How many galaxies dot the night sky? Astronomers used to think it was 100 billion. Now, a new study suggests the actual number is 10 times that amount, Astronomy Now reports. To get their new count, researchers converted deep space images from the Hubble Space Telescope into 3D and built new mathematical models to estimate the number of galaxies that hadn’t yet been seen. According to those results, about 90% of the galaxies in the observable universe are too faint or far away to be seen by the current generation of telescopes, the researchers report in a paper soon to be published in The Astrophysical Journal. The data show that in the universe’s first few billion years, galaxies were much smaller and more plentiful compared with now, when many are much more massive after merging together.