Apr 3, 2020 10:18 PM
Conifer is top tree in urban sound absorption test
https://www.bbc.com/news/science-environment-52139333
INTRO: The larch was found to be the most effective tree when it comes to absorbing noise with its bark. The conifer was the most effective out of 13 tree species in a laboratory-based sound absorption test. The researchers say the findings can help urban planners use trees for noise control. The results have been published in the Applied Acoustics journal. The study assessed 76 samples from 13 tree species that displayed a variety of different bark characteristics... (MORE)
https://www.youtube-nocookie.com/embed/mBcTXBhYzfM
Carbon-14 Spiked Worldwide Over 1200 Years Ago, And The Sun Is To Blame
https://www.forbes.com/sites/startswitha...a30a0a3e81
EXCERPT: . . . As far as we can tell, the levels of carbon-14 remained roughly constant throughout the world throughout the past few millennia. The only known fluctuation in this pattern, at least as of the early 2010s, was from the detonation of nuclear weapons in the open air. And yet, in 2012, we got a scientific shock: in approximately the year 774/775, two independent cedar trees in Japan were analyzed for carbon-14 in their rings, and saw a tremendous spike that was some 20 times larger than natural variations could explain.
The only natural explanation that makes any sense is if, right around that time, Earth experienced an excessive bombardment of these cosmic rays, creating a spike in the amount of carbon-14 that gets created. Even though it's a small excess in absolute terms — just 1.2% more carbon-14 than normal — it's far above any natural variation that we've ever seen.
Moreover, it's a spike that's subsequently been confirmed to exist in tree rings around the world, from Germany to Russia to New Zealand to the United States. The results agree across countries, and could be explained by anything from increased solar activity to a cosmic flare to a direct hit from a distant gamma-ray burst. But the carbon-14 evidence has subsequently been joined by a few other historical and scientific peculiarities, and with the latter enabling us to solve the mystery.
Historically, a "red crucifix in the heavens" was recorded in the Anglo-Saxon Chronicle of 774, which could correspond to either a supernova (no remnant has ever been found) or to an auroral event. In China, an anomalous "thunderstorm" was recorded in 775, so notable that it was the only such event recorded.
But scientifically, the tree-ring data has been joined by ice core data from Antarctica. While the tree-rings show a spike in carbon-14 in 774/775, the ice core data shows a corresponding spike in radioactive beryllium-10 and chlorine-36, which suggest an association with a strong, energetic event of solar particles. An event such as this would have perhaps been on par with the now-famous Carrington event of 1859, which is the largest recorded solar storm in recent history, with the historical data remaining consistent with this explanation as well.
Two other events have subsequently been unearthed that could show similar spikes in these isotopes: a slightly weaker outburst in 993/4 and an even earlier one dating back to ~660 BCE. The combined data from all three events point to a common origin that necessarily involves a large flux of protons in a specific energy range.
This is consistent with a relatively common event seen in the Sun: the ejection of solar protons. However, it's not consistent with the gamma-ray burst scenario, which cannot produce the necessary proton flux to explain the beryllium-10 simultaneously. [...] Every so often, the Sun does eject energetic particles right in the direction of Earth. ... We now know there are a variety of solar events that impact Earth, and that the largest-magnitude events we've experienced occur more than once-per-millennium. (MORE - details)
https://www.bbc.com/news/science-environment-52139333
INTRO: The larch was found to be the most effective tree when it comes to absorbing noise with its bark. The conifer was the most effective out of 13 tree species in a laboratory-based sound absorption test. The researchers say the findings can help urban planners use trees for noise control. The results have been published in the Applied Acoustics journal. The study assessed 76 samples from 13 tree species that displayed a variety of different bark characteristics... (MORE)
Carbon-14 Spiked Worldwide Over 1200 Years Ago, And The Sun Is To Blame
https://www.forbes.com/sites/startswitha...a30a0a3e81
EXCERPT: . . . As far as we can tell, the levels of carbon-14 remained roughly constant throughout the world throughout the past few millennia. The only known fluctuation in this pattern, at least as of the early 2010s, was from the detonation of nuclear weapons in the open air. And yet, in 2012, we got a scientific shock: in approximately the year 774/775, two independent cedar trees in Japan were analyzed for carbon-14 in their rings, and saw a tremendous spike that was some 20 times larger than natural variations could explain.
The only natural explanation that makes any sense is if, right around that time, Earth experienced an excessive bombardment of these cosmic rays, creating a spike in the amount of carbon-14 that gets created. Even though it's a small excess in absolute terms — just 1.2% more carbon-14 than normal — it's far above any natural variation that we've ever seen.
Moreover, it's a spike that's subsequently been confirmed to exist in tree rings around the world, from Germany to Russia to New Zealand to the United States. The results agree across countries, and could be explained by anything from increased solar activity to a cosmic flare to a direct hit from a distant gamma-ray burst. But the carbon-14 evidence has subsequently been joined by a few other historical and scientific peculiarities, and with the latter enabling us to solve the mystery.
Historically, a "red crucifix in the heavens" was recorded in the Anglo-Saxon Chronicle of 774, which could correspond to either a supernova (no remnant has ever been found) or to an auroral event. In China, an anomalous "thunderstorm" was recorded in 775, so notable that it was the only such event recorded.
But scientifically, the tree-ring data has been joined by ice core data from Antarctica. While the tree-rings show a spike in carbon-14 in 774/775, the ice core data shows a corresponding spike in radioactive beryllium-10 and chlorine-36, which suggest an association with a strong, energetic event of solar particles. An event such as this would have perhaps been on par with the now-famous Carrington event of 1859, which is the largest recorded solar storm in recent history, with the historical data remaining consistent with this explanation as well.
Two other events have subsequently been unearthed that could show similar spikes in these isotopes: a slightly weaker outburst in 993/4 and an even earlier one dating back to ~660 BCE. The combined data from all three events point to a common origin that necessarily involves a large flux of protons in a specific energy range.
This is consistent with a relatively common event seen in the Sun: the ejection of solar protons. However, it's not consistent with the gamma-ray burst scenario, which cannot produce the necessary proton flux to explain the beryllium-10 simultaneously. [...] Every so often, the Sun does eject energetic particles right in the direction of Earth. ... We now know there are a variety of solar events that impact Earth, and that the largest-magnitude events we've experienced occur more than once-per-millennium. (MORE - details)