Brian Cox

Phil Plait A new paper just published in the prestigious Astrophysical Journal makes a stunning claim: There are 10 times as many galaxies in the Universe as we previously thought. At least. The total number comes in at about 2 trillion of them. Now, let me be clear. What the astronomers did was look at extremely deep images of the Universe taken in surveys, for example the Hubble Ultra Deep Field. That’s a lot of galaxies. Surveys like the UDF are limited. The astronomers who did this research had an interesting problem. The answer is two-fold. Those numbers change with distance. At the same time, these faint galaxies are easier to see close to us, and harder farther away. They calculated this for all kinds of galaxies, right down to really small ones with about a million times the mass of the Sun. They can then combine these two pieces of information: How many faint galaxies there are near us and how bright they are, with how many galaxies of a given mass are in a volume of space. NASA,ESA, H.

Dr. Michio Kaku