Life precursors in space
doi:10.1038/nindia.2008.251 Published online 30 July 2008
Researchers have devised computational models to spot probable life precursor molecules that inhabit star forming regions in space1. The models provide vital insights into light signals emanating from such space-faring molecules.
The large carbon-based molecules known as polycyclic aromatic hydrocarbons (PAHs) might hold the key to origin of prebiotic molecules and even seeding of life on an earth-like planet.
Scientists have long wondered about unidentified absorption and emission of light from remote locations in space. Increasing evidence linked such phenomena to existence of PAHs. These molecules are actually large carbon molecules such as benzene, naphthalene and pyrene. They can be churned out in terrestrial fuel combustion. After being excited by ultraviolet rays, the PAHs cool and emit light in the range of infrared colours with wavelengths between 6 and 8 microns (visible colours are about 0.4 to 0.7 microns).
The new model takes into consideration small, medium and large PAHs. It relies on theoretical infrared data of PAHs having 10 to 96 carbon atoms. The PAHs were found to emit infrared light at wavelengths 7.6, 7.7 and 7.8 microns.
"Nearly 20% carbon of the universe is estimated to be made up of these molecules," says lead researcher Shantanu Rastogi from the Department of Physics of Deen Dayal Upadhyay Gorakhpur University. He says that the presence of complex carbon-based molecules points to the possibilities of prebiotic material and space-based origin of life.
- Pathak, A. et al. Modeling the interstellar aromatic infrared bands with co-added spectra of PAHs. Astron. Astrophys. 485, 735-742 (2008) | Article |