The Parker Solar Probe was launched by NASA, heading for the Sun.
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A solar flare from the sun created a geomagnetic storm, which caused Toronto's stock market to halt.
Using Johannes Kepler's predictions, French scientist Pierre Gassendi became the first person to witness Mercury's transit between the Earth and the Sun.
A conjunction of Sun, Mercury, Venus, Mars, Jupiter, Saturn, and the Moon occurred.
Physicists in New Zealand observed a record-breaking solar flair.
Dutch astronomer Johannes Fabricius discovered sunspots.
