Discovery of 2 trillion galaxies rocks scientific community

The findings also help answer the question: Why is the night sky so dark? With trillions of galaxies, each containing billions of stars, shouldn't we be in a cycle of never-ending light?

Courtesy of: NASA
Courtesy of: NASA

The aptly named Majestic Sombrero Galaxy has a brilliant white core encircled by thick dust lanes. The galaxy — one of the estimated 2 trillion in our universe — is 50,000 light-years across and 28 million light years from Earth.

There are a mind-boggling two trillion galaxies in the Universe — about ten times more than was previously believed, astronomers reported on Thursday

Using over 20 years of images collected by the aging Hubble Space Telescope and other sources, an international team of scientists, led by professor of Astrophysics at the University of Nottingham Christopher Conselice, created a 3D model of the observable universe.

They found a much more densely packed cosmos than expected.


Hubble as seen from the spaceship Discovery during its second servicing mission in 1997.

The team compared their findings with current models of galaxy formation in the latest edition of the Astronomical Journal and stressed the importance of having an accurate count of our cosmos.

“The evolution of the number density of galaxies in the universe, and thus also the total number of galaxies, is a fundamental question with implications for a host of astrophysical problems including galaxy evolution and cosmology,” Conselice wrote in his published study.  

The darkness and the light.

One other interesting result from the 15 year-long study is answering another important question.

“We also show how these results solve the question of why the sky at night is dark, otherwise known as Olbers' paradox,” Conselice wrote.


Hailed as 'The Most Important Image Ever Taken', this image is what the Hubble telescope saw after peering into an apparently dark section of sky for 10-days. To the surprise of many astronomers, thousands of galaxies appeared.

Many have tried to answer Olbers’ paradox, named after the 18th-century German astronomer Heinrich Wilhelm Olbers. including the poet Edgar Allan Poe who wrote at length on the topic.

Poe’s theory was: The universe isn’t infinite, and the speed of light has a limit, therefore we don’t see every star’s light all the time on Earth. 

It seems Poe was onto something.

Conselice wrote that finite nature of the universe — which Poe referenced — is indeed one of three reasons that we have darkness at night.


The night sky on Mars is still dark, even though it lacks much of an atmosphere. This view, taken 80 minutes after the Martian sunset by Curiosity Mars rover includes Earth as the brightest point of light in the night sky. Earth is a little left of center in the image, and our moon is just below Earth. (Click on image to enlarge)

“It would thus appear that the solution to the strict interpretation of Olbers’ paradox, as an optical light detection problem, is a combination of nearly all possible solutions - redshifting effects, the finite age and size of the universe, and through absorption,” Conselice wrote.

NASA has backed up Conselice's findings in a statement, expanding on his team's theory for explaining Olbers’ paradox.

"Starlight from the galaxies is invisible to the human eye and most modern telescopes due to other known factors that reduce visible and ultraviolet light in the universe. Those factors are the reddening of light due to the expansion of space, the universe's dynamic nature, and the absorption of light by intergalactic dust and gas. All combined, this keeps the night sky dark to our vision," NASA's statement said.

So when can we see the rest of the stars?

We are reaching the limits of what Hubble can offer in terms of resolution and reach.

Currently, we can see about 10 percent of the galaxies out there, but new technology will help.

NASA, along with other international space agencies, have been hard at work building a next-generation deep space telescope.

Planned to launch in 2018, the James Webb Space Telescope (JWST) promises to provide unmatched resolution and reach, with an ablity to see farther into our universe and provide a better understanding of our cosmos.


As big as a tennis court and as tall as a four-story building, a full-scale model of the James Webb Space Telescope model was on display at the South by Southwest Interactive Festival in Austin, Texas.

"It boggles the mind that over 90 percent of the galaxies in the Universe have yet to be studied," Conselice said in a statement

"Who knows what interesting properties we will find when we observe these galaxies with the next generation of telescopes," he continued.

Source: 
TRTWorld and agencies