is called the April Lyrids.

The meteors themselves contained in this dust stream are classed as “medium fast”, in that they travel around 28 miles per second (100,000 miles an hour). Faster meteors travel around 36 miles per second (130,000 miles per hour). Lyrids number an average of 15 to 20 per hour when at maximum. Bursts in the past have numbered almost 100 per hour in 1803 and 1922, and a major burst of about 250 per hour in 1982.

A meteor itself is essentially dust and small solid particles of rock and sand left behind by the comet as it travelled through space. Coming from the depths of the outer Solar System where it would have been frozen at almost absolute zero, it warms up as it gets closer to the sun. Just like water ice in a hot saucepan melts and lets off steam, the same effect happens with the comet when its carbon dioxide ice sublimes from ice directly to a gas. As the gas is expelled, so too is any amount of attached rock and dust, leaving behind it a glistening trail of debris for the rest of time.


How and where to look

On Sunday night of the 22nd, look towards the northeast after 10pm. Low down near the horizon will be a bright blue-white star. This is Vega, and it the brightest star in this part of the sky that night (and 5th brightest overall). Vega is one of 5 key stars that make up Lyra. The other 4 lie beneath it in a small parallelogram shape. This is the area of sky t look for a rise in meteors. Lyra will rise higher as the night progresses, getting to its highest point almost directly overhead around 6am in the growing morning twilight. In the small hours of the morning, you will also see brilliant Jupiter shining brightly low down in the south.

All you need to observe meteors is a your eyes, and a comfortable chair. Your chair should have some reclining feature/posture to it to prevent you getting a crick in your neck while holding your head skyward! Wrap up warm, and bring a flask of soup or tea too – coffee can actually make your body feel cold quicker, as the caffeine amongst other chemical in it restricts blood flow to your extremities (hands, toes, nose and ears etc).

Then just sit back and enjoy the show!


-Seanie Morris.

 

Editors Note: Feel free to contact me for diagrams etc. associated with this article.