Observable universe contains two trillion galaxies, 10 times more than previously thought

Date:
October 13, 2016

Source:
Space Telescope Science Institute (STScI)

Summary:
Using data from deep-space surveys taken by NASA's Hubble Space Telescope and other observatories, astronomers have performed a census of the number of galaxies in the universe. The team came to the surprising conclusion that there are at least 10 times as many galaxies in the observable universe than previously thought. The results have clear implications for our understanding of galaxy formation, and also helps shed light on an ancient astronomical paradox -- why is the sky dark at night?

Excerpt:
Conselice and his team reached this conclusion using deep-space images from Hubble and the already published data from other teams. They painstakingly converted the images into 3-D, in order to make accurate measurements of the number of galaxies at different epochs in the universe's history. In addition, they used new mathematical models, which allowed them to infer the existence of galaxies that the current generation of telescopes cannot observe. This led to the surprising conclusion that in order for the numbers of galaxies we now see and their masses to add up, there must be a further 90 percent of galaxies in the observable universe that are too faint and too far away to be seen with present-day telescopes. These myriad small faint galaxies from the early universe merged over time into the larger galaxies we can now observe.

Source Article:
https://www.sciencedaily.com/releases/2016/10/161013111709.htm