Question

One of the biomarkers we might use in the search for extraterrestrial life is the presence of _____ because it would be hard to explain its presence in the atmosphere except by the presence of biology.

Answer 1

Oxygen is considered a biomarker in the search for extraterrestrial life, as it is usually associated with biological activity such as photosynthesis on Earth. The challenge lies in distinguishing biological sources of oxygen from non-biological ones, ensuring that scientists do not misinterpret 'false positives' in the atmospheres of exoplanets.

Step-by-step explanation:

One of the biomarkers we might use in the search for extraterrestrial life is the presence of oxygen because it would be hard to explain its presence in the atmosphere except by the presence of biology. Oxygen is a significant biomarker as its abundance on Earth is closely linked to life processes such as photosynthesis. While the search for exoplanet life is complex, scientists look for atmospheric biosignatures that are difficult to produce through non-biological processes. However, we should also consider potential 'false positives' where oxygen might accumulate on planets due to processes like ultraviolet radiation interacting with the atmosphere in the absence of biological activity, as hypothesized for planets orbiting M-dwarf stars.

Our investigations into potential biospheres on distant planets are informed by conditions on Earth, but researchers remain cautious, as Earth's current biosignatures have not always been present throughout its history. Understanding the limitations of biomarker evidence is crucial in the ongoing quest to discover life beyond our planet.

Answer 2

Oxygen is a biomarker in the search for extraterrestrial life, hard to explain without biology. Scientists must rule out nonbiological processes, like ultraviolet radiation causing false positives, before confirming biological sources.

Step-by-step explanation:

One of the biomarkers we might use in the search for extraterrestrial life is the presence of oxygen because it would be hard to explain its presence in the atmosphere except for the presence of biology.

Oxygen is a global indication of life on a planet that could be detected remotely, often through an unusual atmospheric composition.

However, in the search for exoplanet life, scientists must carefully consider and rule out nonbiological processes that might account for the presence of certain biomarkers, such as the accumulation of oxygen in the atmosphere from the action of ultraviolet radiation on planets orbiting M-dwarf stars without the need for biology. These are known as "false positives" and understanding where they might exist is critical to our search for life beyond Earth.