(1) Variations in the timing of perihelion and aphelion are caused by a u2018wobblingu2019 in the Earth's axis of rotation as it rotates around the Sun.(2) Mars is at aphelion(3) Mars is at aphelion(4) Furthermore, any resonance with the Earth is illusory in that Mercury is not well placed for observations except during its brief greatest elongations near its aphelion .(5) This affects the climate because the influx of solar energy to our planet would then vary between perihelion and aphelion by a larger proportion than at present.(6) There are small cyclic variations in those apparent sizes because the Earth-Moon distance changes as the latter moves between perigee and apogee, and the Earth-Sun separation alters as the former moves between perihelion and aphelion .(7) This is because at aphelion the planet is moving slowest, and consequently it is less likely to pass across the Sun during the critical window.
