The conversation between human and AI assistant.
Why are planetary orbits ellipses?
That makes sense. Are there other shapes that planetary orbits can take on?
Actually, circular orbits are a special case of elliptical orbits with zero eccentricity. So, it's possible for a planet to have a perfectly circular orbit, but that would require very specific initial conditions. In general, it's much more likely that a planet's orbit will be elliptical with some amount of eccentricity.