Gillian Knapp had just gotten out of prison when she came walking into Princeton Astrophysics Department building. It was a soggy afternoon in New Jersey and she found me sitting in the lobby. She ushered me down a corridor into her office and welcomed me and offered me a seat. I sat down.
An acclaimed astronomer, with over 100,000 citations on published papers, Professor Knapp is also an advocate for education in prisons. Gillian Knapp has been entering New Jersey State prisons for years in order to educate the men closed off to society. She had just returned from teaching these men when we met.
With all her accomplishments and brilliance one could naturally be intimidated, however, her glowing blue eyes, kind demeanor, and slight stature, she has blessed the world with an approachability many others do not possess.
When Professor Knapp agreed to my interview request I was ecstatic. I had found a recent paper on Kappa Andromeda B which I was eager to discuss, however, the interview turned into so much more than I thought it would.
Professor Knapp has been involved with the Strategic Exploration of Exoplanets and Disks with Subaru project, SEEDS. Most notably, SEEDS was able to discover “Super Jupiter” which is in the Andromeda galaxy orbiting a massive Star, Kappa Andromeda. Professor Knapp had a bottle of beer named after the exoplanet on her desk, sent to her with a note from the brewery, stating every great accomplishment deserves celebrating. She subsequently told me the beer bottle was empty and we had a laugh.
The data being collected on Kappa Andromeda B is a joint effort to determine how these cooler stellar objects form. The possibility of fusion within their cores and atmospheric pressure, temperature and composition are also being analyzed. I asked Professor Knapp if her thoughts of Kappa Andromeda B was a brown dwarf or a planet, she simply said those terms did not make much sense and she was merely interested if it was fusing in the core. But she isn’t that much involved with the Kapa Andromeda B research. The exciting thing is what made this type of research possible. Professor Knapp played a pivotal role in a groundbreaking research program that propelled astronomy to new levels.
The Sloan Digital Sky Survey, or SDSS, officially launched operations in the year 2000, but not without a decade or so of planning and design. SDSS revolutionized astronomy. Not only in the way we are able to observe the universe but the way scientists worked together in order to successfully complete the task. Astronomers have a tendency to get possessive over their specific areas of research. It has been said they will claim galaxies and other stellar objects as their own. The possessive terms “My Galaxy” and “My Star” have been used from time to time. The SDSS changed this. The agreement was to allow anyone to work on anything at any time. Researchers had the choice to work on anything they chose to, or not. If a researcher did not want to work on a certain topic or with a certain person, this was cool. After some getting used to, the complete freedom made the project incredibly successful.
Prior to the advancement of digital imaging, astronomy was bound by the tedious task of developing and sorting film in order to filter different spectrums. The typical astronomer would point a telescope into the sky and capture a very small area for a few hours. Then they would be faced with the daunting task of sorting out the data collected. This would take months. Not to mention the numerous hours away from actual observation.
When Professor Knapp’s husband, Professor James Gunn, who is also a Princeton faculty member, developed technology that captured larger areas of the sky by way of digital imaging SDSS was bound to be a success. The only issue was there wasn’t a computing system in place to process all the amount of data this technology produced. Professor Knapp managed the software project which allowed the goals of SDSS to come to fruition.
Professor Knapp managed a team of research staff, faculty, and students in order to develop a computing software that would handle, analyze and process the data produced by the new imaging software. This development was the first of it’s kind and single handily changed the field of astronomy. Computational astrophysics origins are firmly rooted in the work of Professor Knapp. Astronomers could now do things that were never being done before with the new software.
The SDSS takes detailed photographs of the sky in a large sweeping movement, much like a panoramic photograph you take on a mountainside. This is different because all other telescopes on earth are taking photographs of very small areas. Professor Knapp introduced me to Professor Gunn during our meeting. Professor Gunn described the operation to me as the telescope is much more efficient because it “scans” the area of the sky. It isn’t snapping pictures of small portions of the sky, rather scanning sections much larger than what had been previously possible.
This panoramic-like data collection was made possible by the development of large silicon wafers used in conjunction with a spectrograph. This allows astronomers to gather information on 5 different colors of light. Thirty electronic light sensors, known as charged-coupled devices or CCDs, are used in order to capture images of the sky. These CCDs were designed specifically for the telescope and are unique as they are able to move electrons on the wafers and generate pictures from the absorption of the light released by the electrons. Each CCD is made up of over 4 million pixels. A CCD receives light through a different color filter, making multiple light observation possible simultaneously. Over 200 Gigabytes of data is collected in a single night, which is then processed by the computing software.
I was shown an example of these CCDs while at Princeton, along with the metal plates used in the spectroscopy process. Each metal plate is designated for a particular portion of the sky. Predrilled holes mark the specific objects, whether a galaxy or other stellar mass, that it is dedicated to observing. Spectrograph fibers are plugged into these small holes, by hand, on the face of the plate in order to measure the spectrum and determining the distance and size of the objects. The entire process of setting the fibers takes about 45 minutes. Professor Gunn said they had played with the idea of using robotics to perform the task but abandoned the idea.
Mapping our universe is crucial to the understanding of how galaxies, planets, and stars are formed. Professor Knapp explained to me how we are able to see the timeline of the expansion of our universe after the big bang. She made the analogy of throwing a pebble into a pond and the pond immediately freezing. The ripples in the ice would be saved as they were frozen. We can see these ripples at the edges of the galaxies which is a timestamp of the way they developed. This ripple effect was produced by early hydrogen gas becoming neutral, prior to that it was ionized, and the rapid expansion caused a density fluxation imprint, which is visible in our universe today in the 3-dimensional distribution of galaxies.
While speaking to Professor Knapp on the success of SDSS, the subject of information sharing came up. SDSS allowed data to be released, by way of the internet, allowing the public to witness the groundbreaking discoveries like never before. This ease of distributing information to the public was also very much a first for astronomy. It allowed for excitement to build around the project and all of the accomplishments to be celebrated. The first five years marked the projected end of the SDSS, however, due to the incredible success the survey was extended, time and time again. SDSS is still going strong after 30 years with the 5th incarnation of the project starting this summer and running into 2025. The most recent project objectives include the search for black holes, further mapping of the Milkyway galaxy, determining the origin of planets and star formations.
I love celebrating physics in any way, shape or form. I think the best thing about the SDSS is the unique metal plates. The team signs them and sends them off to deserving recipients. It is similar to a rockband signing an album. If that isn’t punk rock, I don’t know what is. The SDSS is expanding just like the universe we are trying to investigate. Without the work of Professor Knapp, literally, none of this would be possible. So when I look into the night sky tonight, having a little more knowledge based on the SDSS data releases. I am going to tip my hat to Gillian Knapp because I do not think that happens nearly as often as it should. Thank you Jill. Thank you for everything.