アメリカ自然史博物館のインスタグラム(amnh) - 7月22日 07時34分

Phobos just photo-bombed Mars. The sharp eye of NASA's Hubble Space Telescope has captured the tiny moon Phobos during its orbital trek around the Red Planet. Because the moon is so small, it appears star-like in the Hubble pictures. Over the course of 22 minutes, Hubble took 13 separate exposures, allowing astronomers to create a time-lapse video showing the diminutive moon's orbital path. The Hubble observations were intended to photograph Mars, and the moon's cameo appearance was a bonus. A football-shaped object just 16.5 miles by 13.5 miles by 11 miles, Phobos is one of the smallest moons in the solar system. It is so tiny that it would fit comfortably inside the Washington, D.C. Beltway. The little moon completes an orbit in just 7 hours and 39 minutes, which is faster than Mars rotates. Rising in the Martian west, it runs three laps around the Red Planet in the course of one Martian day, which is about 24 hours and 40 minutes. It is the only natural satellite in the solar system that circles its planet in a time shorter than the parent planet's day. #phobos #mars #photobombed #amnh #nasa #redplanet #solarsystem #photobomb
Photo: NASA

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