Cartwheel final by NASA Hubble/JWSTNASA
Building on Legacy
NASA’s James Webb Space Telescope builds on the legacy of the Hubble Space Telescope by seeing even further into the universe, revealing how the first galaxies formed and searching the atmospheres of exoplanets for molecular signatures that could support life.
Webb Jupiter 2 by Image credit: Webb NIRCam composite image (two filters) of Jupiter system, unlabeled (top) and labeled (bottom). Credit: NASA, ESA, CSA, Jupiter ERS Team; image processing by Ricardo Hueso (UPV/EHU) and Judy Schmidt.NASA
In addition to other planetary systems, Webb will also study objects within our own solar system.
Hubble Space TelescopeNASA
Hubble has allowed investigations of the cosmos that previously had never been seen before. Hubble’s main focus is visible light (what human eyes can see) and ultraviolet light, and a small portion of infrared light. However, Webb mainly “sees” infrared light — but why?
Carina Nebula by James Webb Space Telescpe (2022-07-12) by NASA, ESA, CSA, and STScINASA
Stars and planets in their early stages of formation can be hidden behind galactic dust, which absorbs visible light. Infrared light can penetrate this dust, allowing Webb to see behind the dusty clouds — unveiling the cosmos.
Additionally, light from extremely distant objects, such as the first galaxies, has been stretched to longer wavelengths in the infrared due to the expansion of the universe.
Toddlers to babies hubble by ESA/Hubble & NASA, RELICSNASA
If you compare how deep Webb can see into the cosmos in relation to Hubble, then Hubble can see the equivalent of "toddler galaxies" and Webb will be able to see "baby galaxies" thanks to its focus on the infrared side of the spectrum.
James Webb Space Telescope's First Deep Field (2022-07-12) by NASA, ESA, CSA, and STScINASA
Webb sees more distant, infant galaxies, because that light has had to travel farther through the expanding universe; the stretching of space reddens the light passing through, and the light from the most distant galaxies gets reddened into the infrared light that Webb can see.
webb:hubblemirror by NASA/Michael McClare, Aaron E. Lepsch, Krystofer KimNASA
There is also a significant difference in mirror size between Webb and Hubble. Webb’s primary mirror is approximately 6.5 meters in diameter, where Hubble’s primary mirror is 2.4 meters in diameter.
Webb Explained Slide 4 (2017-05-13) by NASA/Chris GunnNASA
The larger mirror gives Webb 6.25 times more light collecting area than Hubble, and a much larger field of view. Just as a large bucket standing out in the rain collects more water, a larger mirror can collect more light from objects in the distant cosmos.
Webb’s larger mirror enables similar angular resolution of Webb in infrared light to that of Hubble in visible light. Angular resolution is directly related to the wavelength of light, and inversely related to the diameter of the collecting mirror, which is bigger for Webb.
A BALL AEROSPACE TECHNICIAN STANDS WITHIN A JAMES WEBB SPACE TELESCOPE ARRAY FOR TESTING. by DAVID HIGGINBOTHAMNASA
This means you need a wider mirror to compensate for the longer wavelength, to get similar resolution to Hubble.
Webb Explained Slide 1 (2020-03-05) by NASA/Chris GunnNASA
Webb's Tools
These advances will allow deeper observations into the universe when combined with Webb’s science instruments, which are extremely sensitive to infrared light.
NASA Webb Telescope (2017-12-08)NASA
NIRSpec
The Near-Infrared Spectrograph, also called a spectrometer, is used to disperse light from an object into a spectrum. This spectrum can then be analyzed revealing some physical properties about the object.
Webb Instruments Perfected to Microscopic Levels (2017-12-08)NASA
NIRCam
The Near-Infrared Camera is Webb’s primary imager. Its goal is to detect light from the earliest stars and galaxies, as well as young stars in the Milky Way.
NASA Testing the Webb Telescope's MIRI Thermal Shield (2017-12-08)NASA
MIRI
The Mid-Infrared Instrument will allow us to observe the light of distant galaxies and newly formed stars, even faintly visible comets.
NASA Shines a Spotlight on a Webb Telescope Test (2017-12-08)NASA
FGS/NIRISS
Fine Guidance Sensor/Near-Infrared Imager & Slitless Spectrograph. FGS allows the telescope to point with precision & stay on target to get the required quality images & accurate spectra. NIRISS focuses on first light & exoplanet detection, & exoplanet transit spectroscopy.
NASA's Webb Telescope Clean Room 'Transporter' (2017-12-08)NASA
Hubble and Webb will work together to make complementary observations. All previous space science telescopes have enabled new views of the universe, and the James Webb Space Telescope is the newest window to the mysteries of the cosmos.
More Resources
Check out these links to read, watch and learn more!
James Webb Space Telescope Videos | NASA
‘NASA STEM Stars’: Program Manager | NASA
James Webb Space Telescope STEM Toolkit | NASA
Introduction to the Electromagnetic Spectrum | Science Mission Directorate (nasa.gov)
James Webb Space Telescope First Images | NASA, STSCI
Follow Hubble and JWST on social media!
Hubble Twitter
Hubble Facebook
Hubble Instagram
JWST Twitter
JWST Facebook
JWST Instagram
Author: Rosemary Ferreira
Editors: Julie Freijat, Bill Steigerwald, Thaddeus Cesari, Maddie Arnold
