Where do the molecules, considered to be the building blocks of life, come from? Do they originate in space? A new study, published in the Journal of Chemical Physics, shows that a number of small organic molecules can indeed form in a cold, space-like environment full of radiation.
As part of the research, scientists at the University of Sherbrooke in Canada created simulated space environments, and prompted chemical reactions that resulted in the building blocks of early organisms. The findings, therefore, suggest that the compounds needed for larger molecules, such as proteins and carbohydrates, to develop may have extraterrestrial origin.
After recreating the conditions of outer space in the lab, the researchers placed thin films of ice containing methane and oxygen into a vacuum. These ices, used to imitate materials found around dust grains in extraterrestrial molecular clouds, were then irradiated with electron beams, as a stand in for the radiation they would face in space.
The researchers found that the procedure led to the formation of a variety of small organic molecules in the icy films. These types of icy environments also exist on celestial objects like comets, asteroids and moons.
"All of these icy surfaces in space are subjected to multiple forms of radiation, often in the presence of magnetic fields, which accelerate charged particles from the stellar (solar) wind toward these frozen objects," the researchers said in a statement.
"Previous studies investigated chemical reactions that might occur in space environments through the use of ultraviolet or other types of radiation, but this is a first detailed look at the role of secondary electrons."
A huge amount of secondary electrons are produced when high-energy radiation, such as X-rays or heavy particles, interacts with matter. These electrons, also known as low-energy electrons (LEES), are still energetic enough to induce further chemical reactions.
The research group found that a variety of small organic molecules like propylene, ethane and acetylene were produced in icy films of frozen methane subjected to LEEs. The study was published in the Journal of Chemical Physics on Tuesday.
"Indirect evidence for many other small organic molecules, including methanol, acetic acid and formaldehyde was found. In addition, both X-rays and LEEs produced similar results, although at different rates," the researchers said.