Francis Halzen won the Nobel Prize in physics on Tuesday for his efforts to demystify a rare group of neutrinos, tiny cosmic particles that scientists believe offer clues to how the universe evolved.

“It was a great surprise and I obviously didn’t expect it,” Halzen said, speaking to the committee by phone from Italy, in a call broadcast at the news conference to announce the winner.

Halzen said it was predicted before that he would win the Nobel Prize but the announcement still made him feel “strange.”