Credits

David Münnich - For creating such an epic riddle and giving millions of puzzle-solvers a great time
My girlfriend - Minus Mu's image
jpt64 - Minus Epsilon and feedback
Maka - Minus Theta's image
The notpron community - For being awesome as well as giving me valuable feedback

Password Boxes / Account Registration:
negativize, phpBB

Riddle Ideas / Execution:
negativize (45, -alpha, -beta, -gamma, -delta, -epsilon, -zeta, -eta, -theta, -iota, -kappa, -lambda, -mu, -nu, -xi, -omicron, -pi, -rho, -sigma, -tau, -upsilon, -phi, -chi, -psi, -omega, sol, luna, mercurius, venus, terra, mars, jupiter, saturnus, uranus, neptunus, pluto)
jpt64 (-epsilon)

Webpage / Riddle Visual Design: negativize + David Münnich (thanks for the inspiration)