Slightly to the side

Did you know that Earth's tilt affects the school year?

We might refer to Planet Earth as ‘the globe’, but we know it is more like a slightly flattened sphere —experts would say it’s an oblate spheroid— that is also askew. These two details have major consequences for the climate, the night sky, the way we register locations, and even the way schools plan their academic year. How much does the Earth's being at an angle affect us? Let’s find out!

Why is Earth’s axis tilted? The most widely accepted theory is that, millions of years ago, a young planet Earth collided with another celestial body and was left permanently askew. Earth’s axis, supposedly straight before, now has a tilt of 23.5 degrees. It is also believed that the Moon is a product of this collision.

The Earth is permanently tilted, but it’s not static. The degree of the tilt varies slightly across a cycle of thousands of years, which would explain why seasons were harsher or milder across history. But what keeps the Earth from having a more extreme shift? The Moon. All celestial bodies have their own gravity, and they can affect each other. Moon’s gravity has a pull on the equatorial bulge (Earth’s widest part) and prevents it from being affected by other surrounding planets, while also keeping the axial tilt stable.

The different seasons are the first major consequence of the axial tilt. As the Earth orbits around the Sun, it remains tilted in the same direction, which means that, for half of the orbit, one pole is directly facing the Sun, while the other is directly away. For the next half of the orbit, the positions are reversed. The pole closer to the Sun experiences Summer, while the opposite pole goes through Winter (which means that yes, the Southern hemisphere celebrates Christmas during Summer).

When a compass signals North, what is it pointing towards? Spoiler: not the North Pole. The North Pole (also known as True North, or Geographic North) it is a fixed point in the Arctic Ocean intersected by the rotational axis. Maps and coordinates use this point as a reference for the North. A compass, however, points towards the North of the Earth’s magnetic field, which is constantly shifting. The difference between the two Norths is called declination, and is essential for navigation and map reading.

The Earth is a sphere, but most maps are flat. Something is not adding up, and it’s all the fault of a man called Gerardus Mercator, who, in the 16th century, mapped the Earth in a way that represented the meridians and parallels as straight lines. While this was excellent for navigation, it had its negatives: a size distortion. The farthest land masses are from the equator and closest to the poles, the most inflated in size they appear. For example, in the Mercator projection, Greenland appears close in size to the entire African continent, when in reality it is closer in size to the Democratic Republic of Congo.

We all know the difference between the Northern and the Southern hemispheres, but did you know the difference between the Eastern and Western ones? Unlike North and South (which are divided by the equator and experience opposite seasons), the Eastern and Western hemispheres are more of a cultural division, even though they are separated by the Prime meridian and antimeridian. The Eastern Hemisphere is commonly associated with "the Old World" (though it includes Australia), and the Western Hemisphere is "the New World".

Hemispheres split the world equally in size, but not in content. The Northern Hemisphere contains the majority of the Earth’s land mass (around 68%), while the Southern Hemisphere holds the majority of the water (around 80%). As the Northern side has more land, it also houses the majority of the world’s population, around 90%.

North and South experience opposite seasons, but what else is opposite? Storms and whirlpools spin depending on their location—clockwise in the South, counterclockwise in the North—, and the shape of the crescent moon is perceived inverted —a waxing crescent looks like a D from the North and a C from the South.

While bigger celestial objects, such as the Sun or Moon, are visible from any point on Earth, some can only be seen depending on your location. Constellations that are located closer to the Poles are only visible from that hemisphere, and have traditionally been used for navigation and orientation. In the Northern hemisphere, the main examples are Polaris (the north star), Ursa Major (a constellation that contains the Big Dipper), Ursa Minor, Cepheus, and Cassiopeia. For the Southern Hemisphere, the main examples are Crux (the Southern Cross), Centaurus, and Carina.

Most institutions plan their year around Summer, which means that in the Northern Hemisphere, the Academic year usually starts around September and ends in May or June of the following calendar year, while there’s a Winter break in time for Christmas and New Year. In the Southern Hemisphere, the calendar and academic years are matched: the academic year usually begins in March and ends mid-December, right before the Holidays, while Winter break usually falls in July.

The 12 longest-living animals on Earth (and how they cheat time)

Nature doesn’t just create beauty, it crafts survival miracles. While most animals have short lives, a rare few have mastered the art of staying alive for centuries, even millennia. These aren’t just long-lived creatures; they’re nature’s ultimate time travelers. From the frozen depths of the oceans to the darkest corners underground, they’ve developed bizarre, brilliant strategies to cheat death. Get ready to meet 12 animals whose lifespans will absolutely blow your mind.

Record age: up to 15,000 years

This unassuming sea sponge thrives in the freezing waters of Antarctica, where temperatures hover around 28.6 °F—so cold that biological processes hit the brakes. In such icy conditions, metabolism slows to a crawl, allowing these sponges to live for thousands of years.

