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NASA's forthcoming Spectro-Photometer for the History of the Universe, Epoch of Reionization, and Ices Explorer (SPHEREx) mission is poised to become a game-changer in the field of astronomy. Unique among its peers, SPHEREx will capture the cosmos in over 100 colors, albeit in the infrared spectrum, providing the most colorful and comprehensive cosmic map ever constructed. This ambitious mission is slated for launch no later than April 2025 and heralds an exciting new chapter in the study of the universe.
As we understand it, the colors we see are a representation of various wavelengths of light. What makes SPHEREx extraordinary is its ability to observe these myriad colors across an unprecedented range, focusing on infrared light, which is just beyond the visible spectrum for humans. Using the technique known as spectroscopy, SPHEREx will dissect the light from countless stars and galaxies into individual colors — similar to a prism creating a rainbow from sunlight — providing vital details about the universe's composition and the distances of celestial objects.
This mission has three key scientific objectives. Firstly, by mapping the 3D positions of vast numbers of galaxies, SPHEREx will enhance our understanding of inflation, the rapid expansion that stretched the universe exponentially mere moments after the Big Bang. This epoch left a lasting imprint on how galaxies are distributed, which, in turn, could offer fresh insights into the inflationary process itself.
Secondly, SPHEREx is set to measure the total light emitted by galaxies across cosmic history — or, in other words, the cosmic glow. Previous attempts to estimate this have been based on the extrapolation of observations from individual galaxies, possibly overlooking faint or distant sources. With SPHEREx, scientists aim to track how galactic light production has evolved over time.
The third major investigation for SPHEREx centers on life's building blocks: water, carbon dioxide, and other life-essential molecules. Specifically targeting more than 9 million unique directions within the Milky Way, the mission will quantify the prevalence of these molecules, significantly contributing to our understanding of their availability during planet formation.
SPHEREx sets itself apart from other space telescopes like Hubble and James Webb by combining wide, all-sky coverage with the detail-oriented spectroscopy typically applied to individual objects or small areas. The integration of data from these varied sources will enable scientists to compose a holistic and vivid portrait of the cosmos.
Managed by NASA’s Jet Propulsion Laboratory (JPL), the SPHEREx mission sees the combined expertise of BAE Systems, which is responsible for the telescope and spacecraft bus, alongside a scientifically diverse team from across the United States and South Korea. Caltech’s IPAC will process and archive the data, ensuring the SPHEREx dataset becomes a valuable resource for the scientific community at large.
With its novel approach to cosmic observation, SPHEREx stands on the threshold of potentially groundbreaking discoveries about the universe, its origins, and the conditions for life as we know it. Eagerly anticipated by astronomers and cosmologists alike, the mission's embodiment of NASA's innovativeness and exploration spirit is poised to satisfy our longing to understand the cosmos in all its colorful glory.