Yes, Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, and Pluto used to be one.
Our solar system is made up of one star - the Sun - and everything held in orbit around it. Some distant stars have been determined to have planetary objects surrounding them, too, but there is still more unknown about those than known.
The sun
Retrograde Motion
Because it is the planetary system of Sol, another name for the Sun.
Aristotle's model of the solar system was geocentric, meaning that everything in the solar system revolved around Earth. Ptolemy added in the way the planetary bodies moved, although they still moved geocentrically.
It makes up about 70% of all the planetary matter in the solar system.
Jupiter and Earth are part of the same solar system (all the planets and other objects orbiting the Sun). Jupiter's planetary system has four main moons: Io, Europa, Ganymede, and Callisto.
planetary science
Our solar system is made up of one star - the Sun - and everything held in orbit around it. Some distant stars have been determined to have planetary objects surrounding them, too, but there is still more unknown about those than known.
Small objects that we can detect in space are all in the solar system and they all orbit the Sun and obey Kepler's laws of planetary motion, as do all the planets, asteroids etc.
The sun
planetary
Retrograde Motion
A spinning cloud of dust began to compress to form the sun; small planetary objects formed; hydrogen and helium became concentrated in the outer solar system to form the outer planets.
Jupiter is a member of the star Sol's planetary companions.
Astronomy is the study of the Solar System. Planetary Science, or a Planetologist, studies the planets.
Because it is the planetary system of Sol, another name for the Sun.