Big Bang… Bigger Science?
By Prof. Paul Padley
Department of Physics and Astronomy
Rice University
In order to make great scientific discoveries, it is important to build great experiments. Outside Geneva, Switzerland, the most complex experiment ever built will soon start collecting data, and it is worth asking why scientists are convinced that something new will be found with it. Let’s look at the history of Big Bang science and see what lessons we can draw from that.
In 1929, Edwin Hubble published his paper A Relation Between Distance and Radial Velocity among Extra Galactic Nebulae.
http://www.pnas.org/content/15/3/168.full.pdf+html
This is the paper which established that the universe is expanding, in a way consistent with there being a “big bang.” What is interesting to note is that Hubble was working at one of the greatest observatories of its day, Mt. Wilson. He was using the 100-inch telescope, which was a phenomenal instrument for its day and by having access to it, was able to collect the data that established what we now call the “Hubble Constant.”
Read about the history of Mt. Wilson at:
http://www.astro.caltech.edu/palomar/history.html)
This was a revolutionary observation that changed how we understand the universe.
Measuring the Hubble Constant is one of the fundamental cosmological measurements that can be made. Refining the precision of that constant is an important goal for science and was one of the motivating goals for building the Hubble Space Telescope. The name was no coincidence, it was a name not just in honor of Edwin Hubble, but in honor of one of its primary scientific missions — measuring the Hubble Constant.
More than just measuring the Hubble Constant, it turns out this telescope has completely upset our view of the universe. When I was a student, I was taught that there was a Big Bang and that the universe was expanding. Gravity was acting on the matter in the universe and the expansion was slowing down. An important question was whether the universe was open or closed, that is — would gravity cause the universe to collapse back in on itself, or not? Scientists were hoping to resolve that question with the Hubble Space Telescope.
What they found was completely unexpected: It appears that the expansion of the universe is not slowing down, in fact, it is speeding up. The expansion of the universe is accelerating! This was a completely surprising result. I remember sitting in the auditorium at CERN when Saul Perlmutter of the Supernova Cosmology Project (http://supernova.lbl.gov/) presented this result (which was simultaneously obtained by the High-z Supernova Search team (http://www.cfa.harvard.edu/supernova//HighZ.html). The auditorium was full of skeptical scientists ready to shoot down the claim. However, one by one, all the hostile questions were answered and the result has stood the test of time.
The accelerating expansion of the universe is now one of the greatest mysteries in science. What is clear is that the universe is not going to collapse down on itself — it is being blown apart. What is also clear is that it took a new facility such as the Hubble Space Telescope to make this amazing discovery possible. The scientists working on the Large Hadron Collider at CERN are anticipating that they are going to make amazing unanticipated discoveries – it’s what happens when you build tremendous new facilities.
Learn more about cosmology and the related facilities at http://www.aip.org/history/cosmology/index.htm
