Directions for teachers: Ask students to read the online Science News article “Organic molecules in an ancient Mars meteorite formed via geology, not alien life,” which describes new research into the origin of organic material found in a space rock, and answer the following questions. A version of the article, “Meteorite’s organics aren’t signs of life,” appears in the February 12, 2022 issue of Science News.
1. In the 1990s, what did scientists report about a meteorite from Mars that was found in Antarctica?
The meteorite contained organic molecules.
2. At the time, what were two theories that scientists came up with to explain the finding?
Scientists thought that the molecules either were produced by life on Mars or were contaminants from Earth.
3. Name two ways that organic molecules can form.
Organic molecules can be formed by living organisms or through nonbiological, or abiotic, processes.
4. What has recent research revealed about the meteorite’s organic molecules?
A new study suggests that organic molecules in the meteorite resulted from geologic processes on Mars, not alien life.
5. How and where do scientists now think the molecules formed? Describe the evidence that supports the scientists’ claim in your answer.
Organic molecules in the meteorite probably formed during two chemical reactions — serpentinization and carbonation — on Mars a long time ago. The molecules were found amid by-products of the reactions, which occur when minerals and water meet. The amounts of different types of hydrogen in the organic material suggest that the molecules developed on Mars, not naturally on Earth or as part of laboratory experiments.
6. What does the new finding and evidence from other Martian meteorites suggest about the formation of organic molecules on Mars? What about the search for life on the planet?
Abiotic processes probably have been producing organic molecules on Mars for much of the planet’s history. Understanding how abiotic processes create organic compounds on Mars could help scientists investigate how life, if present, might impact those reactions.