Title: It's the heart of Kerbin a black hole? Considering the surface gravity is 9.8 m/s and the radius of Kerbin is about 300km, just imagine the density. Imagine the density of the core... Imagine the gravity of the core... Imagine the black hole sucking in the whole of kerbin
Above 20km, go ahead and use that Nuclear Engine Feel free to use strap nuclear engines on your lander fro Minmus, Gilly and low-gravity surfaces. NEVER USE IT TO LAND IN A ATMOSPHERE.