Scientific investigation reveals that Clyde Tombaugh was not the first to detect Pluto

If you ask Google "who discovered Pluto", it will tell you Clyde Tombaugh. And that is a lie.

Sort of.

Just weeks before New Horizon's highly anticipated flyby of the dwarf planet, researchers at the Carnegie Institution for Science found an astronomy image from 1925 with some perplexing notes including the word, "Pluto."

If the notes were right, it would mean that Pluto was first observed 5 years before Clyde Tombaugh - the man credited for finding Pluto - announced his first observations of Pluto in 1930.

But observing something and figuring out what it is are two different things entirely.

Cynthia Hunt, who found the evidence in the institution's historical collection of astronomical photos, cross-referenced the location of Pluto with software and found that in fact, Pluto had been detected years before Tombaugh.

Here's, Pluto, circled in blue, in one of the 1925 photos:

With a little more digging, Hunt found that the men behind the photos were astronomers Gustav Stromberg and Nicholas Mayall. But the duo didn't report their findings until 1931, a year after Tombaugh's discovery.

And when it comes to scientific discoveries, it's all about who publishes first. So, Tombaugh reaped the credit and benefits for the discovery.

It's likely Stromberg and Mayall didn't know what they were seeing; if they had known, they might have published their findings much sooner.

Here's a page from Stromberg and Mayall's 1931 paper (they mention the name "Pluto" since that title had already been established by Tombaugh a year earlier):

Ninety years after it was spotted by Stomberg and Mayall, New Horizons has almost made it to Pluto. The NASA spacecraft has been tasked with finding more information about the dwarf planet and its moons: their geology, atmosphere, composition, and much more. It's scheduled to fly by Pluto on Tuesday, July 14.

Watch how Carnegie Institution made the discovery.