NASA James Webb Space Telescope
- It’s possible that we can now see a galaxy as it looked just 235 million years after the Big Bang.
- Further spectroscopic analysis will reveal more information about the stars in the earliest galaxies and give us a more accurate age for them.
- Webb’s Cosmic Evolution Early Release Science Survey is finding many extremely old galaxies.
A team in Scotland is celebrating after catching a view of what may be the farthest galaxy humans have ever seen.
University of Edinburgh researchers used the James Webb Space Telescope to spy on a corner of the early universe as it appeared only 235 million years after the Big Bang; the galaxy is an astonishing 35 billion light-years away. The team is cautiously optimistic, since scientists need to fully verify galaxies’ ages with further analysis, but catching sight of stars this far away is remarkable, because the universe has been expanding ever more rapidly since the Big Bang 13.8 billion years ago.
Researchers have included this galaxy, called CEERS-93316in their study of six faraway galaxies published to the pre-print server arXiV on July 25. The work has not yet been peer-reviewed.
The galaxy appears to us in infrared light, Webb’s specialty. As light travels farther and farther distances, it stretches into the infrared portion of the visible spectrum, which means it’s no longer visible to humans. Astronomers use “redshift” to measure how much the light has stretched, indicating its age. A higher redshift indicates that the light has traveled farther, while a lower redshift means the light is closer to us. CEERS-93316 has a high redshift of 16.7, according to the team’s paper.
New, distant object discoveries have been arriving fast since Webb began its deep and wide field sky survey, called the Cosmic Evolution Early Release Science (CEERS) Survey. It’s meant to find galaxies at the oldest possible cosmic age. Along the way, researchers hope to discover how these earliest galaxies formed. Another galaxy the survey found has an impressive redshift of 14.3, appearing as it was about 280 million years after the Big Bang.
Lately, Webb has been revealing views of the universe in unprecedented detail, with the first images emerging on July 12. Astronomers will use Webb’s instruments to perform a detailed spectroscopic analysis on all the galaxies CEERS finds with the help of the Near Infrared Spectrograph instrument. It’s an array of a quarter-million “microshutters,” which are like miniature movable windows, just 0.1-by-0.2 millimeters in size, according to NASA.
This array can let in light only from galaxies that astronomers are examining, while keeping the rest of the view dark. This laser-focus indicates more clearly how light has extended into the infrared band, because it breaks down the light into its component wavelengths. The breakdown also provides a clearer picture of the spectra, or colors within the light, which disclose information about the object’s temperature, mass, chemical composition, and other physical properties, per NASA.
Astronomers will learn what kind of stars inhabited Galaxy CEERS-93316 at the time their light started the journey towards Webb. For example, the first stars, born about 100 million years after the Big Bang, were made of hydrogen and helium, the oldest elements in the universe. Many of these stars burned out, exploded as supernovas, or turned into black holes. Over time, material from supernovas and the nuclear fusion inside later stars created many of the other, heavier elements we now know about, including oxygen, carbon, iron, and gold.
Once the spectroscopic analysis is complete, it could be good reason for another celebration, as astronomers learn more about this cosmically ancient galaxy’s age, and what the life of its stars was like.
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