Nukes#

Nukes allow you to bomb enemy planets and kill up to 50% of enemy ground units and up to 50% of buildings per battle turn. The extent of damage done is decided by the number and strength of nukes deployed. Nukes are deployed between the space battle and the ground battle, which means that nuke-carriers could be destroyed in space prior to deployment. As such, it is sometimes a good idea to clear enemy fleets above the planet so that you do not loose the nukes.

Nukes may be used for some tasks like destroying a large ground army or as a way to destroy enemy buildings and damage his economy. Nukes could also be used as a way to destroy housing to conquer developed enemy planets instead of  occupying  them. Nukes are often chosen as the way of eliminating an enemy's mid-late round home world and other major production centers. In these cases, multiple sets of nukes may be dropped to maximize the amount of damage dealt to the planet.

Nukes designed at a higher tech level are more cost effective.

Nukes are not available until your empire reaches 2,000 tech level.

The cost of producing nukes can be reduced by developing  Nuke Plants .