Air Date: Week of September 26, 2025

The Vera C. Rubin Observatory sits on the mountain ridge Cerro Pachón in Chile. (Photo: RubinObs/NOIRLab/SLAC/NSF/DOE/AURA)

The new Vera C. Rubin observatory telescope in Chile features the largest camera ever built, at about the size of a small car, and will soon begin photographing the entire southern sky repeatedly for a full decade. Clare Higgs, an astronomer on the Rubin Education and Public Outreach team, joins Host Aynsley O’Neill to share how this new telescope can help advance our understanding of dark matter, reveal hard-to find interstellar objects, and much more.

Transcript

DOERING: It’s Living on Earth, I’m Jenni Doering.

O’NEILL: And I’m Aynsley O’Neill.

Ever since Galileo began to study the heavens, telescopes have provided a window into the wonders of our universe, from supernovae to distant galaxies. And in recent years, innovations like the James Webb Space Telescope have produced images of those wonders with more depth and detail than ever before. Now astronomers are looking forward to yet another leap in their field. Later this year, the new Vera C. Rubin observatory telescope will start photographing the entire southern sky repeatedly for a full decade, looking for changes in the universe. Here to tell us more about what this could mean for science is Clare Higgs, an astronomer on the Rubin Education and Public Outreach team. Welcome to Living on Earth, Clare!

HIGGS: It's great to be here.

O'NEILL: So what is the Vera C. Rubin observatory, and what kind of data will the new telescope there be collecting?

HIGGS: The Vera C. Rubin observatory is a brand new observatory that is just completing construction and getting close to starting its operations. It's located down in Chile, high up on a ridge called Cerro Pachón. And this observatory is, it's amazing. It's so exciting. It is essentially going to create the greatest cosmic movie ever made that's how I like to think about it. We are creating a survey, so repeatedly scanning the southern sky for a decade, and so we're going to create this enormous data set that is going to be interesting on so many fronts for so many different areas of astronomy.

O'NEILL: And I mean, there are lots of cool telescopes in the world, but this new one is, as far as I can tell, unlike any we've had before. So tell us what makes it so groundbreaking.

HIGGS: Yeah, so the Rubin Observatory is a survey telescope, which is not new. There have been other survey telescopes before, but the size of this telescope, the size of our camera, and the way we're scanning the sky, and the depth and the cadence, how quickly we're scanning the sky, is all new. So we have the largest camera ever built. It's about the size of a small car, so it's huge.

O'NEILL: Wow!

HIGGS: Yeah, and it's a 3200 megapixel camera. It's enormous. I'm not particularly tall. I'm about five foot two, but the lenses are almost exactly my height in diameter. So these are absolutely enormous lenses on the front of the camera, and we take an image about every 40 seconds, and we do that all night, every night, for 10 years. So that volume of data is enormous, and it's a very sensitive camera, and we take these very large images, so they are about 10 square degrees on the sky. To give you a visual of what that is, about 45 full moons would fit inside each image. So there are enormous pictures we take, lots of them with this huge camera, and doing that really quickly allows us to create this amazing survey.

O'NEILL: And so when you say these pictures are taken every 40 seconds, will the survey just essentially be almost like a massive time lapse?

HIGGS: Yeah. So there's a couple things that come out of this survey, and that's one of the things I'm really most excited about, is the fact that there are many ways you can use this data. Depending on what science questions you're interested in, and you want to study, you can look at this data in many ways. So yes, you could use this data as a giant time lapse. One of the other things we do is essentially add all these images together, and when you add the images together, stack them together, you can see very deep and so you can see very faint sources as well. So you could either look at it as a time lapse and see things that vary and change and move in the night sky. So things like supernova and asteroids, you can detect those, or you can stack them together and see distant galaxies and distant galaxy groups in the faint universe. And those distant objects can tell us about the history of the universe, because essentially, telescopes are time machines. When you look far away, you're actually looking back in time, because light takes time to get to our observatory. And so studying that distance universe is studying that ancient universe, which is really fascinating.

O'NEILL: And now the survey that you've mentioned is going to take place over 10 years. It sounds like the telescope will be collecting just a massive amount of data. It's kind of even hard to fathom. So how can we conceptualize just how much data we're talking about here?

HIGGS: Yeah, so every night, Rubin produces about 20 terabytes of data, which means that the survey in total, is hundreds of petabytes of data. So it's an enormous amount of data.

O'NEILL: You said petabytes. And I went, I haven't even heard that prefix before.

