Every so often, scientists get excited about finding water somewhere other than Earth. NASA's recent discovery, which showed signs of briny water on Mars, may have made headlines -- but there's water on a lot of worlds in our solar system.
So why can't we go to those places?
Water is vital for life as we know it. But we also need a variety of other elements to survive, such as carbon and nitrogen. These elements allow us, and all other flora and fauna on Earth, to conduct biological processes such as protein production, cell division, and respiration. Humanity, along with most life on Earth, also requires a very narrow temperature range. The frozen surfaces of many of the water-covered worlds in our solar system are deadly cold.