Discovery

The atoll of Tetiaro is a string of tiny islands in French Polynesia, about 60km away from Tahiti. The islands – known as ‘motus’ to local Polynesians – are unique ecosystems that are crucial nesting sites for native seabirds. But invasive species threaten to disrupt these fragile environments – a fate seen across many islands in the Pacific. Rats arrived with early human settlers and have driven bird species off some of the islands. Meanwhile introduced mosquitoes have thrived in the warm conditions, and now act as vectors for diseases such as the Zika virus. Rat eradication experts have travelled to one of the uninhabited islands in the atoll, called Reiono, to attempt an experimental eradication of thousands of rats with one mammoth poison bait drop. They’re also using this as an opportunity to better understand why eradication attempts have been less effective on tropical islands. At the same time, on another island in the chain called Onetahi, researchers are releasing swarms of sterilised male mosquitoes to try to rid this motu of the disease-carrying pest. Join Carl Smith from ABC Australia for the third episode of The Chase: a special four-part series about science on the run. Picture: The Pacific rat (Rattus exulans) is smaller than many other invasive rat species, but it’s still been linked to localised extinctions of island birds, Credit: Carl Smith

The Night Parrot was supposed to be extinct and became a legend among birdwatchers in Australia: a fat, dumpy, green parrot that lived in the desert and came out at night. The last bird seen alive was promptly shot dead in 1912. Over 90 years later, a decapitated Night Parrot was found beside a fence in outback Australia, and the hunt for a living bird was on. Ornithologists descended onto the arid plains of Australia’s vast arid interior, but it took another seven years for a single photograph of a live bird. Incredibly, a population of night parrots had survived. Their exact location is kept secret, and people are still looking for more – or more precisely, listening for more, using acoustic traps to identify calls. Dr Ann Jones from ABC Australia takes a huge microphone for a spin in the desert to join the hunt for the legendary Night Parrot. (Photo: Ullala Boss is a Birriliburu Indigenous Ranger, Elder and Traditional Owner and knows the dreaming stories of the Night Parrot. Credit: Dr Ann Jones)

On this mission, SOFIA is setting out to study Titan, Saturn’s biggest moon, by flying into the faint shadow that it casts as it blocks the light from a faraway star. It’s a phenomenon called an occultation, and if the mission succeeds, it will reveal new details about Titan’s atmosphere. SOFIA is a very unusual observatory. It is a 747 aircraft with a hatch in the side, which opens in flight to reveal a large, custom-built telescope – carefully engineered to work inside a moving jet plane. Its full name is the Stratospheric Observatory for Infrared Astronomy, and it’s a joint project of Nasa and the German space agency, DLR. The catch? That shadow is moving across the earth at 22 kilometres per second. Join Dr Jonathan Webb from the ABC in Australia for episode one of The Chase - a special four-part series about science on the run. (Photo: SOFIA is a heavily modified 747SP which was acquired by Nasa in the mid-1990s after spending 20 years as a passenger jet. (Credit: Wayne Williams)

The Six Cornered Snowflake, a booklet written by Johannes Kepler as a New Year's gift, sought to explain the intricate and symmetrical shape of winter's tiny stars of snow. His insightful speculations about minerals and geometry were the beginning of the modern understanding of crystals. Philip Ball tells the story of how Kepler became a key figure in the scientific revolution of the 17th Century. He was a precocious mathematician who became an adviser to Emperor Rudolf II in 1600. Although he contributed to the idea that the sun, not the earth, was the centre of the solar system, his role at the court was to be an astrologer. Philip brings the story of the shape of the snowflakes up to date. It was only 20 years ago with the development of the maths of fractals that we got to understand the formation of the myriad patterns of snowflakes.

2000 years ago Lucretius composed a long poem that theorised about atoms and the natural world. Written in the first century BCE, during a chaotic and frightening time when the Roman Republic was collapsing, Lucretius encouraged people to feel free through contemplating the physics of the Universe. He said that despite living through a time of bloody civil wars and dictatorship people should not believe they were sheep who had to follow those in power. Naomi discovers that the poem is an epic, beautiful and persuasive piece of work. It begins with a discussion of atoms. Lucretius, like Epicurus, followed the Greek tradition in believing that the universe is composed of tiny, indivisible particles. De Rerum Natura asks us to consider that all that really exists in the universe are these atoms and the void between them. Atoms are indestructible, the number of atoms in the universe is infinite and so is the void in which the atoms move. What Lucretius is saying here was revolutionary then – and still has the power to surprise. He’s saying that there are no supernatural forces controlling our lives, no fate pulling the strings, if there are gods they’re made of atoms just like everything else. There is nothing else. Naomi discusses the life of Lucretius and his poem with classicist Dr Emma Woolerton of Durham University. And she talks to particle physicist Professor Jonathan Butterworth of UCL about which of his theories still holds water today. Picture: Gathered sheep, Credit: Chris Strickland, Getty Images