jääjättiläistä

Jääjättiläinen is a Finnish term that translates to "ice giant" and refers to the giant planets in our solar system, specifically Uranus and Neptune. These planets are distinguished from the terrestrial planets like Earth and Mars by their immense size and their composition, which is primarily made up of hydrogen and helium, with significant amounts of frozen volatile substances such as water, ammonia, and methane. This abundance of frozen compounds is what gives them their "ice giant" designation, as opposed to the "gas giants" Jupiter and Saturn, which have a higher proportion of hydrogen and helium and are less dominated by ices.

Uranus and Neptune share many characteristics, including their blue-green appearance, which is due to the methane in their atmospheres absorbing red light and reflecting blue light. Both planets have extensive ring systems, though they are much fainter and less prominent than those of Saturn. They also possess numerous moons, many of which have unusual retrograde orbits, suggesting they may have been captured rather than formed with the planets. The internal structure of ice giants is believed to consist of a rocky core surrounded by a deep mantle of icy materials, all enveloped by a gaseous atmosphere. Due to their great distance from the Sun, these planets are extremely cold, with atmospheric temperatures dropping to well below -200 degrees Celsius. Their discovery and study have significantly advanced our understanding of planetary formation and the diversity of worlds within our solar system and beyond.