I grew up in the southern hemisphere, in Australia, but I’ve lived in the northern hemisphere for the better part of the past 20 years. You’d think that would be enough time to have gotten used to the seasons being opposite, but the truth is it still strikes me as a curious novelty.
Firstly, there’s the fact that I grew up with a summer birthday (February), which was always celebrated with some sort of outdoor activity. Now that my birthday is in the dead of winter, well, it’s just not the same.
Then there are other times of the year that remind me of the difference – like the upcoming equinox on September 22, 2016, when the sun will be directly overhead at the equator, and after which time it will appear to journey southward, affording more and more daylight to the antipodes as it goes.
At this time of year, while those of us in the northern hemisphere are sensing the start of the colder months, the southern hemisphere is beginning to bloom with life: longer days, spring flowers, hay fever, BBQs, spring cleaning, trips to the beach, and trading in the winter coat for a sun hat.
Seasons (and therefore equinoxes) occur on any planet that has a significant enough axial tilt. Earth’s is 23.5 degrees. As the Earth makes its journey around the sun each year, the northern and southern hemispheres take turns being angled more directly toward the sun. This more direct sunlight is more concentrated and therefore hotter – as known as “summer.”
Mars’s tilt is the closest to Earth’s, at 25.19 degrees, so the seasonal changes there are comparable to Earth’s. Mercury, at 0.01 degrees, does not experience any perceptible seasonal change.
Uranus has the most extreme tilt of the planets – 97.9 degrees – and therefore the most extreme seasonal changes. Each entire hemisphere remains in darkness for the whole of winter and in daylight for the length of summer. What’s more: Uranus’s long orbit of the sun – 84 Earth years – means that each season stretches on for a whole 21 years.
There’s something I like about these opposites though. I think they remind us of a sense of global balance. They remind us that, though we all share the same planet, we have different perspectives on things – whether because of the cultures we live in, the languages we speak, or the seemingly simple question of which degree of latitude we live at.
Whichever hemisphere you live in, you’re bound to have already started noticing the shift in the seasons. Whether the trees around you are turning the fiery colors of fall, or are preparing to burst forth in spring colors, changes happen quickly at this time of year.
Originally from Australia, Tanya Fox spent several years living and working in Germany, where she happened to meet a nice young man from Oregon. She ended up moving to Portland to marry him, where they now live with their two children. She works as a freelance editor, proofreader, writer, and translator, and delights in the wide variety her work brings her. She can be contacted for publishing projects.
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