Chiron is a unique celestial body residing in the outer solar system, specifically orbiting between the gas giants Saturn and Uranus. Discovered in 1977, it was the first identified member of a class of objects now known as centaurs. These bodies exhibit characteristics of both asteroids and comets. Unlike typical asteroids, Chiron possesses an icy composition and can display comet-like activity, including forming a fuzzy cloud of gas and dust known as a coma.
Chiron’s Orbital Velocity
Its average orbital speed is approximately 8.06 kilometers per second (about 18,000 miles per hour). This speed, however, is not constant throughout its journey. Chiron follows a highly elliptical path, meaning its distance from the Sun varies considerably. One complete orbit around the Sun takes Chiron roughly 50.7 years.
At its closest point to the Sun, known as perihelion, Chiron can come within about 8.55 astronomical units (AU) of our star. Conversely, at its farthest point, called aphelion, it can reach distances of approximately 18.87 AU from the Sun. This substantial difference in distance directly impacts its instantaneous speed as it travels along its elongated orbit.
What Determines Its Speed
Chiron’s speed is governed by celestial mechanics, particularly Kepler’s laws of planetary motion and the Sun’s gravitational influence. According to Kepler’s second law, a body in orbit sweeps out equal areas in equal amounts of time. This means that when Chiron is closer to the Sun, the gravitational pull is stronger, causing it to accelerate and move faster.
As Chiron recedes from the Sun towards its aphelion, the Sun’s gravitational force weakens. This reduction in gravitational pull causes Chiron to slow down in its orbit. Its eccentric orbital path, with a high eccentricity value around 0.38, amplifies these speed variations, leading to noticeable changes in velocity throughout its 50-year journey.
Putting Chiron’s Speed in Perspective
Chiron’s average speed of about 8.06 kilometers per second is considerably slower than Earth’s orbital speed. Our home planet travels around the Sun at an average of nearly 29.78 kilometers per second, which translates to approximately 67,000 miles per hour. This means Earth orbits the Sun more than three times faster than Chiron.
Chiron’s speed is also far greater than speeds experienced on Earth. A typical commercial jet aircraft cruises at about 0.21 to 0.26 kilometers per second (770 to 930 kilometers per hour). Even Earth’s orbital motion is slow compared to the speed of light, which travels at 299,792.458 kilometers per second in a vacuum.