Why Do We Have Seasons?

The sun came up — but it's COLD today! And yesterday I was hot in May! Why does the world go warm and cool? Same sun, same orbit — what's the rule?

Earth is tilted! TILT! TILT! Like a top a little bit BUILT With a lean — about twenty-three — That's the secret, you and me!

When YOUR half leans toward the sun, Sunbeams hit you HEAD ON, son! Bright and straight — your half gets HOT — Summer's what you call that spot!

But the OTHER half leans AWAY, Same sun rays come in at a slant all day, Spread out thin like butter too wide — Winter's where those folks reside!

Tilt, tilt, the Earth is TILTED! Twenty-three degrees enlisted! Half a year you lean toward — Half a year you lean ignored!

And six months later — switch the show! Your side's the side that's leaning low! Now THEY get summer, YOU get snow — Around and around the seasons go!

How do we know? How do we know? People stuck sticks in the ground long ago, And watched the shadow at high noon In summer, in winter, in autumn, in June!

Long shadow, short shadow, slant or straight — The angle of the sun goes up and down with date!

Same stick, same noon, the shadow REWROTE — Long when it's cold, short when it's hot! The sun rides higher when summer's near, And lower in winter — year by year!

(Eratosthenes used the same sun-and-shadow trick in two different cities — to measure the EARTH ITSELF!)

You can try it! Get a flashlight bright, Shine it straight on paper white — Now tilt the paper — see the spot SPREAD OUT THIN — and not so hot!

Tilt, tilt, the Earth is TILTED! Twenty-three degrees enlisted! That's the dance with the summer sun — The lean is why the seasons run!

So put on shorts or grab a coat — Same big sun keeps Earth afloat! The tilt's the trick, the orbit's true — A skewered globe, and me, and you!