Is There Life on Mars?
Mars is the best place to search for life beyond Earth. We haven't found it yet — but the search is intensifying.
Why Mars?
- River valleys and lake beds
- Polar ice caps
- Minerals that form in water
- Perseverance rover is exploring an ancient river delta
Where there was water, there may have been life.
What We're Looking For
- Organic molecules (not proof of life, but suggestive)
- Isotope ratios that indicate biological processes
- Microfossils in rocks
- Methane (possibly produced by microbes)
Current Missions
- Exploring Jezero Crater (ancient lake bed)
- Collecting samples for future return to Earth
- Ingenuity helicopter — first powered flight on another planet
- Found organic molecules
- Detected seasonal methane variations
- Exploring Utopia Planitia
The Viking Controversy
In 1976, Viking landers performed life-detection experiments. One experiment gave positive results, but most scientists interpreted them as chemical reactions, not life.
The debate continues to this day.
Underground Life?
- Protection from radiation
- Possible liquid water (geothermal heating)
- Stable temperatures
Life on Mars, if it exists, is likely underground.
Sample Return
The best way to confirm life is bringing samples to Earth's labs. NASA and ESA are planning a Mars Sample Return mission for the early 2030s.
If we find life on Mars — even microbial — it would be the greatest discovery in human history.
Related Reading
Listen to the Full Course
Explore the Red Planet in Space Exploration.