Emily Levesque: How Have Telescopes Transformed Our Understanding Of The Universe? Astronomers once gazed at the night sky and charted the stars using their naked eyes. Astrophysicist Emily Levesque describes how generations of telescopes have unlocked the wonders of the universe.

Emily Levesque: How Have Telescopes Transformed Our Understanding Of The Universe?

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It's the TED Radio Hour from NPR. I'm Manoush Zomorodi. And I want to start the show on a mountaintop in Chile, 8,000 feet above sea level at Las Campanas Observatory.

OSCAR DUHALDE: Yes, Las Campanas is in the northern part of Chile in what we call the Norte Chico, the small north.

ZOMORODI: This is Oscar Duhalde. He's an instrument and operations specialist. And before that, he was a telescope operator there.

DUHALDE: As telescope operator, I was in charge to guide the telescope during the night.

ZOMORODI: On February 24, 1987, Oscar was working his usual shift, guiding the telescope by hand, which he says is exhausting.

DUHALDE: And we start to observe by about 22 hours, 21:30, 22 hours. And by 2 a.m., I say it's enough. I decide to have a coffee at this time.

ZOMORODI: So he gets his coffee and heads outside for a break.

DUHALDE: In all the sky, especially in the South, you see a lot of stars, especially here in Chile. The sky was beautiful - you know, the summer sky in Las Campanas.

ZOMORODI: And high above, Oscar sees our neighboring galaxy, the Large Magellanic Cloud. He had spent the previous few years taking detailed images of this galaxy.

DUHALDE: For that reason, I recognized very well that part of the sky. And around the LMC, the Large Magellanic Cloud, there is only one bright star. And I use that star always for focus the telescope.

ZOMORODI: But when Oscar looks up this time, something is different.


DUHALDE: Immediately, I recognize a new star there that I was sure wasn't there before (laughter).

ZOMORODI: A new star. So Oscar tells Barry Madore, one of the astronomers, about it and then realizes it actually may be a supernova - an exploding star.

DUHALDE: Barry look at me and say, Oscar, a supernova at the LMC? I said, well, it's difficult but not impossible.

ZOMORODI: So you actually spotted a supernova just by looking up into the sky - no telescope?

DUHALDE: (Laughter) Well, at that time, I didn't realize how powerful my eye was. It's not easy to recognize a new star in any place of the sky. And in that moment, the excitement start. I say, well, we did it (laughter).

ZOMORODI: Oscar became the only living person on the planet to discover a supernova with the naked eye, our oldest tool for peering into the universe.

EMILY LEVESQUE: For millennia, people have been studying the stars with the naked eye. And it's really astonishing to look at what people were able to discover and what people were able to learn just through stargazing.

ZOMORODI: This is Emily Levesque. She's an astrophysicist, and she writes about the history of astronomy.

LEVESQUE: Ironically, the first instances of sort of using telescopes for astronomy began just a few years after the last naked-eye supernova. There was a naked-eye supernova in 1604. And just a few years after that, we started using telescopes to study the universe. And then it was 300-odd years later, in 1987, when Oscar Duhalde saw another naked-eye supernova. And now we had these beautiful modern telescopes at our disposal to try and study it. So you can see why that would have been such an exciting discovery when it happened.


ZOMORODI: Our senses can only take us so far in understanding the world around us. But with the right tools, we can look further, see deeper and push past those limits. We can venture into uncharted territory...

LEVESQUE: Are we alone in the universe?

ZOMORODI: ...And ask questions we didn't even know we had.

LEVESQUE: Where did we come from? Where is the universe going? What is our place in it?

ZOMORODI: Because sometimes big discoveries only happen if we're willing to fall down the rabbit hole.

ARIEL WALDMAN: I just about fainted (laughter) I feel like.

CHARLIE JANE ANDERS: Give us something to reach for...

RICK DOBLIN: I think we could talk about the human mind, the unconscious as the final frontier.

ANDERS: ...And something to dream of.

ZOMORODI: So today, on the show, we're traveling Through the Looking Glass to explore strange new worlds using telescopes, microscopes and even our unconscious minds. But first, back to Emily Levesque. She says that long before Oscar Duhalde spotted the supernova with his naked eye, astronomers were using something almost as primitive to make sense of the sky - small plates of glass.

LEVESQUE: Astronomers were using these very delicate glass plates to capture images from telescopes. The plates were chemically treated so they would respond to light. And then when you loaded one of these plates into a telescope's camera and opened the shutter, you would get this exquisite little black-and-white image of whatever the telescope was pointed at.


ZOMORODI: Needless to say, these fragile pieces of glass were pretty hard to work with.

LEVESQUE: Astronomers would mess with the chemical treatment that dictated how the plates responded to light. They would slice them down to size to fit into the cameras. They would do all this work in the dark because once you expose a plate to light, it starts to darken.

ZOMORODI: But scientists made huge discoveries with these glass plates, including one in 1923 by someone you may have heard of before - Edwin Hubble.

