In July 2022, NASA released the first full-color images from the James Webb Space Telescope. Scientists who had dedicated careers to the instrument shared photos of themselves in tears. Astronomers who had waited two decades finally got to see what it could do. The images showed thousands of galaxies in a patch of sky so small that a grain of sand held at arm's length would cover it.
What Is JWST?
The James Webb Space Telescope is a joint project of NASA, the European Space Agency, and the Canadian Space Agency. It launched on Christmas Day 2021, after decades of delays and cost overruns that had made it one of the most scrutinized science projects ever funded.
Webb sits roughly 1.5 million kilometres from Earth at a gravitationally stable point called L2. From there, it always faces away from the sun, allowing its infrared detectors to stay cold enough to pick up the faintest signals from the distant universe.
How It Differs from Hubble
Hubble, launched in 1990, transformed our view of the universe. Webb is designed to go further. While Hubble mostly observed visible and ultraviolet light, Webb is optimized for infrared wavelengths. This matters because light from the most distant objects in the universe gets stretched into infrared as it travels across billions of years of space.
Webb can observe galaxies that formed only a few hundred million years after the Big Bang, roughly 13.5 billion light-years away. Hubble could not get close to that.
What Scientists Are Learning
The early results have already surprised researchers. Galaxies in the early universe turned out to be far more massive and structured than existing models predicted. This suggests that galaxy formation happened faster in the early universe than anyone expected, and some theoretical models may need revision.
Webb is also studying planets in our own solar system with new precision, mapping dark matter distributions, and observing the birth and death of stars in nearby galaxies. The data it produces is so rich that it will keep astronomers working for decades.
The Search for Life Around Other Stars
One of Webb's most important tasks is studying exoplanet atmospheres. When a planet passes in front of its star, some of the starlight filters through the planet's atmosphere. Webb analyzes that filtered light to detect chemical signatures. It has already detected carbon dioxide in the atmosphere of an exoplanet.
Scientists are looking for combinations of gases like oxygen, methane, and water vapor that together would be difficult to explain without biological processes. A confirmed detection of that kind would be the most significant discovery in human history.
What Comes Next
Webb is designed to operate for at least 20 years. It has barely begun its work, and the discoveries have already been remarkable. The telescope that took decades to build and launch is now quietly rewriting our understanding of the cosmos, one observation at a time.