The Solar System
The Solar System consists of the
Sun and those celestial objects bound to it by gravity.
These objects are the eight planets and their 166 known moons, four dwarf planets and billions of small bodies,
including asteroids, icy Kuiper belt objects, comets, meteoroids, and interplanetary dust.
Broadly, the charted regions of the Solar System are the Sun, four terrestrial inner planets, the asteroid belt,
four gas giant outer planets, the Kuiper belt, the scattered disc, and ultimately perhaps the hypothetical Oort cloud.
A flow of plasma from the Sun (the solar wind) permeates the Solar System. This creates a bubble in the interstellar
medium known as the heliosphere which extends out to around the scattered disc.
In order of their distances from the Sun, the eight planets are: Mercury, Venus, Earth, Mars, Jupiter, Saturn,
Uranus, and Neptune.
As of mid-2008, four smaller objects are classified as dwarf planets: Ceres is in the asteroid belt, while the other
three (Pluto, Makemake, and Eris) all orbit the Sun beyond Neptune.
Six of the planets and two of the dwarf planets are in turn orbited by natural satellites, usually termed "moons" after
Earth's Moon, and each of the outer planets is encircled by planetary rings of dust and other particles.
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Our Sun
The Sun is the star at the center of the Solar System. The Earth and other matter (including other planets, asteroids, meteoroids, comets and dust) orbit the Sun, which by itself accounts for about 99.8% of the Solar System's mass. Energy from the Sun, in the form of sunlight and heat, supports almost all life on Earth via photosynthesis, and drives the Earth's climate and weather.
The diameter of the Sun measures about
1.4 million kilometers, which means that you could put 109 Earths around it at the
equator.
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The Immediate Competition
Okay, so, knowing the size of our Sun,
let's compare it with the direct competitors:
Sirius is about 2.5 times the size of our Sun;
Pollux is about 9 times the size of our Sun;
Arcturus is about
25 times the size of Sun
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