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Creationism/Evolution Title: Supernova drive evolution? Here we go again, try to prove evolution and coming up with nothing. All this is interesting but really only gives us an idea about timing of supernova in our region and by my reading, any time soon The Earth was bombarded by debris from a series of stellar explosions with the closest supernova occurring about 2.3 million years ago, two new studies indicate. The timing of the showers coincide with major changes in temperature and fauna on Earth, suggesting supernovae may have played a role in the planet's evolution. The studies focus on iron-60, a radioactive isotope that is produced in the dying phase of a star and is ejected into space by the explosion and carried across space embedded in grains of dust. Some [researchers] claim the cosmic rays [from supernovae] could have triggered more cloud formation which would have led to a temperature drop. Dr Anton Wallner of the Australian National University and colleagues analysed iron-60 particles found up to five kilometres deep in the Earth's crust and in sediment on the ocean floor. The team analysed 10 samples taken from the Pacific, Atlantic and Indian oceans — including just off the coast of Perth. Since iron-60 was found in each of the major oceans, it was reasonable to assume a uniform global distribution and therefore ruled out the iron-60 was the result of an impact event, such as by a meteor, he said. Dating of the iron-60 particles, published today in Nature, showed they were from supernovae between 3.2 and 1.7 million years, with evidence also of a supernova about eight million years ago. Dr Wallner and his team, including researchers from Australia, Europe, Japan and Israel, believed the supernovae occurred about 300 light-years from Earth. "It would have been as bright as the full moon so you could see it in daylight, and this would have been very spectacular," Dr Wallner said. The supernovae would have also led to an "enhancement of cosmic rays coming to Earth" by as much as 15 per cent, he added. "Some [researchers] claim the cosmic rays could have triggered more cloud formation which would have led to a temperature drop," he said. This had led to speculation that the supernovae may have played a role in climatic events during the Earth's evolution. Dr Wallner did note the "coincidence" that the older supernova coincided with temperature changes in the late Miocene around 8 million years ago, while the earlier supernovae corresponded with a cooling of the planet as it moved into the Pleistocene period. But he said there was "more work to do" on dating of the iron-60 before any hard conclusions could be drawn. Post Comment Private Reply Ignore Thread |
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