Finding extraterrestrial life isn’t necessarily as simple as looking for it with our eyes. A lifeform might be too small to see, or too far away, or too different than what we expect to find. In addition to direct observation, we can also infer (deduce) the presence of life by looking at traces (clues) that a living thing leaves behind.

Detecting electrical activity

• Many living things on Earth have electrical activity (for example: an ECG recording of the human heart’s electrical signal).
• If we detect the presence of an electrical signal that shows a pattern or that is not noise, this might be evidence for the presence of a lifeform.