還亮著的光
這一支是核心畫面的字面用法：光真的還在，你看得見。
noun · C1
The light that stays in the sky after the sun has gone down — usually soft orange, pink or purple — in the short time before it gets properly dark.
夕陽餘暉；天邊的餘光
核心畫面
You can picture afterglow as a sky ten minutes after sunset: the sun is already behind the hills, and the orange is still there. The source is gone; the light has not caught up yet. Everything else the word does is that same gap, measured on something else — a cooling wire, or a person on the bus home after a win.
afterglow 可以想成日落十分鐘後的那片天：太陽已經躲到山後面了，橘色還在。來源走了，光還沒跟著走。這個字做的…更多收起
afterglow 可以想成日落十分鐘後的那片天：太陽已經躲到山後面了，橘色還在。來源走了，光還沒跟著走。這個字做的每一件事，都是同一個空隙，只是換個地方量——換成一根正在冷卻的金屬絲，或是贏球之後坐在回程公車上的人。From the word’s history
From after- + glow. The word says its own picture: the glow that comes after.
由 after-（之後）加 glow（發光、暖光）構成。這個字等於把自己的畫面直接寫在臉上：後來還在發的那道光。
Wiktionary etymology supplied in the evidence packet (kaikki:3f6f69a190036ae4:1252047701): From after- + glow.
Two branches
還留著的感覺
把天上的光換成心裡的暖，其他都照抄：來源結束了，東西還在，而且會慢慢散掉。
noun · C1
The warm, happy feeling that stays with you for a while after something good has happened, even though the thing itself is over.
餘韻；還留著的好心情