Newton's law of universal gravitation ... massaged and manipulated with a lot of calculus and geometry ... predicts that closed gravitational orbits are ellipses.
The circle is such a precise special kind of ellipse that a circular orbit never occurs. The chance of it is like the chance of flipping a coin and having it land standing up on its edge ... possible, but very improbable.
A planet's orbit's around which it revolve around the Sun is not a circle. It's an ellipse — a ring that's "flattened." The Sun (which is also called the planet's center) holds one ellipse target. A concentration is among two inner points helping to decide an ellipse's form.
In all atoms, the number of protons = number of electrons, as a result the atom is neutral. Losing or gaining electrons will make the atom electrically charged and we call an electrically charged atom an ion.
Ca 2+ would be the symbol because losing two negative electrons makes calcium's nucleus more positive by two protons.
The higher the bird flies, the bigger the shadow it casts, however, for the shadow to be visible enough the plane or bird would have to be close to the line directly from the sun.
