World’s largest atlas of universe’s gas bodies compiled, could decode how galaxies form, evolve

China’s Five-hundred-meter Aperture Spherical radio Telescope (FAST) has achieved a significant breakthrough in astronomy. FAST has produced the largest-ever atlas of neutral hydrogen sources across the universe, according to a report.The milestone marks a significant step in humanity’s effort to understand how galaxies form, evolve and interact on the largest scales.Reports revealed that the FAST detected 156,411 neutral hydrogen sources during two years of observations. The observations cover approximately 19,500 square degrees of the sky—nearly half of the entire celestial sphere. Neutral hydrogen is one of the most fundamental forms of matter Neutral hydrogen is one of the most fundamental forms of matter in the universe. Often described as the raw material from which stars and galaxies develop, it also preserves information about the evolution of the cosmos.Astronomers can detect neutral hydrogen through the characteristic 21-centimeter radio emission it produces. Unlike visible light, radio waves at this wavelength can pass through significant amounts of cosmic dust, allowing scientists to observe gas that may otherwise remain hidden.FAST is particularly well suited to this task because of its enormous collecting area and high sensitivity. Its observations provide astronomers with a powerful tool for studying the distribution of hydrogen and, consequently, the structure and evolution of galaxies. New dataset represents dramatic expansion over FAST’s earlier observations Known as FASHI DR2, the new dataset represents a dramatic expansion over FAST’s earlier observations. The telescope’s first dataset, released in January 2024, contained 41,741 detections and itself established a world record.The latest survey has increased that number to 156,411—almost four times the earlier FAST figure. According to the report, FAST has also surpassed the record of the US Arecibo Telescope’s ALFALFA survey, which had been a leading neutral-hydrogen survey for nearly two decades. The scale of the new catalogue is particularly important because it gives researchers an unprecedented number of individual galactic measurements. Each detection effectively provides scientists with another piece of information about the distribution of matter in the universe.The significance of the project extends well beyond simply counting galaxies. Researchers can use the enormous dataset to investigate some of the most important questions in modern cosmology.The observations are expected to contribute to research into galaxy formation and evolution, the distribution of dark matter and the development of large-scale cosmic structures. Scientists have also been able to extend measurements of the neutral-hydrogen mass function to galaxies containing roughly one million times the mass of the Sun. Another important achievement is the measurement of the local density of neutral hydrogen with a statistical precision of approximately 0.6 percent, described in the report as the most accurate measurement of its kind to date.Such precision matters because even small improvements in astronomical measurements can help scientists test existing theories about how the universe developed and refine models of cosmic evolution.The latest catalogue is expected to further encourage international cooperation, particularly in areas such as galaxy evolution, cosmology, large-scale cosmic structures and the identification of possible sources of gravitational waves.The significance of the project extends well beyond simply counting galaxies. Researchers can use the enormous dataset to investigate some of the most important questions in modern cosmology.