exoplanets, alien life, Extraterrestrial Life, Extrasolar Planets, Biosignatures, Atmosphere

Leading space organizations have estimated several potentially livable extrasolar planet, orbiting adjacent stars. The chase for Extraterrestrial life in these spots, which are beyond difficult to visit in person, will start with a look for biological products in their atmospheres. It could be plausible to narrow down this search for extraterrestrial life by studying the extrasolar planet’s atmosphere and examining its seasonal changes. These atmospheric fingerprints of life, called biosignatures, are likened to the fingerprints that only biological life is expected to leave in the atmosphere. These biosignatures will be identified using cutting-edge telescopes that measure the components of gases existing in the atmosphere of the exoplanets that are light years far from Earth.

It is exceptionally unlikely that researchers will visit exoplanets at any point in the near future, so the search for extraterrestrial life or alien life should start by concentrating at their atmospheres, says new investigation, reports Phys.Org.

Nevertheless, the paper also points out a concern that it’s a complicated job because biosignatures in context of single measurements of atmospheric gases of the particular planet could be misleading or inaccurate.

So to make this approach feasible in practical terms, and with the funding from the NASA Astrobiology Institute, scientists from the University of California, Riverside’s Alternative Earths Astrobiology Center are creating the first ever quantitative framework to catch dynamic biosignatures based on seasonal changes in the atmosphere of Earth and how it varies year by year, states the report.

As our planet Earth orbits the Sun, with its tilted axis gets fluctuating levels of sunlight in different times of the year. The most noticeable indications of this phenomenon are the changes it goes through in the weather and the length of days. In any case, the changes in weather additionally have an effect on the atmospheric composition, states the report. The northern side of the equator, for instance, has a larger part of the planet’s vegetation, so in the summer, the northern half of the globe has a measurably limited level of carbon dioxide and a greater level of oxygen.

“Atmospheric seasonality is a promising biosignature because it is biologically modulated on Earth and is likely to occur on other inhabited worlds,” said Olson. “Inferring life based on seasonality wouldn’t require a detailed understanding of alien biochemistry because it arises as a biological response to seasonal changes in the environment, rather than as a consequence of a specific biological activity that might be unique to the Earth.”

In addition to the tilt of axis as on Earth, remarkably elliptical orbits, as opposed to axis tilt, could yield seasonality on extrasolar planets, or exoplanets, growing the scope of conceivable targets. As stated in the paper, using an imaging technique called spectroscopy, the specialists recognize the opportunities and pitfalls associated with identifying the seasonal formation and reduction of oxygen, carbon dioxide, methane, and their discovery.

They additionally displayed variances of air oxygen on a life-bearing planet with low levels oxygen content, similar to that of Earth billions of years prior. They found that ozone (O3), which is created in the atmosphere by the reaction including oxygen gas (O2) created by life, would be an all the more effortlessly measurable marker for the seasonal inconstancy in oxygen than O2 itself on feebly oxygenated planets.

“It’s really important that we accurately model these kinds of scenarios now, so the space and ground-based telescopes of the future can be designed to identify the most promising biosignatures,” said Edward Schwieterman, a NASA Postdoctoral Program fellow at UCR. “In the case of ozone, we would need telescopes to include ultraviolet capabilities to easily detect it.”

Schwieterman said the difficulty in searching for extraterrestrial life is the uncertainty of information gathered from so far away. False positives – nonbiological processes that take on the appearance of life and false negatives – life on a planet that creates less or no biosignatures are both significant concerns. “Both oxygen and methane are promising biosignatures, but there are ways they can be produced without life,” Schwieterman said.

The head writer Stephanie Olson said examining seasonal changes in oxygen or methane would be more instructive. “A potentially powerful way to assess exoplanets for inhabitation would be to observe their atmospheres throughout their orbits to see if we can detect changes in these biosignature gases over the course of a year,”.

The author further adds, “In some circumstances, such changes would be difficult to explain without life and may even allow us to make progress towards characterizing, rather than simply recognizing, life on an exoplanet.”

Timothy Lyons, who is a professor of biogeochemistry in UCR’s Department of Earth Science and director of the Alternative Earths Astrobiology Center, says that this work enhances the fundamental strategy to searching for extraterrestrial life on very far away exoplanets.

“We are particularly excited about the prospect of characterizing oxygen fluctuations at the low levels we would expect to find on an early version of Earth,” Lyons said. The professor further adds to the statement, “Seasonal variations as revealed by ozone would be most readily detectable on a planet like Earth was billions of years ago, when most life was still microscopic and ocean dwelling.”

This research is financed by the NASA Astrobiology Institute and the National Science Foundation (NSF) Frontiers in Earth System Dynamics (FESD). Other than Olson, Schwieterman, and Lyons, the study paper’s authors are Andy Ridgwell and Stephen Kane from UC Riverside, Victoria Meadows from the University of Washington, and Christopher Reinhard from the Georgia Institute of Technology.

The only thing that could make extraterrestrial life possible on any extrasolar planet is its atmosphere. While, it is exceptionally abnormal that researchers will visit exoplanets or extrasolar planet at any point in the coming future, so the search for extraterrestrial life will probably start by analyzing biosignatures of their atmospheres. According to this recent study, the scientists believe that the biological products in the atmospheres of potential exoplanets may support in detecting extraterrestrial life. With the title “Atmospheric Seasonality As An Exoplanet Biosignature”, the study paper outlining the investigation was published today in The Astrophysical Journal Letters.


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