Why Rainbows Always Appear Opposite the Sun

课文

1. A rainbow forms when sunlight enters a raindrop, bends, reflects off its inner surface, and exits at a specific angle.

   彩虹形成于阳光射入雨滴后发生折射、在内表面反射，再以特定角度射出的过程。

2. This process separates white light into its component colors because each color bends by a slightly different amount.

   这一过程将白光分解为不同颜色，因为每种颜色的折射程度略有差异。

3. Red light exits the drop at about 42 degrees from the original sunlight direction, while violet exits at about 40 degrees.

   红光以约42度角射出雨滴，紫光则约为40度。

4. Since all raindrops at that precise angle relative to your eye and the sun contribute to the arc, you see a circle centered on the antisolar point.

   由于所有与你的眼睛和太阳成该精确角度的雨滴共同构成圆弧，你看到的彩虹是以反日点为中心的圆。

5. That point lies directly opposite the sun — so if the sun is behind you, the rainbow appears ahead.

   反日点正对太阳方向——因此当太阳在你身后时，彩虹就出现在你前方。

6. You can never walk to the end of a rainbow because it moves as you move, always maintaining that 42-degree geometry.

   你永远无法走到彩虹尽头，因为它会随你移动而移动，始终维持约42度的几何关系。

7. From an airplane, under the right conditions, you might even see a full circular rainbow around your shadow.

   在飞机上，若条件合适，你甚至可能看到围绕自己影子的完整圆形彩虹。

8. The brightness and clarity of a rainbow depend heavily on drop size, sunlight intensity, and background contrast.

   彩虹的亮度与清晰度很大程度上取决于雨滴大小、阳光强度及背景对比度。