WeatherTalk: Earth is not flat, but it is smooth
From the top of Mt. Everest to the bottom of the Mariana Trench is only 12.3 miles.
FARGO — To drive across the plains of northern North Dakota to the Turtle Mountains is an amazing sight. Suddenly, the land rises around 400 feet, and the flora and fauna change with the altitude increase. In western South Dakota, the Black Hills suddenly rise 3,000 feet above the plains, and shortgrass gives way to ponderosa pines. West of Denver, the Palmer Divide is a sudden rise of up to 8,000 feet above the high plains of Colorado.
However, it is significant to note that the change in elevation from the top of Mt. Everest, at 29,029 feet above sea level, to the bottom of the Challenger Deep in the Mariana Trench, 36,070 feet below sea level, in the Pacific Ocean is only 12.3 miles. When compared to Earth's average diameter of 7,918 miles, the elevation change on the surface amounts to 0.15% of the planet's diameter. From space, the surface of the Earth looks as smooth as a billiard ball.