I don't regard the existence of life elsewhere as a speculation.

Why would we think that we are alone?

Hi, I'm Ian Bremmer and welcome to the GZero World Podcast, an audio version of what you can find on public television where I analyze global topics sit down with big guests and make use of small puppets.

This week I sit down with renowned Harvard astrophysics professor Abilob, who made headlines in recent months by theorizing that alien life

may exist. And he's still at Harvard. And then he may have spotted

evidence of it as recently as 2017. No news on 2019, but let's get to it.

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The Avey Loeb, Professor, Director of the Astronomy Department here at Harvard, founder of the Black Hole Institute,

many of the things we could say. Welcome to the program. Thank you for having me.

And I guess you should be welcoming me here because, of course, I've invaded your space,

and it's a rather special place. Can you tell our audience where we actually are right now?

Well, we are at the Harvard College Observatory that was constructed about 170 years ago

with this telescope here.

And only a century later, the Harvard Astronomy Department as an educational institution was established.

Before that, it was mostly about research,

and there were many important discoveries made in this building.

For example, Cecilia Payne Kapashkin,

one of the previous chairs of the astronomy department,

in her PhD thesis, discovered that the sun is made mostly of hydrogen. And at the time, there was a lot of resistance to the idea,

and eventually it turned out that most of the universe is made of hydrogen, unlike the Earth.

Now, you're presently chair of this department,

...