Comets, the Kuiper Belt and Oort Cloud
comet hale-bopp
Comets originally form as balls of ice and rock in the Kuiper Belt and Oort Cloud
Kuiper Belt & Oort Cloud Facts
  • Objects orbiting in the Kuiper Belt and Oort Cloud are mainly composed of rock, ice, ammonia and methane.
  • When objects from the Kuiper Belt and Oort Cloud enter the inner solar system they become comets due to interactions with the sun.
  • There are thought to be at least 70,000 objects in the Kuiper Belt with a diameter over 62 miles (100 km).
  • The dwarf planets Pluto, Eris, MakeMake and Haumea all orbit in the Kuiper Belt.
  • The Kuiper Belt is named after the Dutch astronomer Gerard Kuiper.
  • There are possibly 2 trillion icy bodies in the Oort Cloud.
  • The Oort Cloud extends so far it almost reaches a quarter way to the nearest star Proxima Centauri.
  • Objects found in the Oort Cloud are believed to be remnants from the early formation of the solar system that were thrown far into space by the gravity of the giant planets.
  • The Oort Cloud is named after another Dutch astronomer Jan
    Hendrik Oort.

oort cloud
The Oort Cloud is composed of icy objects which surrounds the solar system
The Kuiper Belt
The Kuiper Belt is located at around 2.8 billion miles (4.5 billion km) from the sun and extends several billion miles. It is similar to the asteroid belt except it is around 20 times larger, and instead of being primarily composed of rocks objects found here also contain methane, ammonia and ice.
The Oort Cloud
The Oort Cloud begins at 750 billion km from the sun and ends at the very edge of our solar system, almost 1 light year from the sun. It is a massive spherical cloud containing billions of icy bodies. Occasionally these bodies get knocked out of their orbit and enter the inner solar system, they then become comets. Although some comets originate from the Kuiper Belt most come from the Oort Cloud.


Comet Bombardement of Early Earth
Comet Bombardment of Early Earth
Comets are icy bodies from the Kuiper Belt and Oort Cloud which enter the inner solar system. Comets originating from the Kuiper belt have short orbital periods below 200 years, bodies from the Oort Cloud have orbits ranging from 200 years up to millions of years. When these icy objects enter the inner solar system the effects of solar winds and radiation vaporizes the ice creating a thin atmosphere around them known as a coma, occasionally they will also develop a tail.

It is believed that the gravitational pull of the outer planets bring bodies from the Kuiper Belt into the inner solar system. Objects in the Oort Cloud are effected by giant molecular clouds or passing stars that can nudge them out of their orbit. As comets cross the orbital paths of planets they do occasionally collide with them, as was the case in 1994 when fragments of Comet Shoemaker-Levy 9 hit Jupiter.

Comets are extremely important in the development of planets as they possess vital volatile elements, including most importantly water. In its early life planet Earth was bombarded by comets, creating liquid water oceans on its surface, without this event it is possible that life may not have developed on our planet.
Comet Missions
There has already been several stunningly successful missions to study comets, Giotto in 1986 studied Halley’s Comet and then went on to make a close pass of Grigg-Skjellerup in 1992. Stardust captured comet dust from Comet Wild 2 in 2004 and returned those samples safely to Earth. It then went on to make a flyby of comet Tempel 1. In 2005 an even more ambitious mission was launched. Deep Impact was equipped with a probe that would be sent on a collision course with Comet Tempel 1. The probe successfully crashed into the comet in July of that year.
NASA animation of Deep Impact's encounter with Comet Tempel 1

Missions to the Kuiper Belt

New Horizons
New Horizons Launch: January 2006
Arrival: July 2015
Agency: NASA
Summary: After its visit to Pluto NASA is hoping to extend the New Horizons mission to investigate one or maybe two other Kuiper Belt Objects. Mission controllers will search for objects near the craft's flight path that have diameters between 50 to 100 kilometers for a possible flyby.

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