As astronomers anticipate the arrival of the Perseids, an August event that’s one of the year’s most popular meteor showers, there is currently a warm up underway to get us in the mood for some meteors.
July 28 and 29 will see the peak of the Delta Aquarids meteor shower, with as many as 20 meteors an hour being visible. Observers in the Southern Hemisphere will get the best view, but there are opportunities for those in the Northern Hemisphere to witness the Delta Aquarids, too.
Between midnight and dawn, around 2 or 3am, is the best time to catch a glimpse. Delta Aquarid meteors are sometimes a little faint, so a dark sky free of moonlight and artificial lights is very useful.
Fortunately, the start of August brings a new moon and waning crescent moons, meaning darker skies and more visible meteors.
Slooh, an online observatory, is also providing a live broadcast of the meteor shower from an observatory on the Canary Islands, for those unable to get a good view. Here’s a link (That won’t start broadcasting until July 28th):
What causes meteor showers?
Meteor showers occur because the orbits of comets are a little lopsided, and they can veer too close to the sun. At this point, light bolts from the sun release bursts of ice and dust from the comet’s surface, and when this debris follows the comet’s path it forms a tail.
As Earth crosses the orbit of a comet, we pass through the tail. Planets’ gravity attracts the debris, and when it is pulled into Earth’s atmosphere it burns up upon collision with air molecules. The glowing, streaking tails – meteors or shooting stars – can be seen.
Delta Aquarid or Perseid?
Delta Aquarid and Perseid showers will overlap, but which one we are looking at can be ascertained by tracing the meteors backward through the sky to see where they originated from. Delta Aquarids meteors will appear to radiate from the star Skat, or Delta Aquarii, which is in the constellation Aquarius the Water Bearer.
Delta Aquarids meteors will appear to come from the south if being observed from the Northern Hemisphere, while in the Southern Hemisphere they will appear to radiate from just about overhead.
The Perseids, meanwhile, radiate from the constellation Perseus and appear to originate in the northeast or north for those in the Northern Hemisphere, or appear to dart up from the Northern horizon if in the Southern Hemisphere.
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Image credit: Thinkstock
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