Stars
The Moon
The sun
Galaxies
Nebulae
Satellites
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.
Planets but the look like stars
planets stay in the sky due to the pull of gravity
to see what the planets look like. and to see what they would do over time.
Excluding the sun, Sirius appears brightest in the sky from Earth.
Neptune
Yes. To date scientists have discovered well over a thousand planets orbiting other stars. It is believe that a large portion of the stars in the night sky have planets.
The luminosity of the sky makes the planets undetectable. The Moon however can often be seen in the daytime because it's so bright.
People who study the sky continually over a number of nights can see the planets have moved.