Energy production. Energy In physics, energy is the quantitative property that must be transferred to an object in order to perform work on, or to heat, the object. Energy is a conserved quantity; the law of conservation of energy states that energy can be converted in form, but not created or destroyed. The SI unit of energy is the joule, which is the energy transferred to an object by the work of moving it a distance of 1 metre against a force of 1 newton. Common forms of energy include the kinetic energy of a moving object, the potential energy stored
History of UNIT alien threats, and Sarah Jane is concerned that UNIT would treat her son Luke as a test subject with no regard for his human rights should they discover him. UNIT returned in the 2009 Easter special "Planet of the Dead" investigating the disappearance of the 200 bus. Captain Erisa Magambo makes a reappearance from her last in "Turn Left" as the commander of UNIT, aided by the new scientific adviser Malcolm Taylor. They appeared again during "Death of the Doctor" which introduced a UNIT Base at Mount Snowdon. In 2012, after a 3-year absence, UNIT returned to "Doctor Who" in