But There Was No One to Scream
Posted on | September 2, 2009
Good point. Somewhere between infinite and near-zero density lay the very early universe.
Now, we know we’d be able to hear sound in an atmosphere as sparse as Mars’ (which is about 10 grams per cubic meter), and we know we can hear sound through more dense media as well, such as water and rock. If we extrapolate the Universe back until it was as least as dense as Mars’ atmosphere, this means that for about the first day after the big bang, the Universe is dense enough that sound audible to humans can travel through it….
Now, we know we’d be able to hear sound in an atmosphere as sparse as Mars’ (which is about 10 grams per cubic meter), and we know we can hear sound through more dense media as well, such as water and rock. If we extrapolate the Universe back until it was as least as dense as Mars’ atmosphere, this means that for about the first day after the big bang, the Universe is dense enough that sound audible to humans can travel through it.
But wouldn’t inflationary Dopplering have rendered all that noise subsonic?
