Is 918 microns as long as The Circumfrence of Earth?
It's about 0.00000000003 times as long as The Circumfrence of Earth
The length of The Circumfrence of Earth is about 40,075,014,000,000 microns.
(Equatorial)
The Earth — not a perfect sphere, but rather an oblate spheroid with bulged middle — has an Equatorial circumference of approximately 40,075,014,000,000 microns. The first airplane trip around the circumference of the Earth (with a few stops along the way), was completed in 1924 by the United States Army Air Service, and took 175 days.
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