When we think of extraterrestrial life, we always imagine it on rocky planets similar to Earth. But the universe is full of surprises. Some scientists believe that the atmosphere of brown dwarfs could be a conducive environment for the development of microorganisms.
Brown dwarfs are celestial objects with a mass that ranges between that of gas giant planets like Jupiter and smaller stars. Their peculiarity is that they are not capable of maintaining the constant nuclear reactions that make stars possible, so they remain halfway between them and the planets.
According to a recent study by the University of Edinburgh led by scientist Jack Yates, the upper layers of the atmosphere of brown dwarfs have pressures and temperatures similar to those of Earth, and could harbor microbes in updrafts rich in building blocks for the lifetime.
Given that it is estimated that there could be about a billion brown dwarfs in the Milky Way alone, this would skyrocket the number of candidates for possible home to alien organisms.
A cozy atmosphere
The existence of microbes that live in the air currents of our planet has been known for decades. Why wouldn’t something similar happen in the Earth-like atmospheric layers of some brown dwarfs?
In 2013, astronomers discovered WISE 0855-0714, a brown dwarf just 7 light-years away that appeared to contain clouds of water in its atmosphere. Yates and his team have relied on the study of this celestial body to identify what kinds of microbes could thrive in the habitable regions of huge atmospheres composed mostly of hydrogen. In the absence of sunlight, these organisms would feed on chemical nutrients. Observations of the atmospheres of brown dwarfs have revealed that they contain most of the ingredients that life on Earth depends on: carbon, hydrogen, nitrogen and oxygen.
At the moment, the idea is a speculation, but many astrobiologists consider brown dwarfs favorable scenarios for life. Scientists eagerly await the launch of the James Webb Space Telescope, scheduled for October 2018. This observatory will relieve Hubble and will have infrared instruments ideal for surveying the atmosphere of these failed stars that are candidates to contain microscopic aliens.
Photo (NASA / JPL-Caltech / University of Western Ontario / Stony Brook University): The illustration shows what the weather might be like in a brown dwarf.
