An ultra-deep view of galaxies many billions of light years away in the distant Universe. Image credit: NASA, ESA, R. Windhorst, S. Cohen, and M. Mechtley (ASU), R. O’Connell (UVa), P. McCarthy (Carnegie Obs), N. Hathi (UC Riverside), R. Ryan (UC Davis), & H. Yan (tOSU).

How big was the Universe at the moment of its creation?

Everything in the Universe today was compressed into a tiny volume. But how small was it?

“The creation of something new is not accomplished by the intellect but by the play instinct acting from inner necessity. The creative mind plays with the objects it loves.” -Carl Jung

You might think of the Universe as infinite, and quite honestly, it might truly be infinite, but we don’t think we’ll ever know for sure. Thanks to the Big Bang — the fact that the Universe had a birthday, or that we can only go back a finite amount of time — and the fact that the speed of light is finite, we’re limited in how much of the Universe we can see. By time you get to today, the observable Universe, at 13.8 billion years old, extends for 46.1 billion light years in all directions from us. So how big was it all the way back then, some 13.8 billion years ago? Let’s look to the Universe we see to find out.

The Hercules galaxy cluster showcases a great concentration of galaxies many hundreds of millions of light years away. Image credit: ESO/INAF-VST/OmegaCAM. Acknowledgement: OmegaCen/Astro-WISE/Kapteyn Institute.

When we look out at the distant galaxies, as far as our telescopes can view, there are some things that are easy to measure, including:

• what its redshift is, or how much…