Stars, soil and whakapapa - 'We're just caretakers really'
This Matariki, the stars align for Mark and Susannah Guscott - award winners bringing whakapapa and astronomy together on their sixth-generation Wairarapa farm.
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RNZ News
5 hours ago
- RNZ News
Astronomers get first look deep inside a star during supernova explosion
By Ellen Phiddian , ABC An artist's interpretation of supernova 2021yfj. Photo: Supplied: Keck Observatory/Adam Makarenko) Astronomers have peered directly at a star's inner layers for the first time, thanks to a stellar explosion 2.2 billion light-years away. The star was stripped of its outer shells, revealing its dense innards to the Keck Observatory in Hawaii just after it exploded in a cataclysmic blast. The star's demise, reported in the journal Nature , also confirms current theories about stellar evolution. Study lead author and Northwestern University astronomer Steve Schulze said their team was "awestruck" by the discovery, but there's plenty still to uncover about the supernova dubbed 2021yfj. "A lot of work remains to be done to fully understand supernova 2021yfj and its implications for the evolution and fate of massive stars." Stars burn for billions of years, but their deaths can be very abrupt, with supernova explosions over in a matter of hours. Despite detecting thousands of supernovas, their brevity makes it difficult for astronomers to study them in detail. Generally, stars burn by converting hydrogen into progressively heavier elements via nuclear fusion. When massive stars run out of hydrogen, they collapse in on themselves, producing a violent supernova explosion. But before the explosion, astronomers believe a star's heavier elements settle into onion-like layers, with the heaviest - iron - at the core of the biggest stars. Supernovas only happen in stars at least eight times the mass of our Sun, where there's enough pressure to form an iron core - too much iron triggers the explosion. Photo: NASA: NASA/CXC/SAO/JPL-Caltech That iron core is surrounded by layers of lighter elements such as argon, sulphur and silicon, which are in turn surrounded by elements that are lighter still, such as oxygen and carbon. Helium and hydrogen form the outermost layers, or the skin of the onion. Until now, Dr Schulze said, it was nearly impossible to see any of these deeper layers directly. "The silicon- and sulphur-rich layer is buried under many other materials and is therefore inaccessible [by telescopes] under normal circumstances." The astronomers were able to see the true weirdness of 2021yfj because they took advantage of a lucky cosmic moment. In September 2021, a survey of the night sky by the Zwicky Transient Facility in California spotted a bright flash in a star-forming region some 2.2 billion light-years from Earth. Dr Schulze and their team raced to see if any observatories could collect a spectrum - a record of light from the explosion showing elements present - shortly after the supernova happened. The Keck Observatory managed to provide one within a day of the explosion. But rather than seeing the relatively light element shells usually present in a supernova, such as carbon, nitrogen and oxygen, the spectrum was full of heavier elements: silicon, sulphur, and argon. This means that something pulled those upper layers off the star before it exploded, exposing the layers closer to the core. Brad Tucker, an astronomer at the Australian National University who wasn't involved in the research, said this find was an "important confirmation" of stellar structure. "We've always modelled it this way. We've had evidence from our understanding of nuclear physics. "This is that fundamental evidence that proves that model, and that view, is right." The researchers don't know exactly what removed so many outer layers of the star before the supernova. The most likely theory, they suggest, is a massive star more than 100 times the mass of our Sun fired its outer material off in waves right before exploding. Dr Schulze said this behaviour had been seen with a few other stars - although only with their lighter upper hydrogen and helium layers, not the heavier elements below. Dr Tucker agreed this was a likely explanation, and that a star ejecting its lower layers prior to explosion was "the next logical step" after venting the lighter elements. But there are still puzzles in the data. The researchers also found small amounts of helium in the star's debris, for instance, which they don't yet have a good explanation for. Dr Schulze said the supernova they observed was "only one among the more than 10,000 supernovas known, making it a very rare event". Nevertheless, they're confident that astronomers will be able to observe another partially denuded star exploding and learn more about the strange phenomenon. "We are detecting supernovas at an ever-increasing rate due to advances in monitoring the night sky," Dr Schulze said. New facilities, like the Rubin Observatory in Chile, allow astronomers to see supernovas in much greater number, according to Dr Tucker. "We now have surveys that are getting hundreds to thousands of supernovas a year, whereas previously we'd get dozens to maybe 100," he said. - ABC
RNZ News
12 hours ago
- RNZ News
Solar solution for schools
An energy analyst says solar panels on school buildings could rapidly increase electricity supply and slash CO2 emissions for schools. Analyst Peter Bisley modelled what it would take to get solar panels on all schools - where an estimated 16 per cent of the population are most days of the week. He found the panels - taking 5 per cent of available roof space at all schools - would have a capacity of 108 MW, the amount consumed by about 20-thousand houses. And he says the fact that schools' highest demand for energy is during the day, it would be the perfect fit. Schools in New Zealand are encouraged to install solar, but only after energy efficiency improvements like LED lighting or better insulation are done. Peter and his brother William Bisley have sent their modelling to the Ministers of Education and Energy, in the hope their idea will be taken up. Solar panels on a roof. Photo: Fabian Rieger / 123RF
RNZ News
15 hours ago
- RNZ News
Scientists studying deep-sea ecosystem recovery from Tonga eruption
Photo: Supplied / Shane Cronin, University of Auckland A team of scientists from the University of Tasmania is doing research on the Hunga Tonga-Hunga Ha'apai volcano. The 2022 eruption has been the subject of several scientific studies . The 54-day voyage brings together 40 researchers and technical staff from Australia, Tonga, Fiji, New Zealand, the UK, and the US. Voyage chief scientist Rebecca Carey said the "ground zero" underwater scene produced by the eruption offered a unique opportunity to study the recovery of deep-sea ecosystems. The researchers will map the seafloor and sub-seafloor, extract sediment cores, conduct marine life surveys and explore environmental DNA in seawater. Carey said this research will help build resilience and preparedness in the region for future volcanic events. "This volcano is just one of hundreds of shallow submarine volcanoes scattered across the southwest Pacific, whose eruption risks remain poorly understood," she said. "We are aiming to generate data products that support hazard assessments, inform risk models and guide recovery planning, by informing where vital new under-sea communications infrastructure should be installed to provide a back-up option in the event of future cable breaks." The eruption also triggered a tsunami which killed three people and left thousands homeless . This research, done in collaboration with the Tonga Geological Services and other Australian and international partners, is supported by a grant of sea time on ther vessel RV Investigator from Australia's Marine National Facility.
