Dear Sophia,

Yes. The water on our Earth today is the same water that’s been here for nearly 5 billion years. Only a tiny bit of it has escaped out into space. As far as we know, new water hasn’t formed either.

That means there’s a very high chance the water in your glass is what thirsty dinosaurs were gulping about 65 million years ago.

It’s possible that you could drink the same water as a stegosaurus or a T-Rex because of the way water circulates around our planet. A dinosaur, you, and I are actually part of this water cycle, too.

As water on the surface of lakes, oceans, and rivers warms up, it travels into the sky as very tiny droplets, or vapor. When the water vapor gets colder, it turns back to liquid to help form clouds.

When the liquid gets so heavy it can’t stay in the atmosphere anymore, it falls, or “precipitates,” as rain, snow, sleet, hail, or, my favorite, graupel. Once the precipitation reaches the ground or lands in lakes, oceans, and rivers, the cycle continues.

You, a dinosaur, and I drink water, and eat foods that contain this water, too. It’s so refreshing to lap it up from my bowl. We get rid of some water as fluids or gases, such as the ones we let out when we breathe.

That’s what I found out from my friend Kent Keller who investigates the water beneath Earth’s surface. He’s a geologist with Washington State University’s School of the Environment.

He said water also moves in ways we don’t always think about. Scientists have found water trapped in minerals deep within the Earth’s mantle and crust, he explained. This water is even older than dinosaurs. It doesn’t look like liquid water that’s in your glass, but it still made of the same stuff.

“We’ve realized there is a lot of water down there,” Keller said. “There’s as much water chemically speaking, more or less, as there is in the oceans. It’s just in a different form.”

Another place we find water from dinosaur days is in organic matter. When the dinosaurs died, their bodies broke down to become part of the Earth. Over time, some of this organic matter became shale, coal, and oil we use for fuel.

The water dinosaurs drank is in more than just the water we drink, minerals, and organic matter. It’s also what we use to shower, cook, and water plants for food.

Right now, Keller is visiting with fellow scientists at the Global Institute for Water Security in Saskatchewan, Canada. They are curious about how we’ll take care of our water for the future.

“Life as we know it – every cell in every plant and animal — is mostly water. To say it requires water is an understatement,” Keller said.

The water in your glass may be the same water dinosaurs drank, but it’s also the same water that’s going to keep life on our planet in the years to come.

Sincerely,

Dr. Universe

Got a science question? E-mail Dr. Wendy Sue Universe at Dr.Universe@wsu.edu. Ask Dr. Universe is a science-education project from Washington State University.