So far, astronauts have discovered 4164 exoplanets in 3085 star systems, and another 5347 are still waiting for confirmation. With so many planets available for study, researchers can use new restrictions to determine the possibility of a planet being habitable. In fact, the latest estimates say that there may be 6 billion in the Milky Way alone! These discoveries can be seen rekindled interest in searching for extraterrestrial intelligent creatures.
However, although the research on habitable planets focuses on finding evidence of life processes (life signals), historically, searching for extraterrestrial intelligent creatures focuses on scientific and technological activities (technological signals). Under NASA's authorization, researchers from Harvard Smithsonian Astrophysics Center and the University of Rochester are preparing for the new research that will look for different types of potential technological signals.
Traditionally, technological signal search involves using radio telescopes to search the Milky Way and find evidence of artificial radio signals, because radio waves are the way of communication. The new study, “technical signals that describe the atmosphere,” will look for two other time-tested, proven evidence of scientific and technological activities—solar panels and pollutants.
Human activities are the main source of air pollution, most of which come from the process of industrialization. The belief in the study of searching for alien life is that while life may appear in different forms, scientific principles (such as those that govern the application of science and technology) are unified. Therefore, other intelligent creatures may also discover the usefulness of these technologies that are useful to humans. As Frank Baird Jr., a professor of science at Harvard University, said in a CfA press release:
"The technological signals related to advanced alien technology signals are similar to and may surpass the technology we master. Such signals may include atmospheric industrial pollution, urban lights, photovoltaic cells (solar panels), large buildings, or satellite clusters."
solar panels are a rapidly developing method of collecting sustainable energy. According to common sense, other advanced civilizations at the post-industrial development level will regard them as available alternatives to the production of energy. No matter where you look for signals or what you look for, finding technological signals is always a challenge for SETI researchers.
However, when it comes to their research, Lob and his colleagues have some working parameters. Their work is based on previous research, notably a 2014 study (“Detection of Industrial Pollution in the Atmosphere of Exoplanets”), which was co-written and directed by Lob. In this study, the team tried to identify anthropogenic pollutants as potential technical features, with their goal of focusing on fluorocarbons (CFCs). Visualization of ozone layer void caused by fluorocarbons. Source: NPP OMPS/SSAI/Aura OMI/Suomi NPP/NASAAA/DoD Specifically, the team focused on observations of carbon tetrafluoride (CF4) and trichlorofluoromethane (CCl3F), the easiest to detect fluorocarbons (CFCs) because of their absorption properties within the upcoming James Webb Space Telescope (JWST) spectral range, which is expected to operate next year.
When looking for biometrics, scientists often search for chemicals related to life in the planet's atmosphere. Our instruments and methods have been greatly improved in recent years. Current telescopes can directly obtain spectra from the atmosphere of exoplanet - especially when next-generation telescopes, such as the Extra Large Telescope (ELT) and Nancy Grace Roman Space Telescope are put into use. "We have made a lot of progress in understanding how life can be detected from the atmospheres of other planets," said Jason Wright, a professor of astronomy and physics at Penn State. In addition to discovering chemicals naturally produced by life, such as methane, astronomers can also discover artificially produced chemicals and gases (such as through industrial methods). "Our industrial activity pollutes the Earth's atmosphere. If another civilization spends much longer in this regard than we do, then the atmosphere of their planet may show signs of artificial molecules that are unlikely to be produced spontaneously by nature, such as fluorocarbons (CFCs).
space solar panel array conceived by artists. Source: Credit NASA/SAIC
In addition, there are signs of using solar panels. In this case, the previous research conducted by Lob and Manasvi Lingam (Assistant Professor of Astronomy at Florida Tech) came into play. As Avi Lob explained to Astronomy Online via email:
solar panels absorb a certain wavelength of light and then reflect the rest. This leads to the spectral edge of its reflected light, which is significantly different from the "red spectral edge" produced by vegetation. By observing the light reflected on the surface of a planet, you can tell whether it covers solar panels. Solar panels like
are particularly useful for tidal locked planets that have been fixed on one side towards the parent star. A civilization might want to mount solar panels in the day hemisphere that is always facing the star, and then use the energy collected there to illuminate and heat the cold night hemisphere. "
In the past, this work has been difficult because scientists do not know the direction to find technical characteristics. This in turn makes it difficult for these researchers to obtain funds and gain a foothold in the mainstream astronomy community. However, in recent years, the discoveries of exoplanets have surged, many of which are orbited within the star habitable zone and have atmospheric water vapor. These discoveries inject new vitality into the search for intelligent life. Artistic imagination of
Clarke belt (Clarke exobelt) is set in the portrait of Sir Arthur C. Clarke. Source: Caro Waro (@carwaro)
Professor of Physics and Astronomy at the University of Rochester, principal recipient of funding. "Extraterrestrial Civilization Exploration (SETI) has always faced a challenge, which is not knowing where to look, or which stars the telescope is pointing to to find signals. And now it’s different, we have thousands of exoplanets, many of which are in habitable zones where life can form. The rules of the game have changed. ”
Loeb, Frank, Wright works with Mansavi Lingam of Florida Tech and Jacob Haqq-Misra of Blue Marble Space. In addition to finding signs of solar panel use and pollutants, the team hopes to find satellite constellations around planets and stars (also known as “Clarke” Belts), giant buildings and signs of artificial gravity.
Loeb says these signals can be detected with standard ground and space telescopes. In time, he and his colleagues hope to produce the first records and eventually become an online technical feature library.
Many questions raised in their research, including recent questions about whether the solar system is accessed by alien rovers, can be found in Professor Loeb’s forthcoming book Alien: The First Signs of Intellectual Life Beyond Earth.
Author : MATT WILLIAMS
FY: Astronomical volunteer team
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