Going back millions of years into Earth’s history, our planet’s magnetic field has frequently gone its own way. The magnetic north pole has not only wandered through the north, but it has changed places with the south magnetic pole, taking up residence in the Antarctic. Going back millions of years, there’s a regular pattern of pole exchange, with flips sometimes occurring in relatively rapid succession.
Source: arstechnica.com
The physics here isn’t too hard to understand. Scientists have long been able to push around single atoms within clouds of many atoms. In this case, they used two optical “tweezers” at two specific wavelengths.
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The most arrogant astronomer in Switzerland in the mid-20th century was a solar physicist named Max Waldmeier. Colleagues were so relieved when he retired in 1980 that they nearly retired the initiative he led as director of the Zurich Observatory. Waldmeier was in charge of a practice that dated back to Galileo and remains one of the longest continuous scientific practice in history: counting sunspots.
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