Primordial, the first expansion for Planetarium, adds a new frost line to the board, and new cards that allow you to heat and cool planets for extra points at the end of the game. A new Late Bombardment effect clears the evolution track and re-distributes matter around the board, and also creates comets, which can be used as "wild" matter.
This expansion adds two modules to the base game: Epochs and Frost Line. One or the other or both may be added.
Epochs: The solar system begins with no planets. A player may, instead of moving a Matter token or a Planet, create a Protoplanet. Later, a player may play a Proto Evolution card to turn the Protoplanet into a Planet. The first time the Acceleration space is reached, it triggers the Late Heavy Bombardment instead (all the matter on the evolution track fills the empty solar system spaces, and comets may appear. The second time the Acceleration space is reached, Acceleration occurs normally.
Frost Line: This line lies between orbits III and IV (it moves in or out if the Red Dwarf or A-Type star are used). The Low, High, and Final Evolution cards of the normal game are replaced by those in the expansion. Planetary evolution now tracks heat and cold markers. If using the Variable star token, players may spend victory points to vary the star's brightness a notch up or down; this moves the Frost Line accordingly.