We would be able to discern if aliens altered a planet in their solar system to become warmer. The artificial greenhouse gases that would be obvious signs of a terraformed planet have been identified by a recent study from UC Riverside.
Life has been artificially introduced to a terraformed planet. With current technology, the chemicals reported in the study might be visible in the atmospheres of planets outside our solar system, even at relatively low quantities. This might involve the James Webb Space Telescope or a space telescope proposal led by Europe in the future.
Furthermore, there are reasons why such polluting gases might be deliberately employed on an exoplanet, even though they must be restricted on Earth to avoid negative climate consequences.
We object to these emissions because we wish to prevent global warming. However, as humans have suggested for Mars, they might be useful for a society hoping to terraform an otherwise unsuitable planet in their system or avert an approaching ice age,” according to UCR astrobiologist and senior study author Edward Schwieterman.
These gases have to be produced artificially because it is unknown if they exist in large quantities in the natural world. Therefore, discovering them would be evidence of sentient, technologically advanced living species. Technosignatures are the term for these signals.
The extraordinarily long lifetime of the proposed gasses, which could last up to 50,000 years in an atmosphere similar to Earth, is another benefit, at least from the perspective of an extraterrestrial. “They wouldn’t need to be replenished too often for a hospitable climate to be maintained,” Schwieterman stated.
Since CFCs and other refrigerant molecules are virtually entirely man-made and are detectable in Earth’s atmosphere, others have suggested that they are technosignature gases. Nevertheless, in contrast to the fully fluorinated gases covered in the current article, which are chemically inert, CFCs harm the ozone layer, so they might not be as beneficial.
“If another civilization had an oxygen-rich atmosphere, they’d also have an ozone layer they’d want to protect,” Schwieterman stated. “CFCs would be broken apart in the ozone layer even as they catalyzed its destruction.”
CFCs are difficult to detect since they are short-lived and more quickly broken down.
Lastly, in order for the fluorinated gases to affect the climate, they must absorb infrared light. Space-based telescopes may be able to pick up the equivalent infrared signal that is produced by that absorption. With existing or future technologies, these compounds could be found in certain nearby exoplanetary systems by scientists.
The group also took into account the possibility of detecting fluorinated chemicals with the European LIFE program. In comparison to the Webb telescope, which observes planets as they pass in front of their stars, the LIFE mission would be able to directly image planets using infrared light, enabling it to target more exoplanets.
This work was done in cooperation with researchers from NASA’s Goddard Space Flight Center, the Blue Marble Space Institute of Science, Paris University, and Daniel Angerhausen of the Swiss Federal Institute of Technology/PlanetS.
Although the scientists are unsure of how likely it is that they will find these gases in the near future, they are certain that, should they exist, they will be easily detected on the currently scheduled missions designed to characterize planetary atmospheres.
“You wouldn’t need extra effort to look for these technosignatures, if your telescope is already characterizing the planet for other reasons,” Schwieterman stated. “And it would be jaw-droppingly amazing to find them.”
Not only are other researchers excited about the possibility of discovering evidence of sentient life, but they are also excited about how much closer we have come to achieving that objective with existing technology.
Our thought experiment demonstrates the power of the telescopes of the future. Angerhausen continued, “We have the technology, as the first generation in history, to methodically search our galaxy for life and intelligence.
Reference : https://www.sciencedaily.com/releases/2024/06/240625205632.htm