The orbits of the planets are ellipses with the

**Sun**at one focus, though all except Mercury are very nearly circular. The orbits of the planets are all more or less in the same plane (called the ecliptic and defined by the plane of the Earth's orbit).Similarly, it is asked, how long does it take for the planets to orbit the sun?

Earth takes

**365 days**to travel one complete orbit, while Mercury takes**88 days**and Venus takes**224 days**, so the time between alignments will require each planet to make a whole number of orbits around the sun and return to the pattern you see in the figure above.What is the period of rotation for each planet?

The Days (And Years) Of Our Lives

Planet | Rotation Period | Revolution Period |
---|---|---|

Mercury | 58.6 days | 87.97 days |

Venus | 243 days | 224.7 days |

Earth | 0.99 days | 365.26 days |

Mars | 1.03 days | 1.88 years |

Can the orbits of the planets change?

If the Sun and Earth were the only things in the solar system, our

**planet's orbit**would be an ellipse of virtually constant shape and orientation in space. However, because the other**planets**pull on Earth, our**orbit does change**slightly over time, in orientation and in shape. Same for the other**planets**'**orbits**.