Our Universe is be thought of as infinite for we haven’t still managed to etch its boundaries and while astronomers have estimated the number of galaxies in Universe, a new study has shown that there are at least 10 times more galaxies than previously thought.
Initial estimates pegged the total number of galaxies at 100 billion, but that’s not the case claims a new study led by Christopher Conselice, Professor of Astrophysics at The University of Nottingham. The team involved with the study have shown that the number of galaxies in our universe is at least two trillion – ten times more than previously thought. While we have the technology to take a much deeper look at the Universe than what we had a few years back, the technology isn’t still enough to even map out 10 per cent of the Universe leave alone the whole of it. This effectively means that we will haven’t accounted for over 90 per cent of the galaxies in our universe and we will be to see more and more of them as advanced telescopes are developed.
Till then scientific models need to be relied on along with clever analysis coupled with brains of scientists like Professor Conselice. He and his team carried out an extensive study of the cosmos over the course of last 15 years during which they converted pencil beam images of deep space from telescopes around the world, and especially from the Hubble telescope into 3D maps to calculate the volume as well as the density of galaxies of one tiny bit of space after another. Through this painstaking yet fruitful process, the team was able to establish the number of galaxies we have missed out.
Results published in the Astrophysical Journal have been based on the measurements of the number of galaxies at different epochs – different instances in time – through the universe’s history. Researchers examined how many galaxies there were in a given value and this led to the finding that a few billion years ago there were significantly higher number of galaxies in a given volume of space as compared to today. Scientists calculated that there would have been a factor of 10 more galaxies in a given volume of space when the universe was a few billion years old compared with today. Most of these galaxies are low mass systems with masses similar to those of the satellite galaxies surrounding the Milky Way.
By probing deep into space Professor Conselice and his team have been able to go way back in time – more than 13 billion years in the past – to find out how our universe evolved and answer some vexing questions. The implications of this research are many, for instance; galaxies are likely to be forming by merging together. This decreases the number of systems as time progresses which provides a possible solution to Oblers’ paradox – why the sky is dark at night?
Solutions to this in the past were based on the fact that the universe is finite in size as well as in time. However, if we consider all the undiscovered galaxies then in principle the critiera for Oblers’ paradox is met. However, most galaxies in the universe are very distant and their light is absorbed by gas in intergalactic space. Otherwise, we would see the night sky lit up everywhere.