If you assume that the XDF is a typical region of outer space, you can calculate how many XDFs it would take to fill the entire night sky; it’s about 32 million. Multiply by the number of galaxies you find in the XDF—which is around 5,500—and that’s how we arrive at 176 billion galaxies, at least, in the Universe.
http://blogs.discovermagazine.com/crux/2012/10/10/how-many-galaxies-are-there-in-the-universe-the-redder-we-look-the-more-we-see/
Philadelphia: Saunders, 1995: 7. Our telescopes can see many billion of them within reach of modern instruments.. The universe is made up of many galaxies. When galaxies were first discovered they were called island universes because they looked like islands of stars in a dark sea.
http://hypertextbook.com/facts/1999/TopazMurray.shtml
Morrison, David, Sidney Wolff & Andrew Fraknoi. Exploration of the Universe, 7th ed. The universe is made up of many galaxies. When galaxies were first discovered they were called island universes because they looked like islands of stars in a dark sea.
http://hypertextbook.com/facts/1999/TopazMurray.shtml
Exploration of the Universe, 7th ed. Philadelphia: Saunders, 1995: 7. The universe is made up of many galaxies. When galaxies were first discovered they were called island universes because they looked like islands of stars in a dark sea. New galaxies are discovered every day containing large numbers of stars.
http://hypertextbook.com/facts/1999/TopazMurray.shtml
An educational, Fair Use website. The universe is made up of many galaxies. When galaxies were first discovered they were called island universes because they looked like islands of stars in a dark sea. New galaxies are discovered every day containing large numbers of stars.
http://hypertextbook.com/facts/1999/TopazMurray.shtml
But there are maybe 75% more galaxies-per-patch-of-sky in the XDF! Applying the XDF results to the entire sky, we find that there are more like 176 billion galaxies in the entire Universe, a huge increase from our previous estimate from the HUDF.
http://blogs.discovermagazine.com/crux/2012/10/10/how-many-galaxies-are-there-in-the-universe-the-redder-we-look-the-more-we-see/
500 Billion --A Universe of Galaxies: Some Older than Milky Way. he Hubble Space Telescope site estimates there are hundreds of billions of galaxies in the universe. A recent German super-computer simulation estimates that the number may be as high as 500 billion, with many older than the Milky Way.
http://www.dailygalaxy.com/my_weblog/2013/06/500-billion-a-universe-of-galaxies-some-older-than-milky-way.html
June 10, 2013. he Hubble Space Telescope site estimates there are hundreds of billions of galaxies in the universe. A recent German super-computer simulation estimates that the number may be as high as 500 billion, with many older than the Milky Way.
http://www.dailygalaxy.com/my_weblog/2013/06/500-billion-a-universe-of-galaxies-some-older-than-milky-way.html
We are seeing them just 600 million years after the Universe's birth in the Big Bang. Galaxy clusters are the largest structures in the Universe, comprising hundreds to thousands of galaxies bound together by gravity. The developing cluster presumably will grow into a massive galactic city, similar in size to the nearby Virgo Cluster, a collection of more than 2000 galaxies.
http://www.dailygalaxy.com/my_weblog/2013/06/500-billion-a-universe-of-galaxies-some-older-than-milky-way.html
By extrapolating these results over the entire sky (which is some 10 million times larger), we were able to figure out—at minimum—that there were at least 100 billion galaxies in the entire Universe. I even made a video about it. But that’s not the end of the story; not by a long shot. You see, there might be at least 100 billion galaxies, based on what we’ve observed, but there might be more. Galaxies that are too dim to observe with “only” 11 days of Hubble data.
http://blogs.discovermagazine.com/crux/2012/10/10/how-many-galaxies-are-there-in-the-universe-the-redder-we-look-the-more-we-see/
number of galaxies in the universe
There are 500 billion galaxies in the universe.