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Showing content with the highest reputation on 03/08/24 in all areas

  1. https://www.rte.ie/news/2024/0308/1436684-trees-climate/ "The Tiny Forest concept was pioneered by a Japanese botanist, Akira Miyawaki. He pioneered a special method of planting and ground preparation that can be used to grow forests ten times faster than a typical forest (which usually takes 200 to 300 years" "Usually up to five saplings are planted for every square metre and as a result, the trees are forced to grow upwards for sunlight instead of spreading outwards"
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  2. Really? Bold by me. If a 'scientific article' cites Deepak Chopra as serious witness, then it is not serious scientific article. Maybe you should read Susan Blackmore: in her student days she had an OBE, and she started a career as 'believing' parapsychologist. But her serious empirical investigations turned her into the end being a sceptic, and leaving the field of parapsychology. I can highly recommend Dying to Live: Science and the Near-death Experience and The Adventures of a Parapsychologist. From the Wikipedia article:
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  3. [math]a^\mu = -c^2 g^{\mu\nu} \dfrac{1}{T} \dfrac{\partial T}{\partial x^\nu}[/math] For a stationary object in the Schwarzschild metric: [math]ds^2 = \left(1 - \dfrac{2GM}{c^2r}\right) c^2 (dt)^2 - \left(1 - \dfrac{2GM}{c^2r}\right)^{-1} (dr)^2 - r^2 \Bigl((d\theta)^2 + sin^2\theta (d\phi)^2\Bigr)[/math] [math]g_{tt} = \left(1 - \dfrac{2GM}{c^2r}\right) c^2[/math] [math]g_{rr} = -\left(1 - \dfrac{2GM}{c^2r}\right)^{-1}[/math] [math]a^r = -c^2 g^{rr} \dfrac{1}{\sqrt{g_{tt}}} \dfrac{d\sqrt{g_{tt}}}{dr}[/math] [math]a^r = -\dfrac{c^2}{2} \dfrac{1}{g_{rr}\ g_{tt}} \dfrac{dg_{tt}}{dr}[/math] [math]a^r = \dfrac{1}{2}\dfrac{dg_{tt}}{dr}[/math] [math]a^r = \dfrac{1}{2}\dfrac{d\left(c^2 - \dfrac{2GM}{r}\right)}{dr}[/math] [math]a^r = \dfrac{GM}{r^2}[/math] One might be surprised to see that the acceleration of a stationary object in the Schwarzschild metric is exactly Newtonian. But this is due to way the [math]r[/math]-coordinate is defined. The [math]r[/math]-coordinate is defined such that the surface area of a sphere of radius [math]r[/math] is [math]4 \pi r^2[/math]. Thus, for the acceleration field to be a conserved field, the surface integral of this field over the sphere needs to be constant with respect to the [math]r[/math]-coordinate, requiring that the acceleration field obey an [math]r^{-2}[/math] law exactly.
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  4. Liver I think symmetry and simple patterns are part of the deal. That would be my guess anyway. I understand we're just guessing...
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