Scientists may have found a way of locating distant planets capable of nurturing alien life, claims a study, "Sensitive probing of exoplanetary oxygen via mid-infrared collisional absorption", published in the journal Nature Astronomy on 6 January.
Recent research, funded in part by Goddard's Sellers Exoplanet Environments Collaboration (SEEC), and NASA Planetary Science Division's Internal Scientist Funding Model, has identified a strong signal that oxygen molecules produce when they collide.
The new method of seeking out signs of life would involve looking for oxygen in the atmosphere of exoplanets – worlds outside our solar system.
On Earth, oxygen is generated when organisms such as plants, use photosynthesis to convert sunlight into chemical energy.
Scientists are now hoping that NASA's James Webb Space Telescope will be able to detect this oxygen molecule signal in the atmospheres of exoplanets, thus offering an instrumental breakthrough in the search for alien life.
Exoplanets are planets outside the Solar System. Their discovery stoked renewed interest in the search for extraterrestrial life, as planets that orbit in a star's habitable zone, where it is possible for liquid water to exist on the surface, opened up a new field for astronomers.
However, investigating exoplanets has to happen from afar because with current technology, we can't reach them.
The James Webb Space telescope provides incredible sensitivity for light readings compared to its predecessor, according to NASA, which has worked with Astronomers at UC Riverside in California to develop the new technique.
"Before our work, oxygen at similar levels as on Earth was thought to be undetectable with Webb, but we identify a promising way to detect it in nearby planetary systems," said Thomas Fauchez of the Universities Space Research Association at NASA's Goddard Space Flight Center in Greenbelt, Maryland and lead author of the study.
"This oxygen signal is known since the early 80's from Earth's atmospheric studies, but has never been studied for exoplanet research."
A member of the study team, Edward Schwieterman, a University of California Riverside astrobiologist, added:
“Oxygen is one of the most exciting molecules to detect because of its link with life, but we don’t know if life is the only cause of oxygen in an atmosphere. This technique will allow us to find oxygen in planets both living and dead.”
When oxygen molecules collide, they block parts of the infrared light spectrum from being seen by a telescope.
However, it’s by examining patterns in that light that scientists hope to determine the composition of the planet’s atmosphere. The researchers caution that an abundance of oxygen on an exoplanet may not necessarily mean life, as it could also indicate a history of water loss due to evaporation of oceans.
“It is important to know whether and how much dead planets generate atmospheric oxygen so that we can better recognise when a planet is alive or not,” said Dr Schwieterman.
Although the oxygen signal is strong, considering the vast cosmic distances, the exoplanets will have to be relatively nearby for Webb to detect the signal the atmospheres.
Webb, an international project led by NASA with its partners, ESA (European Space Agency) and the Canadian Space Agency, will be the world's premier space science observatory, when it launches in 2021, with the promise of solving many mysteries in the solar system and looking beyond to distant worlds around other stars.