It is not a matter of if, but a matter of when, the remains of life will be discovered on Mars.
Will such a discovery shake the foundations of Christian faith? The answer lies in the difference between the words indigenous and transported. I reported sixteen years ago1 and in all three editions of The Creator and the Cosmos,2 that the nature and longevity of life on Earth makes the existence of Earth-life's remains on Mars and other solar system bodies a foregone conclusion.
To date, more than 20 Martian meteorites have been recovered. These Martian rocks were blasted away from the grip of Mars' gravity many years ago as asteroids and comets crashed upon that planet's surface. Of all the Martian rocks ejected into outer space, 7.5 percent eventually find their way to Earth. In 4 billion years about 4 billion tons of Martian material has been deposited on Earth.3
The same process operates to bring Earth rocks to Mars, but in smaller numbers. Because of Earth's stronger gravity, fewer Earth rocks escape into outer space from asteroid and comet collisions with Earth. And though Earth's stronger gravity and larger size mean that Earth receives more collisions than Mars, Mars' weaker gravity and smaller size mean less Earth material arrives there. Only 1.7 percent of the rocks escaping Earth's gravity wind up on Mars.
During the 3.8 billion-year-history of life on Earth at least a hundred million tons of Earth material has landed on Mars. Attached to these hundred million tons of Earth material are at least several million pounds of Earth-life remains. Even some viable life may be found in these deposits, but that chance is remote. Only a few microorganism species are hardy enough to survive such a journey to Mars and then only if the journey is atypically rapid (thousands of years instead of millions of years).
Several million pounds of the remains of Earth life seems a lot, but spread out over the entire Martian surface it becomes an extremely thin deposit—an average of about two ounces per square mile. To find it will be challenging. What's more, most of the remains of Earth life on Mars will be very old. Proteins, DNA, RNA, and even the nucleotide molecules that make up RNA and DNA decompose in about 50,000 years or less.4 Unless researchers find a very recent arrival from Earth, the best evidence for life astrobiologists can hope to find on Mars are certain chemical signatures for the broken-down remains of microorganisms.
Four other solar system bodies—the Sun, Moon, Venus, and Mercury—receive more Earth life and its remains than does Mars. Nevertheless, since Mars offers an environment less devastating to life and its remains than do these alternatives, it ranks as the best extraterrestrial candidate on which to search for such signs. If NASA searches long and hard enough, it should find evidence for at least some small amount of life remnants on Mars. Such a discovery will grab headlines for sure, but further study will reveal the source of those remains. Rather than supporting a naturalistic worldview, the evidence will testify to how prolific, diverse, and exquisite is the life God created on Earth during the past 3.8 billion years.