The James Webb Space Telescope (JWST) is a space telescope designed to conduct infrared astronomy. It is the largest telescope in space, and is equipped with high-resolution and high-sensitivity instruments, allowing it to view objects too old, distant, or faint for the Hubble Space Telescope. This enables investigations across many fields of astronomy and cosmology, such as observation of the first stars and the formation of the first galaxies, and atmospheric characterization of potentially habitable exoplanets. Despite Webb's mirror diameter being 2.7 times larger than that of the Hubble Space Telescope, it produces images of comparable resolution because it observes in the infrared spectrum, which has longer wavelengths than the Hubble's visible spectrum.

Wikipedia: https://en.wikipedia.org/wiki/James_Webb_Space_Telescope. Related NASA reference: https://science.nasa.gov/mission/webb/. Description adapted from Wikipedia contributors (CC BY-SA 4.0; https://creativecommons.org/licenses/by-sa/4.0/).