During Earth’s early days, a gargantuan collision left our planet spinning at an angle. That slight incline allowed life as you know it to flourish. But what if this impact caused Earth to rotate at a much more dramatic slant? Like, say, on its side? What would our world look like? Why is Alaska better prepared for this sideways world? And why could human life be no longer possible on this blue rock?
Around 4.5 billion years ago, during Earth’s infancy, our world got slammed by Theia, a Mars-sized protoplanet. This collision was so violent that Earth almost turned into a cloud of vaporized rock. The impact also tilted the Earth’s axis 70 degrees from its orbital axis. Lucky for us and all the life that came after the enormous crash, this extreme tilt decreased over time and settled at 23.5 degrees. And this is the planet you live on at this very moment.
But what if the encounter with Theia had flipped Earth 90 degrees? How would that Earth have differed from our own? So what’s the deal with this tilt anyway? Well, it gives us seasons. As Earth orbits the Sun, our hemispheres take turns facing our star. When the northern axis is pointing toward the Sun, the northern hemisphere receives more sunlight and experiences summer.
Meanwhile, the southern axis receives less sunlight so the southern hemisphere can have its winter. Six months later, it all shifts, and it is now the northern hemisphere that experiences winter while the southern hemisphere enjoys the summer. All because of our planet’s 23.5-degree tilt. Now that’s what I call fair and balanced. But balanced is not a word that would describe the Earth if it had an axial tilt of 90 degrees.
If our planet was spinning on its side, the North Pole would face the Sun head-on, while the South Pole would be completely hidden away from it. After six months, this would change. Now the South Pole would face the Sun while the North Pole would be thrown into darkness. And what would this all mean for you? Dealing with a six-month-long winter and six-month-long summer. That’s what.
It might not sound all that bad, but let me assure you. Your days would be radically different. Whenever one of hemispheres was directly facing the Sun it would get sunlight 24/7 for six months straight. The U.S., Sweden, Japan and all the other countries in the northern hemisphere of the planet would be blasted by constant sunlight for half the year. And I mean, it would be a constant summer day.
You’d have to get used to sleeping while the Sun is up and stockpile your sunscreen. This might sound familiar to residents of Barrow, Alaska, who already experience sunlight for 84 straight days. This is because when the North Pole is angled toward the Sun, all the areas within the Arctic Circle are unable to fully escape its rays. This phenomenon is known as the midnight sun.
How extreme? During July the northern hemisphere could experience scorching 80 to 100 °C (176 to 210 °F) temperatures. That’s hot enough to boil water. The blazing climate would be particularly ferocious at the poles, especially in the north. The rising ocean temperatures would trigger stronger and more frequent hurricanes. And because the weather would now be all over the place, the entire planet would experience severe droughts during the summer months.
And that’s just half the tale. Let’s now take a look at what happens when one of the hemispheres is pointing away from the Sun. Instead of reliable SPF you would need to invest in a good set of headlights, because these six months would be shrouded in darkness. Half of your year would be a long, long night. And on top of those headlights, get your hands on the best winter jacket you can find. The hemisphere’s months-long night would be a freezing one.
It would become as cold as the North Pole is during its winter, with swirls of frigid winds. You’d see blizzards where Florida and Kenya are located today. Magic Kingdom would look more like Castle Black. The good news is that the Earth wouldn’t turn into an ice rock. Even during the coldest months, it wouldn’t be entirely covered in ice.
That’s because the poles wouldn’t experience winter long enough to become completely frozen. Instead, you’d see some seasonal snow stretching from Northern Africa all the way to the Middle East. Only two places might be able to hold on to that snow throughout the year. The Andes Mountains of western South America and the extreme highlands of eastern Africa.
Your best chance at ice fishing could be over the equatorial ocean, which might be the only body of water covered in ice. So what would life be like on this very tilted planet? Well, for starters, a lot of our coastal cities would now be underwater. That’s because on this sideways-spinning Earth, all the ice covering Antarctica, Greenland and mountain glaciers would melt.
This would cause the oceans to rise 70 m (230 ft). Many people would be forced to leave their homes. But the problems wouldn’t stop there. Such extreme temperature variations would make most parts of Europe uninhabitable. If you still wanted to stay there, you’d have to deal with punishing winters followed by boiling hot summers.
On the other hand, Antarctica would hold a relatively stable climate of around 0 to 20 °C (32 to 70 °F). Talk about a swap. When it comes to growing food, we’d be working under a tight timeline. You’d only have three milder summer months to plant and harvest crops. And those months wouldn’t go uninterrupted. The peak of the summer would get so hot that it would burn fields.
You’d only have two 1.5-month periods in the entire year to farm enough food for billions of people. The resulting mass starvation would make it difficult for any civilization to sustain itself. And if you think the unstoppable famine and flooding of habitable land would be awful, wait till you hear about what those summer temperatures would do to you.
Remember how July could bring about temperatures hot enough to brew coffee? Hate to break it to you, but the average human will suffer hyperthermia in 60 °C (140 °F) heat. Your body wouldn’t just suffer from the worst heat stroke imaginable. After just 10 minutes, it would literally boil from the inside out. Starvation, plus flooded cities, plus a world that jumps from frozen to boiling equals checkmate, humanity.
As you can see, when it comes to planetary balance it is all in the details. You can thank our slight 23.5-degree slant for keeping the current weather more or less in check. Otherwise we’d need to seriously put our minds together and come up with ways to control the climate.
- “Why Do We Have Seasons?”. 2022. weather.gov.
- “Why is the Earth Tilted? New Theory Offers Clues on a Dizzy Moment”. 2022. inverse.com.
- “Napkin Math: Will The Leaning Tower Of Pisa Ever Fall?”. 2013. nationalgeographic.com.
- “What If The Earth Spun Sideways On Its Axis”. Andrea Schmitz and Shira Polan. 2021. businessinsider.com.
- “Remains Of Impact That Created The Moon May Lie Deep Within Earth”. Paul Voosen. 2021. science.org.