Episode 366

A Pluto-sized object in the outer solar system has shocked scientists. It’s so tiny that it shouldn’t have an atmosphere - but it does.

Object 2002 XV93, known as a plutino, is a small rock floating about in the Kuiper belt - a doughnut-shaped region of icy objects out near Pluto. What’s surprising is that many dwarf planets bigger than this object can’t hold an atmosphere, so it’s a mystery how this is even possible.

This discovery comes as the decades-long debate about Pluto begins to bubble up again. Pluto was demoted from its planet status in 2006. But now NASA Administrator Jared Isaacman is reigniting the debate - on a controversial mission to make Pluto a planet again.

So with this mysterious object and its unexpected atmosphere, plus the chance of Pluto being reinstated, do we need to change how we define planets? Is everything just a planet now? 

Rowan Hooper and Penny Sarchet are joined by Jacob Aron and James Woodford to discuss the many ramifications of this new finding.

To read more about these stories, visit https://www.newscientist.com/

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