RENEE MONTAGNE, HOST:
We're going to hear, now, about a controversy that 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 is expanding. NPR's Joe Palca has this story on a letter written long ago that clears up whether one scientist stole another's glory.
JOE PALCA, BYLINE: In 1929, American astronomer Edwin Hubble proposed that the more distant a galaxy is, the faster it appears to be receding from us.
MARIO LIVIO: And that has become known as the Hubble law, the fact that, you know, if you have a galaxy that's twice more distant it move twice faster, recedes from us.
PALCA: That's Mario Livio. He's an astronomer who's been working with the Hubble Space Telescope for more than 20 years.
LIVIO: So clearly, anything Hubble is of interest to me.
PALCA: So naturally, Livio was interested when he heard rumbles about Hubble not deserving all the credit for Hubble's law. Now remember, Hubble published his results in 1929. But as it turns out, two years earlier, a Belgian astronomer named George Lemaitre had written a largely theoretical paper reaching the same basic conclusion.
LIVIO: He published this in 1927, but this was published in French in a rather obscure Belgian journal, and so very few people actually knew about it.
PALCA: Here comes the controversy. In 1931, the editor of the Royal Astronomical Society's journal writes to Lemaitre. He tells the Belgian astronomer that more people should know about his paper, and asks if he'd be willing to have it published in English. Lemaitre agreed, and the translated paper appeared in the Society's journal that year.
LIVIO: But mysteriously, some paragraphs from that paper, in particular, the ones discussing what is now called Hubble's law, that part is missing.
PALCA: 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.
LIVIO: There was even some speculation that maybe Hubble himself had some hand in this cosmic censorship, if you like.
PALCA: 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.
LIVIO: I actually discovered a letter that Lemaitre wrote to the editor.
PALCA: The letter revealed that Lemaitre had himself translated the paper.
LIVIO: And he himself omitted those paragraphs.
LIVIO: Because he thought that there was no point, since Hubble's paper already appeared, to repeat his somewhat more tentative conclusions that, you know, appeared before that.
PALCA: Livio describes his sleuthing in the current edition of the journal, Nature. So should Lemaitre get some of the credit for the expanding universe? Probably. Robert Smith is a historian of science at the University of Alberta.
ROBERT SMITH: The way that scientists often talk about discovery is just to identify one person, and that's how it's done in scientific textbooks. But I think that can be somewhat misleading.
PALCA: Smith says discovery is more frequently a process that takes place over time. But University of Rochester astrophysicist, Adam Frank, says getting credit for discoveries helps drive science.
ADAM FRANK: You don't do science for money. I mean, you know, 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. And so, along with the noble inclination to know the universe in and of itself, as social beings, we also want some glory.
PALCA: You could probably say that about journalists, too.
Joe Palca, NPR News, Washington.
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