Other worlds

The distance between objects in space is measured in light years    One light year is equal to six trillion miles   Moving from one planet to the next may be almost impossible with conventional propulsion  The Planets that we can see will possibly have had life that became extinct before earth was able to sustain life  We are alone in our universe  separated by time from any living organism  which is probably why there has been life at all at any time   Take care of the planet we live on