LEVESQUE: Most people know the name Hubble because of our wonderful space telescope that we have right now. But Edwin Hubble was an astronomer in the first half of the 20th century, and one of his biggest discoveries was that there are other galaxies beyond our own.

Early in his career, sort of early in Hubble's time, we thought that our galaxy, the Milky Way, was possibly the whole universe. And Hubble got observations of one of our neighboring galaxies, the Andromeda Galaxy, with glass plates. At the time, Andromeda was referred to as the great Andromeda Nebula, and people weren't quite sure what it was. And Hubble's observations with glass plates meant that he was able to estimate the distance to Andromeda and demonstrate that it must be incredibly far away. It had to be another galaxy.

ZOMORODI: So Hubble made this discovery almost 100 years ago. But the images that we have of Andromeda today, they are so different. They are so detailed compared to when we had to use those glass plates, right?

LEVESQUE: Yeah. So if you Google it, you can actually probably find a picture of the glass plate that Hubble used to make his discovery. And if you look at that plate, you can see these sort of wisps of spiral arms and this hint of what we know today looks like a galaxy. But if you just look up a big, modern photograph of Andromeda, you'll probably see observations with the Hubble Space Telescope, so a very different type of Hubble observation.


LEVESQUE: And nowadays, we can pinpoint and study individual stars in Andromeda down to really exquisite detail. We can study very dim stars in the galaxy. We can watch how the stars move. It's really just amazing how much detail we can now achieve with the observing tools that we have available to us today.

ZOMORODI: Here's Emily Levesque on the TED stage showing a photo of the Vera Rubin Observatory in Chile.


LEVESQUE: This telescope will photograph the entire southern sky every few days over and over, following a preset pattern for 10 years. Computers and algorithms affiliated with the observatory will then compare every pair of images taken of the same patch of sky, looking for anything that's gotten brighter or dimmer, like a variable star, or looking for anything that's appeared, like a supernova.

Right now, we discover about a thousand supernovae every year. The Rubin Observatory will be capable of discovering a thousand supernovae every night. It's going to dramatically change the face of astronomy and of how we study things that change in the sky, and it will do all of this largely without much human intervention at all. It will follow that preset pattern and computationally find anything that's changed or appeared.

ZOMORODI: So it sounds like telescopes today almost remove all of the human aspects of stargazing. But Oscar Duhalde used the most basic tool available - his eyes. Is there still room for spontaneous observation in astronomy?

LEVESQUE: Yeah, so we think of the story of Oscar discovering a supernova with the naked eye as this very unusual one-off. And it was. He was the only living person on the planet to discover a supernova with the naked eye in hundreds of years. But naked-eye astronomy can still sometimes be kind of cool. And the best recent example of this is actually something that happened about a year and a half ago to the star Betelgeuse.

So a lot of people know Betelgeuse. It's the bright red star in one of the shoulders of the constellation Orion. And in the fall of 2019, Betelgeuse started to get dramatically dimmer to the point where you could notice it with your naked eye. And amateur astronomers and small telescope users were the ones who started spotting this. So my colleagues and I were able to, really, on short notice, snatch these brief moments of time on telescopes to try and point to Betelgeuse while it was this dim to try and figure out what was going on.


LEVESQUE: I have a lot of people ask me, you know, how do I get into stargazing? How do I get into astronomy? And there's sometimes an assumption that you have to run out and buy an expensive telescope. But you can enjoy astronomy with just your eyes and just enjoy how beautiful the sky looks and try to look for patterns and look for unusual things. If you have a pair of binoculars, you can get just amazing views of things like the moon. So it's a really wonderful pursuit, even if all you're just doing is looking up and enjoying how beautiful it is.

ZOMORODI: So I have to ask, Emily, I mean - and this is a full confession here - I get kind of freaked out when I spend any time doing astronomy. I think the existential nature of trying to peer into the universe, like, it kind of messes with my head, to be honest. How do you deal with that?

LEVESQUE: It's funny because I've heard several people talk about space and the universe as being scary and the scale of it as just being stunning. And I think it's something that a lot of astronomers never really forget but that we get used to or that we put aside.

And I talked about Betelgeuse and the fact that it had suddenly dimmed. And something that we tucked to the back of our minds was that Betelgeuse is 645 light years away. The light that we were studying from Betelgeuse had left that star 645 years earlier. And whenever you observe an object in the night sky, you're kind of looking back in time. It's like jumping into a tiny time machine. But once in a while, someone would ask me, you know, do you think Betelgeuse has already died as a supernova?

ZOMORODI: Oh, right.

LEVESQUE: Do you think the star's already gone and the light from that supernova just isn't going to get here for another 100 or 200 or 600 years? And I always think, you know, maybe it did, but we won't know for a few hundred years, so let's work at what we have. And that's just an astonishing scale to be working on and dealing with as part of your day-to-day job.


ZOMORODI: That's Emily Levesque. She's an astrophysicist, and her book is called "The Last Stargazers." You can see her full talk at ted.com.

On the show today - Through the Looking Glass. I'm Manoush Zomorodi, and you're listening to the TED Radio Hour from NPR.


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