Using this instrument, each Roman image will capture a patch of the sky bigger than the apparent size of a full Moon. Hubble’s infrared images, taken with its Wide Field Camera 3, are about 200 times smaller. Even Hubble’s widest exposures, taken with the Advanced Camera for Surveys, are nearly 100 times smaller. Over the first five years of observations, Roman will image over 50 times as much sky as Hubble covered in its first 30 years, surveying the sky up to 1,000 times faster than Hubble can while maintaining similar sensitivity and infrared resolution.
Our understanding of the cosmos has grown by leaps and bounds in recent decades, however many mysteries still remain. As the spacecraft’s giant camera, the WFI will help fill in the gaps by looking far across space and probing deep into dusty regions, including the star-studded heart of our Milky Way galaxy. The WFI’s sweeping infrared surveys will unveil countless celestial bodies and phenomena that would otherwise be difficult or impossible to find.
The 18 detectors at the instrument’s heart will enable all of the mission’s science by converting starlight into electrical signals, which will then be decoded into high-resolution images of large patches of the sky. Since the WFI has such an enormous field of view, each image will provide a wealth of information. Scientists will be able to quickly conduct research that could take hundreds of years using other telescopes.
The WFI is designed to detect faint infrared light from across the universe. Infrared light is observed at wavelengths longer than the human eye can detect. The expansion of the universe stretches light emitted by distant galaxies, causing visible or ultraviolet light to appear as infrared by the time it reaches us. Such distant galaxies are difficult to observe from the ground because Earth’s atmosphere blocks some infrared wavelengths, and the upper atmosphere glows brightly enough to overwhelm light from these distant galaxies.
By going into space and using a Hubble-size telescope, the WFI will be sensitive enough to detect infrared light from farther than any previous telescope. This will help scientists capture a new view of the universe that could help solve some of its biggest mysteries, one of which is how the universe became the way it is now.