Artist’s logarithmic scale conception of the observable universe. The Solar System gives way to the Milky Way, which gives way to nearby galaxies which then give way to the large-scale structure and the hot, dense plasma of the Big Bang at the outskirts. Each line-of-sight that we can observe contains all of these epochs, but the quest for the most distant observed object will not be complete until we’ve mapped out the entire Universe. (Credit: Pablo Carlos Budassi; Unmismoobjetivo/Wikimedia Commons)

How far away are we from the location of the Big Bang?

If you think of the Big Bang as an explosion, we can trace it back to a single point-of-origin. But what if it happened everywhere at once?

One of the most difficult concepts for anyone — even a professional astrophysicist — to wrap their minds around is the idea of the Big Bang and the expanding Universe. Off in the far-flung distance, at the limit of what even our most powerful telescopes can see, are galaxies speeding away from us so quickly that the light their stars emitted has been stretched to as much as twelve times their original wavelength. These stretched light waves are a consequence of the expanding Universe, and they are nearly, but not quite, identical for galaxies that we see in all directions in space.

Does that difference, and the fact that one direction has a slightly greater redshift for its objects than the opposite direction, tell us anything about where, all those billions of years ago, the Big Bang actually occurred? After all, we can use redshift to determine when light is receding from us and blueshift to determine when light is heading towards us, and so, if the light left over from the Big Bang is preferentially redshifted in one direction and blueshifted in the opposite direction, can that tell us something…