Early in the history of our solar system,
something mysteriously knocked Earth
slightly off its axis.
So today we tilt at 23.5 degrees.
But what would happen if we tilted even more?
What if Earth spun sideways on its axis?
Well, it wouldn't take long before utter chaos ensued.
One of the most important consequences
of Earth's axial tilt is the seasons.
Seasons happen because the tilt points
different parts of the planet toward the sun
at different times of the year.
But the tilt also means that different parts of the globe
receive different amounts of sunlight during each season.
And that's where a more extreme tilt
starts to cause problems.
Right now, during the summer in the Northern Hemisphere,
places far north, like Utqiagvik, Alaska,
receive 24 hours of sunlight
for 82 days straight.
Because Earth is tilted far enough on its axis
that as the planet rotates,
Utqiagvik never leaves direct sunlight.
On the other hand, the contiguous US
receives a max of 17 hours a day, because after that
it rotates out of daytime sunlight and into night.
But if we tilted Earth's axis even more, to 90 degrees,
the US would get sunlight 24/7, around the clock,
for months on end.
And it's not just the US;
the entire Northern Hemisphere would be like this.
At first, animals would take advantage of the extra light
to find and eat more food, just like Alaskan birds,
which feed their chicks extra nutrition in the summer,
resulting in faster-growing babies
than their southern counterparts.
And plant growth would explode,
since they get their energy directly from sunlight.
Farms in northern Alaska, for example,
grow cabbages the size of rottweilers in the summer.
But while animals and plants would thrive, humans wouldn't.
We evolved to be active during the day and sleep at night.
But if we were exposed to unending sunlight,
our brains would stop producing the hormone melatonin,
which we need to sleep at night.
And that could lead to sleep deprivation,
depression, and, ultimately, a more severe, chronic version
of these symptoms called seasonal affective disorder,
which already affects 9% of Alaskans,
compared to just 6% of the entire United States.
But that's less of a worry than the floods.
Temperatures at the North Pole would more than double,
to 38 degrees Celsius from 15.5 degrees Celsius.
That's hotter than temperatures at the equator today.
As a result, Greenland's ice cap would melt,
causing sea levels to rise by 7 meters,
and flood nearly every coastal city on Earth.
Say goodbye to New York, Copenhagen, and Tokyo.
To make matters worse, the warmer seas
would trigger stronger and more frequent hurricanes,
which form when sea water evaporates at the surface.
And the weather wouldn't get better
when winter comes six months later.
Out of reach of the sun's direct beams
for months at a time, the hemisphere would get colder
than any winter on record.
Swirls of frigid air, called a polar vortex,
which are normally dissipated by warm air in the tropics,
could travel all the way down to the equator.
Imagine blizzards in Florida, Brazil, Kenya!
And all those thriving plants,
they'd die from a lack of sunlight.
Agriculture would collapse as ecosystems crumble
and mass extinctions pile up.
And there would be even more floods, because
meanwhile, the Southern Hemisphere is getting toasty
and the South Pole is home to 90% of the world's ice.
The constant sunlight would raise its temperature
to 38 degrees Celsius from -28 degrees Celsius,
melting the ice and raising sea levels
by a whopping 61 meters.
That's almost as tall as the Leaning Tower of Pisa.
Greenland's flood would look like a puddle in comparison.
So all in all, while a few extra hours
in the summer sun would be nice,
let's leave the extra seasons to Alaska
and be glad the Earth is tilted exactly as it is.