10988
At that time , the source of stellar energy was a complete mystery ; Eddington was the first to correctly speculate that the source was fusion of hydrogen into helium .
 person: Eddington
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 person: Eddington