A moon A planet A star A comet
Hydrogen Oxygen Carbon dioxide Very hot rock
A chemical reaction A nuclear reaction An electrical reaction A magnetic reaction
Combustion of hydrocarbons Photosynthesis Radiant heat expansion A loss of mass
Very hot rock Very hot oxygen Electromagnetic resonance Neutrons
The aero The milky way The snicker The flake
Less than one hundred stars Less than one thousand stars Less than one million stars More than one billion stars