Solar System

Our solar system is filled with a wide assortment of celestial bodies - the Sun itself, our eight planets,dwarf planets, and asteroids - and on Earth, life itself! The inner solar system is occasionally visited by comets that loop in from the outer reaches of the solar system on highly elliptical orbits. In the outer reaches of the solar system, we find the Kuiper Belt and the Oort cloud. Still farther out, we eventually reach the limits of the heliosphere, where the outer reaches of the solar system interact with interstellar space. Solar system formation began billions of years ago, when gases and dust began to come together to form the Sun, planets, and other bodies of the solar system.

 

How Did The Solar System form?

This is an important question, and one that is difficult for scientists to understand. After all, the creation of our Solar System took place billions of years before there were any people around to witness it. Our own evolution is tied closely to the evolution of the Solar System. Thus, without understanding from where the Solar System came from, it is difficult to comprehend how mankind came to be.Scientists believe that the Solar System evolved from a giant cloud of dust and gas. They believe that this dust and gas began to collapse under the weight of its own gravity. As it did so, the matter in this could begin moving in a giant circle, much like the water in a drain moves around the center of the drain in a circle.At the center of this spinning cloud, a small star begin to form. This star grew larger and larger, as it collected more of the dust and gas that were collapsing into it.Further away from the star that was forming in the center were smaller clumps of dust and gas that were also collapsing.The star in the center eventually ignited forming our Sun, while the smaller clumps became the planets, minor planets,moons, comets, and asteroids.

 

Astroid belt

The asteroid belt is a region of the solar system between the orbits of Mars and Jupiter (2.2 - 3.3 A.U.) in which most asteroids are located. The Asteroid Belt or Main Belt, probably contains millions of asteroids ranging widely in size from Ceres, which at 940 km in diameter is about one-quarter the diameter of our Moon, to bodies that are less than 1 km across. There are more than 20,000 numbered asteroids in the asteroid belt.

 

kuiper belt

The Kuiper Belt is a comet-rich area of our solar system that begins near the orbit of Neptune and continues beyond Pluto. The belt's inner edge is about 30 astronomical units (AU) away from the Sun. Its outer edge is about 50 AU away from the Sun. One AU is equal to the average distance between Earth and the Sun,or about 150 million km (93 million miles).Kuiper Belt objects are in orbit around the Sun. While most of them are found between 30 and 50 AU, some travel much farther from the Sun.

Oort cloud

The Oort cloud, alternatively termed the Öpik-Oort cloud, is a hypothetical spherical cloud of comets situated about 50,000 to 100,000 astronomical unit (AU) from the Sun. This is approximately two thousand times the distance from the Sun to Pluto or roughly one light year, almost a quarter of the distance from the Sun to Proxima Centauri, the star nearest the Sun.The Oort cloud would have its inner disk at the ecliptic from the Kuiper belt. Although no confirmed direct observations have been made of such a cloud, astronomers believe it to be the source of most or all comets entering the inner solar system (some short-period comets may come from the Kuiper belt), based on direct observations of the orbits of comets.There is a theory that periodic (every about 30 million years) disturbances of the Oort cloud by nearby star have been inducing massive falls of comets onto the Earth that caused mass extinction of life on Earth. If that is true, the Oort cloud is very significant in influencing the evolution of life on Earth (by supplying water and destroying life) as well as preserving primitive materials, from which planetary scientists can study the origin and evolution of the Solar System.

 

Lahiru Malaka.

NCAS 2008/2009