Iapetus

Moon
Iapetus Radius

Radius of Iapetus

The radius of Iapetus is one of its most fundamental physical characteristics. The Iapetus radius measures approximately 1,471.2 km, making it 4.33× smaller than Earth. This measurement represents the average distance from the center of Iapetus to its surface, providing crucial information about the celestial body's size and volume.

Understanding the Iapetus radius is essential for calculating other important properties such as surface area, volume, and gravitational characteristics. The radius directly influences how we perceive and study this fascinating object in our Solar System.

Iapetus Semi-Major Axis

Orbital Radius of Iapetus

The Iapetus semi-major axis is a critical orbital parameter that defines the average distance from the Sun. The Iapetus semi-major axis measures 0.02 AU (approximately 3.56e+6 km), which represents the average orbital radius of Iapetus. This measurement is fundamental to understanding Iapetus's position in the Solar System and its relationship with other celestial bodies.

The orbital radius of Iapetus determines how much solar radiation the planet receives, which directly influences its temperature, climate, and overall environmental conditions. This distance places Iapetus in a specific region of the Solar System, each with unique characteristics and scientific significance.

When we examine the Iapetus semi-major axis 0.02 AU, we gain insights into the planet's orbital mechanics, including its orbital period, velocity, and the gravitational forces at play. This parameter is essential for space mission planning and understanding the dynamics of our Solar System.

Iapetus Mass

Mass of Iapetus in kg

The Iapetus mass is a fundamental property that determines many of the planet's physical characteristics. The mass of Iapetus in kg is approximately 1.81e+21 kg, which is 3308.59× less than Earth's mass. This substantial mass creates a significant gravitational field that influences everything from atmospheric retention to orbital dynamics.

Understanding the Iapetus mass allows scientists to calculate other critical properties such as surface gravity, escape velocity, and the planet's ability to retain an atmosphere. The mass also plays a crucial role in determining how Iapetus interacts with other celestial bodies through gravitational forces.

The precise measurement of the mass of Iapetus in kg is essential for space exploration missions, as it affects spacecraft trajectories, landing procedures, and the design of scientific instruments. This fundamental property helps us understandIapetus's formation history and its place in the evolution of our Solar System.

Iapetus Orbital Period

How Long is a Year on Iapetus?

The Iapetus orbital period defines the length of one complete revolution around the Sun. The Iapetus orbital period is 0.02 hours, which is 397808.52× shorter than Earth's year. This orbital period determines the length of Iapetus's year and directly influences seasonal patterns, climate cycles, and temperature variations.

The Iapetus orbital period is directly related to its distance from the Sun, following Kepler's laws of planetary motion. Planets farther from the Sun have longer orbital periods, while those closer complete their orbits more quickly. This relationship helps explain why Iapetus takes the time it does to complete one full orbit.

Understanding the Iapetus orbital period is crucial for space mission planning, as it affects launch windows, travel times, and the timing of scientific observations. This fundamental orbital parameter also provides insights into the planet's formation history and its current position in the Solar System's dynamic structure.

How Far is Iapetus from Earth?

Distance Between Iapetus and Earth

How far is Iapetus from Earth? This is a question that fascinates both astronomers and space enthusiasts. The distance between Iapetus and Earth varies throughout their orbital cycles, but on average, Iapetus is approximately 1.46e+8 km(0.976 AU) away from Earth. This distance changes as both planets orbit the Sun, with the closest approach (opposition) and farthest separation (conjunction) creating significant variations.

The question "How far is Iapetus from Earth?" has practical implications for space exploration. This distance determines travel time for spacecraft, communication delays for mission control, and the amount of fuel required for interplanetary missions. Understanding this distance is essential for planning future missions to Iapetus.

The distance between Iapetus and Earth is not constant due to the elliptical nature of both planets' orbits. When Iapetus and Earth are on the same side of the Sun (opposition), they are at their closest, making this the optimal time for observations and potential missions. Conversely, when they are on opposite sides of the Sun (conjunction), they are at their farthest separation, which can exceed the average distance significantly.

Physical Properties
Mean Radius
1,471.2km
Equatorial Radius
735.6km
Polar Radius
0km
Mass
1.81e+21 kg
Volume
1.66e+9 km³
Density
1.083g/cm³
Gravity
0m/s²
Escape Velocity
0m/s
Flattening
0
Average Temperature
0.0 K (-273.1 °C)
Axial Tilt
0°
Semimajor Axis
3.56e+6km
Perihelion
3.46e+6km
Aphelion
3.66e+6km
Eccentricity
0.028
Inclination
14.72°
Sidereal Orbit
0.02 hours
Sidereal Rotation
0.48 hours
Mean Anomaly
0°
Argument of Periapsis
0°
Longitude of Ascending Node
0°

Overview of Iapetus

Iapetus is a fascinating moon in our Solar System that has captured the attention of astronomers and space enthusiasts alike. With a Iapetus radius of 1,471.2 km, making it 4.3× smaller than Earth's size, this celestial body presents unique characteristics that distinguish it from other objects in our cosmic neighborhood. Positioned at an average distance of 3.56e+6 km (0.024 AU) from the Sun, Iapetus occupies a significant place in the Solar System's architecture. As a moon, Iapetus demonstrates the incredible diversity of natural satellites that orbit larger celestial bodies throughout our Solar System.

