What We’ve Learned From the JWST Three Years After Its Launch

Three years ago, the James Webb Space Telescope (JWST) launched, marking a monumental moment in space exploration. As the largest and most powerful space telescope ever built, it has redefined our understanding of the Universe in just a short time.

From exploring our Solar System to analyzing exoplanet atmospheres for signs of life and delving into the early Universe to uncover its first stars and galaxies, JWST has achieved remarkable breakthroughs. Here’s what we’ve learned—and the new questions that have emerged.

JWST has pushed the boundaries of cosmic observation, capturing light from galaxies that formed when the Universe was just 300 million years old. Among these, a record-breaking galaxy managed to grow to 400 million times the mass of the Sun in a shockingly short time, highlighting the extraordinary efficiency of early star formation.

These ancient galaxies defy expectations. While mature galaxies tend to appear red due to accumulated dust, JWST revealed them to be bright blue and dust-free. Theories suggest intense star radiation or massive supernovae could have swept away the dust, but their true nature remains a puzzle.

Unusual Chemistry in Early Galaxies

JWST has uncovered surprising chemical compositions in these early galaxies. Unlike modern stars, they are nitrogen-rich but have lower amounts of other metals. This discovery challenges existing models of chemical evolution and suggests unknown processes shaped the early Universe’s building blocks.

Using gravitational lensing from massive galaxy clusters, JWST has located faint galaxies that emit four times more high-energy photons than anticipated. These small galaxies may have played a pivotal role in ending the cosmic “dark ages,” when the Universe transitioned from opaque to transparent.

One of JWST’s earliest images revealed an unexpected phenomenon: compact, red-colored objects emitting light at extreme velocities. Initially thought to be dense galaxies, these objects exhibit signs of supermassive black holes yet lack expected X-ray emissions. They also show star-like characteristics, suggesting a hybrid nature. This discovery could illuminate how supermassive black holes and stars evolved together in the early Universe.

Impossibly Massive Early Galaxies

JWST has identified massive galaxies—rivaling the Milky Way—that formed within the first 700 million years after the Big Bang. These findings challenge current models of galaxy formation, which struggle to explain how such colossal structures emerged so early. Cosmologists are now debating whether adjustments to existing theories or entirely new frameworks, possibly involving dark matter, are needed.

In its brief operational history, JWST has already exposed gaps in our understanding of the cosmos. While we refine our models, the telescope promises to uncover even more unknowns. The enigmatic “red dots” were only the beginning—countless hidden wonders still await discovery in the vast expanse of space.

Read Original article: Science Alert

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