A study from UC Riverside suggests that certain artificial greenhouse gases could indicate the presence of intelligent life on distant planets. These gases, which include fluorinated versions of methane, ethane, and propane, are used in industrial applications on Earth and could be detected in the atmospheres of exoplanets using existing technology like the James Webb Space Telescope. The gases are effective at warming planets and could be used to make otherwise uninhabitable planets hospitable. The study’s lead author, Edward Schwieterman, says finding these gases would be a sign of intelligent, technology-using life forms.
UC Riverside has proposed a novel method for detecting extraterrestrial life
A recent study from UC Riverside has proposed a novel method for detecting extraterrestrial life: by identifying artificial greenhouse gases in the atmospheres of distant planets. These gases, which are not known to occur naturally in significant quantities, would be indicative of intelligent, technology-using life forms. This concept of identifying signs of technology from other civilizations is known as technosignatures.
The study suggests that if an alien civilization were to modify a planet in their solar system to make it more hospitable for life, a process known as terraforming, they might use certain gases that are effective at trapping heat. These gases could be detectable even at relatively low concentrations using existing technology, such as the James Webb Space Telescope or future European-led space telescope concepts.
The Role of Artificial Greenhouse Gases in Terraforming
The researchers identified five gases that could potentially be used in the terraforming process. These gases, which are used on Earth in industrial applications such as making computer chips, include fluorinated versions of methane, ethane, and propane, along with gases made of nitrogen and fluorine or sulfur and fluorine.
One of the key advantages of these gases is their effectiveness as greenhouse gases. For instance, sulfur hexafluoride has 23,500 times the warming power of carbon dioxide, meaning a relatively small amount could heat a freezing planet to the point where liquid water could persist on its surface.
Longevity and Detectability of Proposed Gases
Another advantage of these proposed gases is their longevity. They are exceptionally long-lived and would persist in an Earth-like atmosphere for up to 50,000 years. This means they wouldn’t need to be replenished frequently for a hospitable climate to be maintained.
These gases also have the ability to absorb infrared radiation, which impacts the climate and produces a corresponding infrared signature that could be detectable with space-based telescopes. With current or planned technology, scientists could potentially detect these chemicals in certain nearby exoplanetary systems.
The Potential of Current and Future Space Missions
The researchers simulated a planet in the TRAPPIST-1 system, about 40 light-years away from Earth, to arrive at their calculations. This system, which contains seven known rocky planets, is one of the most studied planetary systems aside from our own and is a realistic target for existing space-based telescopes to examine.
The team also considered the European LIFE mission’s ability to detect the fluorinated gases. The LIFE mission would be able to directly image planets using infrared light, allowing it to target more exoplanets than the Webb telescope, which looks at planets as they pass in front of their stars.
The Future of Techno-signature Research
While the researchers cannot quantify the likelihood of finding these gases in the near future, they are confident that if they are present, it is entirely possible to detect them during currently planned missions to characterize planetary atmospheres.
The discovery of such technosignatures would be a significant step forward in the search for extraterrestrial life. As one of the researchers, Daniel Angerhausen, noted, “We are the first generation in history that has the technology to systematically look for life and intelligence in our galactic neighborhood.”
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