- A black hole is a region of spacetime where gravity is so strong that nothing, including light or other electromagnetic waves, has enough energy to escape it. The theory of general relativity predicts that a sufficiently compact mass can deform spacetime to form a black hole. The boundary of no escape is called the event horizon. Although it has a great effect on the fate and circumstances of an object crossing it, it has no locally detectable features according to general relativity. In many ways, a black hole acts like an ideal black body, as it reflects no light. Moreover, quantum field theory in curved spacetime predicts that event horizons emit Hawking radiation, with the same spectrum as a black body of a temperature inversely proportional to its mass. This temperature is of the order of billionths of a kelvin for stellar black holes, making it essentially impossible to observe directly.
- Seattle Neighborhoods: Maple Leaf — Thumbnail History (historylink.org)
Although Seattle’s Maple Leaf neighborhood appeared in the 1890s as a dream of real estate developers, the hilltop community northeast of Green Lake was slow to grow. The last half of the twentieth century saw dramatic changes to the area, but Maple Leaf remained a stable home to middle-class families. The residents were late to organize themselves politically, but their patient and focused persistence soon gained nationwide recognition.