Winter Sun Close Encounter

カートのアイテムが多すぎます

ご購入は五十タイトルがカートに入っている場合のみです。

カートに追加できませんでした。

しばらく経ってから再度お試しください。

ウィッシュリストに追加できませんでした。

しばらく経ってから再度お試しください。

ほしい物リストの削除に失敗しました。

しばらく経ってから再度お試しください。

ポッドキャストのフォローに失敗しました

ポッドキャストのフォロー解除に失敗しました

Winter Sun Close Encounter

無料で聴く

ポッドキャストの詳細を見る

概要

Each winter in the Northern Hemisphere, it feels like Earth is drifting farther away from the warmth of the Sun. In fact, it’s just the opposite. When we measure the size of the Sun in our sky, we find that it actually appears 3.4% larger in winter—because it’s 3.4% closer. More than 3 million miles closer. The Sun is about 95 million miles away in summer, but just 92 million in winter. And this is because Earth’s orbit is elliptical, with Earth following the closer part of its path during the northern winter. You’d expect the nearer Sun to provide more solar energy to our planet and you’d be right: almost 7% more. But its effect is greatly minimized by the 23-degree tilt of Earth’s axis, turning the Northern Hemisphere away from the Sun in the winter. At the same time, in the Southern Hemisphere summer, that extra solar energy is mostly absorbed by the huge southern oceans. The effects may be minor today, but that won’t always be the case. The gravity of Saturn and Jupiter pulls Earth through a long cycle of orbital stances, from nearly circular, to more elliptical. We’re now as close to circular as our orbit ever gets. In about 200,000 years, we’ll be at our elliptical maximum. Then, Earth will receive 23% more solar radiation when closest to the Sun. This varying solar energy will have significant impacts on weather and climate.

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