He did this by relating the light-year to the Astronomical Unit â the Earth-sun distance. One Astronomical Unit, or AU, equals about 93 million miles (150 million km). Another way of looking at it: the Astronomical Unit is a bit more than 8 light-minutes in distance. A light beam takes 8 minutes to travel the 93 million miles (150 million km) from the sun to the Earth.
Lake Superior sits between Ontario, Canada and New York. Lake Ontario is mainly fed by the waters of Lake Erie, which are transported via the Niagara River. Lake Ontario drains into the St. Lawrence River. Lake Michigan is the third largest of the Great Lakes and the only one entirely within the United States.
1 The volume of water in the Great Lakes would cover North America in about 1 metre (3.5 ft.) of water. 2  The water flows from streams and rivers that empty into the Great Lakes, from Lake Superior down through Niagara to Lake Ontario, then into the St. Lawrence River to the Atlantic Ocean. The deepest section in the Niagara River is just below the Falls. 2  It is so deep it equals the height of the Falls above, 52 metres (170 ft.). 3  The Upper Niagara River extends 35 kilometres (22 mi.) from Lake Erie to the Cascade Rapids, which begin 1 kilometre (0.6 mi.) upstream from the Canadian Horseshoe Falls.