## Sunday, June 8, 2014

### Illustrating the size of the universe in terms of memory space

Accidentally, I came over my friend's question "Are we alone in the universe?".
I started thinking. I knew the universe is big and I've read several times that the human mind can't even comprehend the size of it. As always, I thought that the solution lies in simplifying the problem and making things more abstract.

Being a computer scientist, I went for representing it in terms of data :)
Most estimations of the data volume we produced lie below 5 Zettabytes. So, let's assume that we have a hard drive of that size.

Furthermore, assuming every galaxy is of the same size as the Milky Way, we have approximately:
5.1 x 10^22 stars = 510 0000 0000 0000 0000 0000 stars
170 billion galaxies x 300 billion stars
= (number of galaxies in our universe) x (number of stars in our galaxy)

Summed up, we have:
5 Zettabyte = 5×10^21 bytes = 4 x 10^22 bits on our hard drive and 5.1 x 10^22 stars

Imagine we want to make a picture with tiny dots on it, separated by a white space of 1 bit, making each dot represent a star. With all the memory on Earth we couldn't store that image!

Something funny to think about too: every word ever spoken can be stored in 0.001 Zettabytes. If all we did our whole life was naming stars, we would still have to name 1000 times as much as we did.

With all that said, I believe that there is other intelligent life somewhere out there.

References:
http://en.wikipedia.org/wiki/Exabyte
http://en.wikipedia.org/wiki/Zettabyte
http://www.universetoday.com/102630/how-many-stars-are-there-in-the-universe/