When a meteorite enters Earth’s atmosphere, it soon starts to glow. This goes on for a short while before it vanishes, either quietly, or in a flash.
Conventional theory claims that this is due to friction between the meteorite and the atmosphere. However, the magnitude of the explosions observed when large meteorites enter the atmosphere makes it hard to believe that this is all due to heat convection. The difference in electric potential between our atmosphere and the incoming object is a more likely source of such enormous energy.
The glow and the explosions associated with meteorites are most likely electrical discharges. Small objects manage to equalize their electric potential with the atmosphere by sparkling brightly. Larger objects explode.