If you want to know about space-related  happenings in real time, you can follow:

@AuroraMAX  — when are the northern lights visible over Canada? There are other aurora alert services for other locations.

@twisst — tells you when the Interntaional Space Station passes over you

@astronomerstel — the Astronomer’s Telegram: gamma-ray bursts and other snazzy thing

@lowflyingrocks — “.. every near earth object that passes within 0.2AU of Earth”

@spaceweather — “keep tabs on the space environment around the Earth as it is disturbed by the variable output of particles & radiation from the Sun”

What are your favorites?