The Cherenkov effect over K'avor.
The visual phenomenon known as the Cherenkov effect manifested as a blue-colored flame, and it arose from intense levels of hard radiation. This effect could be initiated by the detonation of explosives, for example, fusion or anti-matter bombs, and the associated radiation presented a significant hazard.
In the era of the Galactic Civil War, Princess Leia Organa witnessed the Cherenkov effect within the devastated urban landscape of K'avor located on Shiva IV, and from this, she inferred that an anti-matter bomb was the source.