Mars once had a thicker atmosphere and liquid water on its surface. Nearly every month data from satellites and multiple ground-based systems provide new evidence confirming what was once speculation about the watery past of Mars. But how much water and how long ago did this water exist?
A large amount of water still exists on Mars trapped in permafrost below the surface and possibly even frozen lakes. Despite the abundance of water retained on Mars, most of the water from its past is missing having been lost to outer space. Exogeologists have constructed a general history of Mars in which this watery past existed several billion years ago. Since that time water has been lost to space leaving the planet to be shaped mostly by wind rather than water.
The watery past of Mars – A challenge to a young solar system
When water existed on Mars, how much was there, and where did it all go aren’t just questions for exogeologists. Young-earth creationists believe Mars was created on the fourth day of creation just 6000 years ago. Therefore, they must compress the history of Mars into this short time span. A watery past for Mars raises a more acute question for the young earth creationist – lest call them young mars creationists (YMCs): what caused flooding on Mars and where did the water go?
Real or just apparent history? Many Christians when shown pictures of Mars with its mountains, valleys and countless craters assume that this is the world that God created on the fourth day. The apparent history that a mountain or a crater suggests is no more an indication of real history as a tree with rings in the Garden of Eden, similar sequences of genes between different kinds of organisms or a belly-button on Adam and Eve. We call this explanation for the appearance of creation as the creation with apparent age hypothesis.
However, young Mars creationists don’t believe Mars was created as we see it today. As I hinted recently in a review of the film “Is Genesis History?” YMCs believe that Mars has been radically transformed as an outcome of the curse on Adam for his transgression: “..the Fall impacted the whole cosmos, according to Romans 8:22.” Hence, the mountains, valleys and craters found on Mars today could very well all have formed within the past 6000 years or even more recently if their origins coincide with a global flood on the Earth 4500 years ago.
Most young earth creationists willingly accept the evidence that water once flowed on Mars. They can see that there are massive deposits of sedimentary rock, there are erosion patterns that suggest large rivers and there are shallow areas that have rock types that point to their formation in shallow oceans or lakes. For example, here is Answer in Genesis’ Andrew Snelling in 2007:
“There is no longer any doubt that the surface of Mars has in the past been covered by huge volumes of water which spread over vast areas. These resulted from cataclysmic outflows, which were also responsible for catastrophic erosion of channels and valleys, on a scale far greater than anything comparable on Earth, and deposition of sedimentary strata.” Water activity on Mars: Landscapes and Sedimentary Strata.
I find it rather remarkable that Snelling can observe that a flood on Mars could have effects at even larger scales that on Earth. Furthermore, a global Flood on Mars makes little sense Biblically. Why should God destroy the surface of Mars for the sin of man on Earth?
Dr. Snelling and other Young Mars Creationists seem to be driven to their conclusion that there was flooding on Mars solely on the basis of physical evidence. The Biblical record does not tell us about a cataclysmic flooding on Mars. I find it a bit ironic that YMCs accept the watery past of Mars based on solely on the interpretations of data about the data (eg. they are doing historical science) despite constantly insisting in their literature that the conclusions of historical science are untrustworthy.
So what happened to the water?
Creationists have speculated that there may be connection of the Flood on Earth and changes to the climate and possibly even a flood on Mars at the same time. But the water on Earth is still here – at least most of it – and on Mars most of the water is gone. There is some water in the polar caps on Mars and certainly large volumes frozen in the sediments. But the norther hemisphere of Mars has evidence that a large ocean existed there once and is hard to hide an entire oceans worth of water in sediment and some frozen lakes.
Astrogeologists and chemists have been studying the history of Mars atmosphere and water and have concluded that Mars had a much thicker atmosphere in the past. This is not surprising given that a more substantial atmosphere would be necessary to allow liquid water to be sustained on the surface. And they now agree that there was much more water.
So where did the water and the atmosphere go?
The simplest solution: It escaped into outer space.
This latest research on Mars water provides us with even more evidence that this is what happened. Satellites and numerous models of the interface of the atmosphere with space have measured gasses that are escaping from Mars today just as they are escaping from the Earth’s atmosphere.
One difference between Earth and Mars is that water can escape from Mars far more easily than it can from Earth which may explain why, if both began with water and thick atmospheres, that Mars is so different from Earth today. But what is really fascinating about this model of Mars history is that we can do more than speculate about the past history of Mars. We can test our hypothesis about water on early Mars.
One way scientists can do this is by looking closely at the water itself. There are two forms of water. You can read more about the specifics of these water types here but for simplicity I will simply call them heavy and light water molecules. As you might guess heavy water molecules are less likely to escape the upper atmosphere and so one would expect that as more light molecules escape the ratio of heavy to light should increase over time.
Very precise measurements now available for the Mars atmosphere allow us to compare the ratios of heavy to light versions of water for Mars and Earth. Knowing those ratios the original amount of water can be calculated. What those measurements reveal is that in the polar caps of Mars water for every 1 heavy water molecule there are 400 light ones but on Earth the ratio is 1 heavy water for every 3200 light water molecules. That is eight times as much heavy water on Mars. Therefore if Mars started with similar amounts of heavy water as the Earth then Mars must have had far more light water in the past.The calculations reveal that Mars has lost an arctic oceans worth of water to space.
You might objects and say, but how do we know that Mars ever had the same ratio of heavy and light water? Maybe God simply made Mars with a different ratio of original water molecules. We weren’t there so how could we ever know?
No person was there to measure and record the ratio of water molecules 4 billion years ago but there was something that was there that recorded it for us: rocks that formed on Mars when water was present on the surface. Rocks that formed early in Mars history and trapped water molecules should retain the original ratio of water on Mars. We can measure the water ratios in these rocks today. This has been done with martian meteorites and may also be done with the drill on Mars Curiosity rover.
Water measured in ancient martian meteorites reveal ratios of heavy and light water that is similar to Earth’s current ratio. This is direct evidence that the original water on Mars was similar to water on Earth and therefore the very different ratios observed today are best explained by a dramatic loss of light water from Mars into space.
The escape rate of water from Mars today suggests that such large volumes of water could have been lost to space over a billion years or more. This data is very problematic to Young Mars Creationists who believe that this water existed less than 10,000 years ago. Not only is there the ratio of heavy to light water problem but regardless of the type of water lost, the loss of water to space is not a viable explanation given rather strict physical limits on the rate of water loss given the gravitational constraints of a body the size of Mars. How could trillions of gallons of water be lost to space in just a few thousand years!? YMCs like Snelling will likely assert that the water is still on Mars but he can only do so by suggesting that much of that water remains hidden from our sight. And this explanation would do nothing to account for the ratio of heavy to light water.
Once again, we see that simplest explanation for the data we have collected on Mars water and atmosphere suggests an ancient watery origin followed by billions of years of loss of its atmosphere and water. The young mars creationists must appeal to unknown mechanisms of loss, supernatural intervention, or assert missing data to provide any explanation for what we observe. Mars hardly provides support for a young universe. Rather it shows us that Mars has diverse geological features and an atmosphere that is best interpreted as the result of a lengthy process of development.