Astronomy Practice Exam 2026 – All-in-One Guide to Master Your Astronomy Test!

The estimated number of galaxies in the universe is about 100 billion. This estimate comes from various observational surveys, including deep-sky observations by powerful telescopes such as the Hubble Space Telescope. Early calculations suggested there were approximately 100 billion galaxies, but more recent studies indicate that the actual number might be significantly higher due to the detection of smaller, fainter galaxies.

Understanding the scale of the universe is essential when considering these numbers. The vast distances involved and the limitations of observational technology mean that some smaller galaxies go undetected, implying that the true tally could reach even into the trillions. However, the commonly referenced estimate remains around 100 billion, making it the most widely accepted figure within the scientific community.

This number highlights the incredible complexity and vastness of the universe, filled with diverse galaxies, each containing billions of stars. The other estimates, while they reflect ongoing research and discovery in astronomy, are less often cited in the context of a general number of galaxies currently believed to exist.