Motion is never absolute; it is always measured relative to a specific frame of reference. When a person sits still, they are only at rest relative to the Earth’s surface, which is in constant motion. There is no single point of absolute stillness in the universe from which all other speeds can be measured. The total velocity of any object is a combination of multiple, layered movements, each building upon the last as the frame of reference expands from the planet to the deepest cosmos.
The Speed of Earth’s Spin
The most immediate motion we experience is the Earth’s rotation on its axis, a speed that varies significantly depending on one’s location. At the equator, the planet must cover its largest circumference in the 24 hours it takes to complete one rotation, resulting in the fastest speed of approximately 1,000 miles per hour, or 1,600 kilometers per hour. This rotational speed steadily decreases as one travels toward the poles, where the speed drops to nearly zero.
People do not feel this speed because of the principle of inertia. Inertia dictates that an object in motion stays in motion unless acted upon by an external force. Everything on the planet, including the atmosphere, is moving at the same constant speed, so there is no relative difference to detect. This smooth, non-accelerating motion goes entirely unnoticed in our daily lives.
The Speed of Our Orbit Around the Sun
The next layer of motion involves the Earth’s revolution around the Sun, which carries us at an average velocity of roughly 67,000 miles per hour, or 107,000 kilometers per hour. The Earth’s path is not a perfect circle but an ellipse, which means our orbital speed is not entirely constant throughout the year. The slight variation is dictated by Kepler’s Second Law of Planetary Motion, where a planet must sweep out equal areas in equal times.
This law means the planet moves fastest when it is closest to the Sun at perihelion, and slowest when it is farthest away at aphelion. At perihelion, which occurs around January, Earth’s speed increases to approximately 30.3 kilometers per second. Conversely, at aphelion in July, the speed slows slightly to about 29.3 kilometers per second. This maintains the necessary balance for a stable orbit around our star.
The Speed of Our Solar System’s Galactic Journey
Expanding the frame of reference further, the entire Solar System, including the Sun, Earth, and all other celestial bodies, is moving through the Milky Way Galaxy. Our Sun is located in one of the galaxy’s minor arms, known as the Orion Spur, and is orbiting the supermassive black hole at the galactic center. This colossal orbit carries the Solar System at a speed of approximately 515,000 miles per hour, or 828,000 kilometers per hour.
Despite this velocity, the sheer size of the Milky Way means that one full revolution takes an estimated 230 million years to complete. The solar system is not simply moving on a flat plane; it also oscillates up and down relative to the galactic plane. This complex, corkscrew-like motion ensures that the Solar System never returns to the exact same point in space it occupied previously.
The Speed of the Milky Way Through the Cosmos
The final and fastest layer of motion is the movement of the entire Milky Way Galaxy as it drifts through the cosmos relative to other structures. Our galaxy is part of a cluster known as the Local Group, and this entire collection is being gravitationally influenced by massive, distant structures. By measuring the slight temperature variations in the Cosmic Microwave Background (CMB)—the residual radiation from the Big Bang—scientists can calculate our galaxy’s velocity.
The Milky Way’s speed relative to this cosmic background is estimated to be over 1.3 million miles per hour, or about 630 kilometers per second. This motion is directed toward a massive, distant gravitational anomaly called the Great Attractor. This structure is a large, localized concentration of mass that is pulling the entire Local Group of galaxies toward it. This immense cosmic drift represents the ultimate, compounded speed of every person on Earth through the universe.