On old photographic plates from the 1950s, astronomers found hundreds of thousands of brief flashes. Brightness measurements confirmed they weren't defects but real events linked to solar activity. During magnetic storms, the flashes nearly disappeared, but a couple of weeks later they multiplied — as if invisible particles were scattered and then gathered again.
The likely answer: icy dust grains in Earth's vicinity. They became electrically charged, got tangled in the magnetic field, and clumped into fluffy car-sized balls. Tumbling, these cosmic mirror balls threw off sunbeams, producing the flashes. The mechanism recalls the comet model of Fred Whipple. With the launch of satellites, the flashes vanished — the fragile icy clouds were swept away.
Over the entire observation period, more than 100,000 such flashes were recorded — a true cosmic fireworks display that no one witnessed live. Too fast for the human eye, they left their mark only on glass negatives.