IC 1101 is one of the largest known galaxies in the universe. Its enormous size makes our Milky Way look relatively small in comparison. Scientists estimate that IC 1101 stretches for nearly 1.7 million light-years across, which is roughly equal to placing 17 Milky Way galaxies side by side.
The giant galaxy is located more than one billion light-years from Earth in the Abell 2029 galaxy cluster. It is the brightest galaxy in this cluster and belongs to a special group known as brightest cluster galaxies, which are often among the largest galaxies in the universe.
How Did IC 1101 Become So Huge?
Scientists believe IC 1101 grew over a very long period by absorbing smaller galaxies around it. This process is sometimes described as galactic cannibalism.
When large galaxies come close to smaller galaxies, their powerful gravity can pull the smaller galaxies apart. Over time, the material from those galaxies can become part of the larger galaxy.
IC 1101 appears to have gone through many such mergers. These repeated encounters may have helped it reach its enormous size.
New Images Reveal Its Outer Limits
Scientists have known for many years that IC 1101 is extremely large. However, it has been difficult to determine exactly where the galaxy ends because its outer regions are very faint.
Deep images taken using the Isaac Newton Telescope in 2022 helped researchers study these weak outer regions. The observations provided a better estimate of the galaxy’s true size.
Researchers estimate that IC 1101 is around 520 kiloparsecs, or approximately 1.7 million light-years, in diameter.
Its estimated mass is also enormous, reaching about 3.4 trillion times the mass of the Sun.
The Galaxy May Still Be Growing
Despite its already massive size, IC 1101 may not have finished growing.
Scientists have observed long structures extending from the galaxy’s outer regions. These features could be signs of interactions and mergers with other galaxies.
Astrophysicist Carlos Marrero de la Rosa has noted that the galaxy appears to still be accumulating material. This suggests that IC 1101 could become even larger over time.
Why IC 1101 Is Important
Studying IC 1101 can help scientists understand how the biggest galaxies in the universe form and grow.
Its huge size shows how galaxies can change over billions of years through mergers and the movement of stars and other matter.
Earlier studies had suggested that IC 1101 was exceptionally large, but researchers had difficulty identifying its faint outer boundary. The newer observations have provided a more detailed picture of this enormous galaxy.
A study published on arXiv.org presents some of the most detailed measurements yet of IC 1101.
For now, IC 1101 remains a remarkable example of how enormous galaxies can become. And because it may still be absorbing material from nearby galaxies, this cosmic giant could continue changing for millions or even billions of years.