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   Up to about half of the water on our planet is older than the sun, according to a paper published on Thursday in the journal Science. 
   
   While you next take a sip, ponder this, too: the fact that Earth’s water is so old bodes well for our hunt for wet environments — and, for life — elsewhere in the universe. 
   
   Life on Earth owes everything to the presence of liquid water here, but, even so, scientists don’t have definitive answers for how or when the water got here — or, for that matter, when the water itself was formed. 
   
   
   
   The new research seeks to answer that last question: Was our water made before the sun existed, brewed in the same cloud of dust from which the sun would form? Or did water come later, forming as the Earth also formed? 
   
   As the Washington Post explains, during the sun’s birth a band of unused space dust gathered like skirt hems around it. Such material, called the protoplanetary disk, would go on to form the solar system’s planets. 
   
   Scientists know that water accompanied the sun’s birth but wondered if it might have been destroyed in the process of the sun’s formation, leaving Earth to go it alone in stirring up its own water. 
   
   To find out if the water from that dust cloud made it to Earth, researchers measured the ratio of deuterium, or heavy hydrogen to hydrogen. The findings show that heavy hydrogen levels on Earth are higher than they would have been in the protoplanetary disk. That means that some of our water must predate the sun, when heavy hydrogen was in abundance. 
   
   So, if water can survive a star’s birthing process, and if other solar systems in the universe formed much like ours did, that means that water might be a common ingredient in the making of other planets far from our own. 
   
   “By identifying the ancient heritage of Earth’s water, we can see that the way in which our solar system was formed will not be unique, and that exoplanets will form in environments with abundant water,” said Tim Harries, a professor at the University of Exeter’s Physics and Astronomy Department, in England, and an author of the paper, in a statement. 
   
   “Consequently,” he said, “it raises the possibility that some exoplanets could house the right conditions, and water resources, for life to evolve.” 
   
   Last spring, scientists announced that there could be up to 11 billion exoplanets — planets outside or solar system — that are at just the right distance from their stars to have liquid water, and, perhaps, life as well. ||||| Water with a high deuterium content can only form under specific conditions. The environment needs to be very cold, and there needs to be enough energy to power the reaction that binds hydrogen, deuterium and oxygen. Over the past several decades, researchers have come up with two possible — and competing — explanations of how this heavy water took up residence in our solar system.
target: – If you live and die by food and beverage expiration dates, you might not want to know how old some of our drinking water is. A study finds that 30% to 50% of the water found in our taps and oceans contains molecules created more than 4.5 billion years ago—making them older than our solar system and the sun, the Los Angeles Times reports. The findings from the study, published in Science, indicate that certain water molecules contain a deuterium atom instead of a hydrogen atom (making what's called "heavy water"), which could only be created under very cold, energy-replete conditions—specific conditions that didn't exist before the Earth, sun, and solar system were formed. Earth was actually "born dry," in an extremely hot environment, according to the Times. Scientists believe we eventually received water via comets or asteroids that crashed down on Earth's surface. Figuring out where the water in the comets and asteroids came from, however, is another story, though researchers think they've narrowed it down to two possibilities: that the heavy deuterium water was dispersed among bodies in the solar system during the "violent" process of our sun's birth, or that the heavy water originated from ice found in the gas cloud from which our sun and solar system were born. Either way, researchers say this could indicate that young planets all around the universe contain water: According to scientists, there are up to 11 billion planets outside our own system that could house liquid water and, possibly, life, notes Time. (The amount of water found on Mars surprised scientists around the world.)