Wondering about wild grapes

Monday, August 8, 2011

Wondering about the Pillars of Creation.

We all were awed by the photos that the Hubble Space Telescope has taken, and for that matter, still does.  I believe that the most popular and the one that showed up on all news media was the cold hydrogen gas clouds that were called the Pillars of Creation.  You remember that one, don’t you?  In case you forgot, here is the picture from NASA:

Now that I have refreshed your memory I would like to pass on some information that I just recently learned from reading last months Astronomy magazine. I guess that I never thought about the density of the gas cloud since the picture was so beautiful and awe inspiring that I was mesmerized by it. Look at the pillar on the left, the biggest one. It looks so solid and thick, but things can be deceiving.

The reason it is deceiving to us is that we are not used to looking at things at that scale. These clouds are not measured in miles, but in light-years. A light-year is the distance that light travels through space in one year. Now tell me that a distance like that is easy to comprehend?!?! OK, now let’s put some numbers on that cloud. It measures around 3 light-years and is around a half a light-year thick. The contrast between the pillars and the space around them makes them look almost solid. That is not the case.

The density of that cloud is about 4000 particles per cubic centimeter. Air density at sea level has more than 10 to the 19th power, or 10000000000000000000. That makes the air 2500000000000000 times more dense than that gas cloud. In fact, 4000 paricles per cubic centimeter is far lower than the best vacuum we can achieve here on Earth. The reason it looks so solid is that we are looking through a half light-year of particles. It is the huge scale of the pillars that makes them appear so solid. And, I guess compared to the area around them, they would be considered solid. . . or maybe not.

They are still a wonder and I will keep on wondering about them, how about you?

You all have a good week now, you hear?


  1. Having read science fiction for the last 60 plus years and having read some authors that could really put the sizes and distances into perspective, I still find myself totally awed.
    An old nerd once told me that the density of those clouds was (when the light left) less than the vacuum in an old fashion vacuum light bulb and that if you got close to them you wouldn't be able to see them.
    They fit inside my mind which is another awe filling revelation.

  2. BB, I am not sure if anyone can completely understand what all is out there in the big universe.

    Oldfool, the old nerd was right. It is a lot less dense than any man made vacuum. The wonders of what all is out there. I can't see a fraction of what the Hubble saw, even with my big scope. The trick is to star at it for hours and hours using a sensitive CCD chip.

  3. Those distances boggle my mind for sure. Anymore if the distance is more than I am comfortable driving in one day, It's a dammed long way :-)

    What I wanna know is, Who measured it and what'd they use to do it?

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  5. Ben, I know what you mean about a damned long way. BTW, they can measure size by triangulation, and for stuff far away they take readings when the earth is at both its right and left fartherest swing around the sun in relation to the object. The density is calculated on how an object reacts to other stuff in the arear. If that don't work they hire the little green (or grey) men to take care of it. . .Deleted the first comment cause my fingers got mixed up on the key board.

  6. I used to have that picture as wall paper years ago. Matter of fact I rotated between it and many others taken by Hubble. They were all awe inspiring.

  7. A light year is about the distance from El Paso, Texas to Junction, Texas in the summer. A least it seems like it.

  8. David, the Hubble sure did produce some amazing pictures. It opened up the universe to all of us.

    Barney, I know what you mean in this weather, especially if your AC quit on you.