The Earth is in perpetual motion through space. While it may feel as though we are standing still, our planet engages in a complex array of movements.
The Illusion of a Still Earth
For much of human history, the prevailing view placed Earth as the unmoving center of the universe. This geocentric model suggested that the Sun, Moon, and all other celestial bodies revolved around Earth. This belief arose from everyday observations, where the Sun appeared to traverse the sky and stars seemed to rotate around us each night. People concluded that if they did not feel any movement, Earth must be still.
This perspective was reinforced by the lack of perceptible motion, which made the idea of a stationary Earth seem logical. Early thinkers, including Aristotle, contributed to this view that Earth was at rest, with celestial objects attached to spheres that rotated around it. The absence of any sensation of movement meant the geocentric model remained unchallenged for centuries.
From Earth-Centered to Sun-Centered
A significant shift occurred with Nicolaus Copernicus, who proposed a heliocentric theory in 1543, placing the Sun at the center of the universe with Earth and other planets orbiting it. Copernicus’s model suggested Earth had multiple motions, including a daily rotation on its axis and an annual revolution around the Sun. This challenged the established geocentric view.
Later, Galileo Galilei’s observations with a telescope provided compelling evidence supporting the heliocentric model. He observed Jupiter’s moons orbiting Jupiter, demonstrating that not all celestial bodies revolved around Earth. Furthermore, Galileo’s discovery of the phases of Venus, similar to the Moon’s, proved that Venus orbits the Sun, not Earth.
Johannes Kepler refined the understanding of planetary motion by formulating his laws in the early 17th century. Kepler showed that planets move in elliptical orbits, not perfect circles, with the Sun at one focus. His laws also revealed that a planet’s speed varies during its orbit, moving faster when closer to the Sun. These discoveries provided a precise mathematical framework for the heliocentric system.
Our Planet’s Constant Journey
Earth is constantly in motion. Our planet spins on its axis, completing one rotation approximately every 24 hours, which causes day and night. At the equator, this rotational speed is about 1,670 kilometers per hour (1,037 miles per hour).
In addition to its rotation, Earth revolves around the Sun. This takes approximately 365 days to complete, defining our year and contributing to the changing seasons. Earth’s average speed as it orbits the Sun is about 107,000 kilometers per hour (67,000 miles per hour).
The Sun, along with our entire solar system, is also in motion, orbiting the center of the Milky Way galaxy. This galactic orbit occurs at a speed of around 828,000 kilometers per hour (514,495 miles per hour). It takes our solar system approximately 230 million years to complete one full orbit around the galactic center. The Milky Way galaxy itself is not stationary, moving through space at about 2.1 million kilometers per hour (1.3 million miles per hour).
Understanding the Lack of Sensation
Despite these speeds, we do not feel Earth’s constant motion due to a concept known as inertia. Objects in constant motion tend to stay in constant motion unless an external force acts upon them. Since Earth’s rotation and revolution are smooth and consistent, we, along with everything on the planet, are moving at the same constant speed.
This phenomenon is similar to being on a smoothly moving train or airplane; you do not feel the speed unless the vehicle accelerates, decelerates, or changes direction. Our bodies, the atmosphere, and all objects around us are all moving together at the same velocity as Earth. Therefore, there is no relative motion for us to perceive, creating the sensation of being still.