If aliens were to rock their planet with powerful greenhouse gases like we do, we might understand.
That’s according to a recent thought experiment in which scientists identified five “artificial” greenhouse gases that could be detected in the atmospheres of certain planets if they were present in sufficient quantities. outer planets Using existing technology, James Webb Space Telescope (JWST).
Gases including fluorinated versions of methane, ethane, propane, Soil They are known to be some of the most potent and persistent heat-trapping gases emitted by humans during various industrial manufacturing processes, such as those used to produce semiconductors. Since these substances do not occur naturally in large quantities — at least if we go by Earth chemistry — detecting them in the air of an exoplanet would indicate the presence of technologically advanced species, the scientists say.
On Earth, these gases are dangerous pollutants, and limiting their emissions is vital to combating human-induced pollution. climate changeHowever, being in an unfamiliar atmosphere may not necessarily be bad news.
“For us, these gases are bad because we don’t want to increase warming,” Edward Schwieterman, lead author of the study from the University of California, Riverside, said recently. expression“But they could be good for a civilization that perhaps wants to prevent an approaching ice age or terraform an uninhabitable planet in their system, as people have suggested Anthem“
Relating to: NASA space telescope finds Earth-sized exoplanet that’s ‘not a bad place’ to search for life
This kind of deliberate climate change to create an Earth-like environment is called terraforming. The idea of terraforming Mars has been in nearly every science fiction story, and in recent years, scientists have proposed similar approaches to support long-term colonization. Ideas for warming Mars include melting some of the ice at the planet’s poles and releasing trapped carbon dioxide on its surface, which would then help support the planet’s thin atmosphere like a warm blanket. Still, some remain skeptical of the concept. For example, Paul Sutter, an astrophysicist at SUNY Stony Brook and a contributor to Space.com, wrote in a 2021 article It probably won’t work.Because Mars probably doesn’t contain enough carbon dioxide to trigger a modest warming trend.
More recently, Schwieterman and his colleagues simulated a planet TRAPPIST-1 systema family of seven rocky planets about 40 light years Far from Earth, in the constellation Aquarius, many are considered potentially habitable. For example, the planet TRAPPIST-1f orbits its host star once every nine days habitable zone.
If aliens were to terraform such a planet, the researchers found that JWST would be able to detect five greenhouse gases. One of them, sulfur hexafluoride, has a warming potential 23,500 times greater than carbon dioxide. With a lifetime of at least 1,000 years, the researchers say tiny amounts of this gas would be enough to melt an icy planet to the point where liquid water could flow on its surface to support life (life as we know it, obviously).
“Their long lifetime makes these gases excellent technosignatures to systematically search for compared to shorter-lived signals,” said Daniel Angerhausen, co-author of the study from ETH Zürich. expression“These signatures could even outlive their civilizations if geoengineering experiments fail.”
Similar fluorinated gases could remain suspended in an Earth-like atmosphere for up to 50,000 years, so they “would not need to be replenished very frequently to maintain a hospitable climate,” Schwieterman said in the statement.
Related Stories:
— Young Jupiter-sized ‘cotton candy’ planet could be turning into a super-Earth
— Earth-sized planet discovered around cool red dwarf star shares its name with a biscuit
— Star blasts away atmosphere of giant exoplanet, leaving behind a huge tail
This means that there may be extraterrestrial life on cold planets beyond our own. solar system pump lots of greenhouse gases into their atmospheres to make their worlds more habitable, our current telescopes would be able to detect them. Even if just one in every million molecules of the gas absorbs infrared radiation from its parent star, it will produce a distinctive signature that can be detected by JWST and others. spaceSchwieterman and his team invented -based telescopes.
“If your telescope was characterizing the planet for other reasons, you wouldn’t have to go to the extra effort of looking for these technosignatures,” Schwieterman said. “And finding them would be incredibly surprising.”
These findings are explained as follows: paper It was published June 25 in The Astrophysical Journal.