Destroying one of your own planets, quitting without saving, and then reloading 5 times works.
Planets lost during a war, then later won back count toward the total of 5 planets.
Saving, going to war (fastest with the Grox), losing 5 planets, and then reloading works.
Make colonies near the center of the galaxy while at war with the Grox.
This can be over multiple save files.
You can colonize Earth, giving you the Manifest Destiny achievement, and destroy it 20 times (quitting without saving). This will also get you the Oh The Humanity, Quietus Star, and the Careless Parent achievements.
You can keep on destroying your home planet's towns over and over again to get it.
Notes[]
Players may get this achievement unknowingly when they are trying to find Earth.
