It was discovered Dec 16, 2009, but apparently new data from Hubble confirms it's a water world. More details here - http://www.spacetelescope.org/news/heic1204/

Isn't Europa actually made almost entirely of ice? Europa the moon around Jupiter, I believe.
http://en.wikipedia.org/wiki/Europa_(moon)

Europa has a thick layer of ice, maybe a few or several miles thick, under which is a very deep liquid ocean, but "its bulk density suggests that it is similar in composition to the terrestrial planets, being primarily composed of silicate rock." According to the researchers, "GJ1214b’s radius could be explained by a bulk composition consisting of an ice-rock core surrounded by a H/He/H₂O envelope that has a water mass fraction of 50-85%."

GJ1214b is a giant ball of water 2.7 times the Earth's diameter (Uranus is about 4 times, Saturn about 9). The water must be (tens of) thousands of miles deep. There's nothing like it in our system. I can't even begin to imagine what happens to water at that kind of depth and pressure. What bizarre properties it must have. They mention superfluids and hot ice in the article, but I suspect it's even weirder.
>> ^gwiz665:
Isn't Europa actually made almost entirely of ice? Europa the moon around Jupiter, I believe.
http://en.wikipedia.org/wiki/Europa_%28moon%29

More about it.

*quality

Awarding Kreegath with one star point for this contribution to VideoSift - declared quality by dystopianfuturetoday.