If auroras didn't exist, how would Earth be affected?
Aurora are at the top of a complex pyramid of processes in nature. With them gone, some or all of these other processes are also absent, with very broad impacts to Earth's space environment and the energy input to the upper atmosphere. Their absence would mean that Earth no longer had a magnetic field to protect itself from the full impact of charged particles from the Sun during solar flare events, and from the solar wind. The outer atmosphere would probably stop most of these charged particles, but the chemistry of the upper atmosphere and ozone layer would probably be affected. The ozone layer might probably disappear as other highly charged particles interact with the fragile ozone molecules. Loss of ozone means more damaging ultraviolet radiation and increased cancer rates.
