Question

What are the similarities and differences of the Sun with other stars?

Answer 1

It has a stable orbit around a star and also must be of a certain size. Pluto is not a planet mostly due to the fact that is is smaller that our own Moon. A moon is a rocky celestial body that orbits, mainly, a planet. Big planets may have moons that, if it orbited the star, would be considered a planet.

Answer 2

A subtler aspect of this question might be whether other stars are "suns" in that they have planets of their own. In that case, the answer is "No, not quite." Planets are very common around other stars, orbiting as many as 30 percent of stars similar to the Sun.