JUST HOW BIG IS THIS UNIVERSE in which we find ourselves? I am not an astronomer, but the question has popped into my head on occasion. I suppose the most interesting phenomenon of the 20th century was discovering that no matter how big we discover it to be using state-of-the-art technology, it proves to be staggeringly bigger with new technology. 1
“Using the Hubble telescope and other observatories, astronomers have completed the most accurate census of galaxies in the observable universe to date. The part of the universe that’s visible to us on Earth contains ten to twenty times as many galaxies than previous estimates!
That raises the total to somewhere between 1 and 2 trillion galaxies, which is up from the previous estimate of 100 billion. This means we have to update the number of stars in the observable universe, which now number around 700 sextillion. 2
Previous estimate of galaxies: 100,000,000,000
New estimate of galaxies: 2,000,000,000,000
Current estimate of stars: 700,000,000,000,000,000,000,000 3
How many galaxies?
Because the cosmos emerged some 13.8 billion years ago, we’re only able to observe objects up to a certain distance from Earth. Anything outside this Hubble Bubble is invisible to us because the light from these distant objects simply haven’t had enough time to reach us.
It’s difficult—if not impossible—to know how many galaxies reside outside this cosmological blind spot.
To come up with the new figure, an international team of astronomers from the University of Nottingham used deep space images from Hubble and combined them with data collected by other astronomers.
The researchers say there must be a further 90% of galaxies in the observable universe that are too dim and far away for us to see using current telescopes.”
FEATURED IMAGE: The photo at the top of this page is of Abell S1063, a cluster of galaxies whose huge mass acts as a cosmic magnifying glass and enlarges even more distant galaxies, so they become bright enough for Hubble to see. I cropped the original photo (immediately above) and added color to make it a wee bit more eye-catching and to provide a somewhat darker background for the title of this article.
“This view of the cluster, which can be seen in the centre of the image, shows it as it was 4 billion years ago. But Abell S1063 allows us to explore a time even earlier than this, where no telescope has really looked before. The huge mass of the cluster distorts and magnifies the light from galaxies that lie behind it due to an effect called gravitational lensing. This allows Hubble to see galaxies that would otherwise be too faint to observe and makes it possible to search for, and study, the very first generation of galaxies in the Universe.” (Hubble)
Finally, most of the paragraphs in quotation marks above were adapted from an article titled “We Were Very Wrong About the Number of Galaxies in the Universe” by George Dvorsky for Astronomy (October 13, 2016). The original article consists of 432 words; my adaptation is 220 words, so there’s more to read of Mr Dvorsky’s piece.
1 Almost like it’s growing its size to meet our growing expectations.
2 I believe that 700 sextillion is a bit more than the gazillions that Scrooge McDuck bragged of having.
3 That’s a current estimate for stars. With these new galaxies, that number then becomes minimally 700,000,000,000,000,000,000,000 x 10, or maximally x 20. And that’s just the 10% of the universe we can see.
Using figures with twenty-three zeros, we are reaching numbers so large that we might as well be discussing infinity. In which case, even if intelligent life is the merest of accidents, it’s a mere accident that has probably occurred billions of time. Already. Right now, as I type this, there could be another me out there writing an article about the number of galaxies in the universe. There could be another you reading that article. And you know what that means? Somewhere, many Elvises live with lots and lots of fans …