The Little Bang

Big BangWhichExploded.jpg
Actually, this is the Cat's Eye Nebula (image from


Student visualize the big bang as happening at some small point somewhere in empty space that
expands to fill the universe.

This misconception is mostly taught correctly (by Neil Degras Tyson and others), but is paired with the wrong visuals (again by Neil Degras Tyson and others). Note the depiction of empty space around the Big Bang in the images included. (The first two images are typical of what students might find when doing a Google Image Search of the Topic.) This Leads to the idea that there is somewhere in space that we can "stand", exist or float where the big bang could have been viewed from.
Notice the Blank Space around the Edges, implying that we're standing outside the Universe. (from

This misconceptions is related to how students think about infinity, and density. Infinity and density are common ideas, but they aren't covered together (or completely in the case of infinity). Students ideas about infinity don't quite match infinity (no, if you manage to get to the speed of light, you can't go just a little bit faster, infinity+1 is about the same side as infinity, there might be a "To Infinity" but there isn't a "and Beyond!") as a mathematical idea.

An example of this disconnect between what is shown and what is taught. Between 10 seconds and 12 seconds
we are standing outside of the Universe.

Correct Way to Describe:
Hard to see, but the early universe was very bright during some phases, and this may be closer to what it would have looked like.

One possible way to discribe the origins of the universe would be to say: The Big Bang is an explosion OF SPACE. Imagine sitting inside all the stars, galaxies, dark matter, and atoms in the entire universe, and imagine them all being in the same "place". Then, the density of the universe starts to change! We
have the same about of stuff (sort of) but now there is more space in between all of the stuff.

When describing the Big Bang, it's more useful to talk about the size of the universe as a density. The
Universe is by definition infinitely big, it is just that infinity can get more spread out.