Index.of Jpg Metart Jenny Receding A Distant Ship Smoke On The Horizon?

Receding a distant ship smoke on the horizon? - index.of jpg metart jenny

Because the earth is round, there is no observable horizon.
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As the pressure of the atmosphere should appear flat on the surface of the earth and disappear on the horizon?

Refractive index of standard air at sea level
n = 1.00029