Using the Hubble Space telescope and other observatories, astronomers have completed the most accurate census of galaxies in the observable universe to date. In terms of the actual number, let’s just say we were way the hell off.
The observable universe—that is, the part of the universe that’s visible to us on Earth—contains 10 to 20 times as many galaxies than previous estimates. That raises the total to somewhere between one and two trillion galaxies, which is up from the previous best estimate of 100 billion galaxies. Consequently, this means we also have to update the number of stars in the observable universe, which now numbers around 700 sextillion (that’s a 7 with 23 zeros behind it, or 700 thousand billion billion).
And that’s just within the observable universe. 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.