Italian astronomer Giovanni Donati became the first person to observe the spectrum of a comet.
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A powerful meteor exploded over the Bering Sea.
Astronomer Edwin Hubble formally announced the existence of other galactic systems at a meeting of the American Astronomical Society.
Jupiter's moon was found to have a liquid ocean under a thick crust of ice.
American Astronomer William Henry Pickering discovered Phoebe, one of Saturn's moons.
The USA's first space station, Skylab, was launched into Earth's orbit.
