Starts With A Bang #18: Why isn't Pluto a planet anymore?

03/26/17 • 21 min

In 1930, Clyde Tombaugh discovered Pluto: our Solar System's ninth planet. For over 60 years, the Plutonian system was the only one known beyond Neptune, and Pluto retained its planetary status for all that time despite its diminutive size. Yet an explosion of exoplanets and of other Trans-Neptunian Objects within our own Solar System beginning in the 1990s meant that we'd need to reconsider what it means to truly be a "planet". The debate still rages today, but astronomers agree: when it comes to the planetary club, Pluto simply doesn't belong. Here's why!

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Starts With A Bang #17 - When Was The First Star Born?

Our Universe was born pristine, with no stars, galaxies, molecules or even stable atoms, some 13.8 billion years ago. Yet today, we're filled with all the complex structure we see today, including with planets, organics and even something as complex and differentiated as a human being. So how did we get here? We had to form stars and galaxies, and evolve the Universe to a point where the raw ingredients to make us existed in great enough abundances and in the right conditions. There are some steps we're still learning about in this story, including how the very first stars came to be. Want to learn about it? Find out on this latest Starts With A Bang podcast!

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Starts With A Bang #19: Is Time Travel Possible?

Is time travel possible? Of course it's inevitable in some sense, as we always move through the Universe at the "boring" rate of one second per second. But what about traveling into the future? If we go, can we ever come back? And what about back in time? Would it be possible to alter the past, or revisit a historical event as an observer? The mathematics of relativity opens the door to a lot of possibilities, but the physical Universe has a lot to say about it, too.