CHAPTER 05 · Read Cosmos
Mars exploration and evidence of life
Do traces of life necessarily constitute evidence of life?
Explore this chapter ↗Let's begin! The experience allows you to directly interact with the scenes and observation tools.
Separate hopes from evidence on Mars
Chapter 5 of the original book juxtaposes the imagined and actual exploration of Mars. The initial interpretation of faint features, such as canals and civilizations, did not align with the closer observations.
The probes and landers pose more specific questions: Was there an environment suitable for liquid water? What reactions are occurring in the soil? Can these reactions be explained by non-biological processes?
OBSERVE · Start with evidence
Three pieces of evidence
- There are landforms that suggest the presence of past water.
- The Viking experiments involved reactions that require interpretation.
- The Viking mission did not establish a definitive conclusion about the existence of life on Mars.
While Mars may be different from what is expected, exploration continues.
New commentary following Mars exploration in chapter 5 of the original book. It distinguishes traces of water, conditions favorable to life, and confirmation of life.
What should be filled in?
There are many gaps in interpretation for objects that are only vaguely visible. Considering the expectation of reading canals and civilizations into the Martian "river" like appearance, consider whether you have simply observed the form and explained the cause.
More precise observations may overturn the initial narrative. This does not mean that the exploration failed, but rather that it provides an opportunity to adjust the explanation to match the observations.
Questions to ConsiderThe close-up view is different from what was expected. What record should you leave?
Was there water? Was there life?
Evidence of past water activity is important for understanding the history of a planet. However, finding conditions that are favorable to life and actually confirming the presence of life are different things.
If a reaction is observed in a soil experiment, the cause must be explained. If you do not consider the possibility that a non-biological process could produce the same result, you will be led to interpret the reaction as evidence of a particular conclusion.
Questions to ConsiderThe experimental reaction is compatible with life. What next?
The value of stating "we don't know yet."
The fact that Vikings did not establish the existence of life does not mean that the investigation has found nothing. The next questions can be started on more specific surface and experimental data.
Dividing results only into "success" or "failure" misses the intermediate process of gaining knowledge. Keep track of what you have learned, what you have ruled out, and what you have deferred judgment on.
Questions to ConsiderWhat should be the final sentence of the investigation report?
Discoveries and their limits
The search for life is not about abandoning expectations, but about demanding stronger evidence. Claims about the possibility of life, compatible reactions, and the definitive confirmation of life are all distinct.
Differentiate between what has been confirmed and what remains to be investigated about Mars, and suggest one question for the next expedition.
Explore this chapter ↗Evidence and further reading
To overcome the limitations of telescopes, we must send observers directly. What should we measure?