Astronomers have made an exciting discovery using the James Webb Space Telescope (JWST) – they have confirmed that a distant smudge of light named "Maisie’s galaxy" is one of the earliest known galaxies in the universe. Maisie’s galaxy began emitting light more than 13 billion years ago, placing it among the four oldest galaxies in the universe whose ages have been confirmed by spectroscopy. This confirmation is significant because Maisie’s galaxy was one of the first distant galaxies identified by the JWST and the first to be spectroscopically confirmed.
The discovery of Maisie’s galaxy was made during the JWST’s debut season of observations in August 2022. Initially, the object’s extreme brightness and redshift suggested it was extremely old. However, judging an object’s redshift based on brightness alone can be misleading. To get a more accurate understanding of the object’s age, astronomers used spectroscopy, a technique that splits light into its component frequencies to reveal its true nature. Using the JWST’s Near Infrared Spectrograph, researchers analyzed the light of Maisie’s galaxy and another galaxy called CEERS-93316. The spectroscopic analysis confirmed the extreme age of Maisie’s galaxy, but revealed that CEERS-93316 was not as old as initially estimated. This unusual case shows the importance of spectroscopy in accurately determining the age and nature of distant objects in space.
Distant Galaxy Confirmed to be Among the Oldest in the Universe
Astronomers using the James Webb Space Telescope (JWST) have made an exciting discovery – a distant galaxy that is one of the earliest known in the universe. Nicknamed "Maisie’s galaxy" after lead researcher Steven Finkelstein’s daughter, the object emitted light over 13 billion years ago, just 390 million years after the Big Bang. This places Maisie’s galaxy among the four oldest galaxies in the universe whose ages have been confirmed by spectroscopy, a technique that breaks down light into its component frequencies.
What makes this discovery particularly thrilling is that Maisie’s galaxy is not just one of the first distant galaxies identified by the JWST, but it is also the first to be spectroscopically confirmed. Initially detected in August 2022 during the telescope’s debut season of observations, the object’s extreme age was deduced from its brightness and redshift, which signifies how light stretches into redder wavelengths as it travels through the expanding universe. A higher redshift indicates a more distant and older light source.
However, judging an object’s redshift based solely on its brightness can be misleading. Different elements within stars and galaxies emit light at different frequencies, which can make an object appear older and farther away than it actually is. To overcome this challenge, astronomers use spectroscopy to analyze the various frequencies of starlight, revealing the true composition of the object.
Using the JWST’s Near Infrared Spectrograph, the researchers examined the light from two ancient objects: Maisie’s galaxy and another galaxy known as CEERS-93316. While Maisie’s galaxy’s spectroscopic analysis confirmed its age and distance, the same was not true for CEERS-93316. The intense emission of light from hot hydrogen and oxygen within the galaxy made it appear bluer and therefore older than it actually was. The revised estimate places CEERS-93316 at around 1 billion years after the Big Bang, removing it from the list of oldest known galaxies.
Maisie’s galaxy now joins a select group of four other galaxies confirmed by spectroscopy to have formed between 300 million and 500 million years after the beginning of the universe. The discovery of these ancient galaxies is a significant achievement and provides valuable insights into the early stages of the universe.