In the show description above, I paraphrase "a long, long time ago in a galaxy far, far away," which is, of course, from the opening of the movie "Star Wars." It serves as a nice touchstone for the public that is, coincidentally, scientifically accurate. If a galaxy is far, far away, then any news we have about it could only be from long, long ago. In fact, given the large spiral galaxy shown in one of the ending shots of "The Empire Strikes Back" (a shot that is definitely NOT scientifically accurate), the adventures of Luke, Han, and Leia must have taken place at least several million years ago. But I doubt George Lucas knew his opening line was scientifically correct. After all, he didn't know that a "parsec" is a unit of distance, not time.
The initial press release for the Hubble Deep Field (HDF) in January 1996 states that the image contains "at least 1,500 galaxies." This number was the result of rather quick image processing and analysis, as the observations had only been completed about two weeks prior. Later, improved study revealed the number of objects in the HDF to be closer to 3,000. Why the rush? The American Astronomical Society (AAS) holds their winter meeting &mdash one of the best events at which to publicize a major result &mdash each January. Also, the HDF data was shared immediately with the entire astronomical community, and the AAS meeting was the perfect time to get the word out.
The concept of "out in space equals back in time" is a fundamental part of thinking like an astronomer. It can, however, lead to some confusion in dating events like supernova explosions. Supernova 1987A was observed on Earth in 1987, but, since the explosion took place in the Large Magellanic Cloud (LMC), the event really occurred about 170,000 years earlier. One tries to be careful to differentiate between the date it was observed and the date it exploded, but it is easy to slip. Just think, if supernovae occur about once a century, there are about 1700 stellar explosions that have already occurred in the LMC, but which we have yet to see. Going further, most of the major astronomical discoveries of the rest of our lives have already happened, and astronomers are just waiting for the light from those distant objects to reach us. That's thinking in terms of space-time.
The film explores the Great Observatories Origins Deep Survey (GOODS) and highlights the changes in galaxy shapes with distance, and therefore time. The film features a journey into the GOODS image with all the galaxies placed at their correct relative distances based upon their measured redshifts. One thing to note is that the distances in the film are compressed by a factor of several hundred to make a better film shot, but otherwise the visuals are all Hubble data. We created a similar journey into the Hubble Ultra Deep Field for the IMAX film "Hubble 3D."
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