JWST discovers a first galaxy growing from the outside in!

The James Webb Space Telescope (JWST) has made a remarkable discovery. The telescope discovered a galaxy in the early universe that appears to have grown from the outside in. This galaxy, known as JADES-GS+53.18343−27.79097, formed just 700 million years after the Big Bang. It is significantly smaller than our Milky Way, but has an unusual growth pattern in which stars form more quickly at its outer edges than at its dense center. This discovery confirms theoretical predictions about how galaxies could have formed in the early universe.

Growth of galaxies: a new discovery

Astronomers have long hypothesized that galaxies in the early universe might have grown “in reverse,” but these ideas have until now lacked observational evidence. Using JWST’s advanced capabilities, researchers were able to study galaxies previously hidden behind gas and dust. The discovery, published in natural astronomy, represents the first observation of such a phenomenon and opens new avenues for understanding the evolution of galaxies. William Baker, a graduate student at the University of Cambridge, explained how the observation was like “checking your homework” since it confirmed long-standing patterns.

Looking back in time

This galaxy was identified through JWST’s JADES (JADES) Advanced Deep Extragalactic Survey project, which collects light from distant objects, allowing astronomers to study the past of the universe. Using the telescope’s Near Infrared Spectrograph (NIRSpec), scientists calculated the ages of the galaxy’s stars. They discovered a dense core surrounded by rapidly forming stars in a disk of gas and dust. The galaxy doubles in size every 10 million years, much faster than the growth rate of the Milky Way.

Sandro Tacchella, professor of astrophysics at the University of Cambridge, noted that this discovery raises important questions about galaxy formation. The researchers now plan to determine whether other galaxies from this period exhibit similar behavior.