The Search for Life Beyond Earth

How do we search for life beyond Earth, and how would we know if we had actually found it? The Search for Life Beyond Earth explores the science behind one of humanity’s oldest questions, beginning with a surprisingly difficult problem: what is life? From the characteristics of life as we know it on Earth to the possibility of “life as we don’t know it”, the talk will examine the methods used to search for biosignatures on Mars, ocean worlds, and distant exoplanets.

But detecting a possible sign of life is very different from demonstrating that life exists. Through cases such as the ALH84001 Martian meteorite and the reported detection of phosphine in the atmosphere of Venus, we will explore how intriguing observations can challenge scientific interpretation and why alternative explanations matter. The talk will also introduce NASA’s Confidence of Life Detection (CoLD) framework and consider a fundamental question at the heart of astrobiology: what evidence would be enough to convince us that we have discovered life beyond Earth?

About Dr. Thilina Heenatigala

Dr. Thilina Heenatigala (he/him) is a university professor at the Earth-Life Science Institute (ELSI). His work explores astrobiology and the search for life beyond Earth, with particular interests in how scientists evaluate evidence for potential life and how astrobiological discoveries intersect with society. His research spans life-detection methods, scientific uncertainty, planetary exploration, and the broader questions raised by the possibility of discovering life elsewhere in the universe.

• The talk will be in English
• Participation is free
• The talk will be in-person at BioClub and online at https://zoom.bioclub.tokyo