AST101H5 Lecture Notes - Lecture 2: Ancient Greek Astronomy, E-Book, Astronomical Unit
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The answer is we live on earth, a planet. Solar system = the sun and all the objects that belong to the sun - a large family. Ratios compare two number. one value is a multiple or fraction of another number, more informative than the pure number. Radius of moon/radius of earth = 1738km/6378km = 0. 272. Make sure to keep the same unit. Numbers can be astronomically large or small. It is easier to write very large (and very small) numbers in scientific notation. See appendix a1 at the end of the textbook for an explanation for. Familiar units, such as km, are too tiny for astronomy. Invent new units that are more appropriate. Distance can also be expressed in how much time it takes light to travel that distance. The edge of the solar system = apx. halfway to the nearest star. Travelling at highway speed (100km/h) the trip would take:
