Life may therefore be spread throughout the Universe

Mar 30, 2012 08:12 GMT  ·  By

In a paper published in the March 30 issue of the top journal Science, experts proposed that the organic molecules which enabled the development of life here on Earth were first formed in the protoplanetary disk around the young Sun.

The conclusion belongs to a series of computer simulations, which revealed that the dusty structures contained all the necessary ingredients to form such molecules. As the planets formed, these molecules made their way to multiple worlds at the same time.

A protoplanetary disk is made up of leftover materials from when a new star is born. It is now accepted that blue stars form from collapsing hydrogen and dust clouds. However, when this happens, not all the materials in the original cloud go into the new stellar object.

The leftovers accumulate in a disk that rotates around the star, and gradually begin to interact. Small dust particles cling to each other, forming centers of gravity that eventually go on to become the seeds of rocky planets, asteroids, gas giants, meteorites, comets and so on.

What the new computer models suggest is that the protoplanetary disks may also be capable of forming organic molecules, not just clumps of rock. Undoubtedly, the most interesting aspect of the new study is that it applies to all newly formed stars, and their disks, regardless of where they are.

This implies that – if conditions in the early solar system are replicated elsewhere – life may develop and thrive on other worlds as well. It would then be up to each exoplanet in these star systems to support the development of primitive life, Space reports.

According to geophysicist Fred Ciesla and astrobiologist Scott Sandford, ultraviolet light is needed to promote the development of organic molecules inside protoplanetary disks. “The origin of these organics has been a mystery,” Ciesla explains.

“There have been a number of places where they have been thought to have formed, and none are mutually exclusive,” adds the expert, who is based at the University of Chicago. Sandford is a researcher at the NASA Ames Research Center (ARC), in Moffett Field, California.

They explain that, in this context, the term organic molecules refers to elements such as nitrogen and carbon, and to complex molecules such as amino acids and nucleobases. The latter form the backbone for DNA and RNA.

“The dynamics and the processes that we've put in the model here, we don't expect them to be unique to our solar system. We expect this to be present in all planet-forming disks,” Ciesla concludes.