Earth.
Saturn was the first planet discovered to have rings.
first known
Rings.
The large and spectacular ring system of Saturn made it the first planet known to have rings, although Jupiter, Uranus and Neptune all are known to have faint rings.
Because it is the only planet with which we have first hand experience.
The first planet after the asteroid belt is Mars. It is the fourth planet from the Sun in our solar system.
Mercury ( the planet) is at the first . That is why it is hottest planet known , as it is located at the most nearest place to sun
The Earth (but it was not known that it was a planet at that point. When the concept of "planet" came into use there were 5 known planets:MercuryVenusMarsJupiterSaturnNote that at that point in time (ancient Sumerian or Babylonian civilization) the Earth was still not considered what we today call a "planet".
The first inner planet is Mercury. It is the closest planet to the Sun in our solar system and is known for its extreme temperature variations, ranging from very hot to very cold.
Of note, first, Haumea is a dwarf planet, not a planet. Although very little is known about its surface, it is highly unlikely that it has any volcanoes.
Mars is known as a red planet.
What is special about this planet is that it is the only planet with oxygen,water,and it is the only known planet known where people can live.Second known.