There are always planets visible in the night sky; but sometimes you need to get up early instead of staying up late. Here in May 2009, for example, Mars, Venus and Jupiter are all nicely visible in the pre-dawn darkness.
People who study the sky continually over a number of nights can see the planets have moved.
You can see the Milky Way in the night sky when you are in a location with very little light pollution, usually away from cities and urban areas. The best times to see the Milky Way are during the summer months when it is high in the sky and the nights are warmer.
We know it by observing that the stars blink in the sky while planets do not blink.
because some of the planets reflect lights from the sun like Venus.
Telescopes can be used.
You can see all of them in the sky at night.
No. Planets do not have comets. They are not related to planets. They are just objects flying through space that we can see in the sky.
You won't see it every 20th of November, but in some years it is visible then. Lots of websites will tell you where and when to see it. If you don't see it then in a particular year, there will be other times of the year that you will see it. If it is visible then, you will be able to see it on other nights around then, as it can be seen for months when it is visible.
Stars The Moon The sun Galaxies Nebulae Satellites
Planets but the look like stars
In winter months.
planets stay in the sky due to the pull of gravity