The common belief is that an exoplanet which is rich in oxygen, one of the essential elements for life on Earth, might also host life, following the example of our world. However, in a shocking new study, scientists concluded that alien planets with oxygen in their atmosphere might not necessarily house extraterrestrial life, and that’s because the commonly-accepted biosignatures may be a false positive for life on exoplanets.
“People used to suggest that oxygen and organics being present together indicates life, but we produced them abiotically in multiple simulations. This suggests that even the co-presence of commonly accepted biosignatures could be a false positive for life,” explained Chao He, the new study’s leading author.
Even though the Earth’s atmosphere consists of several elements, such as 20 percent oxygen and the rest made of nitrogen, argon, and carbon, researchers hypothesized during previous studies that the presence of oxygen in the atmosphere of alien planets might indicate for the presence of life. Chao He, however, found out that this is not the case, in reality.
Alien Planets With Oxygen In Their Atmospheres Might Not Necessarily House Extraterrestrial Life
After performing several simulations in which they tested gas mixtures that are “consistent with predictions for super-Earth and mini-Neptune type exoplanet atmospheres,” the scientists, led by Chao He, observed that many of the biosignature containing oxygen, that could be identified in the atmosphere of exoplanets, might be a false positive.
The gas mixtures used by researchers contained water, carbon dioxide, ammonia, and methane. The scientists heated the samples to temperatures between 80 to 700 degrees Fahrenheit, and then they placed the mixtures into Planetary HAZE (PHAZER) chambers and exposed them to UV light and plasma. In the end, the researchers noticed that the various compounds within the mixtures produced oxygen and organic matter such as formaldehyde and hydrogen cyanide.
“Our laboratory results indicate that complex atmospheric photochemistry can happen in diverse exoplanet atmospheres and lead to the formation of new gas products and haze particles, including compounds (O2 and organics) that could be falsely identified as biosignatures,” said the scientists in the study’s abstract.