It was Johannes Kepler in 1618.
Ellipse.
The shape of the orbit of each planet is an ellipse. An ellipse is a geometric shape that is like a flattened circle. The Sun is located at one of the foci of the ellipse, not at the center.
This particular innovation was made by Johannes Kepler, which resulted in the observations of the planets finally falling precisely into the calculations that were made with the heliocentric theory.
Elliptical
Johannes Kepler discovered that the Earth revolves/orbits the Sun in an ELLIPSE. He also discovered that the Sun is NOT at the centre of the ellipse, but at one of the foci ; (plural of focus). The other focal point being 'blind'. From this we have the definition, that as the Earth orbits the Sun , 'It sweeps equal arcs in equal times'. As the Earth orbits, it speeds up and slows down. It is moving at its fastest when passing the Sun at it nearest point ( perigee) and slowest when at its furthest point ( apogee). Have a look in Wikipedia under' Johannes Kepler.
Kepler
The path is called an "orbit", and it has the shape of an ellipse, the Sun being at one focus of the ellipse.
This orbit is called an ellipse. An oval shape.
He discovered that avery planet has a ellipcial orbit, which means oval.
Johannes Kepler formulated the laws of planetary motion in the early 17th century, including the discovery that planets move in elliptical orbits with the sun at one of the foci.
Planets remain almost perfectly spherical as they move around the sun. The paths they follow are ellipses, with the sun at one focus of each ellipse.
False. The term is elliptical. Eclipse is what happens when planets and moons pass in front of one another or the sun.