James webb deep field

The James Webb Space Telescope's Deep Field reveals thousands of galaxies invisible to Hubble, providing the sharpest view of the early universe.

About this subject

The James Webb Space Telescope (JWST), launched on December 25, 2021, captured its first deep field on July 11, 2022. The image, known as Webb's First Deep Field, shows the galaxy cluster SMACS 0723 as it was 4.6 billion years ago. Due to gravitational lensing, the cluster magnifies even more distant galaxies, some with redshifts above 8, corresponding to less than 600 million years after the Big Bang. JWST primarily operates in the infrared, allowing it to penetrate cosmic dust and observe stars and galaxies forming in the earliest epochs. Compared to Hubble, which observes in visible and ultraviolet light, Webb can see objects 100 times fainter. Colors in the images are assigned to different wavelengths: blue for shorter light, green for medium, red for longer, revealing composition and distance. Webb's deep field has already led to discoveries such as extraordinarily bright and massive galaxies in the early universe, challenging galaxy formation models. JWST is a collaboration between NASA, ESA, and CSA, with an estimated budget of US$10 billion, and is expected to operate for at least 10 years, revolutionizing astrophysics with data on exoplanets, black holes, and cosmic evolution.

Frequently Asked Questions

What is the James Webb Deep Field?

It is a long-exposure image from the James Webb Space Telescope revealing thousands of extremely distant galaxies, some of the oldest ever observed, allowing study of the early universe.

What is the difference between Webb's Deep Field and Hubble's?

Webb observes in infrared, capturing more distant and dusty galaxies that Hubble cannot see. Hubble's Ultra Deep Field shows objects up to 13 billion light-years away; Webb has already seen galaxies at 13.5 billion light-years.

How are Webb images colorized?

Scientists assign colors to different infrared wavelengths: blue for shorter waves, green for medium, red for longer. This helps identify chemical composition and galaxy distance.