1610-01-07 astronomical discovery

Galileo begins observations of Jupiter’s moons

Category: Discoveries and Scientific Results › Type: Discovery

Galileo observed points of light near Jupiter that subsequent observations established as orbiting moons.

1610-04-19 astronomy theory

Kepler suggests a solar influence on comet tails

In a letter to Galileo, Kepler proposed that a solar breeze pushes comet tails away from the Sun.

1613 CE Year only solar science

Galileo publishes Letters on Sunspots

Galileo argued that sunspots are features of the Sun rather than bodies passing in front of it.

1619 CE Year only astronomy theory

Kepler’s third planetary law published

Kepler related a planet’s orbital period to the size of its orbit.