One of my greatest interests is Astronomy and the Universe. I remember as a younger boy my grandfather had a telescope, but I never really thought much of it. During my high school years I started watching shows on the Universe and my interest slowly started to rise. Throughout college I took some Astronomy courses and started to realize just how vast the Universe is. The majority of us go about our days living our lives and never really consider how small and insignificant we really are. Here is an animation that may give you a slight understanding: www.micro.magnet.fsu.edu/primer/java/scienceopticsu/powersof10
Our visible universe (how far we can see from Earth in any direction) is 13.7 billion light years. The speed of light is 670,616,629.384 miles per hour. Why do I mention mph? Because that's a term we use everyday… it's a speed we can relate to… we are supposed to drive 55mph, modern airliners fly at around 500mph, the fastest jet man has made (SR-71) hit a record just above 2,000mph. If we were to fly in an airliner to the edge of our visible universe (which by the way is 91,874,478,225,608,000,000 miles away) it would take 20,975,908,270,686.7 years (20 trillion years!). The size of the visible universe is incomprehensible to the human mind. These distances we cannot wrap our minds around.
The next time you look up at the night sky, remember you are not seeing stars as they are now, you are seeing them as they were years ago. The closest stars to us are about 4 light years away, in other words they are so far away it takes light (traveling at the insane speed I mention above) 4 years to reach us. Even our own Sun, the closest star to us, is so far away it takes light about 8 minutes to travel to us. If the Sun vanished now at this instant, we would still have light for 8 minutes.
There are so many other mind boggling things in the Universe, such things as neutron stars, black holes, gamma bursts, etc, which keep my mind spinning when trying to comprehend it.