Solar System
The Solar System comprises
the Sun and its planetary system of eight planets, their moons, and other non-stellar
objects.
It formed 4.6 billion years ago from the
gravitational collapse of a giant molecular cloud. The vast majority of the system's mass is in the Sun, with most of the
remaining mass contained in Jupiter. The four smaller inner planets, Mercury, Venus, Earth and Mars, also called the terrestrial planets, are primarily composed of rock and
metal. The four outer planets, called the gas giants, are substantially more massive
than the terrestrials. The two largest, Jupiter and Saturn, are composed mainly of hydrogen
and helium; the two outermost planets, Uranus and Neptune, are composed largely of substances
with relatively high melting points (compared with hydrogen and helium), called
ices, such as water, ammonia and methane, and are often referred to
separately as "ice giants". All planets have almost circular orbits
that lie within a nearly flat disc called the ecliptic plane.
The Solar System also contains a
number of regions populated by smaller objects.The asteroid belt, which lies between Mars and
Jupiter, is similar to the terrestrial planets as it mostly contains objects
composed of rock and metal. Beyond Neptune's orbit lie the Kuiper belt and scattered disc, linked populations of trans-Neptunian
objects
composed mostly of ices. Within these populations are several dozen to more
than ten thousand objects that may be large enough to have been rounded by
their own gravity. Such objects are referred to as dwarf planets. Identified dwarf planets include
the asteroid Ceres and the trans-Neptunian objects Pluto, Eris , Haumea, and Makemake. In addition to these two regions,
various other small-body populations includingcomets, centaurs and interplanetary dust freely travel between regions. Six
of the planets, at least three of the dwarf planets, and many of the smaller
bodies are orbited by natural satellites, usually termed "moons"
after Earth's Moon. Each of the outer planets is
encircled by planetary rings of dust and other small objects.
The solar wind, a flow of plasma from the Sun, creates a bubble in the interstellar medium known as the heliosphere, which extends out to the edge of
the scattered disc. The Oort cloud, which is believed to be the source
for long-period comets, may also exist at a distance
roughly a thousand times further than the heliosphere. The heliopause is the point at which pressure from
the solar wind is equal to the opposing pressure of interstellar wind. The Solar System is located within
one of the outer arms of the Milky Way galaxy, which contains about 200 billion
stars.
source : wikipedia
source : wikipedia
Written by সাদমান
I am sadik, simply sad :).Studied in Chittagong University,Bangladesh;Department of Geography and Environmental studies.
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This is really interesting. Very useful information has been conveyed in this article! Thanks for sharing.
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