This curve resembles a flattened circle. The eccentricity describes how much the ellipse differs from a circle. An orbit with an eccentricity of 0 is a circle. An orbit with an eccentricity of 1 would be an open curve called a parabola. No planet would stay in orbit with that kind of path.
Most planets have orbits with very low eccentricity, close to zero.
Their orbits are very nearly circular. Venus has the most circular orbit. The least circular orbits are those of Mercury and Pluto. Pluto's orbit is so elliptical that it sometimes moves closer to the Sun than Neptune. There is no danger of a collision because Pluto's orbit is so highly inclined.