Complex sentence: Lightning discharges are considered to be the primary natural source of Schumann resonance excitation, lightning channels behave like huge antennas that radiate electromagnetic energy at frequencies below about 100 kHz.
Split into simpler sentences: Lightning discharges are considered to be the primary natural source of Schumann resonance excitation. Lightning channels behave like huge antennas that radiate electromagnetic energy at frequencies below about 100 kHz.