The World Science Festival is winding down here in New York City. The first event I attended was “Afterglow: Dispatches from the Birth of the Universe”. I wanted to go to this event for two reasons. First, I had always heard about how we were able to detect radiation from the Big Bang, essentially proving the Big Bang theory as describing the origins of the universe, but I couldn’t quite wrap my head around how that was possible. Second, the venue was really close to my apartment.
Lawrence Krauss kicked the evening off with a quick explanation of cosmic microwave background radiation, the all-pervading radiation that emanates from the Big Bang, and how it was discovered. The field of cosmology is really an exercise in cosmic archaeology. Because light takes a certain amount of time to reach our planet, the light that we see shows us not how something looks now, but how it looked in the past. For example:
- When we look at the sun, we’re looking eight minutes into the past – Okay, I get it
- When we look at some of the closest stars, we’re looking a few light years into the past – Yep, got that too
- If we look out far enough, we should be able to see radiation from the big bang – 13.7 billion years ago – and picture what the universe looked like in its early years – Okay, now I’m lost
The top map represents a totally featureless, uniform radiation emanating from the Big Bang, as John Mather said, the cosmic background radiation is “smoother than a billiard ball”, but there are differences and features. Finding those differences was the reason Mather won the Nobel Prize in physics in 2006. Mather helped create the first complete map of the universe, the image in the middle from the COBE satellite. If you’re interested in how the COBE and WMAP maps were generated, check out NASA’s website here and here.
In addition to learning about cosmic radiation and the origins of, well, everything, the evening offered several great lessons about science in general:
Sometimes waiting is a good thing
As Mather was preparing to send the COBE satellite up into space, the project was delayed due to funding issues. The money earmarked for COBE was shuttled over to fund the Hubble telescope, which, as Mather pointed out, turned out okay. In the years that the COBE project lay dormant, receiver technology had advanced considerably so that the receivers that ended up on COBE were much more sensitive than those that were originally planned. That extra sensitivity turned out to be crucial for detecting differences in the background radiation and the field of cosmology could have turned out to be much different.
Sometimes it’s good to be wrong
Before the COBE map came out, theorists were developing various ideas of how structure formed in the universe. Among them was David Spergel, who had written extensively on what he thought was a beautiful, elegant theory called the phase transition. Immediately upon viewing the COBE map for the first time, Spergel knew that the last 4-5 years of his work were utterly wrong. After picking himself up and dusting himself off, Spergel realized that the new COBE results opened a whole new world of questions that needed answering.
No matter how much you plan, always expect the unexpected
When Amber Miller sent part of her telescope from Minnesota to Texas by truck, they took every precaution they could think of to ensure that it arrived safely. However, they didn’t count on the truck going missing. Eventually, the telescope was recovered and transported safely to its destination, with a very relieved Miller, who might be one of the only scientists who can honestly say that she’s had an experiment truck-jacked.