[Taqwus]

You attack planets just like any ship/unit -- move into their square and confirm combat. You do have to watch for weapon platforms and satellites, however (always check the Cargo tab of a defender's planet, and of his transports and carriers), and certain weapons are better (e.g. planetary napalm only hits planets and WPs, but it does a *lot* more damage than standard anti-ship weapons).

Nasty things you can do to colonies and planets include...

- Destroy the colony outright, by attacking with weapons.
- Destroy only the colonists themselves, not facilities, via neutron bombs. Useful before invasion.
- Destroy only certain facilities, via smart bombs.
- Invade the colony with troops (note: quite difficult, it seems. Not sure what the rules are here).
- Cause it to join you, or form its own side, via espionage ('Puppet Political Parties').
- Blockade it, by simply remaining in orbit (which slows its production, IIRC, and should deny its resources to the owning empire; it should probably also make it unhappy).
- Drop plague bombs on it, which causes plague (which causes mass death and corresponding unhappiness every turn until cured or colony wiped out. Nasty, especially if your opponent never bothered to research even Biology and it's Plague V...)
- Destroy the planet, IIRC, using tectonic bombs.
- Destroy the planet and everything else in the entire system, by either exploding a star (into a nebula) or collapsing one (into a black hole).

------------------
-- The thing that goes bump in the night