On May 1, 2025, NASA’s SPHEREx (Spectro-Photometer for the History of the Universe, Epoch of Reionization and Ices Explorer) mission commenced its full-sky survey, capturing the universe in unprecedented detail across 102 infrared wavelengths. This marks a significant milestone in SPHEREx’s mission to map the cosmos and unravel the mysteries of the universe’s origins.
A new eye on the cosmos
SPHEREx is designed to survey the entire sky using infrared light, which is invisible to the human eye. By capturing light in 102 different infrared colors, SPHEREx can detect and analyze cosmic phenomena that other telescopes might miss. This includes observing the distribution of galaxies, the presence of organic molecules, and the universe’s large-scale structure.
The telescope employs spectroscopy, which allows it to break down light into its component wavelengths. This enables scientists to determine the composition, temperature, and distance of celestial objects, providing a three-dimensional map of the cosmos.
Capturing the sky: First images
Each day, SPHEREx captures approximately 3,600 images, each containing about 100,000 light sources, including stars and galaxies. These images are taken using six detectors, each equipped with filters that allow them to observe different infrared wavelengths. By combining these images, scientists can create a comprehensive map of the sky, revealing structures and patterns that shed light on the universe’s history.
One of the first images released shows a region of the sky at a wavelength of 3.29 microns, revealing a cloud of dust composed of polycyclic aromatic hydrocarbons, molecules similar to soot or smoke. At a different wavelength of 0.98 microns, the same region appears without the dust cloud, illustrating how varying infrared wavelengths can unveil different cosmic structures. A third image, captured at a wavelength of 0.96 microns, reveals the glow of ionized gaseous sulfur (SIII). All of these images are of NGC 1760, an emission nebula.
Mission objectives
SPHEREx aims to address several fundamental questions in astrophysics:
- Origins of the universe: By mapping the distribution of galaxies, SPHEREx will help scientists understand how the universe expanded after the Big Bang.
- Galaxy formation: The telescope will study how galaxies evolved over time, providing insights into the processes that shaped them.
- Ingredients for life: SPHEREx will search for water and organic molecules in the Milky Way, contributing to our understanding of the building blocks of life.
Looking ahead
Over the next few years, SPHEREx will continue its all-sky survey, creating four complete maps of the cosmos. These maps will be invaluable for researchers studying the universe’s structure and evolution. The data collected will also complement observations from other missions, such as the James Webb Space Telescope, enhancing our overall understanding of the cosmos.
As SPHEREx continues its mission, the astronomical community eagerly anticipates the discoveries that lie ahead. With its unique capabilities, SPHEREx is poised to revolutionize our understanding of the universe and our place within it.
Clear skies!
