🚀 Faster, Please! — The Podcast #21

It was only three decades ago that astronomers first discovered planets outside our solar system. Since then, astrophysicists have found more of these "exoplanets" — including some Earth-like worlds that exist in their star's habitable zone. Today, astronomy has moved far beyond pointing a lens at the night sky, so I've brought on Gioia Rau to describe her work on exoplanets, as well as how AI and recent declines in launch costs will change astronomy.

Gioia is an astrophysicist and program scientist at Schmidt Futures. Previous to joining Schmidt Futures, Gioia was a research scientist at NASA’s Goddard Space Flight Center.

In This Episode

* NASA’s exoplanet discoveries (1:19)

* Innovation in telescopes and astronomy (5:57)

* The near future for astronomy (16:02)

* Americans’ enthusiasm for space (22:04)

Below is an edited transcript of our conversation.

NASA’s exoplanet discoveries

James Pethokoukis: When I hear that there's been a discovery, that NASA has discovered an Earth-sized world inside the habitable zone of its star, I think, are there people there? Is there intelligent life there? When you hear that, what do you think? What strikes you? What are the implications you draw? What do you want know more of?

Gioia Rau: That's a great question. As a scientist, I have many questions after this discovery. I would like to … discover which other molecules are in there. I would like to understand better what the size of this planet [is], what is its atmosphere and its surroundings. But as a human, as a person, and also as a scientist, it completely blows my mind. I'm so excited by the multiple discoveries. The James Webb Space Telescope is great to understand the atmosphere of these exoplanets, but what really kept us going from zero to 5,300—where we are now in terms of how many exoplanets have been confirmed—is first Kepler and then TESS.

What is TESS?

TESS is another telescope of NASA. It has discovered many, many exoplanets. It has scanned both atmospheres of the sky. And actually, at NASA, my group has used TESS with light curves … [and a] neural network, and so through artificial intelligence we were able to discover 181 new planet candidates. Those are incredible machines. Let's say TESS is our searcher, but then to really understand what is in there, what's the composition of this planet, we need …

How many Earth-like, in a very broad sense, worlds have we found that are in habitable zones?

That’s a very good question, and I don't have the number on the top of my head, but those are just a bunch.

At some point we had discovered none. And it wasn't that long ago that we probably had not discovered any of these?

Right. The difficulty is in defining what is Earth-like. There are multiple meanings of this. One is the distance from the parent star that is similar to the distance between the Earth and our own sun. So this is called a “habitable zone.” But another measure of Earth-like is the size of the planet, or the fact that it's rocky versus gaseous. Definitely, TESS is the telescope that has helped us a lot with such discoveries.

And even before we had found any of these, I imagine there was considerable speculation that obviously they had to exist, there had to be all kinds of planets outside our solar system. But we had not discovered them. And yet, I imagine it's been a pretty wonderful run we've had from going from pure speculation to beginning to analyze what these planets, whether they're Earth-sized or not, what other worlds are like.

Absolutely, and it's just about 30 years, 33 years, that we’ve known that, actually, other planets, exoplanets—which by definition are planets outside our own solar system­­­­­­—exist. Before it was, as you mentioned, just a speculation. But the first ever planet was discovered around 33 years ago. And so since then, really our revolution began. And, actually, these two scientists that co-authored and discovered the first exoplanet have just recently been awarded the Nobel Prize.

Innovation in telescopes and astronomy

It might seem to some people that NASA hasn't really done much since the Apollo program. But there's a lot more to space science than crewed missions. It seems to me like NASA’s doing a whole lot of things right now.

Absolutely. The time we are living now is a time of revolution for so many aspects in space exploration. Not only human exploration, which of course during the Apollo time peaked, and now hopefully also with the Artemis mission, named after the sister of Apollo in Greek mythology, is coming. But the James Webb Space Telescope, which is really a marvel of engineering. We never before have thought that we could put a telescope inside the rocket like an origami and then deploy it in the atmosphere. And we are discovering with Webb so many different things about the universe. Our early universe: Webb is basically a machine to look back in time. With its infrared vision, we will be able to look back over 13.5 billion years. But also with Webb we can discover galaxies over time, again, with the infrared sensitivity. So to discover even the earliest and faintest galaxies. We can discover the life cycle of the stars, as in the infrared, Webb which is able to look through the dust clouds which are otherwise opaque to the visible light. But also we are, as we mentioned before, ab