New evidence that about 1,500 years ago a comet exploded over North America. Some of the locals actually built a comet-shaped mound (since lost) recording the catastrophe. But now chemical fingerprints seem to confirm the oral tradition.

“The fiery blast of a comet tearing through the atmosphere would have devastated the landscape below, clearing forests, damaging agriculture and possibly wiping out villages. These losses would have greatly disrupted crop harvest, limited access to resources and likely interrupted trade activity”.

Like I say, we really should spend more time looking up at the big, intermittent threats hanging over our heads.