The spring equinox occurs on the 20 March, marking the point when spring starts in the northern hemisphere and autumn starts in the southern hemisphere. The word ‘equinox’ comes from the Latin words aequi, which means equal, and nox, which means night. At this instant the Sun lies above the equator and both poles of the planet are illuminated, meaning that on this day the length of daylight and night time are the same.
Aurora lovers also like the equinox because at this time of year there are more cracks in the Earth’s magnetic field and this can lead to great aurora displays.
There is something called the ‘Russell-McPherron effect’ this is named after geophysicists Christopher Russell and Robert McPherron which says that as both magnetic poles of the Earth are at right angles to the solar wind, the solar wind becomes more potent hence at this time of year when there are equal amounts of daylight on the Earth in both hemispheres there is more chance to see a spectacular aurora.
www.theramblingastronomer.co.uk
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