Lecture on Space Basic

General objective of this lecture is to present on Space Basic. A star (our sun) is part of a galaxy. A planet (earth) orbits a star. A moon (our moon) orbits a planet (earth). From the perspective of an Earthling, outer space is a zone that occurs about 100 kilometers above the planet, where there is no appreciable air to breathe or to scatter light. One light year is the distance travelled by light in a year. It takes light from the sun 8 minutes to get to the earth. It takes 4 light years for light to reach the nearest star (alpha centauri). It takes light 100,000 light years to get to the edge of our galaxy.