We think of planet Earth as very large. Consider the distances: New York to Dubai on a 747 takes 12 hours travelling at speeds of 400 to 500 miles/hour. That's far.
Earth is a planet, and only a medium sized one, circling around a medium sized star that we call the sun, that constitutes the Solar System.
The Solar System is part of what is called the Milky Way Galaxy. This Galaxy contains 300 billion stars! A more or less accurate estimation of the number. This number is about the same as the number of the grains of sand in all the oceans on Earth!! The diameter of the Earth is about 13000 kilometers, and that of the Sun (which is a star) 1.4 million Kilometers. So our sun, which is an ordinary medium sized star, is HUGE.
The no. of galaxies in the observable Universe are also about 300 billion!!!
Makes you wonder about man's significance on a grain of sand!
The nearest Galaxy to our Milky Way Galaxy is the Andromeda Galaxy. This is at a distance of about 3 million Light Years. A light Year, as we all know, is the distance light travels in one year; so if we start travelling at the speed of light it will take us 3 million years to get to good old Andromeda.
Now here is the clincher. The Milky Way and Andromeda galaxies are are heading for a head-on collision! They are approaching each other at about 6000000 miles an hour, and at that slow speed it will take them 4 billion years to collide. And what will happen when they collide?? Apparently no great fireworks, just a mingling of the stars, a few unremarkable collisions, and a change in the configuration of our own Solar System. Thats all
http://science.nasa.gov/science-news/sc ... andromeda/