James Webb: the telescope that sees to the beginning of time

2022

On December 25, 2021, an Ariane 5 rocket launched the most complex and expensive scientific instrument ever built by humans: the James Webb Space Telescope (JWST). After 25 years of development, countless budget overruns (from $1 billion to $10 billion), and 344 critical single points of failure during deployment, Webb successfully reached Lagrange point L2, 1.5 million km from Earth.

Unlike Hubble, which sees in visible and ultraviolet light, Webb observes in infrared. This is crucial because light from the most distant galaxies has been "stretched" by the expansion of the universe from ultraviolet and visible into infrared, a phenomenon called cosmological redshift. Webb can see light that traveled 13.5 billion years, close to the beginning of the universe.

Webb's primary mirror is 6.5 meters in diameter (compared to 2.4 meters for Hubble), made of 18 hexagonal beryllium segments coated in gold. The sunshield, the size of a tennis court, cools the instruments to -233°C, essential for detecting faint infrared radiation.

The first images, released on July 12, 2022, left the world speechless. Webb's Deep Field showed thousands of galaxies in a patch of sky the size of a grain of sand held at arm's length. Some of these galaxies existed just 300 million years after the Big Bang.

Webb found massive galaxies in the early universe that shouldn't exist according to our models: galaxies too large, too fast. It detected organic molecules in protoplanetary disks. It analyzed the atmospheres of exoplanets, finding water, CO2, and other molecules. It photographed Neptune, Jupiter, and asteroids with unprecedented clarity.

The James Webb telescope doesn't seek simple answers. It asks questions we couldn't formulate before. Every image is a window into a universe far older, more complex, and more beautiful than we imagined.