Interesting ( .. maybe ?) Facts on distances / size of things : Some Perspective – II

What is the Size of:

Here is a nice list of the size/length (diameter) of some things in the universe (in meters) :

  • The Size of a proton or a neutron can reach 10-12 meters in length
  • The Size of  an Atom : roughly , the covalent size of a silver atom is 1.5 x 10-10 meters
  • The Size of a Cell : A bacterium is roughly 10-6 meters in length
  • The Size of a Human : 1-2 meters
  • The Size of the Earth : diameter in the order of 107 meters (1.2 x 10^7)  
  • The Size of the Sun : diameter in the order of  109 meters
  • The Size of the Galaxy : roughly  1021 meters in diameter
  • The Size of the Universe : A lower bound of  1027 meters

At the end of this post there is a link to an interesting interactive infographic that gives a nice idea of the size of things, starting from the infinitely small (Planck area) , to the largest possible (universe)  … Although I am not very sure of the correctness of the estimates (and visualization integrity) of extremely large quantities in that infographic , especially when we reach the size of the universe …  – there is a discussion on them and ‘observable’ universe is different from universe …

Also we must differentiate between the ‘size’ of things , and the ‘distance’ between things in space … keep in mind also that size in terms of length/diameter , is very different than area or volume (in case you’re trying to figure out how many items of x does y fit)


Side Note:

A googol ( 10100 ) is 1 followed by a 100 zeroes :


A googolplex is the number 10googol, i.e. 10(10100)


More on Upper Limits

Some upper limits on the size of the universe are 10115 , 10122 or 1010122 meters (a unit doesn’t really matter much at this scale)  … 10122 is 1 followed by 122 zeroes, or a gogol multiplied by a quadrillion. 1010122 is 1 followed by a quadrillion googol zeroes. 101010122is 1 followed by 1010122 zeroes. These numbers are so vast that they are essentially the same in whatever units we could use to list them.

essentially these somehow become ‘philosophical’ limits … one of them is calculated based on the probability of reaching another volume in space that has similar conditions and structure like our universe (1)



this topic is just a small opportunity to contemplate  the sheer scale of things in our world … how insignificant some numbers can be , and even some concepts.

The idea of something so large that the unit in which you measure it doesn’t matter is an interesting mental shortcut into understanding the sizes we’re talking about.

Thinking about these numbers raises beautifully the issues of how centric can we really be in this universe, as the sizes here put a new light on the 20-80 rule if we are to assume some uniqueness for ourselves as human..

Hard not to be moved and amazed  !



Here is a video that helps illustrate the power of an extra 0 , and some sizes of things :


Here is the infographic too :

The Scale of The Universe 2 — Click to open



1. “Parallel universes. Not just a staple of science fiction, other universes are a direct implication of cosmological observations.”, Tegmark M., Sci Am. 2003 May;288(5):40-51.



See the Previous Post about ‘Perspective’ , but in terms of Time here :



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