All living things contain a large proportion of water. For example, around two-thirds of the human body is made up of water. Although most people could survive quite a long time without food, they would die within a few days if they had no water. More of the surface of the Earth is covered by water than by land — a fact that has an enormous effect on the climate of all parts of the Earth. Although it is a simple compound of oxygen and hydrogen, water plays a very complex role on our planet.
From those simple starter organisms to the most complex plants and animals, water has played a critical role in survival ever since. In humans, it acts as both a solvent and a delivery mechanism, dissolving essential vitamins and nutrients from food and delivering them to cells. Our bodies also use water to flush out toxins, regulate body temperature and aid our metabolism. No wonder, then, that water makes up nearly 60 percent of our bodies or that we can’t go for more than a few days without it.
Besides being essential for our bodies to function, water also promotes life in numerous other ways. Without it, we couldn’t grow crops, keep livestock or wash our food (or our bodies, for that matter). Water has also advanced civilization, providing a means for travel for entire parts of the world and a source of power for factories. Because water can also exist as a vapor, it can be stored in the atmosphere and be delivered as rain across the planet. Earth’s oceans also help regulate the planet’s climate, absorbing heat in the summer and releasing it during the winter. And of course, those same oceans serve as a home for countless plants and animals.
While no one argues against the importance of water to life on Earth, it’s fair to wonder if life could exist elsewhere without it. The answer is a resounding “maybe.” Scientists are almost certain that, at a minimum, life requires a liquid of some sort to survive, with ammonia and formamide being the most promising alternatives. Both liquids have their own set of problems, however. Liquid ammonia only exists at extremely cold temperatures, making it unlikely that organisms could find the energy to support metabolism. Formamide, on the other hand, actually stays liquid over a larger temperature range than water, and like water, it’s a solvent capable of dissolving many organic materials, but so far scientists have found little evidence that the solvent could support life.
If life forms that don’t require water do exist, they’d be very different than the life found on Earth. For instance, rather than being carbon-based, such life may arise from silicone compounds. A recent study even suggests that an alternative life form might be lurking in our solar system. Researchers studying Titan, a moon orbiting Saturn, noticed that hydrogen in the moon’s atmosphere wasn’t found on the surface. One explanation for the missing hydrogen is that life forms are consuming it, just as we consume oxygen.
So far, however, we simply don’t have enough information to say whether or not life could exist without water. We know with certainty, however, that life on Earth definitely couldn’t.
Picture Credit : Google