I Spy With My Little Eye

The Hubble Ultra Deep Field

Uncropped Hubble Ultra Deep Field image

Greetings, Everyone. Today I’m going to talk about something special, the Hubble Ultra Deep Field photograph, which was taken over a 4 month period in 2003-2004. The HUDF is the deepest look into the sky that humans have created, at least so far, and I find it to be a mesmerizing image. The articles that I’ve written up to this point have really been kind of a preparation for this one, getting you used to the ideas of “big” and “deep” as they relate to astronomy, and hopefully add to the impact of the HUDF image.

You have undoubtedly heard of and seen images of the Hubble Deep Field photographs which were taken in 1995 and 1998. The HDF examined a tiny portion of the sky near the handle of the Big Dipper for 10 days in 1995. The size of the area examined is the size of a dime seen from 75 feet away, and the photograph shows nearly 2,000 galaxies. It was big news at the time.

In 2002, the Hubble got an upgraded camera for performing surveys (ACS) that has twice the field of view and greater sensitivity than the camera used for the HDF, and allows the Hubble to see objects 2 to 4 times fainter. Astronomers chose an area of the sky below the constellation Orion, and in late September 2003, they started taking exposures of the area, and by mid January 2004, an exposure time of 11.3 days had been accumulated with the ACS and the Near Infrared Camera and Multi-object Spectrometer (NICMOS). When all of the exposure data had been assembled, it yielded the photograph at the top of this article, showing over 10,000 galaxies. The oldest galaxies in the image date from 800 million to perhaps as little as 400 million years after the Big Bang. I find that to be a very mind boggling piece of information, in fact, I think I’ll go have a lie down for a few minutes…but not on the TV remote thank you

Whoo, that’s better. Another thing to keep in mind while looking at the HUDF image, is that except for a handful of local stars, every dot of light in the image is a galaxy. My, but there are a lot of them, aren’t there? And this from an area of the sky that would fit inside the largest impact crater on the moon, or as one astronomer put it “like looking at the sky through an eight foot drinking straw”. Personally, I have never looked through an eight foot drinking straw at anything, so I’ll have to take his word for it.

Here is an excellent cropped image that doesn’t fall apart when you click on it for the large version:

Large High Quality HUDF image – Click to enlarge

All of the information that I’ve used in this article was taken from The HubbleSite website:


I urge you to go and visit the site, there is much more information there, and tons of wonderful pictures that are too large to try and post here, as WordPress complains bitterly when I force it.

Here is a cool video I found there that zooms into the HUDF:


The video loads slowly for me, but it’s worth waiting for.

So, was it worth it, or did I just waste your time?

  • Deartháir

    This makes my brain hurty with awesomeness.

    • dmilligan

      Then I did good, huh boss?

      • Deartháir

        I seriously cannot stop staring at the enlarged image. The galaxies are just gorgeous, and to see that many of them, all different kinds, clustered together like that… to say it "boggles the mind" is such an understatement, I don't think there are words.

        "It's awesome, Mr. President."
        "What, like a hot dog?"
        "Like a billion hot dogs, sir. It's the dog's bollocks."

        • dmilligan

          If you're looking at the enlarged image, look for galaxies that are spindly or not symmetrical. Those are the first galaxies forming over 13 billion years ago. It's hard to come to grips with that. Stuff like that is why I love astronomy and astrophysics and cosmology.

  • mr. mzs zsm msz esq

    That video was well worth it. Do you know if the part that is labeled DSS is from the Sloan Digital Sky Survey? Man I hope the JWST funding comes through.

    • dmilligan

      I believe that they are referring to the Sloan survey. There are several digital surveys that I found references to, so I might be wrong. The one I couldn't find a reference to was the GEMS survey. It might be something internal to Goddard.

    • skitter

      Seconded on the video.
      I think a boost valve stuck shut, and my mind melted into a single lump.

      Edit: Some back of the envelope calculations later, I measured off how big a night-sky poster would have to be for the ultra deep field to be 1mm^2. Using wiki numbers (1/28,000,000) and who knows what sort of projection, I came up with ~5.3m^2. I imagined that on my floor, and then had to lie down.

      • dmilligan

        Yes, any way you fool around with it, you keep coming up with 'very big'. Nice thought experiment.

      • mr. mzs zsm msz esq


  • Charles_Barrett

    Thank you for reminding us all just how insignificant we all are, beyond the scope of our block, our neighborhood, our family and friends, our nation, and our planet.

    Food for thought.

    • skitter

      There are so many things we can't even see, and the uncrossable emptiness is even vaster.

      • dmilligan

        Yes, vast stretches of empty space, and vast stretches of time to cross it. Once you understand that, it makes you realize just how slender the odds of humans ever encountering intelligent aliens are. Then you watch a TV show on UFOs and can't help but laugh.

    • dmilligan

      Yes, food for thought is the primary reason behind my posts on astronomy. I'm hoping that I can help people realize what an amazing place our universe is if you just look around a bit. Placed against the scale of the universe, we are less than dust, and that is very hard for a lot of people to swallow. If you can get pass that, however, there are lots of cool things for an intelligent dust speck to look at in wonder.
      I hope that wasn't too sappy. Sometimes I really suck at expressing myself.

  • texlenin

    You think it's a long way down to the chemist's!
    Not even close.

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