The Roman Space Telescope is simpler than the James Webb Space Telescope. It has a smaller main mirror—7.9 feet wide—about three times smaller than Webb’s. Roman cannot see as deeply into space as Webb, but it can see much larger areas of the sky at once. This wide view will allow scientists to count billions of stars and galaxies across the Universe and study dark matter and dark energy, which together make up about 95% of the Universe. The remaining 5% consists of ordinary matter that we can see and touch.
Roman is often compared with the Hubble Space Telescope because both have mirrors of the same size. As a result, Roman will produce images as sharp as Hubble’s. The big difference is inside the telescope. Roman uses advanced detectors that are especially sensitive to faint infrared light.
These detectors work in a way similar to night-vision devices, but they are designed to detect different wavelengths of light.
The detectors are part of Roman’s main camera, called the Wide Field Instrument. It contains 18 detectors, each with about 16 million pixels, forming a 300-megapixel camera. This makes it the largest infrared camera ever built. In comparison, Hubble’s infrared camera uses only one detector with about one million pixels.
Because of this powerful camera, Roman will observe a much larger area of space than Hubble. It can recreate Hubble’s famous Ultra Deep Field image with the same clarity, but over an area at least 100 times larger, revealing countless more stars and galaxies
