Astronaut Sergey Kud-Sverchkov captured from ISS the Moon over Earth. The main part of Earth’s atmosphere is due to stratosphere which extends to 50km. From the image the atmosphere looks thick but it only accounts for 0.8% of the Earth’s radius 6,371km.

Credit: Sergey Kud-Sverchkov, Roscosmos

Reference: Sergey Kud-Sverchkov’s Tweet
See earthview photo gallery: LiVEARTH