The key to this photograph is the tilted horizon, which exaggerates the feeling of vertigo and adds to the sense of disorientation and suspension that the photo creates.
A key feature of a black hole is its radius. Scientists call this the "event horizon" because it marks the edge beyond which light cannot escape.
其中最关键的一点就是黑洞的半径，科学家称之为“视界”，这个边界的存在决定着光线是否能逃离黑洞。
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They offer me a gold key and lead me to broaden my narrow horizon, enrich my benighted brain and open my closed heart. They will never be mean to help me.