It's Cold Out There
6 December 2011
Hoping for a snow day? Well, if you lived on Jupiter's icy moon Europa you might have to call it an "ice day," and it wouldn't come seasonally either, it would be every day. And a "day" on Europa is quite long: about the equivalent of three and a half 24-hour long Earth days -- that's about 60 hours. It is also -260 degrees Fahrenheit there (and even colder at the poles: -370 degrees Fahrenheit). (I don't think that you would like that.)
No, you would not, and you could not live on a place like Europa, but yet this ice on Europa (and on other places) intrigues us -- we want to learn more about it. Why are we so interested in ice? Ice hints at the possibility for life.
Ice is one of the three phases (solid, liquid, gas) of an element or compound, such as H2O (a.k.a. water). Water freezes and becomes a solid at 32 degrees Fahrenheit. Now, water is one of the building blocks of life and is essential to life here on Earth. Cool fact: Did you know that 75% of the Earth's freshwater is ice? That is a large percentage of all the water available for us to drink -- and survive. If we have found ice elsewhere, this hints at the possibility for past life on the other planets, and the moons of the planets.
Ice or evidence for ice -- yes, even water ice -- is found on many of the planets, the Moon and the moons of the planets. However, ice can be made out of many elements, such as nitrogen and carbon dioxide. The ice giants' (Uranus and Neptune) compositions are made up of different amounts of different kinds of ices. Saturn's rings are made up of 90% water ice. Mars has water ice and carbon dioxide ice located mostly near its poles. The Moon's ices are found in craters in the lunar south pole. Even close to the sun, and hot, Mercury has the possibility for ice in its perpetually shadowed polar regions.
One hypothesis as to how the Earth and the other planets and moons obtained ice and water on their surfaces (and beneath) is from incoming comets. Comets are considered to be "dirty snowballs" being made up of ice and dust. During the period of heavy bombardment in our solar system's history, a comet (or comets) could have impacted our Earth and the other bodies in our solar system and deposited its ices.
The solar system is a cold place, and yet ice gives us something to be excited about: Ice on the other planetary bodies gives us hope that one day we could discover some form of life out there. Ice is nice -- take a look below and see for yourself. (10 images total)
Learn more about snow on Earth: