Thu 17 Apr 2008
I’ve been watching “The Universe” on the History Channel .. its quite fascinating to learn about all the recent discoveries in astronomy. It got me thinking .. just how big IS the universe?
With Wikipedia and Google and OpenOffice Calc, I did some calculations to try and grasp the size of the universe using objects I could comprehend.
Starting with one grain of salt here in my home offce in Tempe, AZ, I decided to make this my “Earth”. So everything I know here on Earth would be shrunk to just one grain of sand (all the people, all the oceans, all the continents .. the sky, the clouds .. everything.) Granted, I can’t quite totally comprehend the size of the earth as I have only journeyed across such a small portion of it, but alias, it is now for all intents and purposes one grain of sand.
The Sun (the biggest thing in our solar system) on this scale would be about the size of a basketball. Pluto, perhaps one of the furthest objects most of us feel is part of our solar system would be at its max about 3/4 of a mile from the basketball (at its closest, about a 1/2 mile from the basketball).
Perhaps the next logical place to go would be the nearest star, Alpha Centauri. This would take you out of Tempe .. out of the Phoenix area .. out of Arizona .. even out of the US .. we would pass over Mexico and Central America. We would land somewhere in Peru. Wow. Thats quite far.
To grow a bit larger, lets just get a feel for our own galaxy, the Milky Way. The actual Milky Way is about 100,000 light years across. This (if my calculations are correct) when scaled to where the earth is a grain of sand and the sun is a basketball would make the Milky Way about the same size as the distance of the Earth to the Sun (about 93 million miles wide).
Of course, the Milky Way is but just one of millions, perhaps billions of galaxies. The closest spiral galaxy, Andromeda Galaxy, is about 2.5 million light years away from us. When adjusting for our size scale, this puts the Andromeda Galaxy about 2.4 billion miles away from Earth (the single grain of sand located in Tempe..). At its closest point, this would put the Andromeda Galaxy at about the same distance as Pluto is to the Sun at its closest. Yikes.
That’s only one of 35+ galaxies in our “Local Group” of galaxies.
All said, the Milky Way by itself has over 200 billion stars and probably billions of planets. The “Local Group” of galaxies contains trillions of stars and dozens of galaxies on its own. And it only gets much larger from there. Lets put it this way, if we took those dozens of galaxies and space that makes up the “Local Group” and compared it to what we know as the observable universe (not the entire thing), we could place the local group in its own square mile on earth and what we know of the observable universe would expand completely around the entire earth and then some (at that point in time, the size of the earth would most likely be sub-atomic .. no I’m not going to calculate it tonight.).
Wow. Quite amazing.