# Propagate Earth trajectory for 1 Myr

What is the most accurate way of propagation of Earth trajectory relatively to the Sun? I need to calculate the Earth-Sun distance. Is there any library on Python?

I've used before JPL Horizons, however, it's not useful for propagation for 1 Myr.

• This is rather curious. An extremely similar question was asked 16 hours ago at the space exploration sister site, but by someone who appears to be a different user. Both questions ask for propagation of Earth's orbit over the course of a million years, and both mention JPL Horizons. I'm curious: Are the two of you taking the same class, with the instructor assigning this incredibly bad homework problem? – David Hammen Sep 19 '19 at 11:31
• You probably need to read the papers referred to on Wikipedia's page on the Stability of the Solar System. – StephenG Sep 19 '19 at 19:01
• Are you looking for the orbital period distance or semi-major axis specifically? Earth's distance from the sun varies due to it's eccentric orbit but the semi-major axis is thought to be very consistent with only slight variations due to the sun losing mass over time and a very tiny tidal interaction between Earth and Sun but both of those are very small. Perhaps other factors that are difficult to calculate. We think that planets can migrate and some have significantly, but now, the 8 planets in our solar-system are now very long-term stable. – userLTK Sep 19 '19 at 23:03