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  • The Earth sits comfortably in its orbit

  • tilted on its axis at 23 degrees.

  • Knock the planet over -

  • and it wouldn't be the Earth as you know it.

  • This is WHAT IF,

  • and here's what would happen

  • if the Earth's axis was tilted by 90 degrees.

  • Only two planets in the Solar System lie on their sides -

  • Uranus and the dwarf planet Pluto.

  • Now, if something took the Earth off its stand,

  • the blue planet would have no chance

  • of developing any complex life on its surface.

  • But let's start at the beginning.

  • This axial tilt, or obliquity,

  • is what drives the seasons here on Earth.

  • Before the collision that created the Moon,

  • the Earth's axis was slowly wobbling around

  • somewhere between 0 and 85 degrees.

  • Then, our newly formed Moon stabilized it.

  • But if that collision happened at a different time,

  • things would turn out very different here on Earth.

  • It would be a strange new world.

  • As the Earth made its way through orbit,

  • its poles would be pointing straight towards the Sun.

  • One hemisphere would be shrouded in darkness

  • for six months straight,

  • while the other would be getting cooked

  • by the blazing sunlight.

  • One day on Earth would last a whole year.

  • At the North Pole, the daytime temperatures

  • would rise to a broiling 50°C (120°F).

  • A day at the South Pole would be even worse.

  • Because the South Pole would be located

  • away from climate-controlling ocean currents,

  • it would heat up to an almost boiling 80°C (176°F).

  • The poles would soak up so much heat from the Sun,

  • that they wouldn't even freeze

  • during the six-month-long night.

  • You wouldn't recognize the steaming equatorial tropics.

  • With a 90-degree axial tilt,

  • part of the equator would stay encased in ice all year round.

  • At some point in this Earth's existence,

  • our continents would get clumped together around one of the poles.

  • Inland temperatures in the daytime would get truly hellish -

  • reaching the boiling temperature of water.

  • Clouds could help the situation and

  • not let all the water vapor off the planet.

  • But you wouldn't know.

  • You wouldn't stick around that long.

  • In this scorching heat,

  • the best-case scenario would see

  • just a few kinds of bacteria survive.

  • Those bacteria might evolve

  • into more complex life forms,

  • but they wouldn't be anywhere close

  • to how complex we turned out to be.

  • The reason would be a lack of oxygen.

  • Green plants would be having a hard time surviving

  • during the six months of complete darkness.

  • They'd drop their seeds at nightfall

  • to grow after sunrise.

  • Interestingly enough,

  • if the Earth was 60 million km (40 million miles)

  • further away from the Sun,

  • a 90-degree axial tilt wouldn't be so bad.

  • The temperatures at the poles

  • would never raise above 46°C (115°F) during the day.

  • The coldest it would get at night would be 3°C (37°F).

  • The only place covered with ice would be the highest mountains.

  • So you see, simply orbiting a star in the habitable zone

  • doesn't mean that a planet is actually capable of sustaining life.

  • We're the lucky ones living here on Earth.

  • Maybe one day we'll discover another exoplanet,

  • just like our home.

  • But that's a story for another WHAT IF.

The Earth sits comfortably in its orbit

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地球の軸が90度傾いていたら? (What If Earth’s Axis Was Tilted by 90 Degrees?)

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    林宜悉 に公開 2021 年 01 月 14 日
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