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  • Every year on February 2nd, the people of Punxsutawney, Pennsylvania dress up like it’s 1886,

  • pull a groundhog named Phil out of a box and ask him when winter will end.

  • Not surprisingly, meteorologically-inclined marmots are not reliable predictors of spring.

  • But why divide the year into seasons in the first place?

  • The wordseasonwas born on the farm, since for a long time surviving another trip

  • around the sun meant knowing when to sow your seeds.

  • In most our minds, winter is when it’s coldest, summer is when it’s hottest, and spring

  • and autumn happen in between. You probably figured that much out before kindergarten.

  • But those aren’t the seasons on your calendar.

  • In most of the northern hemisphere, especially in the U.S., the coldest quarter of the year

  • begins several weeks before theofficialstart of winter, and summer leaves out a good

  • chunk of warm weather. How did our seasons get so detached from

  • our seasons?

  • Because Earth’s axis points alternately toward and away from the sun, we know there’s

  • less daylight in winter. and more daylight in summer.

  • So shouldn’t winter be the darkest time of year, and summer the time with most daylight?

  • If we did that, then the solstices *should* fall at the midway point.

  • Several cultures define their seasons exactly this way, and it might sound familiar from

  • a certain William Shakespeare play where the summer solstice falls atmidsummer”.

  • But like a big brisket, Earth cools and heats very slowly, and it takes time for changing

  • solar energy to move the thermometer. Water absorbs even more heat than land, so places

  • near oceans and lakes experience greater lags between more solar energy and warmer weather.

  • The opposite happens in winter, all that water stores heat and keeps things from getting

  • cold as soon as the sun starts to fade.

  • The start of cold or hot periods gets shifted towards the solstices, but in most places

  • they *still* don’t line up with the coldest and warmest quarters.

  • It probably won’t surprise you to learn that a lot of our modern four-season system

  • traces its origins to the Romans. Because so much of their territory was insulated by

  • large bodies of water, the temperatures they experienced lined up neatly with the solstices,

  • which were pretty big deal to ancient astronomers and festival-lovers. This system was applied

  • to a whole hemisphere, even though it didn’t make sense in a lot of places. If anyone can

  • mess up a calendar, it’s the Romans! Numa!

  • Depending on whether you care more about astronomy or temperature, there’s a lot of different

  • ways to define seasons, and none of them are perfect.

  • Of course, most other living creatures don’t worry about any of this stuff, they just follow

  • Earth’s natural climate cycles where they live. Several indigenous Australian cultures

  • define their seasons just this way, starting new seasons based on what plants and animals

  • are around at any time. They’d probably think Groundhog Day makes

  • a lot of sense.

  • Stay curious.

Every year on February 2nd, the people of Punxsutawney, Pennsylvania dress up like it’s 1886,


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B1 中級

季節が意味をなさない理由 (Why Seasons Make No Sense)

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    陳叔華 に公開 2021 年 01 月 14 日