Arrival Of Water

Water, covering 70% of the earth’s surface, we think we know all about it, but we don’t. In fact, we know more about the moon and the surface to Mars than we do about what is covering about three quarters of our own planet. How did it all arrive?
Where did it come from? What role does it play in life? Where else in our solar system is water present?

The remnants of our solar system, failed planets or even the birth of life, asteroids and comets were thought to bring all earth’s water to earth, and even life itself. Comets are frozen chunks of matter, of ice and other matter, were the most logical answer to explain how water arrived. As we all know, the young earth was bombarded by extra terrestrial matter. Water could easily be transported into earth. But then, scientist made a shocking discovery after NASA’s “Stardust” mission. “Stardust” is a spacecraft designed to fly behind a comet, comet Wild 2, and collect samples of the comet material by flying behind its tail. The dust in the tail is collected by a comb of aerogel, a material that is very porous, containing 99.8% of air. It can capture any bits of comet dust that fly past it. The samples collected were sent to the labs. The water in collected is very different with the water here on earth. The samples collected contained a ratio of 1:1 of heavy water, water that is made up of deuterium and oxygen or 2H2O that resembles the physical and chemical behaviours of normal water, to normal water. However, water on earth contains a 2:1 ratio of heavy to normal water. Pure heavy water is 11% heavier than pure water. Comets might have brought some of earth’s water, but not all. Another mystery was : how did the water survive the impact of Thea? Thea, an infant planet that crashed into young earth, which caused the formation of the moon, making Earth completely molten again. This impact would have vaporized all water present on earth. Then, another scientific discovery explained the mystery. Rocks were found around the world that contains water trapped in their porous body. This explains how water was already present when the earth formed, and then comets brought more of it to earth. Then they survived the impact of Thea trapped inside the rocks, and from the water in the rocks, the oceans were formed after the crust solidified again.

Water and life is forever linked. Healthy humans can survive 2 weeks or 14 days without food, but only 2-3 days without water. Water helps us lose heat, expels our waste and enables digestion. It powers photosynthesis in plants, providing the important oxygen that we need in order to survive. It is such a common compound that it’s considered the universal solvent. It makes up 70% of our bodies. It is the basic compound to support life. Extremofiles, micro organisms that live in very harsh conditions, can survive without sunlight, but not water. Water is the source of life, and the thing that started it in the first place.

Water exists not only on earth, but other planets, moons and comets too. Water exists commonly in solid form. Water exist on Pluto, Charon (Moon of Pluto), Enceladus, Europa and Titan in solid forms. Both Europa and Titan are possible candidates to support extraterrestrial life. Europa, a moon of Saturn, Has an iron core like Earth’s and a frozen surface of ice and scientists suspect that under that layer of ice might contain liquid water, which supports life. It has geysers, spewing out ice particles that feeds Saturn’s E ring. Titan, another moon of Saturn, has a methane ocean, but also contains significant amounts of water ice. It has a “methane cycle” that is similar to the water cycles here on earth. There might be extraterrestrial life forms that use the methane for creating energy in some unknown way. Expeditions to the two moons are in consideration by NASA to answer the question of: Are We Alone?