Australasian Science: Australia's authority on science since 1938

Top 10 science stories of 2017

By Joe Milton

2017 has been a bumper year for science yarns, from exploding neutron stars to a crashing spacecraft, and incredible advances in artificial wombs.

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Trump dumped Paris
In June, recently-elected President Donald Trump announced he would pull the US out of the Paris Agreement - the international deal thrashed out in 2016 to tackle man-made global warming. Although not entirely unexpected, the withdrawal was widely criticised in a year which saw 2017 declared one of the hottest years on record, greenhouse gases in the atmosphere reported at record levels, and global emissions from fossil fuels begin to rise again after levelling out for several years. Leaving the agreement will mean the US is the only functioning country that isn’t signed up – even North Korea is on board. However, the withdrawal process takes four years, so the US will remain in the agreement until 4 November 2020, one day after its next presidential election.
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We watched neutron stars explode
In October, physicists and astronomers announced excitedly that for the first time they’d been able to observe the source of gravitational waves - tiny ripples in space time caused by huge celestial events - using visible light, radio waves, x-rays and gamma rays. That meant they could watch events unfold as two super dense neutron stars exploded in spectacular fashion. When detectors first picked up the gravitational waves, a burst of gamma rays in the sky alerted scientists to the location of the source, sending astronomers around the world scurrying for their telescopes, and ushering in a whole new era of astronomy. Australian scientists played key roles, and were the first to detect radio waves from the explosion. Analysing the stars also revealed that distant neutron star explosions are likely to be the source of all the gold, platinum and uranium on Earth.
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Human history got a rewind
In June, the discovery of five ancient Moroccan fossilised skulls revealed that we humans have been around for a whole lot longer than we thought - a whopping 100,000 years longer, in fact. We previously believed humans originated in southern Africa 200,000 years ago, but these newly-unveiled remains - skulls, teeth and bones - show we've actually been around for at least 300,000 years. And the fact that these skulls were unearthed in Morocco hints that Homo sapiens may be even older than that, as we appear to have spread from southern Africa to the north of the continent by then. Australian scientists used a pair of modern dating techniques to pinpoint the time these ancient humans lived.
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A huge iceberg broke free
One of the largest icebergs on record, known as A68, broke away from Antarctica in July, ending years on tenterhooks for polar scientists who had been watching a giant crack in the Larsen C ice shelf grow. The trillion tonne iceberg was more than twice the size of the ACT at at 5,800 square km. The rift has been visible in satellite images since the 1980s, so the breakup was a long time coming, and it is thought to have been a naturally-occurring event, rather than one caused by man-made climate change. However, although global warming probably wasn’t the culprit, Aussie scientists warned that the iceberg’s departure may mean newly exposed glaciers will melt faster, potentially accelerating sea level rises.
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Cassini slammed into Saturn
After 20 long years hurtling through the void of space, 13 of which were spent orbiting Saturn, we bade a fond farewell to the Cassini spacecraft in September. The craft, a collaboration between NASA, the European Space Agency (ESA), and the Italian Space Agency (ASI), was deliberately sent to a fiery end, burning up in Saturn’s atmosphere to avoid contaminating of any of the gas giant’s moons with bacteria of Earth origin. During its mission, Cassini sent back rafts of data on Saturn via CSIRO's team at the Canberra Deep Space Communication Complex, revealing a surprisingly changeable ring system and the birth of a new moon. And it wasn't just Saturn; Cassini also took in Venus, Earth, Jupiter and a passing asteroid en route to the gas giant.
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The first Aussies arrived even earlier
In July, Aussie scientists announced that a treasure trove of Aboriginal artifacts unearthed at a rock shelter called Madjedbebe in NT had revealed that the first Australians arrived here around 65,000 years ago, 5,000 years earlier than we thought. That suggests Indigenous Aussies arrived here before the extinction of the Australian megafauna, the giant animals that once roamed this land. Among the finds were the oldest ground-edge stone axe technology in the world, the oldest known seed-grinding tools in Australia and evidence of stone spear tips. The scientists also found a Tasmanian Tiger jaw painted with red pigment, suggesting that ochre was important in the customs of these ancient first Aussies.
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GM skin saved a little boy's life
In a heart-warming yarn in November, we learned that a seven-year-old Syrian boy had been saved from a potentially lethal skin condition called Junctional Epidermolysis Bullosa (JEB) that gradually eats away at the outer layer of the skin. When he arrived in hospital, the boy had lost around two thirds of his skin and doctors were convinced he would die. But Italian scientists grew him a new skin using cells taken from his own body, which they genetically modified (GM) to remove the disease-causing genes. Then, in a series of operations, they successfully grafted the GM skin to 80 per cent of his body. The great news is that, 21 months after the operations, the boy's new skin is stable and self-healing and he's even able to enjoy a game of football, something that would have been unthinkable before the operations.
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We took aim at killer robots
In August, 116 robotics and artificial intelligence (AI) company bosses signed a letter penned by an Aussie scientist urging the UN to ban lethal autonomous weapons, or killer robots. In it, they warned that robots could lead to war on a scale never before seen, and of the dire consequences should the tech end up in the wrong hands. The letter was similar to one signed by thousands of scientists in 2015, but this was the first time robotics and AI company bosses, including Tesla and SpaceX boss Elon Musk, had thrown their hats into the ring. Their warning came in a year when AI came on leaps and bounds; Google's AlphaGo Zero program taught itself to play the notoriously tricky Chinese game of Go, taking just three days to trump thousands of years of human knowledge, and another AI called DeepStack thrashed human opponents at poker.
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A global sperm count showed a 50% drop in the west
The fact that sperm counts have fallen dramatically in men in the western world has been known for years, but in July scientists confirmed and quantified that drop by analysing all the existing studies of male sperm counts around the world. They found sperm counts in Australia, Europe and North America have dropped by 52.4 per cent in just 40 years. The reasons for plummeting sperm numbers remain mysterious, although the scientists suggest that western men's exposure to modern commercial chemicals could be a factor. Worryingly, they found that dropping sperm numbers aren't stabilising - the decline is ongoing - which could push more men into infertility.
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Artificial wombs offered hope for premmies
In March and again in August, scientists announced that they'd successfully kept premature lambs alive in artificial wombs for much longer than ever before. In the first study, US scientists kept lambs alive for four weeks, and said they developed normally, even opening their eyes and growing wool. In the other, Australian, study, lambs were kept alive for a week. The artificial wombs were essentially plastic bags filled with high-tech amniotic fluid and fitted with artificial placentas and umbilical cords. The technology could be particularly useful for very premature babies whose lungs haven't fully developed when they're born, said the scientists, as it would allow them to continue 'breathing' through amniotic fluid until their lungs are ready to breathe air.

Credit: Australian Science Media Centre