Answering the Universe's Big Questions
Who are NASA's Earth and Space Science Explorers?
The middle school students who track weather to study its effect on bursting tree buds. And the scientist studying black holes in distant galaxies. But also the teacher whose class shares Earth science data with students around the world. And the engineer who designs robotic instruments to probe hard-to-reach planets. All of these people are Earth Explorers, Space Science Explorers or both. The Earth Explorers and Space Science Explorers series features NASA explorers, young and old, with many backgrounds and interests.
When Saurabh Jha was young, he received a telescope as a gift. "I would use it not even knowing exactly what I was looking at. I liked thinking about what was out there." Jha was interested in science and enjoyed learning about how the world works.
"During my senior year of high school, I took an advanced physics class, and I knew going into college I wanted to do something with physics," Jha says. He enjoyed seeing the practical applications of a theoretical science like physics. Jha grew up in New Jersey, where he says the skies are never truly dark at night, so it was not until a family trip to the Grand Canyon that he first saw the Milky Way. He knew for sure then that he wanted to be an astronomer.
In undergraduate school, Jha was able to play a significant role in astronomy research. At Harvard University, he had the opportunity to work with professor Robert Noyes. Noyes had built a high-precision spectrograph, an instrument that separates incoming light waves into the frequency spectrum of different colors. They used the spectrograph to search for extrasolar planets -- planets outside our solar system. "I just happened to be in the right place at the right time," Jha says. "And we did discover an extrasolar planet, orbiting Rho Coronae Borealis, a star in the constellation the Northern Crown."
As a researcher, Jha has been immersed in two exciting areas of science: extrasolar planets and supernovas. Supernovas are stars that reached the end of their life cycle and exploded. "It is really amazing how so much in the class I teach, we could not have taught 15 years ago because there weren't a bunch of extrasolar planets that were known. The fact that astronomy, which is perhaps the oldest of all the sciences, is still evolving and changing is very exciting."
Jha began his work on supernovas as a graduate student and has continued to make contributions to astronomy. In 1998, Jha worked with a team that observed supernovas receding at the edges of the universe. The team wrote a paper, concluding that the expansion of the universe was accelerating, not decelerating as was previously believed.
For this discovery, the lead author on the paper, Adam Riess (Johns Hopkins University and Space Telescope Science Institute), and the leader of the team, Brian Schmidt (Australian National University), shared the 2011 Nobel Prize in Physics with Saul Perlmutter (University of California Berkeley, leader of a competing team). Jha attended the ceremony in Stockholm, Sweden, where he had the chance to reconnect with other team members. Jha admits that the recognition is nice. "It's great that it turned out to be surprising and we learned something totally new about the universe, but even if we had not, the excitement of doing that science would still have been there."
Jha spends most of his time studying Type 1a supernovas, which are the remnants of a star that has completed its life cycle, become a white dwarf, and then exploded. Supernovas have "the promise to help answer some fundamental questions about the universe -- How old is the universe? What is its fate going to be? ... Philosophers can discuss those questions at length, but the idea that you can make actual observations and measurements to try and answer those big questions really appealed to me."
Currently, Jha and Riess, with their colleagues and students, use images from NASA's Hubble Space Telescope to find supernovas with the highest redshifts. The redshift occurs as the expansion of the universe stretches light to longer wavelengths: for example, from the blue to the red end of the visual spectrum. The larger the redshift of an object, the more the universe has expanded and the older and more distant the object is. The current model of the accelerating universe predicts what the universe may have been doing in the past. Supernovas help test these predictions.
Jha's research grant from NASA also allows him to spend time at the Keck Observatory in Hawaii to follow up supernova discoveries made with Hubble and confirm the supernova is a Type 1a and measure its redshift. "Science, and especially this kind of science, is an adventure," Jha says. "You don’t know what you're going to find. To me, the adventure is that process of asking an interesting question and figuring out how you can solve that problem -- what kind of observations do you need, what kind of objects should you look at, what kind of data should you collect."
Astronomy is special, Jha notes, because of its general appeal and the broad involvement and immersion that are possible. Amateur astronomers can make important contributions to the field. Indeed, they are sometimes responsible for finding the supernovas that scientists then study. "There's a synergy between the amateur community and the professional community that is unique to astronomy. It is really a rich subject in terms of exploring it at different levels. If it is something people are interested in, I just encourage them to keep pursuing it and advocating for our continued involvement in science and in astronomy as a nation."
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Brandi Bernoskie/Institute for Global Environmental Strategies