Size of the universe

The size of the universe refers to the relative size of the universe and entities contained within it. The universe is vast; it's been expanding for almost 13.8 billion years, at a considerable fraction of the speed of light, so it's roughly 13 billion light years across. This means that the universe is ~1.3 x 10²⁶ m across. People are usually not quite 2 m tall, atoms are about 10^-10 m across, nuclei are about 10^-15 m across. While mathematics says there's a difference of a factor 10⁴¹, and that could be written out: 100 000 000 000 000 000 000 000 000 000 000 000 000 000x, it's hard to wrap one's mind around numbers like this.

There are some very good on-line tools to help compare the sizes of various objects in the universe:

• The King Centre for visualization in science, specifically their scale of the cosmos
• The htwins project (click on the start button and then click on the notes to mute the music)
• Hyperphysics has a nice analogy here that helps scale the size of the universe.

Here's a video from IMAX cosmic voyage (music from "The Matrix" movie-trilogy and "Awake" by Jake Kaufman):

Please contact us with other tools showing the size of the universe in cool and interesting ways.