An ellipse is given by the equations x^2/a^2+y^2/b^2=1
You'd have to ask the earth what it's ellipse is though.
An ellipse.
Ellipse
It's almost a circle, but actually it's an ellipse.
The Sun does NOT lie at the centre of an ellipse. The Sun is at one of the two foci of an ellipse. Have you ever drawn an ellipse with two pins a piece of string and pencil on a board. Insert the two pins into the board/paper. Loosely loop the string over the pins, and tighten with the edge of a pencil. Keeping the string taught with the pencil you can draw an ellipse. The positions of the two pins are the foci of the ellipse. Astronomically, the Sun lies at one of these pins. This was discovered by the Astronomer , Johannes Kepler, who gave us the law, that the Earth sweeps equal arcs in equal times about the Sun . The other focus may be thought of as a 'blind' focus. Have a look in Wikipedia under 'Johannes Kepler'. NB The plural of the noun 'focus' is 'foci'. 'Focuses' is when the word 'focus' is being used as a verb.
The Earth's orbit is elliptical and it takes a year to get round the ellipse once. The ellipse is almost a circle - the minor axis is only 0.014% smaller than the major axis. The Sun is off-centre by 2.5 million kilometres and the Earth is closest in January (147.1 million km) and furthest in July (152.1 million km), when it is at either end of the major axis of the ellipse.
An ellipse.
Ellipse.
ellipse
A point on an equation for an ellipse centered on the Sun.
Ellipse.
Earth travels in an ellipse around the sun
Ellipse
Ellipse.
Earth's orbit (revolution) around the Sun is not circular - it's an ellipse. However, this ellipse is fairly close to a circle.
The path of the Earth's orbit is an ellipse. The Sun is positioned at one of the two foci of the ellipse.
It's almost a circle, but actually it's an ellipse.
It's almost a circle, but actually it's an ellipse.