Just before this BBC podcast gets underway, here's something you may not know.

My name's Linda Davies and I Commission Podcasts for BBC Sounds.

As you'd expect, at the BBC we make podcasts of the very highest quality featuring the most knowledgeable experts and genuinely engaging voices.

What you may not know is that the BBC makes podcasts about all kinds of things like pop stars,

poltergeist, cricket, and conspiracy theories and that's just a few examples.

If you'd like to discover something a little bit unexpected, find your next podcast over at BBC Sounds. This is the Witness History Podcast from the BBC World Service with me Bethanhead and

today we go back to a crucial moment in space exploration when Pluto which for decades had been thought of as the most distant

planet in our solar system, was stripped of its planet's status and demoted to dwarf planet.

For 76 years it was regarded as the ninth planet in our solar system.

But today, scientists have downgraded Pluto.

It's just too small.

I would say a critical thing that led to the forced reckoning with

Pluto was the discovery of things even more massive than Pluto and objects of the same scale as Pluto out there.

And the realization that Pluto is not unique in any particular way.

Mike Brown is an astronomer at the California Institute of Technology and he's the man

responsible for downgrading Pluto. He specialized in studying the Kuiper belt. Like the asteroid belt, it's a band of astronomical bodies left over from the formation

of the solar system. In 2005, Mike and his team found an object called Eris and that was it.

If it hadn't been for Eris, Pluto could possibly have been swept under the rug forever.

And the reason why is because by the early 2000s it was clear to astronomers

that Pluto was part of the Kuiper belt there's just no question about it.

But it was also clear that you know nobody really wanted to change the status of Pluto.

It would be hard, it would cause problems.

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