The Asteroid as a Catalyst for Discussion

Earth’s “close encounter” with asteroid 2012 DA14 and the Russian meteor shower on the same day have gotten me thinking about the origin of life. After all, evidence from carbon and nitrogen isotopes suggest that some of life’s key chemical ingredients may have hitched a ride to Earth on meteorites (see, for example, the papers referenced at the end of this post).

It might be interesting to ask students to pretend that the asteroid unexpectedly collides with Earth, and it’s their job to figure out whether it contains life or organic chemicals from space. What would they look for? What sort of evidence would convince them that any cells or molecules really came from space (rather than Earthly contaminants)?

If you have ideas for integrating this current event into your biology classroom, please share!


  • Engel, M. H., and S. A. Macko. 1997. Isotopic evidence for extraterrestrial nonracemic amino acids in the Murchison meteorite. Nature, vol. 389, pages 265–268.
  • Martins, Zita, Oliver Botta, Marilyn L. Fogel, and six coauthors. 2008. Extraterrestrial nucleobases in the Murchison meteorite. Earth and Planetary Science Letters, vol. 270, pages 130–136.
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