Alignment of Semi-Major Axis of Orbits So I'd like to ask whether the semi-major axis of planetary orbits are aligned? Logically, they shouldn't be, but many websites act as if they are. If they're not aligned, what's the angle between the reference xy axis and the semi-major axis of the orbits of planets?

Thanks!
The major axes of the planets are not aligned.

The major axis passes through the perihelion, the solar system barycentre and the aphelion. So by looking up the Longitude of perihelion we can find the direction of the major axis:

planet  Longitude of perihelion 
M       77
V       132
E       103
M       -24
J       15
S       93
U       171
N       45


There is no evidence of alignment.