HIGGS: Mmmhmm, exactly. So a petabyte is 1000 terabytes. So it's one level larger when we think of the scale of data. And one way to think about how much data that is, is if you watch the entire Lord of the Rings extended 4k movie series continuously for three weeks, that's 20 terabytes of data. So Rubin does that every single night.

O'NEILL: Oh wow, every night! Really dedicated Lord of the Rings fans here.

HIGGS: Exactly, exactly. And then one other way to understand the data that is being produced. So alerts are basically produced in almost real time. So they're sent out within minutes of an observation being taken, and they track changes in the night sky, so think about things that flash, move or blink. And those alerts, Rubin is expected to produce up to about 10 million of those each night.

O'NEILL: Wow.

HIGGS: So it's a lot of data.

O'NEILL: I know there's so much that we can be expecting to learn here, but let's talk about a few of the specific things you know. What are the astronomers and scientists you've talked to most excited about here?

HIGGS: If you ask that question to 100 Scientists, I think you would get 100 different answers. So it's a great question, but some of the broad science themes that we talk about for Rubin are exploring dark matter and dark energy, mapping our own galaxy, the Milky Way, doing a census of our solar system, and exploring that dynamic sky, the changing sky, looking at these things. So that's kind of four broad science areas. One little example that I will highlight that came up in the last couple months is, I don't know if you heard about the new interstellar object that was observed. This is the third such object that we as humanity have ever observed. And these are objects that come from solar systems, other than our own, small objects that are, you know, invisible to any observatory because they'd be usually too far away. There was a new one observed in July of this year. And so that brings our grand total to three. Rubin is an amazing observatory for finding and detecting these kind of objects. And so hopefully we'll go from a group of three of these objects to maybe 10, maybe 20, maybe 50. And having a sample of these objects allows us to create a much more complete picture of what kind of objects these are, where they're coming from, and start asking, you know, questions about other solar systems.

O'NEILL: So just briefly explain for us what dark energy or dark matter is. How would the survey help us learn about these things?

HIGGS: So dark energy and dark matter are two elements of our universe, and this was actually part of Vera C. Rubin, the astronomer for whom our telescope is named after, part of her research was on dark matter. So dark matter is essentially a mysterious form of matter which holds structures in our universe together. So Vera Rubin's research, she was looking at spiral galaxies, and she noticed how fast they were rotating, and essentially she looked at how fast they were rotating, and then how much baryonic matter. So stuff that you can see, this is like you and I, gas, dust, stars. She looked at the baryonic matter, and she saw how fast they were rotating, and she said, "Hang on a second. There must be something else here." And so that was really the first compelling evidence for dark matter. Dark energy, on the other hand, is essentially it's a force that is causing our universe to expand. So you may have heard of the factor universe expanding, but it's not only expanding, it's accelerating in this expansion. So dark energy is is part of the driving force behind that. One of the ways that Rubin Observatory can help us understand dark matter is by using something called weak lensing. And so this is a phenomenon where, as light from galaxies travels through our universe, the presence of dark matter will cause distortions in their shapes. And if you can measure the shape of a lot of galaxies, and a lot, you know, hopefully you're talking millions, tens of millions. Rubin will look at 20 billion galaxies. So that's a lot of galaxies. That's what we need. You can map the structure of these distortions, which allows you to understand the matter that it has passed through, which gives you an insight into the dark matter structure of our universe.

O'NEILL: And now I know that a number of images have been released so far, I think, from June of this year. So can you describe a few of those to me? You know, ones that really stood out to you?

HIGGS: Yeah, so in June of this year, we released our first look images that we took early in commissioning, and we're really excited to share with the world, as it's the first glimpse of what Rubin can do, and then the kind of the amazing imagery that is to come once the survey starts. My personal favorite image is our cosmic treasure chest image. And so this is a image of the southern part of the Virgo cluster. So this is a nearby galaxy cluster. And this image was comprised of over 1100 exposures, so it's about three and a half trillion pixels worth of data, and it was taken in just over 10 hours of observations to compile this absolutely enormous image. So I absolutely love this image, because I feel like it really demonstrates the fact that Rubin is going to revolutionize many different areas of science, because in this one image, you can see things at many different distances and many different types of structures. So if you look at the image, probably the first thing that would catch your eye are these large galaxies, think big elliptical galaxies and spiral galaxies, and these are all part of the Virgo cluster, so this is kind of our nearby universe. Behind that is an absolute sea of, kind of red blobs, and those red blobs are all galaxies at larger distances, well beyond the Virgo cluster. Also in this image, you can see stars from our own galaxies. And then one thing that's really cool that we did is usually when you create an image like this, where you take a lot of exposures and you stack them together, you lose everything that moves. So you'd lose all the asteroids, but we actually added them back in. We have an app to explore this image called Skyviewer. And in Skyviewer, you can turn the asteroids back on, and you can see these tracks of all these moving objects. And so that's our solar system. So in this one image, you have the asteroids in our solar system, the stars in our Milky Way, the galaxies in Virgo in our local universe, and then the distant universe behind as a sea of red distant galaxies. And it's just this huge swath of science in one image.

