There are even more galaxies in the universe than we thought

Alan Martin October 14, 2016

We’ve always known the universe was a big place, but our estimates keep getting revised upwards, adding more and more zeroes as we go along. The latest jump, based on 3D modeling of images collected over 20 years through the Hubble Space Telescope, reckons there are ten to 20 times more galaxies than previously thought. That’s somewhere between one and two trillion, for those struggling to keep count.

There are even more galaxies in the universe than we thought

If your mind wasn’t already blown trying to keep these figures in your head, this big increase means the number of stars in the universe also gets a bump up. And given there are 100-400 billion stars in our galaxy, the figure elsewhere gets a bump to around 700 sextillion (or 7,000,000,000,000,000,000,000 stars). Some estimates reckoned there were already around 100 stars for every grain of sand on Earth and, well, now there’s a fair few more.

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The study comes out of the University of Nottingham. Professor Christopher Conselice led a group of researchers who converted two decades’ worth of deep space images from Hubble into 3D to measure the number of galaxies at different points in our universe’s history. In tandem with a new mathematical model that allowed the scientists to infer the number of galaxies our current generation of telescopes can’t currently observe, they realised that in order for the numbers to add up, we must only be able to see around 10% of the galaxies in the universe. 20_times_more_galaxies_than_thought

“It boggles the mind that over 90% of the galaxies in the universe have yet to be studied,” said Conselice. “Who knows what interesting properties we will find when we observe these galaxies with the next generation of telescopes?”

It also appears that while our estimates of galaxy numbers keep going up, the real number has actually shrunk. Indeed, the research reveals that there were once around ten times as many galaxies in a given volume of space as we have today. This, the scientists believe, is because many of the small and faint galaxies ended up merging together quite early on – relatively speaking, we’re still talking a few billion years old – in the universe’s life.

All of this, of course, just makes the Fermi Paradox all the more puzzling. If we have two trillion galaxies in the universe, all hosting millions to billions of stars inside, then where are all the aliens?

Images: Tom Hall and Alexander Kaufhold used under Creative Commons