Equation 76 · Part 3 · A Horizon Is a Toll Booth, Not a Loophole
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What this part means
Capital delta attached to a quantity marks a difference between two values of that quantity; the article’s sign convention determines the order.
Its job in the formula
Capital delta attached to a quantity marks a difference between two values of that quantity; the article’s sign convention determines the order.
Full expression→change→Article meaning
The passage around this formula
[ 11 ] . Setting equal to a demanding but realistic dilution-refrigerator base temperature of 10\, and solving for the required clearance gives r2.810^{-14}\, — a few nuclear radii from the horizon. For a supermassive hole, in other words, the ambient Hawking bath stays colder than any laboratory cryostat until the processor is closer to the horizon than an atomic nucleus, twenty-odd orders of magnitude closer than the point at which the support-acceleration bill already becomes unpayable. Cooling is a genuine, non-negotiable line item — it is what ties this construction to horizon thermodynamics at all — but for this mass scale it is not…
Learn the underlying idea
Addition combines quantities; subtraction measures the signed difference between them. Parentheses show what is combined before the rest of the expression is evaluated.
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Sources cited in the surrounding passage
These citations provide research context; check each source for the exact claim it supports.