Kepler mission announces two exoplanets in the habitable "zone"

The planets are the right temperature and size to support liquid water.

The Kepler mission, a NASA project to find and profile planets outside of our solar system, has announced the discovery of two potentially habitable exosolar planets.

The planets are part of a system, Kepler-62, which is thought to contain five roughly earth-sized planets. The biggest is almost twice earth's size; the smallest slightly more than half.

That alone is notable, because the normal way the Kepler mission identifies planets is by measuring the gravitational they exert on their star. A big enough planet will pull the star slightly closer to the earth when it's on one side, and slightly further when it's on the other. That causes a minute fluctuation in the brightness of the star, measured from our planet, which the Kepler orbital observatory can sense.

But only the largest gas giants have such an effect, and while they are noteworthy finds in themselves, they aren't habitable. To find smaller planets, the mission looks at stars which have other fluctuations in light – due to planets passing in front of them. They then have to model every possible reason why those fluctuations could occur, and hope that they find that the most likely cause is exoplanets traversing the star.

The planets which they've found this way aren't just earth sized, though. Two of them, each measuring around 1.5 times the size of earth, are roughly the same distance away from their star as we are. Their orbits take a third and two thirds of an earth year each, but, because their star is less bright than our sun, they receive 1.2 and 0.4 times the light, respectively, that we do.

That will equal one hot planet and one cold one – but either of them might be in the so-called "habitable zone", where liquid water can exist. And liquid water is the only universal prerequisite we know for life.

The authors note that their method cannot tell if the planets are even rocky, as opposed to gas giants, let alone whether they actually have an atmosphere or water. But they are some of the best candidates we've found to date.

And crucially, we've found them fast. The Kepler telescope has been in orbit for around half its expected life, but it's already produced a vast amount of data to crunch. It's discovered almost 3,000 possible exoplanets, and has already found one that could have water. If the hit rate stays high, there could be many more.

Johannes Kepler, the 16th century astronomer for NASA's mission is named. Image: Hulton Archive/Getty Images

Alex Hern is a technology reporter for the Guardian. He was formerly staff writer at the New Statesman. You should follow Alex on Twitter.

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With everything from iPhones to clothing turning monochrome, is the West afraid of colour?

If modern design appears particularly achromatic, it only reflects the "chromophobia" which courses through the history of Western thought.

To many English observers, 1666 – the year that the poet John Dryden christened the annus mirabilis, or “year of miracles” – wasn’t especially miraculous. The country was gripped by plague and, after a hot, dry summer, the Great Fire cut a swath through London. But for Isaac Newton, then still a student, it did prove illuminating. It was in 1666 that he first used prisms to prove that white light was not a pure, indissoluble substance but was made up of different coloured rays. This was such a profound challenge to the prevailing world-view that even Newton was shaken. “I perswade my self,” he wrote, “that this Assertion above the rest appears Paradoxical, & is with most difficulty admitted.”

The belief that colours are inferior and therefore naturally subordinate, rather than fundamental, was not new in Newton’s day, nor did it end with his discovery of spectral colour. A pattern of chromophobia – an aversion to colours – courses through Western thought.

Writing in the fourth century BC, Aristotle argued: “The most attractive colours would never yield as much pleasure as a definite image without colour.” For Renaissance artists, this idea was defined by the division between disegno, drawing or design, and colore. Disegno was the foundation of any serious artistic endeavour. The preference for achromatic, “intellectual” form is also evident in architecture. Despite rock-solid evidence from the 19th century proving that Greek marble buildings and statues were once brightly painted, the classical ideal has remained anachronistically bleached. And while modernist and postmodern architects have made some use of colour, the primacy of form is unmistakable in the work of everyone from John Pawson to Zaha Hadid and Toyo Ito.

A broad cultural dislike of colour is curious because, speaking in evolutionary terms, our ability to see it has been crucial to our success. Colour vision in primates developed between 38 and 65 million years ago and makes us better able to find ripening red and yellow fruits amid green foliage. Neurons devoted to visual processing occupy much more of our neocortex real estate than those devoted to hearing or touch. Estimates vary but the Optical Society of America has suggested that it may be possible for humans to distinguish between up to ten million different shades.

And we have put this skill to good use. Bold colours have been used by many cultures to mark temporal and spiritual power. Tyrian purple, a rich, reddish dye said to resemble clotted blood, was made using an extract from two different kinds of Mediterranean shellfish and was beloved by emperors in the ancient world. A single pound of dyed cloth would cost a skilled craftsman three years’ wages and became steadily more expensive as the shellfish became rarer.

But even as such saturated colours were coveted, they also elicited disgust. The manufacture of many, including Tyrian purple, involved ingredients such as stale urine and dung. Dye and paintworks were relegated to the urban fringes. Increasingly, the wearing of bright colours was seen as vainglorious and ungodly. Protestants indicated their humility by whitewashing over jewel-coloured murals and smashing stained-glass windows in churches, and by restricting their sartorial palette predominantly to black. An echo prevails today in men’s suits: colours are largely confined to small accessories such as ties and white shirts are held up as the ne plus ultra of refined sophistication. (The late Apple co-founder Steve Jobs went one better, opting for a uniform of identical black turtlenecks.)

One reason for this distrust is that colours are difficult to conceptualise. Do they exist physically, or only in our brains? Does everyone see them the same way? Colours have been maligned as chaotic, fickle, irrational and female. The early Christian thinker St Augustine of Hippo accused them of “a seductive and dangerous sweetness”.

Our ambivalence to colour, however, has profited white. Like black, white has not been classed as a real colour since Newton. It has almost become an anti-colour. Take Apple, for example. Although Sir Jony Ive is usually credited with the company’s love for monochrome products (it was certainly Ive who brought this to its apogee), the trend predates his arrival. It can be traced back to the “Snow White” design language developed in the 1980s. Today, as consumer neophilia demands that technology be continually refreshed, Apple’s higher-end products are available in the smallest range of colours – usually just white, black and, for the Asian market, gold – while those lower down come in a slew of fruity brights.

White is not only big business for Apple. In 2014, a Californian man named Walter Liew was found guilty of 20 counts of economic espionage and sentenced to 15 years in jail for selling the secret to a very special shade of titanium-oxide white, used in everything from luxury cars to tennis courts, to Chinese firms for $28m.

Perhaps the final word on the matter should go to Le Corbusier. In 1925, the great modernist recommended that all interior walls should be whitewashed, to act as a moral and spiritual restorative. But he wasn’t just advocating white for white’s sake: although he continued to dabble with colour, he disapproved of it, too. “Let us leave to the clothes-dyers,” he wrote, “the sensory jubilations of the paint tube.”

“The Secret Lives of Colour” (John Murray) by Kassia St Clair will be published on 20 October

This article first appeared in the 26 May 2016 issue of the New Statesman, The Brexit odd squad