The moon, of course, because it revolves around the Earth.
The sun and the moon are not planets. The sun is a star and the moon is a natural satellite. The brightest planet in Earth's sky is Venus.
Sputnik was the first satellite to orbit the Earth. It was Russian and transmitted a radio signal. It is possible that a earlier satellite could be in orbit, without any communications this would be the same as a cannon shell etc. So long as an object can reach orbit it will constantly drop towards the planet and because the planet is round the object will rotate around being pulled by gravity
A geostationary orbit is an orbit of the Earth that is circular, over the equator, and at the right distance to have a period of 24 hours. A satellite in such an orbit appears to hang motionless, always at the same point in the sky Anything else is a non-geostationary orbit. A satellite in one of those appears to move in the sky, so that if you want to communicate with it, you need a movable dish.
what keeps planet earth from fallin out of the sky
An example of the moon is the disk or crescent of light you see in the night sky. The largest satellite of Earth. Any natural satellite of a planet. (literary) A month, particularly a lunar month.
Planet Earth - 2006 Eye in the Sky was released on: USA: March 2006
A Geosynchronous or Geostationary satellite. The orbit period of a satellite will be longer the further it is away from the planet, so these have to be quite far away to match the rotation period of the earth. They orbit the earth once every 24 hours, so stay in the same apparent position when 'seen' from earth. This means that satellite dishes receiving signals from it can remain still, pointing in one direction rather than having to track it across the sky - a big advantage.
That happens when the satellite enters Earth's shadow.
Satellites may fall out of the sky because they get too close to Earth. In that case, Earth overwhelmed the power of the satellite's propelling system and slowly but surely dragged the satellite into the Earth's atmosphere.
Only planet Earth was involved since Earthling were the ones who couldn't identify the object.
yes
From Earth, Venus is the brightest planet in the night sky.