New Haven School, where I teach science, is a residential treatment center for girls who have experienced trauma and other challenges. During the summers, since we can’t send our students home until they have completed their treatment program, we hold elective classes that help the girls make up any missing credits. I have continued to teach in-person during the COVID-19 pandemic; during the summer of 2020 one of the classes that I taught was astrobiology, the study of life beyond Earth.
Astrobiology is a unique science because it does not actually have a subject. No life has yet been found beyond Earth. It therefore focuses on how we might discover and identify that life, what its characteristics might be, and where we should look for it. We study Earth analogs, organisms living in extreme environments similar to what might be found on other planets (which we call extremophiles) and how life could have originated and evolved on early Earth. As such astrobiology is part biology, part astronomy, part geology, and part educated guesswork. Astrobiologists come from many disciplines ranging from astrophysics and radio telescopy to microbiology and paleobotany. Just take a look at the many research areas listed for the scientists at the SETI Institute in Mountain View, CA at:
I have had the privilege to meet and even work with a number of astrobiologists, including a number with the SETI Institute such as Dana Backman and Coral Clark with my participation as a SOFIA Airborne Astronomy Ambassador. In March 2012 I participated in a field research study of biological soil crusts, an extremophile that grows on the soils in the Mojave National Preserve and elsewhere in deserts around the world. The crusts in that area are black patches that form small groups of mounds; they are a small ecosystem consisting of cyanobacteria, fungi, and other components living in a symbiotic relationship under extreme conditions of dryness and heat. We collected samples from three sites along the Kelbaker Road between Baker, CA and Kelso Station. One area was along a wash with more frequent water and the crusts appeared highly concentrated and healthy. One area closer to Baker was of medium concentration, and the final area was near Baker and had the least concentration of crusts.
We returned the samples for testing at the Desert Studies Center on Zzyzx Road neat Baker, and I helped to study the mineral content of the soils and identify the geologic formations near the sample areas to see if geology and minerals might be responsible for the differences. We also put the soils through a soil sieve to determine the percentages of clay, sand, and loam in the soils. Other people in our group studied ATP content, nitrogen fixation, chlorophyl abundance, and other metabolism markers. Catalase and polymerase chain reactions (PCR) were done in real time at the Desert Studies lab, the first time I had ever seen this done in person. Samples were also sent to labs to determine the types of archaea and cyanobacteria living in the crusts through DNA sequencing. I wrote about my experiences with this study in earlier posts on this blog site.
Some of the scientists on our expedition included Rakesh Mogul of Cal Poly Pomona and later with NASA’s Office of Planetary Protection; Parag Vaishampayan of NASA’s Spaceward Bound program, which trains prospective science teachers in field research and data analysis techniques; Chris McKay of NASA Ames Research Center; and Rosalba Bornaccorsi of the SETI Institute. A paper describing the results of our study was published in Frontiers in Microbiology on 23 October 2017 titled “Microbial community and biochemical dynamics of biological soil crusts across a gradient of surface coverage in the central Mojave Desert.” You can read it here:
I am listed as one of many co-authors, as there were quite a large group of us including three practicing classroom teachers (including one from Australia) and a number of pre-service teachers in the CSU system. My involvement was part of an award for winning third place in the Mars Education Challenge the year before, sponsored by Explore Mars, Inc., the group that organizes the annual Humans to Mars (H2M) conference in Washington, DC. Chris McKay is a member of the Board of Directors, as is Penny Boston, another noted astrobiologist.
As Dr. McKay put it during our research expedition, the reason we study biological soil crusts (BSCs) and other extremophiles is that they provide us with clues about the nature of life itself and how it adapts under difficult environments, such as that found on early Earth. The first living things on Earth were archaea similar to the organisms living in the BSC community and date to about 3.5 billion years ago, when Earth’s atmosphere was a thick, hot blanket of carbon dioxide. Atmospheric oxygen only occurred on Earth because cyanobacteria started pouring free oxygen into the oceans, which at first was chemically bonded with iron in ocean water but eventually became so prevalent that it is now 20% of Earth’s atmosphere. It is an obvious marker that life exists on this planet, something that could be seen from many light years away and which we are now beginning to look for in the atmospheres of exoplanets with the Kepler and TESS missions and soon with the James Webb Space Telescope.
We also study extremophiles because they act as canaries in coal mines; as our climate changes, extremophiles living on the edge of existence are the most sensitive to changes. They can be an early warning system that our environment is becoming unlivable.
For my astrobiology class this summer, I wanted to involve my students in a group project that would stretch their abilities and lead to a useful result. We decided to create a school astronomy magazine which we would publish quarterly, titled Ad Adstra Per Educare (To the Stars through Education). Students in the class would write a series of articles, most around 200 words to act as sidebars but at least one article that could be a feature article of at least 800 words. As we discusses the nature of life, its characteristics and the factors necessary for it to develop during out first week, each student picked an extremophile and wrote an article about it. They also picked an astrobiologist and wrote a short biography.
In an effort to teach quality and professionalism to my students, I have implemented a form of Critique similar to that used at High Tech High and developed by Ron Berger and others at Expeditionary Learning. Each student was asked to Critique the articles of two other students for each assignment and make positive suggestions in a kind and useful manner. You can read more about this process here:
The students then incorporated these suggestions as they revised their articles, and I acted as editor to make final suggestions. The best articles, those that have been through three drafts, have been included in the first edition of our magazine, which has a theme of Life in the Extreme. I am including the transcript of an interview I did with Chris McKay in our first edition. It will be on this blog as my next post.
Because of the privacy requirements of my school, only the first initials of the authors will be used. The images in the magazine have been partially created by my media design class from this summer. Others are my own photographs. Other editions will follow, including our second edition on Life in the Solar System, focusing on Mars and a landing site selection activity my students presented to each other. Our third edition will be on the Nearby Stars and a 3D model of the stars out to 15 light years away that my students built as a culminating activity. Our fourth edition will be on the Search for Extra Terrestrial Intelligence. Other editions will come from future classes; my physics class this coming year has been accepted for the ExMASS program (Exploring Mars and the Asteroids by Secondary Students) through the Lunar and Planetary Science Institute. We will report on our research as the fifth edition.
The first edition of our magazine is now available here, if you want to download it or read it:
Ad Astra 1-1 Life in the Extreme-s
We hope you enjoy our magazine. Some of the best articles will be posted on this blog. Given the great need for online activities that can be done at home by students due to school closures from the COVID pandemic, the magazine will include a series of lesson plans I have developed for my own classes. These include an update on how to use Mars, lunar, and USGS 3D terrain data; how to build our 3D star model; and other lessons. Please let us know how you have liked our magazine and how you have used it in your research or classes.