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Scientists now believe that we will be able to detect signs of life on planets beyond our solar system in the coming decades, but to do this, new tools and techniques will be needed. Researchers around the world have just produced a roadmap for developing techniques that can ultimately answer the question of whether we are alone in the Universe. This work was published this month in five articles in the journal Astrobiology . These papers will serve as a reference for future research on how scientists can search for signs of life in the cosmos using telescope observations.
Scientists believe that there can be planets around almost every star in the galaxy. Planets orbiting stars beyond our own Sun are called "exoplanets". In fact, the pace of discovery of exoplanets has been so fast – more than 3,500 have been discovered since the first in 1992 – that a meeting of scientists from many disciplines was urgently needed to synthesize the knowledge to improve our ability to find signs of life. these new exoplanets. Formed three years ago, Nexus for the Science of Exoplanet Systems (NExSS) is an international network that brings together researchers from diverse disciplines to understand how we can characterize and possibly look for signs of life, called biosignatures, on exoplanets. As we can not currently visit exoplanets, scientists must use telescopes to search for biosignatures. These observations will have to push our telescope technology to its limit.
To this end, NExSS has produced a comprehensive series of articles describing the past, present and future of research on looking for signs of life on exoplanets. These major papers are the result of two years of work by some of the world's leading researchers in astrobiology, planetary science, earth sciences, heliophysics, astrophysics, chemistry and biology. This work began with online meetings followed by a face-to-face workshop held in Seattle, Washington in 2016, where scientists exchanged ideas and debated new plans on how best to identify life on worlds other than our solar system. Several members of the Earth-Life Science Institute (ELSI) and researchers from other institutes in the Tokyo area participated in these activities, either in person or remotely. These discussions formed the basis of articles published in Astrobiology .
The articles identify several problems in this research and propose solutions. There are two main types of signals that scientists plan to look for. A type is in the form of the gases that life produces, for example the oxygen you are breathing right now, which has been made by plants or photosynthetic microbes. They also plan to look for light reflected from life itself, such as the color of leaves or the pigments that color algae in the oceans and hot springs of Yellowstone. These types of signatures can be observed on Earth from orbit, and astronomers are studying new telescope design concepts that could detect them on exoplanets.
The group discusses ways in which nature could "deceive" living scientists, or vice versa. Scientists are examining how a planet could produce oxygen – which is abundant on Earth through lifelong biological photosynthesis – and how the planets with life can have biosignatures in addition to oxygen. Thinking about these types of planets in advance, scientists are now better prepared to distinguish such worlds from truly inhabited planets, and how to expand the catalog of biosignatures that scientists can look for in the future.
quantify the life chances and clarity of his signals on other worlds, which is an incredibly important and difficult challenge. The data that astronomers collect on exoplanets will be relatively sparse; they will not have samples from these planets, and instead will have data from only one point of light in this world. By analyzing fingerprints of gases and atmospheric surfaces in this light, they will discern as much as possible about the exoplanet. This includes inferences about the atmospheric composition and climate of the planet, and the presence of oceans and continents. By systematically combining this information and developing new models, scientists will be able to analyze whether data from a planet can be better explained by the presence of life. Based on these models, they plan to establish confidence levels to know if biology is present in this world. The new work highlights the need to consider planets in an integrated way, which includes multiple disciplines and perspectives.
Finally, new instruments will be needed – the telescopes that will make the necessary observations for this work. This includes both terrestrial and space observatories, and the two telescopes in use today and others that will be built decades into the future. These new technologies will not only improve the evaluation of the sizes and orbits of these distant worlds, but will also allow a more in-depth analysis of their atmospheres and surface properties. Eventually, they could tell us if they have the potential to shelter life. Mission concepts with biosignature detection as a central engine are discussed for launch in the 2030s.
"Since the mid-20th century, we have seen significant advances in methods and technologies that we can use to observe and characterize the exoplanets.Many of them have been tested on large uninhabitable planets, "said Yuka Fujii, researcher at ELSI and senior author of one of the articles. The scope of the observations is now extended to exoplanets of the size of the Earth, potentially temperate. The data that will be collected over the next decade will allow scientists to better study the planets that can support life. "The search for life on exoplanets at light-years is an ambitious challenge – it will not conclude with the detection of a single characteristic, but will require long-term efforts to accumulate a set of" signatures "that can not be explained by any The authors concluded with the promising assessment that, considering the upcoming technologies and current knowledge about the distributions of exoplanets, the detection of atmospheric signatures of a few potentially habitable planets could even arrive before 2030.
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Materials Provided by Tokyo Institute of Technology . Note: Content may be subject to change in style and length.
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