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Dimensional Analysis and Black Holes (2019) [pdf]

63 点作者 segfaultbuserr超过 1 年前

3 条评论

sieste超过 1 年前
The "let's assume the result is proportional to a product of powers" ansatz always threw me off a bit. Why not additive, or including some function of the independent variables? Is there a better justification than "it often gives the correct result?"
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jvanderbot超过 1 年前
&gt; We assume the hole is small compared to the size of the earth, and the package light compared to the mass of the earth, so we can neglect h and m.<p>If you&#x27;re going to write a paper that builds intuition, you should write one on this problem. Physicists always make magical simplifying assumptions that drive me absolutely bananas. And wow! Things get so much simpler but are still correct to an order of magnitude.<p>The same thing they do when gathering &#x2F; discarding possible factors.<p>I actually suspect this is revisionist. Most folks would probably start with various factors &#x2F; powers and guess-and-check until some of those factors have zero power and the dimensions work out.<p>Relevant XKCD: <a href="https:&#x2F;&#x2F;www.explainxkcd.com&#x2F;wiki&#x2F;index.php&#x2F;793:_Physicists" rel="nofollow">https:&#x2F;&#x2F;www.explainxkcd.com&#x2F;wiki&#x2F;index.php&#x2F;793:_Physicists</a>
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jvanderbot超过 1 年前
&gt; It turns out you can take an arbitrary shape and split it into tiny rectangles<p>Citation needed?
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