A Happy and star filled New Year

By Paul Downing

WELCOME
to 2007 and to a new year of things happening "up there." My subject
for the start of the new year is planets. Those of you
who follow these things will know poor Pluto was recently demoted from a planet
to a minor planet by the International Astronomical Union. This leaves us with
eight planets, of which six are normally visible to the naked eye – Mercury,
Venus, Earth (of course), Mars, Jupiter and Saturn.

The
reason I chose planets this issue is because one of the most interesting and
visually spectacular has returned to our night skies. If you look in the
eastern sky at about
10pm you should see Saturn
as a bright yellowish star rising. To help you locate it, perhaps wait another
hour to let the Earth turn a bit and you should see a sickle shaped "question
mark" of stars rising. This is the head of Leo the Lion, and the bright
yellow star just to the right of the bright white star at the dot of the
question mark is Saturn.

In
a telescope, Saturn is an amazing sight (see photo) with the beautiful ring
system, and you can see them in even a small telescope, although binoculars are
not really powerful enough.

The
word planet is derived from the Greek word planasthai
(meaning to wander) and the ancients knew enough about the sky to notice these objects
wandering around in the sky as the weeks and months passed. Two of the visible
planets, Mercury and Venus, orbit the Sun inside our own orbit so we never see
them very far from it. They appear to us to move up and down either side of the
Sun as they move along their orbital paths.
Venus is that very, very bright object which we see in the evening or
morning sky, depending on which side of its orbit it is located relative to
Earth. We will be talking more about Venus in the coming months as it starts to
appear in our evening sky. Mercury is
much closer in to the Sun and is very difficult to see unless you know exactly
where and when to look. Some people go through a lifetime and never see it. This
summer we will have a try and see if we can spot it together one fine evening
just after sunset. The outer planets, Mars, Jupiter and Saturn are different. Because
they orbit further out than the Earth, it is possible for them to be on the
opposite side of our sky from the Sun. We have talked about Saturn but if you
want to see Jupiter, it has just gone around the back of the Sun and is rising
in the morning as a brilliant white star about two hours before sunrise. See if
you can spot it!

This article was printed in January 2007

Send your astronomy questions to [email protected]

Also
see www.paulandliz.org

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