Did You Know...
... that the Kuiper belt is similar to the asteroid belt that is located between the orbits of Mars and Jupiter, only 20 times wider!
However, the Kuiper belt objects (KBOs) are mostly made up of frozen volatiles of ammonia, methane and water (commonly termed as "ice"), unlike asteroids that are small masses of rock. Astronomers suggest that the belt and the spherical Oort cloud located behind it, are made up of remnants from the beginning of the Solar System. The objects that form a part of the Kuiper belt and the Oort cloud, are collectively known as the trans-Neptunian objects.
The Kuiper belt, discovered in 1992, derives its name from Gerard Kuiper, the astronomer who had predicted its existence. It is also referred to as the Edgeworth-Kuiper belt, because Kenneth Edgeworth was the first person to suggest that comets and icy bodies might exist beyond the orbit of Neptune. This UniverSavvy article brings to you some facts about this little-known region in the far end of our Solar System.
Fascinating Facts about the Kuiper Belt
The Kuiper belt is elliptical and spans across 2.5 to 4.5 billion miles.
The Kuiper belt is located at a distance of 7.5 to 9.3 billion miles from the Sun.
There exists a wide variation in the size of the Kuiper belt objects. While some of them are as big as a planet, others are smaller than asteroids. Several KBOs revolve around the Sun, while others are comets with a very short lifespan. There are a few objects in the belt that are larger than most asteroids, but not large enough to be called a true planet. These objects are known as "dwarf planets".
In 2006, three Kuiper belt objects, namely, Pluto, Haumea, and Makemake, were classified as dwarf planets.
The first KBO to be discovered was Pluto (discovered in 1930), but back then no one was aware of the existence of the belt. It is also the largest known member of the Kuiper belt, and is 2360 km across. It was earlier considered to be a planet.
The first modern KBO was discovered in 1992, and was named QB1. Since then, more than a thousand KBOs have been discovered.
The Kuiper belt is believed to be the source of short-period comets that orbit the Sun.
KBOs are classified into three distinct orbital substructures, namely, resonant objects, hot classicals, and cold classicals. The classification is based on the following parameters.
- Their average distance from the Sun (semimajor axis)
- The closest they come to the Sun (perihelion distance)
- The inclination of their plane of orbital to that of the planets of the Solar System
The KBOs that are in a mean motion resonance with Neptune, are termed as the resonant objects. The KBOs with perihelion distances between 35 and 40 AU, are known as the hot classicals. Cold classicals are KBOs with an inclination of 2.6°.
Most objects of the Kuiper belt have orbits that are stable for over 100 million to 1 billion years.
Scientists believe that some moons of planets in the Solar System, namely, Saturn's Phoebe and Neptune's Triton, have originated in the Kuiper belt.
Plutinos, named after the dwarf planet Pluto, are a class of KBOs that share the same 2:3 resonance with Neptune.
Interestingly, the composition of KBOs is similar to that of comets!
The classical Kuiper Belt is a region of the belt that is densely populated and located at an approximate distance of 45 AU from the Sun.
More than 100,000 KBOs are believed to exist, some of which are more than 100 km in diameter.