Some have reached impressive sizes of over 3 feet tall and have been around since mammoths were still thundering across the tundra. They don’t move, they don’t stress, and they barely change, just quietly existing while centuries pass them by. Their secret to extreme longevity? Glacial patience, deep-sea stillness, and a lifestyle that redefines "low-maintenance".

Age: technically… infinite

This tiny jellyfish, no bigger than a fingernail—less than 0.2 inches—is like the ocean’s very own Benjamin Button. What makes it truly extraordinary is its ability to rewind its life story, flipping back to a youthful, juvenile stage whenever it wants. While it’s not completely invincible (predators and other threats are still very real), if left undisturbed, it can keep hitting the reset button on aging indefinitely, making it one of the most fascinating "time-benders" in nature.

Record age: 507 years

In 2006, a special clam was discovered buried deep in the seabeds of the North Atlantic. Scientists were able to determine that it had been there since at least 1499—that’s centuries before the United States was even a thought! This ancient marvel, nicknamed "Ming", was able to perfect a slow-and-steady approach to life. Growing at a snail’s pace and barely budging, Ming’s sedentary lifestyle turned out to be a brilliant strategy for beating the clock. Who knew doing almost nothing could be the ultimate secret to longevity?

Record age: estimated 392 years

These sharks aren’t your average ocean cruisers—they can stretch over 20 feet long and weigh up to 2,200 pounds. But what’s really mindblowing is how slowly they move, like they’re in a permanent state of deep relaxation. Living in the icy Arctic waters, these giants don’t hit adulthood until they’re about 150 years old, and some can glide through the depths for nearly 400 years. Imagine that! These ancient swimmers were already around before America declared independence... and they are still out there, silently roaming the seas!

Record age: over 211 years

This whale is a true ocean giant, stretching up to 60 feet long and weighing a staggering 200,000 pounds. But what makes it stand out isn’t just its size but its age. Some of these majestic creatures carry harpoons from the 1800s still lodged in their skin, like walking history books. Just picture living so long that you’re literally carrying outdated technology embedded in your body—talk about being a time traveler of the seas!

Record age: 200 years

Spanning the chilly Pacific coastline from California all the way up to Alaska, this spiky little ball—about 7 inches across—is full of surprises. It munches on algae and calls the deep, dark ocean its home, thriving at depths of up to 300 feet. Don’t let its size fool you: this prickly creature is a true elder of the cold seas, quietly outliving many ocean neighbors while keeping a low profile. A tough, slow-living veteran wrapped in spikes!

Record age: 226 years

Meet Hanako, a legendary Japanese koi who swam through life for an astonishing 226 years. Scientists discovered how old she was by studying the rings on her scales, much like counting the growth rings of a tree. These colorful, ornamental fish aren’t just symbols of good fortune; they’re also secret long-lifers with the potential to celebrate over two centuries of birthdays, as long as they get the right care and a peaceful pond to call home.

Record age: 190 years

Jonathan is a male tortoise living on the remote island of Saint Helena in the South Atlantic Ocean. He was born back in 1832, and he’s still happily chomping lettuce and soaking up the sun today. Weighing in at more than 400 pounds and measuring around 3 feet long, Jonathan holds the title of the oldest known living land animal on the planet. If he could share tales, they’d span nearly two centuries of history. Imagine that!

Record age: 152 years

This ancient-looking fish, with its whisker-like barbels, looking like a tiny underwater submarine, prowls the lakes of North America. It can reach an impressive length of up to 7 feet and weigh around 200 pounds. These slow-living creatures don’t rush into adulthood—they start breeding only around age 20—and then take their time cruising through life at a leisurely pace. Believe it or not, one legendary catch in Wisconsin was estimated to be over 150 years old!

Record age: over 90 years

This chunky, night-loving parrot from New Zealand is a true oddball—it can’t fly, snores like a grumpy grandpa, and smells like fresh flowers. Despite its quirks, this bird boasts an impressively long lifespan. Sadly, it teeters on the edge of extinction. The oldest known kakapo, affectionately named Richard Henry, lived 90 years, earning him the title of the charmingly eccentric elder statesman of the avian world.

Record age: 37 years

This tiny, kooky rodent—barely 3 inches long and just over an ounce in weight—could’ve been cast straight from a sci-fi apocalypse flick. Dwelling in vast underground colonies across Africa, it’s practically invincible to cancer, pain, and the usual effects of aging. Scientists are fascinated by this little marvel, even if it’s not winning beauty contests anytime soon. Its superpowers make it a star in longevity research!

Record age: estimated 100+ years

Lobsters have a totally different rulebook than us when it comes to aging. They don’t really grow old; they just keep getting bigger and bigger. Some giant lobsters weigh over 40 pounds and stretch beyond 3 feet long. Their biggest threats? Not old age, but predators or the risky process of shedding their shells. In theory, they could live forever if left alone—but let’s be honest, not many get to enjoy a peaceful, lobster-sized retirement!