A team of astrophysicists has discovered six potential galaxies hidden in James Webb Space Telescope images that could have existed 500 to 700 million years after the Big Bang. These candidate galaxies are massive, with nearly as many stars as the Milky Way Galaxy. The discovery calls into question current cosmological theory, as the early universe was thought incapable of organizing itself so quickly. The findings come from the telescope’s Cosmic Evolution Early Release Science Survey. While more data is needed to confirm their existence, the researchers’ preliminary observations show how James Webb could rewrite astronomy textbooks.

In astronomy, red light is usually associated with old light. Because the universe has been expanding since the beginning of time, galaxies and other celestial objects move farther apart, and the light they emit spreads out. The redder the light appears to human instruments as it stretches. The team discovered that their old galaxies were also massive, with the mass of tens to hundreds of billions of sun-sized stars, comparable to the Milky Way. These primordial galaxies, however, had little in common with our own, forming hundreds of new stars every year for the universe’s entire history.

The researchers need to gather more data to confirm their findings, but if even one of these galaxies is confirmed, it will test our understanding of cosmology. Erica Nelson, co-author of the study and assistant professor of astrophysics at The University of Colorado Boulder, compared the rapid pace of discovery with James Webb to Hubble’s early days when scientists believed galaxies did not form until billions of years after the Big Bang. Researchers quickly discovered, however, that the early universe was far more complex and exciting than they could have imagined. Nelson is ecstatic about the discoveries, which are the culmination of a journey that began when she was in elementary school.

The study has been published in Nature.

References

• Labbé, I., van Dokkum, P., Nelson, E., Bezanson, R., Suess, K. A., Leja, J., Brammer, G., Whitaker, K., Mathews, E., Stefanon, M., & Wang, B. (2023). A population of red candidate massive galaxies ~600 Myr after the Big Bang. Nature, 1–2. https://doi.org/10.1038/s41586-023-05786-2
• Strain, D. (2023, February 22). Webb telescope spots super old, massive galaxies that shouldn’t exist. CU Boulder Today; CU Boulder. https://www.colorado.edu/today/2023/02/22/webb-telescope-spots-super-old-massive-galaxies-shouldnt-exist