Astronomers are also interested in the composition of this rock because it is probably a remnant from the formation of the rocky inner planets of our solar system some 4.5 billion years ago. Conn. Astronomers have discovered a new object orbiting the sun that is smaller than a planet but larger than most known asteroids. The object is classified as a minor planet, like thousands of other asteroids and comets in our solar system. Astronomers officially recognize nine major planets. EB173 is too small to fit that category.
Astronomers believe the Kuiper Belt is filled with hundreds of thousands of small, icy objects.
Several, including EB173, are much larger. Pluto was discovered by Clyde Tombaugh in 1930. Many astronomers believe it would be classified as a minor planet in the Kuiper Belt if it were found today. Astronomers are interested in studying the Kuiper Belt because they want to know more about how the Earth and other major planets formed. They think the icy bodies within the Kuiper Belt are well preserved remnants of the early solar system, which formed about 4.5 billion years ago.