نجوم و کیهان‌شناسی

همراه با زحل، اورانوس و نپتون، مشتری یکی از غول­های گازی منظومه شمسی است. جرم آن به تنهایی دو برابر و نیم مجموع دیگر سیارات است. جرم داخلی آن را عمدتاً هیدروژن (71%) و هلیوم (24%) تشکیل می­دهد و 5% باقی­مانده به عناصر سنگین­تر اختصاص دارد. از اینرو ترکیبات آن همچنان شبیه سحابی خورشیدی­ای است که از آن ساخته شد. جالب است بدانید اگر مشتری جرم بیشتری داشت، قطر آن عملاً کاهش می­یافت، بنابراین حجم آن حداکثر حجمی است که یک سیاره با این ترکیبات می­تواند داشته باشد.

[1]- هیدروژن فلزی هیدروژنی است بسیار فشرده، به­گونه­ای که الکترون­ها می­توانند به­راحتی، شبیه به فلزات، در آن حرکت کنند.

With Saturn, Uranus and Neptune, Jupiter is one of  the gas giants of  the Solar
System and its mass exceeds that of  all the other planets combined by two and a
half  times. Its interior mass is primarily made up of  hydrogen (∼71%) and helium
(24%) with ∼5% of  heavier elements. Its composition thus closely follows that of 
the solar nebula from which it was formed. Interestingly, if  Jupiter were to acquire
more mass, its diameter would actually decrease, so it is about as large as a planet
of  its composition could be.
Jupiter is thought to consist of  a dense core surrounded by a layer of  liquid
metallic hydrogen lying under an outer layer, about 1000 km thick, composed
very largely of  molecular hydrogen. Jupiter is perpetually covered with a cloud
layer about 50 km thick. The clouds are composed of  ammonia crystals arranged
into bands of  different latitudes made up of  light coloured zones between darker
belts. The orange and brown colours in the Jovian clouds are caused by compounds
containing phosphorus and sulphur exposed to ultraviolet light from the Sun. At
differing latitudes, the darker clouds so formed deeper within the  atmosphere are
masked out by higher clouds of  crystallizing ammonia producing the pale zones
seen between the belts.

"Introduction to astronomy and cosmology" Page 108