Cybertron is definitely not orbiting around the Earth's Sun or anywhere within the Solar System or Milky Way galaxy. According to the Marvel comics, it began in Alpha Centauri, although its orbit deteriorated making it a rogue wandering world.

If Cybertron was that close, then they could've simply returned to Cybertron via a basic rocket - okay sure, Cybertron would still be ravaged by the Autobot-Decepticon war at that time, but it surely would've been better than staying on Earth... on Cybertron they would've had better chances of mustering resources in building a functioning transwarp starship (they still had surviving transwarp drives from the Axalon and Darkside/Terrorcrasher) .

Quote Originally Posted by roller
yeah but isnt rhinox looking at our solar system and there is a black metallic looking planet around our sun?
I believe he was looking at an image of Cybertron orbiting around its own sun. In Beast Machines Cybertron is shown to have a fixed orbit around a star - and Cybertronian time is measured according to this orbit (stellar cycles).