The Universe is Big!

“Space is big. You just won't believe how vastly, hugely, mind-bogglingly big it is. I mean, you may think it's a long way down the road to the drug store, but that's just peanuts to space.”-Douglas Adams

In the book Hitchhiker's Guide to the Universe by Douglas Adams, the ultimate punishment is the Total Perspective Vortex. A person is shown a view of the entire universe and themself in relation to it. Only one person survives the experience.

If you'd like to experience this on a lesser scale, see the recent deep field Hubble Telescope picture at Astronomy Picture of the Day and understand the scale...

1. Galaxies are big with 100 billion stars on average. (see photo above) At the speed of light our closest star is 4 light years away. Our Milky Way is 100,000 light-years from edge to edge. The light we are now seeing from the center of our galaxy (50,000 LY) was emitted when homo sapiens left Africa to spread across the world.

2. The deep space image at http://antwrp.gsfc.nasa.gov/apod/ap091209.html shows hundreds, if not thousands, of galaxies. The oldest pictured are over 12 billion years old. Three times older than our Solar System.

3. Now for the kicker. The new picture by Hubble covers an amount of sky equal to a grain of sand held at arm's length. Imagine the photo repeated for every dot in the sky!

Bottom Line

It's not easy for the mind to grasp big numbers and large scales. I've read that there are an estimated 100 billion galaxies. So if the photo and grain of sand give you an idea of the vast number of galaxies, remember that I said above that our Milky Way has 100 billion stars. The same number as the number of galaxies. And many of those stars have planets. So what are the odds that in all the vastness of our galaxy, we are unique in having life?

Some scientists call this the Fermi Paradox - why haven't we found other life yet? Statistically it should exist in abundance.