出典:Wikipedia
出典:『Wikipedia』 (2011/07/21 19:03 UTC 版)
The Solar System consists of the Sun and the astronomical objects bound to it by gravity, all of which formed from the collapse of a giant molecular cloud approximately 4.6 billion years ago. Of the many objects that orbit the Sun, most of the mass is contained within eight relatively solitary planets whose orbits are almost circular and lie within a nearly flat disc called the ecliptic plane. 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, 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 ices, such as water, ammonia and methane, and are often referred to separately as "ice giants".
太陽系.
the solar system
the solar system
太陽系.
the planetary system
the solar heat
太陽向点.
the solar apex
the sunbeam
the sun's rays
the solar calendar
the solar year
sunlight―the sun's rays
heliography―(一回なら)―a heliograph
a heriogram
紫外の