Though, the image in that header seems to have been ran through some Photoshop filters; the original image from the OP was color and didn’t have any sketch lines, if I recall right.
I found the original image on Tineye ; it appears to be a piece of Mass Effect fan art (the Citadel station in the background is a dead giveaway). One of the originals can be seen on DeviantArt. I am somewhat saddened that the image appears to have been used without attribution, however.
It was the image at the top of this quite good post that I ran across coincidentally:
http://facingthesingularity.com/2011/from-skepticism-to-technical-rationality/
Though, the image in that header seems to have been ran through some Photoshop filters; the original image from the OP was color and didn’t have any sketch lines, if I recall right.
I found the original image on Tineye ; it appears to be a piece of Mass Effect fan art (the Citadel station in the background is a dead giveaway). One of the originals can be seen on DeviantArt. I am somewhat saddened that the image appears to have been used without attribution, however.