"I've just always been fascinated by the night sky," he said.
His project, called "An automated search for gravitationally lensed quasars in the Sloan Digital Sky Survey," looks at objects called quasars that appear unusually bright at night and that scientists have theorized are the cores of old galaxies, he said.
He said his project allows researchers to examine the relationship between dark matter and dark energy, which he hopes will confirm the universe is expanding. His project can help scientists examine past trends, and use that to determine where the universe is heading, he said.
Though scientists have studied topics similar to Pranav's project, he said his project uses a new method. He will be up against projects addressing Alzheimer's, renewable energy, a smartphone app and a robot that can cultivate a garden, among others.
He presented an earlier version of the project as a finalist in the Google Science Fair last year, though he didn't win.
"But, you know, we'll see how it goes this year," he said. "I'll try my best, of course."
Pranav said his interest in science comes largely from his parents, and from trips as a young child to Fermilab near Batavia.
His father, an engineer by training who now works in a corporate legal department, has always been interested in science, and used to go to public talks at Fermilab on weekends. Pranav said he was about 6 when he started going with his father, Siva Muthuswamy, after Pranav discovered a book about physicists lying around the house.
"It was definitely a little weird," Pranav said.
Neither Pranav nor Muthuswamy understood much of what the Fermilab scientists were talking about, but Pranav said he was inspired. Once, he said, he ran into an IMSA founder at one of the talks and was able to get his autograph.
Muthuswamy said he was proud to see his son addressing challenging questions years after he first began looking into them.
"It's like we have a common language to talk about," he said.
Pranav's sister shares the family interest in science, Muthuswamy said. She is now studying music at Indiana University, but she and Pranav began researching quasars together years ago, and she has in previous years entered her own project into the science fair.
But it isn't all about science for Pranav. He also plays cricket and basketball, and enjoys taking "calming" walks, he said. He participates in quiz bowls, and placed in the Scripps National Spelling Bee.
Though he wants to do well, the science fair at the end of September isn't all about winning, Pranav said. Last year, he and his dad explored Google's headquarters, and he got to ride in a self-driving car.
They talked to scientists at Google and a national science news correspondent, Muthuswamy said.
"I was thrilled," he said. "I was like a kid in a candy store."
Pranav was excited to meet teens from across the country, and he keeps up with contestants from Ukraine, Ireland and Australia on Facebook. Though many of last year's contestants have moved on to "bigger and better things," Pranav said, he is excited to talk to this year's entrants and learn more about their projects.
"It's interesting how you can communicate with people through science, even if you don't know their language," he said.
©2015 The Beacon-News (Aurora, Ill.) Distributed by Tribune Content Agency, LLC.