Dutch astronomer Johannes Fabricius discovered sunspots.
Sunspots are regions of reduced surface temperature on the sun.
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The Japanese Space Agency sent two robots to explore an asteroid aboard their Hayabusa-2 spacecraft.
Project Starshot was announced by Yuri Milner, Stephen Hawking, and Mark Zuckerberg.
Charles Messier discovered the Whirlpool Galaxy.
The USSR's Luna 15 robotic spacecraft was launched from the Baikonur Cosmodrome in Kazakhstan.
Voyager 1 passed Pioneer 10 to become the most distant human-made object in space.