When distant planets pass in front of their stars, their atmospheres filter the light, leaving traces of chemical constituents. JWST, which has become a kind of eye on space, is able to detect gases in the atmospheres of planets. But what would it look like if an alien civilization had their own version of JWST and decided to observe the Earth?
Most of the Earth’s atmosphere is made up of nitrogen and oxygen, but other gases, albeit in smaller amounts, can have a significant impact on our planet.
The effects of climate change have become apparent and can be observed from afar. This important discovery raises interesting questions about the nature of Earth’s atmosphere and whether aliens can recognize the signs of an intelligent civilization.
A team of astronomers conducted a study, calculating what the characteristics of the Earth’s atmosphere would look like in infrared light.
Their analysis showed the presence of a variety of gases, including methane, carbon dioxide, ozone, and even CFCs, which have been present on Earth for 33 years.
In such an off-world scenario, the presence of CFCs would be strong evidence of an artificial source, as they do not occur naturally. The biosphere and the “technosphere” would come under scrutiny, and alien observers would certainly be surprised.
Despite the noisier signals, the team was still able to isolate methane, carbon dioxide, and ozone. However, without context, these gases by themselves do not indicate the presence of intelligent life, but they can arouse interest and raise questions.
Using the Earth as a model, astronomers are going to better understand the atmospheric features of exoplanets like our own.
An interesting test object is the TRAPPIST-1 planets: seven Earth-sized exoworlds orbiting a red dwarf. If they have an atmosphere, JWST can help determine their habitability.
Among the 4,000 planets within 50 light-years of Earth, there may already be civilizations that are watching us.
However, the Fermi Paradox, which is why they didn’t contact us, remains one of the most exciting questions in astronomy and the search for extraterrestrial civilizations.