Heliocentrism
From RationalWiki
Heliocentrism, or the theory that the Earth revolves around the sun, replaced geocentrism as the prevailing astronomical paradigm despite Christian threats of torture against its proponents such as Galileo.
One century after Galileo, Kepler's observations and Newton's calculations demonstrated that heliocentrism is correct, and also showed that Earth does not revolves around Sun following a circle, but an ellipse (the Sun is one of the two focuses of the ellipse, not the center). Of course if one needs even more precision, the focus is not the center of the Sun but the barycenter of the Solar System, and the trajectory is not an ellipse but a more complicated movement influenced by other planets; actually the difference is negligible, and to be fair, Earth's influence over Sun's movement is negligible compared to the Sun's one.
Now we also know that this barycenter orbits the Milky Way Galaxy in about 200 million years. This movement is negligible in calculating orbits in the Solar System, because relativity proved that accelerations are absolute, but constant linear speed has no effect. The movement is circular, but the circle is so large it looks like a linear movement.
And if you really want to get technical. the Milky Way, together with the Andromeda Galaxy and an assortment of smaller galaxies in the "Local Group", orbit a common barycenter with a large number of other galaxies concentrated in the Vega Supercluster about 35 million light-years away.
If that's not good enough for you, there is dipole anisotropy in the Cosmic Microwave Background Radiation which equates to a motion of 368 km/sec in the general direction of the constellation Leo, which is the sum of the motions of the sun, the galaxy, the Local Group, and the Vega Supercluster. If you launch a spacecraft in the opposite direction at that velocity, it will be at rest relative to the universe taken as a whole.
Heliocentrism was recently decried as an "Atheist Doctrine" by Blogs 4 Brownback blogger Sisyphus.
