Changing axes units

I have plotted a graph in mathematica, where the x axis is in seconds. I want to scale the axis so it displays years instead.

My plotting function is as follows:

Plot[sol1[t], {t, 0, 1 * 10^(16)},    PlotRange -> All    FrameLabel -> {"Time (s)", "Velocity (ms-1)"},    PlotStyle -> {Red, Thickness[0.01]}] 

Any help would be appreciated.