Some scientists refer to the frost line as the “Goldilocks Zone” — where conditions for life may be “just right.” Generally, inner planets are smaller and denser than their counterparts, and have few to no moons or rings circling them.The outer planets, meanwhile, often have dozens of satellites and rings composed of particles of ice and rock.
In the inner Solar System, we find the “Inner Planets” – Mercury, Venus, Earth, and Mars – which are so named because they orbit closest to the Sun.
In addition to their proximity, these planets have a number of key differences that set them apart from planets elsewhere in the Solar System.
Between its eight planets, 176 moons, 5 dwarf planets (possibly hundreds more), 659,212 known asteroids, and 3,296 known comets, it has wonders to sate the most demanding of curiosities.
Our Solar System is made up of different regions, which are delineated based on their distance from the Sun, but also the types of planets and bodies that can be found within them.
And our Moon, the only one we have, is comprised of a mixture of various rocks and minerals.
Mars is the fourth and final inner planet, and also known as the “Red Planet” due to the rust of iron-rich materials that form the planet’s surface.
It has no moons of its own and is comprised mostly of iron and nickel.
Mercury is one of the densest planets in the Solar System.
Venus is often called the “morning star” because, with the exception of Earth’s moon, it’s the brightest object we see in the sky. Earth is the third inner planet and the one we know best.
Of the four terrestrial planets, Earth is the largest, and the only one that currently has liquid water, which is necessary for life as we know it.