徳赢手机版科学家们预计到2025年将计算出地球内部的燃料量。

Published: Sunday,September 11,2016 - 05:07 inPhysics & Chemistry

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By 2022,徳赢手机版科学家预计,在日本的Kamland五个地下探测器上,每年至少能探测到536次反中微子事件。意大利的Borexino,SNO+ in Canada,and Jinping and JUNO in China.
Ondrej Sramek

Earth requires fuel to drive plate tectonics,volcanoes and its magnetic field.Like a hybrid car,Earth taps two sources of energy to run its engine: primordial energy from assembling the planet and nuclear energy from the heat produced during natural radioactive decay.徳赢手机版Scientists have developed numerous models to predict how much fuel remains inside Earth to drive its engines -- and estimates vary widely -- but the true amount remains unknown.In a new paper,a team of geologists and neutrino physicists boldly claims it will be able to determine by 2025 how much nuclear fuel and radioactive power remain in the Earth's tank.The study,authored by 徳赢手机版scientists from the University of Maryland,Charles University in Prague and the Chinese Academy of Geological Sciences,was published on September 9,2016,在《自然》杂志上科学报告.

该研究的作者之一威廉·麦克多诺说:“我徳赢手机版是那些创造了地球组成模型并预测了地球内部燃料数量的科学家之一。马里兰大学地质学教授。"We're in a field of guesses.At this point in my career,我不管我是对是错,I just want to know the answer."

To calculate the amount of fuel inside Earth by 2025,the researchers will rely on detecting some of the tiniest subatomic particles known to science -- geoneutrinos.These antineutrino particles are byproducts of nuclear reactions within stars (including our sun),超新星,黑洞和人造核反应堆。They also result from radioactive decay processes deep within the Earth.

Detecting antineutrinos requires a huge detector the size of a small office building,housed vwin徳赢app下载about a mile underground to shield it from cosmic rays that could yield false positive results.Inside the detector,徳赢手机版scientists detect antineutrinos when they crash into a hydrogen atom.The collision produces two characteristic light flashes that unequivocally announce the event.The number of events 徳赢手机版scientists detect relates directly to the number of atoms of uranium and thorium inside the Earth.And the decay of these elements,along with potassium,地球内部的绝大多数热量都来自于燃料。

到目前为止,detecting antineutrinos has been painfully slow,with 徳赢手机版scientists recording vwin徳赢app下载only about 16 events per year from the underground detectors KamLAND in Japan and Borexino in Italy.However,researchers predict that three new detectors expected to come online by 2022--the SNO+ detector in Canada and the Jinping and JUNO detectors in China--will add 520 more events per year to the data stream.

“一旦我们收集了五个探测器三年的反中微子数据,we are confident that we will have developed an accurate fuel gauge for the Earth and be able to calculate the amount of remaining fuel inside Earth," said McDonough.

The new Jinping detector,which will be buried under the slopes of the Himalayas,will be four times bigger than existing detectors.位于中国南部海岸附近的地下朱诺探测器将比现有探测器大20倍。

"Knowing exactly how much radioactive power there is in the Earth will tell us vwin徳赢app下载about Earth's consumption rate in the past and its future fuel budget," said McDonough."By showing how fast the planet has cooled down since its birth,we can estimate how long this fuel will last."

Source:University of Maryland

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