On this date in 1877, American astronomer Asaph Hall discovered Phobos, the larger of Mars' 2 moons. He discovered the other moon, Deimos, later that year.
Crepuscular rays form around twilight when particles in the atmosphere reflect the sun's light beams toward our eyes. See photos of the phenomenon here.
The New Horizons spacecraft saw a heart-shaped feature on Pluto during its 2015 flyby. New computer simulations suggest an impact created Pluto's heart.
Polaris marks the end of the handle of the Little Dipper. The 2 outer stars in the bowl of the Big Dipper point to Polaris and help you find the Little Dipper.
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