You inspired a quick blog entry (Here sans images)
If we do a google or youtube search on size differences you quickly get a few examples showing how small our sun is relative other stars. That in itself can be very humbling and awe inspiring. But there's more, and I think this might blow your mind.
I'll try to keep it simple, to make it as understandable as possible
We'll start somewhat small, say our solar system. I wanted to visualize the solarsystem graphically and to scale. Something I found very very difficult, given the sizes present. One has to make such a HUGE picture for a planet such as mercury to fill even one pixel that my (hopelessly inadequate and - for this task - unsuited) software crashed. (If you attempt this, use vector graphics) I have not tried later, but I could easily draw it using the proper software. Problem is, with the sizes involved it wouldn't make much sense.
To illustrate you can use a roll of toilet paper. Draw the sun on one end, make sure not to draw it bigger than 1 cm. Then you can, if the roll is about 43 meters long (141 feet), barely fit pluto on the other end.
The earth would be one meter away from the sun at this scale and have a diameter of roughly 0.09 mm. (0.0036 inches). Pretty hard to spot.
But, our solar system is pretty small, actually
Enter the Milky Way. Our home is a large flat disc of stars. MANY stars. About 100 to 400 billion of them. It's a little hard to count them from our vantage point. And it's wide, so wide that if you hitched a ride on a photon (a beam of light) it would take you a hundred thousand years to cross the galaxy across it's diameter. Keep in mind that at that speed travelling from the earth to the moon would take 1.2 seconds. A journey which took the Apollo 11 four days.
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The Milky way, our home.
The milky way is big, and on a photo showing every star as a single point there are so many it would appear as a layer of white dust on a black background. Yes, our galaxy is big. But it's not the only galaxy.
Say we hitch a ride on our photon for a million years in any one given direction from earth. Then we stop and take a look around us, making a new map of our surroundings. At this distance the universe appears almost empty.
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A few galaxies close by. This group contains about 700 billion stars, yet notice how empty the space they occupy seems.
Zooming out ten times, and we get a larger cluster of galaxies, and space seems less empty. In this map every single non-black pixel is a whole galaxy!
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Galaxies galore. The virgo supercluster of galaxies.
It contains at least 100 groups of galaxies, trillions of stars.
This is getting impressive, isn't it? And quite impossible to really understand. But wait, if we zoom even further out, or more accurately map all we CAN see from the earth this is how the universe will appear:
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The visible universe. This contains about ten million superclusters each with trillions upon trillions of stars, and many many times that many planets.
It's HUGE. And notice how it seems like a latticework, dust clumping a little together in an interesting pattern. This is as far as we can see. Here, as far as our telescopes are concerned, the universe ends. And when we see this far out - in any direction - we see galaxies. Billions and billions of them. The light from each of which has taken almost 13.7 billion years to travel from it's original stars all the way to our cameras.
To show you what the universe looked like roughly 13.7 billion years ago, here's a photo taken by the Hubble space telescope in 2003-2004. It is called the Hubble Ultra Deep Field, and is of a tiny area of the sky which appears completely blank and empty to other telescopes. It shows approximately 100 000 galaxies, the most distant of them is about 13 billion lightyears from earth. That means that if the universe did not expand it would take us 13 billion years travelling at the speed of light - the fastest speed there is - to reach it.
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The Hubble Ultra-Deep Field. This image shows 100 000 galaxies. The light from which was about 13 billion years old when the picture was taken in 2004 (not that much older now in other words)
And you thought an elephant was big ;-)
