Ours is a universe of energy, from powerful jets ejected from black holes to the raw nuclear fury of our Sun. But, the total amount of energy in the universe maintains perfect equilibrium--no more can be added or taken away. Because of this, there are enormous amounts of energy being transferred...electric, thermal, kinetic and magnetic energy are just a few that keep our universe balanced--and create awesome cosmic events and stellar displays.

• Neil deGrasse Tyson
• Erik Thompson
• Alex Filippenko

• David Brin
• David Ackroyd
• Michio Kaku