James Webb Identifies 800-Million-Year-Old LAP1-B as Earliest Universe's Most Metal-Poor Galaxy
Updated
Updated · Livescience.com · May 31
James Webb Identifies 800-Million-Year-Old LAP1-B as Earliest Universe's Most Metal-Poor Galaxy
1 articles · Updated · Livescience.com · May 31
LAP1-B, seen as it was 800 million years after the Big Bang, has been confirmed as the most metal-poor early-universe galaxy yet observed, with oxygen abundance just 1/240 that of the Sun.
30 hours of JWST spectroscopy, aided by a galaxy cluster that magnified the target about 100 times, let astronomers measure the ultra-faint galaxy's chemistry despite its extreme distance and dimness.
Its elevated carbon-to-oxygen ratio matches predictions for debris from Population III star explosions, giving researchers rare direct evidence of how the first stars began enriching the universe with heavier elements.
Less than 3,300 solar masses of visible matter and a likely dominant dark-matter halo make LAP1-B a close match to ultra-faint dwarf galaxies near the Milky Way, linking them to primordial 'fossil' ancestors.
The Nature study gives JWST a new path to hunt even more chemically primitive galaxies and trace the earliest stages of galaxy formation during the Cosmic Dark Ages.
How did the first stars create carbon but swallow oxygen, leaving a bizarre chemical fingerprint on the earliest galaxies?
What determined which of the universe's first galaxies survived for 13 billion years while countless others simply vanished?
LAP1-B: Discovery of the Most Chemically Primitive Galaxy Sheds Light on the Universe’s First Stars and Cosmic Evolution
Overview
The discovery of LAP1-B, an ultra-faint and chemically primitive galaxy that existed just 800 million years after the Big Bang, offers crucial insights into the early universe. Its incredibly dim light was too faint to be seen directly, but the James Webb Space Telescope, with its unmatched sensitivity, captured it thanks to the massive galaxy cluster MACS J0416. Acting as a cosmic lens, this cluster bent and amplified LAP1-B’s light by a factor of 100, making it detectable. This breakthrough reveals how advanced technology and natural cosmic phenomena together allow us to explore the universe’s earliest moments.