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Chris
(10) from South Africa asked:
I need to know an explain to the
following questions:
Why do stars appear to move across the sky in the evening? Is this
because the earth is rotating?
The
other question was If you look at the sky between 7pm and 8pm and then
again at 9pm, what will you see happening to the stars? Is the
answer that they are moving across the sky
?
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Hi Chris,
You are right about the
reason the stars appear to move across the sky. It is because the Earth is
rotating and not because the stars are moving - the stars stay
where they are but because the Earth has span around a bit, they look like
they have moved. It is difficult to notice the stars moving if you look
constantly at the sky because they appear to move so slowly, but if you
looked at the sky every few minutes, or, as in your example, once
between 7pm and 8pm and again at 9pm, you will notice that they have all
moved slightly. The Sun is actually a star and that moves across the sky
in exactly the same way as the other stars simply because the Earth is
rotating. If you see an object that looks like a star in the night
sky, but doesn't appear to have moved with the other stars, you are
actually looking at a planet!
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| Do
galaxies have planets in them or are they just stars? |
Galaxies are full of both
stars and planets. It is believed that most stars have planets orbiting
them. You actually live in a galaxy called the Milky Way, and the Sun is
just one of billions of stars in your galaxy. Like the Sun, a lot (if not
all) of the other stars in the Milky Way also have planets spinning around
them.
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