A Hubble image of distant galaxies captured as part of the Great Observatories Origins Deep Survey, data from which was included in the study. Credit: NASA, ESA/Hubble
There are at least ten times more galaxies in the observable Universe than we can currently see, according to a new study using the Hubble Space Telescope.
Initial predictions using Hubble’s Deep Field Imagessuggested the observable Universe contains between 100 and 200 billion galaxies, but a new study claims this figure is actually ten times greater.
The study has also provided new insight into an historic astronomical paradox: why is the sky dark at night?
Christopher Conselice from the University of Nottingham led a team that used deep space images and data from Hubble to peer as far as 13 billion years into the past.
Converting the images into 3D, they were able to measure the number of galaxies that existed at different times in the history of the Universe.
Computer models enabled the team to calculate that many more galaxies exist than current space telescopes can observe.
In fact, the study concluded that 90% of the galaxies in the observable Universe are at the moment too faint and far for us to see on Earth.
In studying the visibility of distant galaxies from Earth, the team concluded that, in theory, each patch of sky contains part of a bright galaxy. But if this is true, then why does our sky appear dark at night?
The answer is that the galaxies are unobservable from Earth because their light cannot reach our planet.
This is due a number of factors: redshifting, ever-changing properties of the Universe and the absorption of light by dust and gas on its way to Earth.
“It boggles the mind that over 90% of the galaxies in the Universe have yet to be studied.
Who knows what interesting properties we will find when we observe these galaxies with the next generation of telescopes,” says Conselice.