Orbits
Channel: Eye On The World
Date: 28/03/2023

The orbit of a planet can be calculated using Kepler's laws of planetary motion, which describe the relationship between the motion of a planet around the Sun and the physical laws governing its motion. The three laws are as follows:

The Law of Orbits: Each planet orbits the Sun in a path called an ellipse, with the Sun at one of the two foci of the ellipse.

The Law of Areas: A line that connects a planet to the Sun sweeps out equal areas in equal times. This means that a planet moves faster when it is closer to the Sun and slower when it is farther away.

The Law of Periods: The time it takes for a planet to orbit the Sun (i.e. its period) squared is proportional to the cube of its average distance from the Sun (i.e. its semi-major axis).

To calculate the orbit of a planet using these laws, we need to know the planet's mass, velocity, and position at a given time. From these parameters, we can use numerical integration techniques (e.g. Runge-Kutta methods) to solve the differential equations that govern the planet's motion under the influence of the Sun's gravity. This allows us to determine the planet's trajectory over time and to predict its future position and velocity.

In practice, the orbit of a planet is calculated using sophisticated computer simulations that take into account the gravitational interactions between the planet, the Sun, and other celestial bodies in the solar system. These simulations can account for the complex, non-linear dynamics of the system and provide highly accurate predictions of the planet's motion.

Here is a table with the orbital data of the eight planets in our solar system
These values are approximate and can vary slightly depending on the method used to measure them and other factors such as gravitational interactions with other celestial bodies.

There are several examples of strange and unusual orbits observed in our solar system and beyond. Here are a few examples:

Highly eccentric orbits: Some comets and asteroids have highly elliptical orbits that bring them very close to the Sun at perihelion and take them far out into the outer reaches of the solar system at aphelion. One example is the comet Halley, which has an eccentricity of 0.97 and takes 76 years to complete one orbit around the Sun.

Retrograde orbits: Most planets and moons in our solar system orbit the Sun and their parent planet in the same direction as the planet's rotation. However, there are some exceptions, such as the moons of Neptune, which have retrograde orbits that take them around the planet in the opposite direction of Neptune's rotation.

Tilted and inclined orbits: The planets in our solar system orbit in roughly the same plane, known as the ecliptic plane. However, some objects have tilted or inclined orbits that take them out of this plane. One example is Pluto, which has an orbit tilted at an angle of 17 degrees relative to the ecliptic plane.

Resonant orbits: Some moons in our solar system have orbits that are in resonance with each other, meaning that their orbital periods are related by a simple fraction. For example, the moons Io, Europa, and Ganymede of Jupiter are in a 1:2:4 orbital resonance, meaning that for every orbit of Io, Europa completes two orbits and Ganymede completes four orbits.

Binary and trinary orbits: Some objects in our solar system orbit each other in binary or trinary systems. For example, the dwarf planet Pluto and its largest moon, Charon, orbit each other in a binary system, while the asteroid system 87 Sylvia has two smaller moons orbiting it.

   Orbital decay refers to the gradual reduction in the altitude and/or speed of an object in orbit around another body, usually due to the effects of atmospheric drag or gravitational interactions with other objects.

In the case of objects in low Earth orbit, such as satellites or the International Space Station (ISS), atmospheric drag is the primary cause of orbital decay. The upper layers of Earth's atmosphere can create a thin but significant amount of friction on objects moving through it at high speeds, which can cause them to lose altitude and eventually reenter the Earth's atmosphere. To counteract this effect, satellites in low Earth orbit need to use onboard propulsion systems to periodically boost their altitude and maintain their orbital speed.

For objects in higher orbits, such as geostationary satellites or some types of space debris, other factors such as solar radiation pressure or gravitational perturbations from other celestial bodies can contribute to orbital decay. In general, the effects of orbital decay become more pronounced the lower an object's altitude or the more eccentric its orbit.