Black Holes to Blackboards: The Magic of Mars
Jeffrey F. Lockwood
Saguaro High School
All too often, physical science and biological science are compartmentalized, and students conclude they have little relevance to each another. But the discovery of possible signs of life on Mars is an opportunity to merge the two.
I remember so vividly the sonorous voice of the narrator on our black-and-white TV, describing the balloon-like creatures that, in 1956, were conjectured to float in the thin and cold martian atmosphere. I was 8 years old and sat transfixed as the Disney cartoonists drew fantastic creatures: eyes on stalks, huge flat feet to traverse the massive sand dunes, horny beaks to harvest lichen from the red desert floor.
Recently, I again sat transfixed as pictures of possible primitive creatures from Mars plucked from, of all things, a meteorite were shown on my color TV [see "Life on Mars...and in Science," p. 24]. I felt a quiet quivering in my insides as I contemplated the fact that science seems to be closing in on the truth about the history of the Red Planet and the questions of whether life once existed there and, even more amazing if true, whether life exists there now.
We teachers may be lucky enough to find out the answers to these questions during our lifetime. But even if we aren't that fortunate, we can spread the excitement of the chase to our students, the evolution of the quest for the truth, and the steps in determining an answer that must not only be demonstrated clearly, but also be validated by the majority of scientists. What could be a more exciting set of questions to examine with your students?
Given the present conditions on the Red Planet, what kind of environment would have had to have been in place on ancient Mars to facilitate the evolution of life? If primitive forms of bacteria were established in the water or ice of Mars billions of years ago, could they still exist, and if so, where might they be hiding? Where would you, if sent as an astronaut to Mars, look for them? What would be needed to provide a final proof that life evolved on Mars? For that matter, what is life?
This is a terrific opportunity to integrate biology into the astronomy curriculum, to show students or let them discover for themselves what constitutes life on Earth. The first chapter of the Life on Earth television series, available on videotape, shows the development of life on Earth and the ways in which simple cells evolved into colonial forms, such as volvox and sponges. The Life Sciences The Living Textbook videodisc set has hundreds of images of bacteria, spores, protists, and algae which students can observe and categorize. The disc also has short movies about the different types of bacteria, the nature of the protozoa in a drop of pond water, spore formation, and the properties of living cells. Students can view commercially produced slides of bacteria, algae, and protists through a compound microscope and compare them to the images of the martian "bacteria."
Better yet, students can find a multitude of different single-cell plants and animals in a sample of pond water. You can collect color sketches of student discoveries and create a class zoo by posting them on a bulletin board. The creatures in the zoo can be further classified (put in cages?) based on their similarities. Students will always find inanimate particles of one kind or another in their pond droplets and sketch them too. (If I only had a nickel for every instance a student thought an air bubble was a living creature!) This mistake can lead to a thorough and student-led discussion concerning exactly what we mean by "living thing."
By studying the characteristics of life on Earth, students can make more informed judgments about the possibility of life on Mars. Life is tenacious. The discovery of colonies of microbes in extremely harsh environments on Earth, such as the undersea "smokers" where temperatures reach 320 degrees Celsius (600 degrees Fahrenheit) and the dry valleys of Antarctica where temperatures drop to ¯70 degrees Celsius (¯100 degrees Fahrenheit), makes the existence of hidden life on Mars at least remotely possible. Could the martian subterranean regions be teeming with hot springs, anaerobic microorganisms, and algae-eating marsworms?
After a discussion on the present climatic and atmospheric conditions on Mars, students can be asked to become artists and "invent an alien." Instead of using the version of this activity in the Universe at Your Fingertips activity manual, in which students construct a model out of cardboard, Styrofoam, and other materials, I ask my students to design and draw their aliens on paper. Then they describe the special adaptive features of their aliens orally to the rest of the class.
After this activity, you and your students can discuss the possibility that their martian aliens actually exist somewhere on or below the surface of present-day Mars. You can ask your students some open-ended questions: If you were an astronaut setting off to look for life on Mars, where would you look first? What tools would you need? If you found life, would you continue to colonize Mars or would you leave the inhabitants alone?
My students also enjoy an exercise in which they examine the famous "Face on Mars" [see "The Face on Mars," The Universe in the Classroom, fall 1993]. Using Viking image 070A13 or 035A72 scanned into the computer, students apply the "NIH Image" software to measure facial parameters and ratios of the face such as the distance between the eyes vs. the length and width of the face and then compare them to George Washington's face on Mount Rushmore and their lab partners' faces. I hesitate to report that the ratios on all three faces are almost identical.
It is human nature to feel the thrill of the hunt, the stalking of the prey. We should take advantage of our students' natural instincts unabashedly and present astronomical research as a hunt for knowledge and as a careful stalking of the truth. One day, one of our students may help to uncover the final truth about life on Mars, and thereby begin the formulation of even more profound questions about the nature of sentient life in our universe.