All planets have their own sun – that’s part of what makes them a planet. They vary a lot in size and distance from their sun. We have found already thousands of planets that are in orbit around other stars – we called these ‘exoplanets’. By looking at how they make the light from their star change we even know how big these worlds are, and from that, and the speed at which their light curves change, also how fast their orbit their suns. What is superinteresting is finding exoplanet worlds that are in the so-called ‘Goldilocks Zone’ – not too hot, not too cold – because these worlds might support life. From our own solar system, which has well over 100 moons but only 8 planets, we know other planets have moons, and there is no reason why exoplanets would not also have moons. In principle, any number of moons is allowed. Maybe only having 1 is unusual.
Yes they do. As Ed mentioned a key criteria for saying a space object is a planet is the fact that it orbits a star. Our star is called the sun. Other stars will be named differently. It is not a requirement that all planets have a moon. But as Ed mentioned some planets have no moon and some have many. Check this NASA article out: https://spaceplace.nasa.gov/planet-what-is/en/.
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