The world isn't what it seems: 3 ways your brain is being fooled by the universe

 Our view of reality is severely limited. The reason for this is simple: we evolved on an African plain three million years ago. And so we have the senses necessary to survive on an African plain: eyes that can see far enough to spot a predator approaching, ears sensitive enough to hear a rustling in the long grass

Those senses have revealed only an infinitesimal fraction of the world and provided us with a certain ‘common sense’. But, at every level, we’re deceived by our ape-like intuition. Most of nature is deeply hidden from us and the world isn’t what it seems.

So many things that seem obviously true are not. And here are just a few…

1. Earth is flat

Apart from the lumps and bumps of mountains, Earth certainly seems flat. But there are several clues that not only is it curved but is, in fact, a large ball. For one thing, receding ships drop below the horizon before dwindling to a dot.

Also, during an eclipse of the Moon, when Earth passes between the Moon and the Sun, the shadow of Earth on the Moon is clearly curved.

Even stronger evidence that Earth is round came from the first circumnavigation of the world in a ship sailed by the Portuguese navigator Ferdinand Magellan. Though he was killed in the Philippines, the voyage was completed by the Basque navigator Juan Sebastián del Cano in 1521.

But, of course, the easiest way to see that Earth is a sphere is from space. And there’s no doubt that what the Apollo 8 astronauts photographed rising above the grey desolation of the Moon half a century ago was a sphere.

Measuring the size of Earth is a bit more difficult. But on a sphere, the mutual distances between four cities are different from what they would be on a flat surface (in fact, the American physicist Steven Weinberg, in his 1972 book, Gravitation and Cosmology, used JRR Tolkien’s distances to deduce that Middle-earth isn’t flat!).

By this means, it’s possible to determine the size of Earth from airline mileage tables and confirm that it’s a sphere.

The first estimate of the size of Earth, however, was made around 240 BC by Eratosthenes, chief librarian at the Museum of Alexandria. He knew that at midday on Midsummer’s Day, a vertical pillar at Syene (modern-day Aswan) cast no shadow because the Sun was directly overhead, whereas one in Alexandria cast a shadow because the Sun was 7° from the vertical.

Knowing the distance between Syene and Alexandria, and using geometry, Eratosthenes deduced that Earth must be round with a circumference of about 40,000km (24,855 miles), which is remarkably close to the modern value.

2. The stars turn around Earth

It seems patently obvious that the stars are wheeling around a stationary Earth rather than the stars are still and it’s Earth that’s turning. For one thing, it’s the way it looks. And for another thing, it’s the simplest explanation.

It’s much more complicated to believe that it’s Earth turning because that requires explaining how the planet can possibly be in motion without any of us noticing.

That conundrum was only explained in the 17th-century by Italian physicist Galileo Galilei. He realised that if you threw a ball on the deck of a ship moving at a constant speed, it would loop through the air just as it would if you were stationary and standing on dry land.

If it wasn’t obvious you were on a ship, you might think you were stationary. Similarly, we can easily be hoodwinked into thinking that we’re stationary even though Earth’s surface is moving – at 1,670km/h (1,038mph) at the equator.

Evidence that Earth is turning came from the trajectories of long-range artillery. They’re deflected to the right (with respect to the direction of travel) in the northern hemisphere and to the left in the southern hemisphere.

This is because the ground beneath the projectiles moves at different speeds at different latitudes. For instance, a projectile travelling north from the equator constantly moves into latitudes where the speed of the ground is slower. From the ground, it therefore appears deflected eastward.

But proving that Earth is rotating still required the invention of the Foucault Pendulum – one of which swings at London’s Science Museum. It’s a simple device named after French physicist Léon Foucault, who, in Paris in 1851, came up with the idea of suspending an iron ball on a steel wire from the dome of the Panthéon.

The extremely long pendulum is free to swing any way it likes, and its motion appears to change direction over time. In fact, the pendulum maintains its direction while Earth turns beneath it. Ultimately, however, the proof that Earth is spinning came from seeing the planet turning against the inky backdrop of space from the vantage point of Earth’s orbit.

3. Creatures are designed for their habitats

This seems obviously true. After all, we all know that sharks are the perfect ocean predators, pine trees are the perfect trees for snowy conditions and so on. As biologist Richard Dawkins says in his 1986 book The Blind Watchmaker: “Biology is the study of complicated things that give the appearance of having been designed for a purpose.”

But no design is at play. It’s simply that ‘mutations’ of DNA, the molecule that in a loose sense transmits blueprints of an organism between generations, producing an enormous variety of different creatures.

The majority turn out to be unsuited for their environments and die of hunger before reproductive age. Only a minority are suited and leave offspring to further the process of adaptation to their environment, a process known as natural selection.

Think of a machine that makes random keys. The vast majority don’t fit a particular lock. But one or two do. Would you say they have been ‘designed’ for the lock? No. Nevertheless, the illusion of design in the natural world is very powerful and, even now, creationists refuse to believe it’s an illusion.

“It’s almost as if the human brain were specifically designed to misunderstand Darwinism and find it hard to believe,” says Dawkins.