Inferior and superior planets

The classification of the planets of the solar system planets in lower and upper planets within the observational astronomy refers to the different conditions of observation by the size of their orbits relative to Earth's orbit. The inferior planets orbit the Sun inside Earth's orbit, the upper outside.

Overview

The inferior planets are:

• Mercury
• Venus

The upper planets are:

• Mars
• Jupiter
• Saturn
• Uranus
• Neptune

Conjunctions

All inferior planets come apart its synodic period in lower or upper Conjunction: They are then seen from Earth, so to speak "in front " or " behind" the sun in the daytime sky. In the months before and after they describe the night sky loops around the sun. You can reach a greater angular distance than about 20 ° (Mercury ) or 45 ° (Venus) from the Sun never.

For the upper planetary contrast, there is only one type of conjunction ( "behind" the Sun), equal to an upper. Instead of an inferior conjunction, they come in opposition: you are right at the midnight sky, to the sun. In the months before and after they describe the night sky from Earth, seen an elongated loop because they are " obsolete " by the earth as it were on the inside lane.

Inner and outer planets

In contrast, the Planetological division into inner and outer planets relates to their position within or outside of the asteroid belt, after which they differ significantly in their chemical composition.