“How fast?” means “What is our velocity?” Velocity is a speed combined with a direction. We can figure out our speed and our direction on the Earth by looking at these 6 motions and directions…
But, before you read these, try to think of the 6 different motions that the Earth has.
Just putting some space in here to give you time to think about the Quiz.
- Rotation of Earth (cycle) – 0.5 km/sec
- Orbit around Sun (cycle) – 30 km/sec
- Solar System through Galaxy (cycle) – 200 km/sec
- Milky Way Galaxy moving toward Andromeda within the Local Group (non-cyclical toward Andromeda)- 109 km/sec
- Local Group motion inside Virgo Supercluster (non-cyclical toward “overdense” regions) – 300 km/sec
- Cosmic Void repulsion (non-cyclical) – 600 km/sec
Earth’s Overall motion = 368 km/sec +/- 30 km/sec depending on season
Our overall direction of motion? The Cosmic Microwave Background (CMB) tells us generally which direction we are moving in: towards the “overdense” regions of the Cosmic Void.
Thanks for Ethan Seigel for gathering all the relevant data points for this quiz.