O'NEILL: Now, from what I understand, this image was not shared just visually, but I believe there was some sort of audio component as well, and we on the radio are always keen to hear about that.

HIGGS: Yes. So this is one of the things that I am so thrilled about, is we released a sonification of this image. And so what this sonification is is a audio representation of the data. So really importantly, it is driven by the data. It's driven by the pixels. And again, you can explore it in our sky viewer, essentially, you can cruise around the image, and as you cruise around the image, you're hearing two things. The color of the pixels you're cruising over will be played, and also the objects as you pass them will be played. The way it works is that redder light and longer wavelengths goes to lower pitches, where bluer light or shorter wavelengths goes to higher pitches, and the volume maps to brightness. And when you pass over objects, galaxies are harp sounds and stars are glockenspiel or time sounds. And so you can explore this image through sound.

O'NEILL: And now the survey hasn't started yet, but once it's up and running, how will the data from it be shared? You know, what's the timeline from the start of the survey to the first data released? And to what extent will the public be able to interact with it?

HIGGS: So the LSST survey should start toward the end of this year, early next year, and there'll be a period of data collecting, and then there will be these data releases. And these data releases will be a compilation of the year or so of data taken before that, which will be shared to the astronomy community. There are some aspects of the data that is collected that will be shared faster and more broadly. So these alerts, those are publicly accessible, and those will be shared on the order of minutes. One way that the public can enjoy and participate in the science coming from Rubin is through citizen science projects. And so we are partnered with The Zooniverse, which is a amazing citizen science platform, and on there, astronomers from the science community will share specific sets of data with a specific science question, and the public is welcome and encouraged and invited to participate in helping to classify that data, which will help inform the science that we can do and be part of the discovery process. And just to give you a sense of scale, Rubin is expected to observe about 20 billion galaxies and a similar number of stars. And you know, the volume of data we've talked about, it's far too much data for one person to look at. And so having these citizen science projects is really a key part of of some of the science that will come out of Rubin.

O'NEILL: Clare, on a personal level, what are you most excited about as we look forward to this survey getting off the ground?

HIGGS: That's a really tough question. There's so many things that are exciting and that I can't wait to see. So my research, personal research area, is looking at dwarf galaxies, and I'm really excited to see how Rubin can find a more complete census, a more complete understanding of these really small galaxies. So personally, I'm quite interested in that, but I think that more broadly, there's two things. One is, I'm excited to see what comes from this community of scientists. Rubin has an amazing community, both based in the United States and Chile, as well as international partners who are so ready to make the most of this data set and this amazing observatory, and so seeing what comes out of this community is I just can't wait. And also, as a slightly mysterious answer, the other thing that I'm really excited about is the unknown unknowns, the things that we don't even know are out there. We don't even know to look for that are going to come out of this data set. We have seen through time with every time there's a new observatory, new technology, that when you look at the sky in a new way, you discover something new and unexpected. And Rubin is looking at the sky in a new way. We're opening up the time domain. We're looking at this changing, dynamic sky. We're making this time lapse of the southern sky, and so who knows what we'll see. I just can't wait to find out what that is.

O'NEILL: Dr. Clare Higgs is an astronomer and a member of the education and public outreach team for the Vera C. Rubin Observatory. Clare, thank you so much for giving us your time today.

HIGGS: It was an absolute pleasure, and I'm so excited to share the Rubin Observatory with you.

O’NEILL: And we’ll let you hear a little more of that data sonification. This is from the “cosmic treasure chest” image that Clare Higgs mentioned, of the Virgo galaxy cluster and objects far beyond.

 

Links

Learn more about the Vera C. Rubin observatory

Look at or listen to Rubin’s “First Look” Images with the Skyviewer App

Browse images from the observatory