<p>Noise on top of the Cosmic Microwave Background spectrum.   Of course you must first remove some anisotropy, foreground objects, correlated detector noise, galaxy and local group velocities, polarizations etc.  Many <a href="http://arxiv.org/abs/astro-ph/0703806" rel="nofollow noreferrer">pitfalls remain</a>.</p>
Alternative Entropy Sources
<p>Okay, I guess this is entirely subjective and whatnot, but I was thinking about entropy sources for random number generators. It goes that most generators are seeded with the current time, correct? Well, I was curious as to what other sources could be used to generate perfectly valid, random (The loose definition) numbers.</p>

<p>Would using multiple sources (Such as time + current HDD seek time [We're being fantastical here]) together create a "more random" number than a single source? What are the logical limits of the amount of sources? How much is really enough? Is the time chosen simply because it is convenient?</p>

<p>Excuse me if this sort of thing is not allowed, but I'm curious as to the theory behind the sources.</p>