In the most inhospitable environments of the cosmos, the ingredients necessary for the emergence of life manage to form.
Thanks to the James Webb Space Telescope, a team has scrutinized the core of a galaxy named IRAS 07251-0248, relatively close to us. This region, normally hidden by immense amounts of dust and gas, could be analyzed, revealing its chemical composition.
False-color image of the galaxy IRAS07251-0248 obtained by JWST.
Credit: Mikulski Archive for Space Telescopes, Space Telescope Science Institute, Association of Universities for Research in Astronomy, Inc., NASA.
For this study, the researchers used two specific tools of the telescope, capable of detecting infrared light. This wavelength easily passes through dust clouds, allowing the study of areas previously invisible from Earth. The collected data thus offered a detailed view of the gas and materials present at the heart of this galaxy.
The analysis revealed an impressive diversity of small organic molecules. Among them, benzene, methane, and several types of acetylene are found. These carbon compounds are considered preliminary steps toward the formation of more elaborate molecules, those that are essential to biological processes.
The observed chemical richness far exceeds the predictions of current theoretical models. According to scientists, this indicates that an active mechanism continuously produces these molecules. They think that highly energetic particles, cosmic rays, could fragment larger dust grains, thus releasing the small organic compounds.
This discovery indicates that highly obscured galactic nuclei could serve as organic molecule factories. Such regions could then chemically enrich their environment, offering conditions favorable to the development of prebiotic chemistry in space.
The work, published in the journal
Nature, opens the way to new studies on the origin and evolution of carbonaceous molecules in galaxies.
The power of infrared
The James Webb Space Telescope (JWST) primarily observes the Universe in infrared, a light that our eyes do not see. This capability is valuable because many cosmic objects, like dust clouds, block visible light but let infrared pass. By using this wavelength, JWST can thus see through obstacles that previously masked entire regions of the sky.
The instruments on board, such as NIRSpec and MIRI, are specially designed to analyze this light. They divide infrared radiation into different colors, like a prism, which allows identifying the molecules present. Each type of molecule absorbs or emits light at specific wavelengths, creating a unique signature that astronomers can decode.
This technique, called spectroscopy, provides detailed information on the chemical composition, temperature, and density of gas and dust. It thus transforms a simple image into a data-rich map, revealing hidden processes at the heart of galaxies or in the clouds where stars are born.
Thanks to infrared, JWST explores extreme environments, from stellar nurseries to dusty galactic nuclei. It thus fills gaps in our understanding of the formation of stars and planets, as well as the distribution of elements essential for life in the cosmos.