# conformal time in Lambda-driven expansion

09 Jan 2013What’s the relation between conformal time and cosmic time (or equivalently between comoving and proper distance) during epochs of exponential expansion? Can you write the relation as a power-law?

physics bonus question: What’s the reason why magnetic fields play such an important role in astrophysics, and electrical fields so little?

maths bonus question: Can you determine the derivative of \(\exp(-1/(1-x^\alpha))\) both at \(x=0\) and \(x=1\) for arbitrary \(\alpha>0\)?