When the Earth's magnetic poles flipped out

Driving the news: In a study published Thursday in Science, researchers analyzed the rings found in ancient kauri trees in New Zealand to produce a radiocarbon archive.

• The tree ring data shows that nearly 42,000 years ago, the Earth's geomagnetic field flipped and stayed reversed for some 800 years before returning to normal.

What happened: Scientists knew that the reversal — called the Laschamp Excursion — had happened, but the new study provides a more accurate time frame.

• It also shows just how catastrophic the event likely was for the Earth and those living on it, including humans and their evolutionary cousins the Neanderthals.
• With virtually no protective magnetic field, and with solar activity at an ebb, the planet was bombarded with high-energy particles from outer space, leading to rapid climate change and spectacular electrical storms.
• It would have been "like the end of days," said Chris Turney, an Earth scientist at the University of New South Wales and a lead co-author on the paper, in a statement.

What's next: Earlier research has indicated that the Earth's magnetic north pole has been moving at an accelerating pace, which could presage another reversal.