All posts by Aeon Magazine

This article was originally published at Aeon and has been republished under Creative Commons.

Why synthetic chemicals seem more toxic than natural ones

Many people believe that chemicals, particularly the man-made ones, are highly dangerous. After all, more than 80,000 chemicals have been synthesised for commercial use in the United States, and many have been released into the environment without proper safety testing. Should we be afraid of the synthetic chemicals that permeate our world? 

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In space, there really might be no place like home

Few topics in science command as much attention as the discovery of extrasolar planets – those as-yet-unseen worlds, light years beyond our own Sun. In the quest to learn whether we are alone in the cosmos, astronomers are teasing out subtle wobbles and periodic dimmings of distant stars: telltale signs that a planet, much too faint to see directly in telescopes, is nevertheless present.

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What kills you when a volcano erupts? It’s not what you think

The blockbuster movie Jurassic World: Fallen Kingdom (2018) involves more than just dinosaurs wreaking havoc. Humans are sent in to rescue some prehistoric critters on the volcanic island of Isla Nublar, and chaos soon begins. The volcano erupts, and everyone runs away as a roiling cloud called a pyroclastic flow approaches. At one point the main character disappears into the cloud. Luckily, some dinosaurs and humans in a strange glass ball fall over a cliff into the sea, and our hero splashes in not long after.

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Space exploration is still the brightest hope-bringer we have

Earle Kyle

I am one of the few African-American aerospace engineers who helped design the Apollo spaceships that took men to the Moon. My great-grandfather was a slave in Claiborne, Alabama, who used primitive tools to work the land. My father was born in Alabama before the Wright brothers made mankind’s first flight. He lived to see men walk on the Moon, twin robotic biology labs land on Mars, and a fleet of four space probes on their way to the stars. But many black people, like the late Reverend Ralph Abernathy, felt that the money used to make these amazing things happen would have been better spent on helping the poorest descendants of American slaves.

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Did European Colonisation precipitate the Little Ice Age?

Many of us think that rapid environmental change is a quintessentially modern crisis. Today, temperatures are soaring, topsoil is washing away, phosphorous is being diluted, forests are retreating, pesticides are sterilising farmland, fertilisers are choking waterways, and biodiversity is plummeting under the onslaught of overpopulated, industrialised societies. Some of these changes are indeed truly new. But many others have deep roots and distant echoes in the early modern period, the years between around 1400 and 1800 when much of the world began to assume its present form. Recently, scientists, geographers, historians, and archaeologists have combined expertise and evidence to reveal just how profound early modern environmental transformations really were.

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What high-speed astronomy can tell us about the galactic zoo

For most of human history, the distant ‘celestial sphere’ was regarded as perfect and unchanging. Stars remained in place, planets moved predictably, and the few rogue comets were viewed as atmospheric phenomena. This began to change with the Danish astronomer Tycho Brahe’s observation of the supernova of 1572 – apparently, a new star – and his studies of the Great Comet of 1577, which he proved was actually a distant object. Nonetheless, the impression of permanence is strong. There are very few astronomical objects that noticeably vary to the naked eye: only the brightest comets, novae and supernovae. For observers in the northern hemisphere, the last naked-eye supernova was in 1604.

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Is bigger always better, or will the tiny inherit the Earth?

As I scuba dive in Oslob Bay off Cebu Island in the Philippines, I see a tiny shadow dart over the surface of the spherical coral block – a minute fish, a goby of the genus Eviota, among the smallest vertebrates in existence, only about a centimetre long and less than 1/10th of a gramme light. It’s about a million times smaller than myself, with the same basic vertebrate body: a spinal cord, a bony skull, a brain, kidneys and a liver. With the exception of gills and lungs, the tiny fish and I share similar sets of organs, just at a very dissimilar size.

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How seeing snakes in the grass helped primates to evolve

Evolution has favoured the modification and expansion of primate vision. Compared with other mammals, primates have, for example, greater depth perception from having forward-facing eyes with extensively overlapping visual fields, sharper visual acuity, more areas in the brain that are involved with vision, and, in some primates, trichromatic colour vision, which enables them to distinguish red from green hues. In fact, what separates primates from other mammals most is their much greater reliance on vision as the main sensory interface with the environment.

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How many great minds does it take to invent a telescope?

On 11 January 1672, the Fellows of the British Royal Society were treated to a demonstration of Isaac Newton’s reflecting telescope, which formed images with mirrors rather than with the lenses that had been used since the time of Galileo. Afterward, the fellows hailed Newton as the inventor of this marvelous new instrument, an attribution that sticks to the present. However, this linear historical account obscures a far more interesting, convoluted story. Newton’s claim was immediately challenged on behalf of two other contenders, James Gregory, and Laurent Cassegrain. More confounding, the earliest known concept of using a curved mirror to focus light predated Newton by more than 1,500 years; the final realisation of a practical reflecting telescope post-dated him by more than a half century.

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We can begin an interstellar mission today – and we should

Fifty-five years ago, Yuri Gagarin rocketed into orbit and began to break our bonds to our planet. To mark the occasion, the nonprofit Breakthrough Institute just announced plans to free us from an even more formidable set of bonds and send a fleet of small spacecraft beyond our solar system, off to the stars. News of the ‘Breakthrough Starshot’ plan was met with great enthusiasm, but also with more than a little skepticism. The distance between stars is vast. Our closest neighbour, the Alpha Centauri system, is 4.4 light years away – roughly 25 trillion miles. The Voyager 1 spacecraft, the fastest object ever created by humans, would take 70,000 years to travel that far. Many reporters greeted the Breakthrough Starshot as an idea grounded more in fantasy than in reality.

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