Great Scott! Doc Brown has just bought 100 grams of Plutonium 241, which has a half-life of 14 years. He plans on storing his Plutonium until he absolutely needs to use it to power his DeLorean/time-machine. The flux capacitor (the equipment necessary for time travel) needs 85 grams of Plutonium to have enough power to travel through time. How long can Doc Brown store his Plutonium for to have enough to time travel.