Is There Water On Mars, What Is It Made Of?

Mars polar ice cap

Written by Thomas Godwin

Updated: May 15, 2023

Share on:


We’ve known for some time that water exists on Mars, in frozen or gaseous form. The thing that intrigues scientists the most these days is whether or not there is liquid water on the red planet. If so, where exactly? If there is liquid water on Mars, the planet has to be geothermal since the surface is simply too cold for water to remain in a liquid state.

While the answer is not conclusive, many scientists either believe or strongly suspect that there is liquid water on Mars and that water once existed in vast quantities across the planet. Water does exist in the form of ice and vapor, along with the frozen CO² otherwise known as dry ice.

Water buried beneath ice is not without precedent, since we have such a thing here on Earth. After all, Lake Vostok sits comfortably, three miles below Antarctica’s ice. Of course, Earth and Mars are different in almost every way, though a body of water sealed beneath an ice shelf is in a more comparable position.

Frozen and Gaseous Water on Mars

Frozen and gaseous water on Mars

These are the two forms of water that we know exist on Mars today. We know water exists in its gaseous form because Mars constantly bleeds it off in the form of vapor, into the atmosphere. Mars has no surface or liquid water because it sublimates from the polar caps whenever Mars goes through a warmer trend.

The ice caps themselves are proof of frozen water. If you were to introduce liquid water on the surface of Mars, instantly, as if you were stepping out into the atmosphere for the first time, it would immediately freeze or boil off. Whether it would freeze or boil would depend on when you expose it and where you’re standing.

Don’t confuse the ice of the polar caps with dry ice, which is also very prevalent on the surface of the red planet. Dry ice is frozen carbon dioxide. It forms in pockets, typically on the surface of the ice caps. There are massive, flowing glaciers of dry ice on Mars. They flow faster than water ice because of the thinness of the atmosphere.

The polar caps of Mars consist of both water ice and carbon dioxide ice (dry ice), with dry ice making up more of the south polar cap than it does in the north. The Korolev crater contains 250 million cubic meters of water ice, making it the largest deposit of water ice on the entire planet.

Where is the Liquid Water?

Mars’ atmosphere is 100 times thinner than Earth’s and is very cold. Because of that, water has no chance in a liquid form for more than a millisecond. That’s why, if there is liquid water, it must be below the surface. Its potential existence suggests the planet is geothermal. Since Mars is so cold, there has to be a source of heat from within to facilitate liquid water.

Though there are thousands of different, tiny indicators that point to the possibility of liquid water, there were two discoveries that lent the idea the most credence. The first was the European Space Agency’s Mars Express Spacecraft. This craft detected light reflections emanating from beneath the polar ice caps.

The craft also detected a slow rise and fall in elevation, coming from both caps, suggesting the existence of liquid water beneath. NASA’s Mars Reconnaissance Orbiter (MRO) often returns data on the narrow streaks that cover certain areas of the planet. These streaks are in the crosshairs because they suggest that water may flow beneath them.

According to the data returns from the MRO, the streaks periodically darken and lighten. They darken when Mars is warmer and lighten when it’s colder. Is it irrefutable proof? Not quite. However, it’s profoundly suggestive that water is flowing, to one degree or another, on Mars’ surface today.

Could Surface, Liquid Water Return to Mars One Day?

Could Surface, Liquid Water Return to Mars One Day?

It’s not likely, at least not in any of our lifetimes or the lifetimes of our children’s children. For such a thing to happen, it would take human intervention or some wildly lucky astronomical event. There are many theories on how water could return to the surface, in a liquid state.

However, thousands of little variables are difficult to calculate and even more difficult to anticipate if a warming process were to initiate on the surface. With all of the frozen carbon dioxide on the planet, heating it is the answer that most concede must happen.

Heating the frozen CO² would cause it to return to its gaseous state, where it would sublimate. As the surface warms, the process would quicken, ultimately turning into an extremely rapid greenhouse effect. Of course, this would melt any frozen water on the surface. However, it probably wouldn’t be enough.

There are existing theories on mass quantities of below-surface water and, at some point, tapping that water would be necessary, whether through drilling or some other method of extraction. None of this would produce an ozone layer on its own, and additional steps are necessary, such as the introduction of specific bacteria into the existing water from the heating process.

Some opine that, in a futuristic scenario, the bacteria of choice would be Cyanophyta, which uses the power of the sun to produce oxygen. Eventually, we could grow plants and introduce trees since vegetation is necessary for CO² absorption and the release of breathable oxygen.

Final Thoughts

While we know that water on Mars does indeed exist, it’s in the form of ice and vapor. The existence of liquid water is speculative, though we’re pretty sure it’s there. Until the day we visually confirm its existence, there will always be a handful of holdouts.

Creating water on Mars and therefore a livable atmosphere, is something that would take well over a hundred years, perhaps hundreds, with today’s technology. It would also require nearly unfathomable amounts of energy and money to gather the resources, move them, and construct them.

All of that to say this: If there is liquid water on Mars, it’s either below the surface or is otherwise unobserved. Ultimately, considering humankind’s current limitations, that’s not likely to change very soon.

Share this post on:
About the Author

Thomas is a freelance writer with an affinity for the great outdoors and Doberman Pinschers. When he's not sitting behind the computer, pounding out stories on black bears and reindeer, he's spending time with his family, two Dobermans (Ares and Athena), and a Ragdoll cat named Heimdal. He also tends his Appleyard Ducks and a variety of overly curious and occasionally vexatious chickens.

Thank you for reading! Have some feedback for us? Contact the AZ Animals editorial team.