Hubble Deep Field

Over Christmas 1995, the Hubble Space Telescope was pointed towards a seemingly empty patch of sky within in the constellation of Ursa Major.  The resulting image is nothing short of remarkable.  While staring into this empty patch of space, Hubble took 342 exposures (each typically 15 to 40 minutes long) over a period of ten days in “ultraviolet, blue, red, and infrared light" (HubbleSite, 1996).  All of these separate images were combined to create the Hubble Deep Field (HDF) photograph.

The Hubble Deep Field image shows almost 3,000 galaxies! This photograph shows these galaxies as they would have been, in some cases, a mere half a billion years after the Big Bang.  This photograph is literally a window into the past.  Some of these galaxies are so young that many of them haven't even had the chance to form stars. We see the galaxies this way because of the time it takes light to travel to us (or, in this case, to Hubble).  Some of the objects in the HDF photo are easily identified as spiral galaxies, even to people like me that have zero experience with astronomy.  According to NASA, a select few of the objects in the foreground of this image are stars that are in our own Milky Way Galaxy while the rest are galaxies unto themselves (ESA/Hubble). Some of the objects in the image are faint because, in this case, they're so far away.   

So, why is this image (and the images that followed it) important?

Not only did this photograph change the world, but it changed our understanding of ourselves and the universe.  In 1995, this was the farthest that we had ever seen into space. NASA pointed Hubble into an empty patch of sky the size of a dime 75 feet away and saw galaxies - thousands of galaxies!  This is an extremely small sample of the universe (estimated at about one 24-millionth of the sky) and in it we can see thousands of galaxies.  Though this is such a small sample of the sky, astronomers consider this to be representative of the "typical distribution " of galaxies throughout the universe. This was substantiated when NASA took another photograph, Hubble Deep Field - South, which took a similar picture in the opposite direction as this original image (ESA/Hubble). 

The HDF image gave astronomers and other scientists valuable insight into how the universe works.  I'm not a science person so, to be honest, I don't understand all of the scientific implications that this image had (but I know that there were many).  Putting these scientific advancements aside,  I think that this image changed the world because of how it changed the way people see the universe.  The HDF provides photographic evidence of how small we are.  We're one planet in a universe full of millions (and possibly billions) of other galaxies.  The potential for civilizations other than ours is not completely out of the question (which I'm sure Fox Mulder would be happy to hear). 

The most significant thing about this image is that it gives us a visual.  Astronomers have estimated that the universe has about 100 billion galaxies in it (Goddard Space Flight Center, 2002).  It's beyond our mental capabilities to visualize that number.  Even visualizing a million is difficult for most of us.  Therefore, when astronomers tell us about all these galaxies outside of ours, that information becomes meaningless because we just can't see it.  The Hubble Deep Field image(s) allow us to see that.  The HDF photograph of 1995 shows 3,000 galaxies photographed in an area the size of a dime! Being able to see the immensity of the universe changes, at least for me, how I think about the universe and the smallness of Earth.

Lastly, I think that we need to be explorers. Columbus crossed the Atlantic, Americans moved West, Neil Armstrong walked on the moon, and we sent a rover to Mars.  Space really is the final frontier.  The Hubble Deep Field gives us an picture (or map, if you will) of where we might someday go. 

Works Cited 

Hubble Deep Field Team and NASA/ESA. "The Hubble Deep Fields." Accessed March 29, 2014. http://www.spacetelescope.org/science/deep_fields/

Williams, R. "Full WFPC2 Mosaic - Full Resolution." The Hubble Deep Field Team and NASA/ESA. Accessed March 29, 2014. http://spacetelescope.org/images/opo9601c/

Goddard Space Flight Center. "Ask an Astrophysicist." November 27, 2002. Accessed March 29, 2014. http://imagine.gsfc.nasa.gov/docs/ask_astro/answers/021127a.html

Williams, R. "Hubble's Deepest View of the Universe Unveils Bewildering Galaxies across Billions of Years." American Astronomical Society Meeting Release, January 15, 1996. Accessed March 29, 2014. http://hubblesite.org/newscenter/archive/releases/1996/01/text/