I recall it well: It was November 1999 and I had wrapped myself up in as many layers as I could and come midnight, I was out under a dark, clear sky with temperatures plummeting. Comfort was my watchword for the night, so I relaxed on a sun lounger, wrapped up and toasty warm in preparation for a long night's observing.
I remember seeing the Milky Way glistening away to the south and the moon was out of sight. The view that greeted me was one that I will remember for the rest of my life.
Unfortunately, this year’s Leonid meteor shower will likely not be as spectacular as the one I saw in 1999 when a meteor erupted overhead every few seconds. The shower peaks every year around Nov. 17 and 18 and is the result of an interaction between the Earth and remnants of the Comet Tempel-Tuttle. The comet travels around the sun and completes an orbit once every 33 years and, as it hurtles around the solar system, it leaves dusty debris along its orbit like a celestial trail of bread crumbs.
When Earth passes through the comet debris, which it does every year, the remnants of Tempel-Tuttle get swept up. If this happens to coincide with a recent passage of the comet then we can encounter storm levels of activity, igniting an impressive meteor display. Sadly, meteor shower forecasts suggest that we'll have to wait until 2032 for the next great display.
This week, instead of hundreds (or even thousands) of meteors per hour, this year's display is expected to peak at around 15 meteors per hour by the early hours of Wednesday (Nov. 18).
To understand why meteor activity tends to intensify during the hours after midnight, imagine a car travelling down a country road when it encounters a swarm of flies. As the car heads through the unsuspecting insects, they all get splatted by the front of the car. In a similar way, as the Earth plows through the stream of meteors, its the forward facing hemisphere of the Earth that gets the best display of splatted meteors. The Earth's spin makes sure that observers located on the forward facing side of the Earth will get the best view, and this happens in the few hours before dawn.
It's not just Nov. 17/18 that meteors from the Leonid display can be seen, they can be spotted any time from around Nov. 6 until the end of the month. To spot them, you need to wrap up warm, find a location far from any city lights and make yourself comfortable. While the peak is expected in the early hours of the 18th, it's a good idea to also keep an eye out on the 17th too as meteors care little for schedules!
You can tell if you have spotted a meteor from the Leonid shower by tracing its path backwards in the sky and seeing if it came from the constellation Leo -- then you will have bagged your first Leonid meteor. It is best not to look directly toward Leo, the best chances of spotting meteors are when you look either side -- just lie back and try to have an uninterrupted view of the sky. Typically, Leonids are fast, travelling through our atmosphere with speeds in excess of 45 miles (70 kilometers) per second!
Read more at Discovery News
No comments:
Post a Comment