This morning my son asked why it was so cold. I replied because it's winter. But then he asked why is it so sunny then.
Honestly kids are great at this: questioning the daily obvious, then making parents realise they know nothing, even if they're tasked with knowing all!
I started out with a satsuma (the Sun) and a lime (Earth), as all science clearly should…
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I explained that when we stand close to a fire, then it's warm. And when we stand further away, it's not so warm. Then, using the lime and satsuma at different distances, showed that the earth being further away from the sun means it's colder.
At the same time, showing that earth still has the same line of sight to the sun, therefore it's still sunny.
And because the earth doesn't go in a perfect circle around the sun, that's why we're further away. And the earth turns on its own axis and that's night and day…
Except that would mean it's winter across the globe all at the same time, and that just ain't so.
That's when I remembered the earth is at a tilt, so I showed my son again, that if the earth is tilting, and spinning on that tilt (imagining that a blemish on the lime was home) we could see that home was always further away from the sun during its rotations and the other side of earth (to home) was closer. Even if marginally.
And that's why it's colder, yet sunny.
But then, the difference between cold and hot is pretty significant, and that's just due to a tilt. This kinda blew my mind. That morning my son had already asked Alexa how hot the sun was, and frankly it's just a jumble of numbers to me: the sun be super super hot.
When I now think of the relatively small tilt in the earth changing the temperature from 0°C to something like 30°C a tiny shift towards the sun is likely to bake the planet the opening of Terminator 2!
I've never really appreciated quite how delicately we hang in the balance.
Also: science provided here may not be accurate or even close. But it's my blog, so I'm allowed to be wrong!