If you want to destroy someones population or land without the risk of sending out your armies you can use missiles. Missiles an effective weapon if you use them correctly. You are limited to 1 missile strike every 24 hours so make sure you do the maximum damage each interval. Below is a table of the missiles available to you, costs, and required research in order to produce them.

Missile Cost Damage Per Missile Max Damage Required Research
Nuclear Missile 5,000 Money 2 Land
150 Population
0.5% of Land
5% of Population
Fusion Missile 16,000 Money 4 Land
400 Population
1% of Land
2.5% of Population
Fusion Technology
Energy Missile 15,000 Money
10,000 Power
8 Land
1,000 Population
1% of Land
5% of Population
Energy Core

Missile Defense
The only effective defense against missiles is to have your missile shields powered. Missile shields can stop upto 100% of enemy missiles before they have a chance to do damage. Defensive state will also power your shields fully, regardless of power level or shield settings.