A controversy erupted earlier this year over who deserved credit for what many say is the most important astronomical discovery of the 20th century: the realization that the universe was expanding.
In 1929, American astronomer Edwin Hubble proposed that the more distant a galaxy is, the faster it appears to be receding from us, a concept that is known as Hubble's law.
Astronomer Mario Livio has worked with the Hubble Space Telescope for more than 20 years. "So clearly, anything Hubble is of interest to me," he says.
That's why Livio pricked up his ears when he heard rumbles about Hubble not deserving all the credit for Hubble's law.
Two years before Hubble published his result, a Belgian astronomer named Georges Lemaitre wrote a largely theoretical paper reaching the same basic conclusion.
"[Lemaitre] published this in 1927, but this was published in French in a rather obscure Belgian journal, so very few people actually knew about it," Livio says.
Here comes the controversy: In 1931, the editor of the Royal Astronomical Society's journal wrote to Lemaitre. He told the Belgian astronomer that more people should know about his paper and asked if he would be willing to have it published in English. Lemaitre agreed, and the translated paper appeared in the society's journal that year.
"But mysteriously, some paragraphs from that paper — particularly the ones discussing what is now known as Hubble's law — that part is missing," Livio says.
Nobody knew who translated the paper, but this year, some scientists suggested the translator was an ally of Hubble's, seeking to obscure Lemaitre's contribution.
"There was even some speculation that Hubble himself had some hand in this cosmic censorship, if you like," Livio says.
Livio decided he had to know the truth, so he went to London, and sorted through all the correspondence the Royal Astronomical Society's journal had for 1931. The second-to-last document he looked at was the prize.
"I actually discovered a letter that Lamaitre wrote to the editor," he says. The letter revealed that Lemaitre himself had translated the paper. "And he himself omitted those paragraphs."
"He thought there was no point," Livio says, "because Hubble's paper already appeared, there was no point to repeat his somewhat more tentative conclusions that appeared before that."
Livio describes his sleuthing in the current edition of the journal Nature.
The 'Glory' In Science
So should Lemaitre get some of the credit for the expanding universe? Probably.
"The way that scientists talk about discovery is to talk about one person, and that's the way it's talked about in scientific textbooks," says Robert Smith, a historian of science at the University of Alberta. "But I think that can be somewhat misleading."
Smith says discovery is more frequently a process that takes place over time.
But Adam Frank, an astrophysicist at the University of Rochester and author of the book About Time, Cosmology and Culture at the Twilight of the Big Bang, says getting credit for discoveries helps drive science.
"You don't do science for money," Frank says. "I mean, you may be able to make a decent living out of it, but you're certainly not going to make a lot of money out of it. So along with noble inclination to know the universe in and of itself, as social beings we also want some glory."