The presence of methane in a planet's atmosphere beyond the Solar System might be a significant sign for living activity in certain situations. If this is the case, it would be a huge step forward in the search for life and one that the NASA James Webb Space Telescope could easily do.
Researchers detailed the study results in Proceedings of the National Academy of Sciences on Monday.
A woman stands near a model of the James Webb Space Telescope (JWST) at NASA Goddard Space Flight Center in Greenbelt, Maryland on April 2, 2015.
Methane Could Be the Key to Finding Life on a Faraway Planet
Vice said a team lead by Maggie Thompson, a Ph.D. student in astronomy and astrophysics at UC Santa Cruz, prepared an updated approach to interpret detections of methane gas on exoplanets, which may be created by biological and abiotic processes.
"We wanted to provide a framework for interpreting observations, so if we see a rocky planet with methane, we know what other observations are needed for it to be a persuasive biosignature," Thompson said in a statement.
Thompson and her colleagues point out that methane is the only biomarker that the James Webb Space Telescope can detect in terrestrial atmospheres. Hence, understanding methane biosignatures is critical for contextualizing these forthcoming findings.
Scientists are already looking for biosignatures in exoplanet atmospheres, such as oxygen, ozone, and carbon dioxide, that might indicate the presence of life.
The chemical characteristics of methane, on the other hand, coincide with the JWST's sweet observational spot at near-infrared wavelengths, making it a crucial molecule in the hunt for extraterrestrial life.
Other simulations using JWST data, as one by co-author Joshua Krissansen-Totton in 2018, revealed that while it will be able to identify and restrict methane abundances, finding oxygen would be far more complex.
Even modest releases from volcanoes may produce enough methane to imitate biological products if it remains stable over extended periods of time. However, in the presence of sunshine, CH4 interacts to make carbon dioxide and hydrogen or forms aerosols that fall to the Earth.
Three Reasons Why Scientists Believe Methane Is An Important Element
The researchers presented methane as a possible biosignature in three parts, which James Webb Space Telescope could easily detect.
UCSC's Department of Astronomy and Astrophysics' Joshua Krissansen-Totton, a NASA Sagan Fellow, told Reuters, "First, it would be unsurprising for life elsewhere to produce methane."
Even if life's biochemistry on other planets differed dramatically from Earth's, given the energy sources believed to be available on rocky exoplanets, methanogenesis is a clear and straightforward metabolic approach for any carbon-based life.
Second, researchers claimed that methane would not last long in the atmospheres of habitable rocky worlds without regular replenishment, potentially by living beings.
Atmospheric methane on Earth is unstable as it is destroyed by the chemical effects of light. Still, it is constantly replenished by biological processes.
Third, nonbiological activities like as volcanism or chemical reactions at mid-ocean ridges and hydrothermal vents would find it challenging to continue replenishment without leaving a "fingerprint" that the methane was not biologically produced.
For example, gas-emitting volcanoes would produce carbon monoxide with methane, but biological activity eats carbon monoxide and lowers its quantity in the atmosphere. Nonbiological processes, they said, could not readily generate rocky planet atmospheres rich in methane and carbon dioxide, as on Earth, but with little or no carbon monoxide.
With Webb and other modern telescopes, scientists hope to get a better understanding of exoplanet atmospheres, analyzing their chemistry when these faraway worlds pass in front of their host stars from Earth's viewpoint.
Methane As A Strong Greenhouse Gas
Daily Mail said Methane (CH4) accounted for nearly 10% of all human-caused greenhouse gas emissions in the United States in 2019.
Leaks from natural gas infrastructure and livestock husbandry are two examples of human activities that produce methane.
Natural sources of methane, such as natural wetlands, also emit gas.
Methane is also removed from the atmosphere through natural processes in soil and chemical reactions in the atmosphere.
Methane has a far shorter lifespan in the atmosphere than carbon dioxide. Still, it is more effective at trapping radiation than CO2.
Over 100 years, the comparative impact of methane is 25 times larger than that of carbon dioxide.
Human activities account for 50-65 percent of total CH4 emissions globally.
Energy, industry, agriculture, land use, and waste management activities all release methane.
Check out more news and information on Space in Science Times.