Physical Characteristics

The Iapetus physical characteristics reveal a world of remarkable dimensions and properties. The Iapetus radius measures 1,471.2 km, making it 4.3× smaller than Earth's size. The Iapetus mass of 1.81e+21 kg represents 3308.6× smaller than Earth's mass, giving this world substantial gravitational influence. With a volume of 1.66e+9 km³, Iapetus occupies significant space in the Solar System.

Orbital Properties

The Iapetus orbit reveals fascinating details about its journey around the Sun and its relationship to other Solar System objects. The Iapetus orbit has a semimajor axis of 3.56e+6 km (0.024 AU), placing it 42.0× smaller than Earth's distance from the Sun. At its closest approach (perihelion), Iapetus comes within 3.46e+6 km of the Sun, while at its farthest point (aphelion), it reaches 3.66e+6 km, creating a 5.7% variation in solar distance. The Iapetus orbit is nearly circular with an eccentricity of 0.028 (1.7× Earth's orbital eccentricity), resulting in relatively stable solar heating throughout its year. The Iapetus orbit takes 0.02 hours to complete (397808.5× smaller than Earth's orbital period), defining the length of its year. The orbital inclination of 14.72° indicates how much the Iapetus orbit is tilted relative to the Solar System's ecliptic plane. This moderate inclination indicates a typical orbital evolution for objects in this region of the Solar System.

Rotation and Tilt

The Iapetus rotation and axial orientation provide crucial insights into its daily and seasonal cycles, as well as its orbital dynamics. The Iapetus rotation period of 0.48 hours (49.6× smaller than Earth's rotation period) determines the length of its day. This extremely fast rotation creates intense centrifugal forces and may contribute to the planet's flattened shape. The Iapetus axial tilt of 0° determines the intensity and nature of seasonal variations. With minimal axial tilt, Iapetus experiences virtually no seasonal changes, maintaining relatively constant temperatures throughout its year. The orbital orientation parameters reveal additional details about Iapetus's position in space. The mean anomaly of indicates the planet's current position in its orbit relative to its perihelion. The argument of periapsis of shows how the orbit's orientation changes over time due to gravitational perturbations. The longitude of ascending node of defines the reference point where the orbit crosses the ecliptic plane.

Temperature and Atmosphere

The Iapetus temperature and atmospheric conditions are fundamental to understanding its habitability and environmental characteristics. The Iapetus average temperature of 0.0 K (-273.1 °C) (-459.7°F) provides the baseline for understanding its climate. These extremely cold temperatures make Iapetus inhospitable to life as we know it, with any atmosphere likely frozen solid on the surface. Compared to Earth's average temperature of 15°C (59°F), Iapetus presents a dramatically different thermal environment. Being closer to the Sun than Earth, Iapetus receives more intense solar radiation, contributing to its temperature profile.

Escape Velocity & Flattening

The Iapetus escape velocity and shape characteristics reveal important details about its gravitational field and rotational dynamics. The Iapetus escape velocity of 0 m/s determines how easily objects can break free from its gravitational pull. This relatively low escape velocity means that gases and light molecules can easily escape into space, making it difficult for Iapetus to retain a substantial atmosphere. The Iapetus flattening of 0.0000% indicates how much the planet's rotation affects its shape. This minimal flattening suggests a nearly spherical shape, indicating either slow rotation or a very rigid internal structure.

FAQs About Iapetus

How big is Iapetus compared to Earth?

Iapetus has a radius of 1,471.2 km, making it 4.3× smaller than Earth's size. In terms of volume, Iapetus is 0.0× the size of Earth. This size difference significantly impacts the planet's gravity, atmospheric retention, geological processes, and overall planetary characteristics.

How far is Iapetus from the Sun?

Iapetus orbits at an average distance of 3.56e+6 km (0.024 AU) from the Sun, placing it 42.0× smaller than Earth's distance from the Sun. This distance determines the amount of solar radiation the planet receives and significantly influences its temperature and climate.

How long is a year on Iapetus?

A year on Iapetus lasts 0.02 hours (397808.5× smaller than Earth's orbital period). This orbital period defines the length of the planet's year and affects seasonal patterns, temperature variations, and the overall climate cycle.

What is Iapetus made of?

Iapetus has a density of 1.083 g/cm³ (5.1× smaller than Earth's density). This density provides important clues about the planet's internal composition. The low density indicates a composition dominated by lighter elements, characteristic of gas giants or icy bodies.

Does Iapetus have seasons?

Iapetus has an axial tilt of . With minimal axial tilt, the planet experiences virtually no seasonal changes, maintaining relatively constant temperatures throughout its year.
Discovery Information
Discovered By
Jean-Dominique Cassini
Discovery Date
25/10/1671
Raw Data