Findings:

• Reality Perception Sphere
• How to test if a ray intersects with a sphere
• Greater East Asia Co-Prosperity Sphere
• separate spheres
• The Dynamic Sphere
• Spheres of Engineering
• formula for the volume of a sphere
• formula for the surface area of a sphere
• Spheres of Chaos
• Riemann Sphere
• at most, spheres (document)
• Meditation I: Of the Things which may be brought within the Sphere of the Doubtful
• Poincaré Sphere
• prismatic sphere
• Sphere Sigils from Mage: The Ascension
• Hoberman Sphere
• Dyson Spheres: A Treatise
• Spheres 2
• on the rotations of the spheres
• Sphere Online Judge
• Odilonk's Ridonkulous Sphere
• Hill sphere
• Armillary Sphere
• S.J. Sphere Juggler (user)
• Photon Sphere
• Private sphere
• Private thoughts in the public sphere
• The Celestial Sphere
• Attraction sphere
• public sphere
• Alexander's horned sphere
• Sphere XP
• 7th sphere
• Blue Sphere
• Sphere del Perdedor
• Sphere of Opposites
• The Human Plutonium Injection Experiments
• Sphere
• The formation of interstellar objects
• Dimple Sphere
• Dyson Sphere
• Plutonium Boss (user)
• The Plutonium Files
• Plutonium Nyborg
• plutonium jones (user)
• plutonium economy
• Plutonium Bomb
• old chestnut: hole in sphere
• Music of the Spheres
• scrying sphere
• Inner Sphere
• How the Sphere encouraged me in a Vision
• How, though the Sphere shewed me other mysteries of Spaceland, I still desired more; and what came of it
• How the Sphere, having in vain tried words, resorted to deeds
• Riddle of the Spheres
• answer: hole in sphere
• plutonium
• geodesic sphere
• The Obloid Sphere
• On the Revolutions of the Celestial Spheres
• Sphere of influence
• social/cultural/religious sphere

If you Log in you could create a "plutonium sphere" node. If you don't already have an account, you can register here.