This is a great little piece about the history of horology, the science of measuring time. We learn all kinds of funky tidbits about how calendars have had to be rectified and how the Pope caused Catholics to lose a week of “time” in the 1500s, with the implementation of the Gregorian calendar (eventually adopted by the English in the 1700s).
It also points out how orbits change speeds and how our axial tilt causes drag. These cycles, along with fluctuations in lunisolar forces are part of the Milankovitch effects, which are theorized to be connected to the planetary recurring Ice Ages.
Although you may be sitting relatively motionless as you read this, the Earth and all of the systems of which it is a part are moving at a neck-breaking speed of 853 km/second, if I did my math right.
Looking from above the North Pole, the Equator spins counterclockwise at about 1,617 kilometers per hour.
Relative to the Sun, Earth orbits counterclockwise at 108,000 kilometers per hour along a path, tilted at 23.4 degrees, to its spin.
Within our local neighborhood of stars, our entire Solar System is drifting 70,000 kilometers per hour, roughly in the direction of the bright star Vega, in the constellation of Lyra within our galaxy, the Milky Way.
On a plane tilted about 60 degrees, looking from above Earth’s North Pole, our entire Solar System races clockwise around the Galactic Center of the Milky Way, at about 792,000 kilometers per hour.
Our whole Galaxy is also moving through the Universe, riding along in the Milky Way, in the direction of the constellations of Leo and Burgo, at a speed of 2.1 million kilometers per hour, towards the Great Attractor, a gravitational anomaly in what’s supposed to be an expanding universe, because it’s doing the opposite, by drawing 10,000 galaxies together, including ours.
All of the above movements are relative to a structure. Earth’s motion around the Sun was described relative to the Sun. The motion of our local group of galaxies was described relative to the Great Attractor, which is itself, rushing toward the Shapley Supercluster.
The 2.1 million kph speed was arrived at by the Cosmic Background Explorer (COBE) satellite, launched in 1989, which is thought to measure the cosmic microwave background radiation (CBR) left over from the Big Bang.
COBE discovered that the Milky Way and neighboring galaxies are moving with respect to this CBR with a well-defined speed and direction and because the CBR is believed to permeate all space, it can be used as the frame of reference to describe the speed of our galaxy, which could also be described as 550 kilometers per second or 1.2 million mph.
A simple addition of all of the above combined movements equals 3,071,617 kilometers per hour, or 51,194 km/second.