any of the planets whose orbit lies outside the earth's orbit

a planet having a compact rocky surface like the Earth's; the four innermost planets in the solar system

the sun with the celestial bodies that revolve around it in its gravitational field

the sun with the celestial bodies that revolve around it in its gravitational field

a geologic system and time period on the planet Mars characterized by low rates of meteorite and asteroid impacts and by cold, hyperarid conditions broadly similar to those on Mars today.

a geologic system and time period on the planet Mars characterized by widespread volcanic activity and catastrophic flooding that carved immense outflow channels across the surface.

a geologic system and early time period on the planet Mars characterized by high rates of meteorite and asteroid impacts and the possible presence of abundant surface water.