If the Milky Way were a grain of salt how big would the universe be?
How Big is the Universe?
Well, it seems to be infinitely big, thus there’s no way to measure it. If we change the question to how big the observable universe is, however, then we can measure it. The farthest point that we can see in every direction is about 14 billion light years away.
This is impossible to imagine. So, I thought how would the Milky Way Galaxy compare to the Universe? I started by imagining a grain of salt to be the galaxy.
There are three grains of salt in a mm. or one grain is 0.33 mm. The Milky Way Galaxy is 100,000 light years in diameter.
Next, I reduce the universe. As mentioned above the galaxy is 100,000 light years in diameter and the observable universe is 14 billion light years in each direction making its diameter 28 billion years. Therefore, the universe is bigger by a factor of 280,000. So, if the galaxy were the size of a grain of salt the universe would be 280,000 mm divided by 3 which equals 93,333 mm or 93.3 meters long.
In a sphere of diameter 93.3 meters our galaxy would be one grain of salt.
An interesting fact about a grain of matter; the number of atoms inside that grain is ten times the number of stars in our galaxy.