The James Webb Space Telescope is the most powerful telescope ever launched into space, its greatly improved infrared resolution, and sensitivity will allow it to view objects too old, distant, and faint for the Hubble Space Telescope, which Nasa designed primarily to conduct infrared astronomy launched on 25 December 2021.
This telescope will take us from the closest mysteries in our own solar system to the closest we’ve ever come to the origin of our universe. Astronomers have discovered approximately 5,000 exoplanets (alien worlds outside our solar system) in the previous 30 years. And, astonishingly, they vary in size, temperature, and mass, orbiting a dizzying array of stars. As a result, the international menu is extensive.
JWST’s primary mirror is made up of 18 hexagonal gold-plated beryllium mirror segments that together form a 6.5-meter (21-foot) diameter mirror, compared to Hubble’s 2.4 m. (7.9 ft). The Webb telescope now has a light-collecting area of around 25 square meters, which is roughly 6 times that of Hubble. JWST will view in a lower frequency range, from long-wavelength visible light (red) to mid-infrared (0.6–28.3 m), than Hubble, which observes in the near ultraviolet, visible, and near-infrared (0.1–1.7 m) spectra.
“With its powerful spectroscopic and imaging capabilities across a wide infrared wavelength range, Webb is poised to revolutionize our knowledge of the composition of these worlds and of planet-forming disks,” said Knicole Colón, the deputy project scientist for Webb’s exoplanet science, in a NASA blog post. “From small, potentially rocky exoplanets up to giant, gaseous ones, Webb will observe these worlds with the transit technique. Direct imaging techniques will be used to study young, giant exoplanets along with the environments in which planets form and evolve around stars, known as protoplanetary disks and debris disks.”
“Beyond gas giants, a number of Webb’s exoplanet targets in its first year of observations are small and orbit stars that are smaller and cooler than the Sun, known as M dwarfs,” added Colón. “While exoplanet discovery began around 30 years ago, many of these small exoplanets around M dwarfs were just discovered in the last few years by surveys like TESS.”