PS COLUMN ARCHIVE

July 30, 2008

Let’s take out children to look up at the summer night sky

Hot summer season is here again. Children are in summer vacation to have more time to spend with their parents. I wish urban children would look up at the night sky during summer holiday to see the world of shining stars. The sun sets in the west to darken the sky, and then I wish children to actually learn that the first evening star looms into view to be followed by many others.

August 7th falls on the traditional Tanabata (Star Festival) of July 7th by the lunar calendar. If the sky is clear, you will see Altair in the constellation Aquila and Vega in the constellation Lyra across The Milky Way. When you shift your gaze a little bit to the east, you will see Deneb in the constellation Cygnus. These three stars form a big triangle in the night sky, so they are called summer large triangular shape. Each one of them is the star of the first magnitude; particularly Vega is the brightest in the summer night sky most likely to make it the first evening star.

It may be interesting to see Perseids Meteor Shower at the midnight of August 13th over the wee hours of August 14th. After the moon goes down the horizon, you will see some of shooting stars in the northeast sky. This is the phenomenon we experience, when the earth goes through the dusts dispersed by Swift-Tuttle Comet. We see them as shooting stars when the dusts plunge into atmosphere to shine bright caused by friction heat.

Besides astronomical show like Perseids Meteor Shower, what we can always see in the summer night sky is the large triangular shape as said before. The triangle can be seen in dark cities with not many neon lightings, but what I really want you to see is The Milky Way on clear nights when you have a chance to go to mountain or sea.

The Milky Way, dully and white, is running across the night sky. In English it is called the stream of milk, while in China from ancient time it is the silver stream (which sounds more poetic). The reason it looks like white stream is because numerous stars are gathering there. Until up to 20th century, the galaxy was considered to be the whole universe. The all stars were believed to have belonged to the groups of The Milky Way. In 1924 Edwin P. Hubble, an American astronomer, discovered cluster of nebulae that does not belong to the galaxy. This discovery became the fist step of the cosmic view of the modern times to produce the new outlook on the universe that The Milky Way is only one of numerous galaxies and the universe is made from numberless galaxies similar to The Milky Way.

At any rate, summer is the best time of a year to appreciate the grandeur of the night sky, which became a little difficult to do in the cities. Once again I really wish to give children opportunities to see the beautiful night sky.

Please send your comments, if any, to pscolumn@planetary.or.jp