Episode 48: ATLAS – Holding up the Heavens!

with Dr Nicolas Erasmus

We’re joined by SAAO Astronomer Dr Nic Erasmus who has been responsible for the newest telescope on the SAAO site (And he’s just had a comet named after him!).

Sutherland has become the latest observatory to host an asteroid tracking system funded by NASA.

The four-telescope Asteroid Terrestrial-impact Last Alert System (ATLAS) system, operated by the University of Hawaiʻi (UH) Institute for Astronomy (IfA), is the first survey capable of monitoring the entire dark sky for hazardous asteroids every 24 hours.

The Sutherland ATLAS station during construction in South Africa. ATLAS-Sutherland lead astronomer Nic Erasmus is in the middle, flanked by SAAO’s Willie Koorts and a contractor operating the crane. Image Credit:  Willie Koorts (SAAO)

The expansion of ATLAS from two existing northern-hemisphere telescopes in Hawaii sees the addition of one telescope at the South African Astronomical Observatory (SAAO) and one in Chile, at the El Sauce Observatory.

On January 22 2022, ATLAS-Sutherland discovered its first near-Earth object (NEO). 2022 BK is a 100-meter asteroid that passed Earth at a distance 17 times that of the distance to the Moon on Jan 28, 2022. It currently poses no threat to Earth. 

Animated sequence of discovery images for NEO 2022BK, the first Near-Earth Asteroid discovered by the new ATLAS-Sutherland station on January 22, 2022. Image Credit: ATLAS

To date, the ATLAS system has discovered more than 700 near-Earth asteroids and 66 comets, including detection of 2019 MO and observations of 2018 LA, two very small asteroids that actually struck the Earth. The system is specially designed to detect objects that approach very close to Earth – closer than the distance to the Moon, about 384,000 kilometres away.

Dan gets a selfie with ATLAS!!

SAAO: http://www.saao.ac.za
ATLAS: http://atlas.fallingstar.com
Minor Planet Center: https://minorplanetcenter.net/

This week’s guest


By Justine Crook-Mansour

[00:00:00] Dan: Welcome to The Cosmic Savannah with Dr. Daniel Cunnama

[00:00:08] Jacinta: and Dr. Jacinta Delhaize. Each episode, we’ll be giving you a behind-the-scenes look at world-class astronomy and astrophysics happening under African skies.

[00:00:17] Dan: Let us introduce you to the people involved, the technology we use, the exciting work we do, and the fascinating discoveries we make.

[00:00:26] Jacinta: Sit back and relax as we take you on a safari through the skies.

[00:00:32] Dan: Welcome to episode 48 and a happy 2022. Today we’ll be joined by Dr. Nic Erasmus, who we’ve spoken to actually in our very first episode, episode one. And we’ll be chatting to Nic about developments that have happened recently with the ATLAS telescope. But before we get into that Jacinta, how was your break?

[00:00:54] Jacinta: Yeah, it was good thanks Dan. And hello everybody. Happy New Year from me as well. Yeah. I’m still in Australia and my family celebrates Christmas, so it was very nice to be able to spend Christmas with them all. It’s been quite a few years since I’ve been able to do that. So that was really awesome. Yeah. Just dealing with the extreme heat down here in the Southern Hemisphere, about temperatures in the forties. I hear it’s the same over there in Cape Town, Dan?

[00:01:18] Dan: Yeah. I’m actually at Sutherland today, at the moment. And we’re visiting the ATLAS telescope, which we’ll be talking about in a moment. And it’s supposed to be getting up to 40 here today. So I don’t know what that is in Fahrenheit for our American listeners, but suffice to say it’s hot.

[00:01:35] Jacinta: Yes, we’re talking in degrees Celsius. Yes. Very hot. Yeah. Sutherland is on a plateau, right? Is it counted as desert sort of weather?

[00:01:46] Dan: Yeah. It’s a semi-desert or a semi-arid region. Although, there has been a lot of rain recently and seasonally a lot of rain because normally it’s very, very dry. And there’s been a bit of a drought for the past few years. But when I arrived here yesterday, it’s green, it’s incredible. And you know, not green by European standards. It’s green by semi-desert standards.

[00:02:08] Jacinta: African standards, yeah.

[00:02:09] Dan: But still very cool and just lovely to be out here. So quiet and yeah, really, really nice place to be.

[00:02:19] Jacinta: Oh, I’m very envious. I still have never been to Sutherland before.

[00:02:22] Dan: So when you make your way back to South Africa, we’ll do an episode up here.

[00:02:28] Jacinta: Yeah. I have been to the Perth Observatory recently though, which I have somehow never been to, even though I grew up here and I’m an astronomer from Western Australia. This was my first time and it was really cool. They’ve got a few big telescopes there and domes, which I’m sure you’d love to see, Dan, kind of similar to the ones – the historical ones – at the SAAO, where you work. So we’re looking at setting up a collaboration between us all.

[00:02:54] Dan: The other thing that happened over the Christmas break, or actually on Christmas Day, was the launch of the James Webb Space Telescope, which we’ve discussed previously.

[00:03:02] Jacinta: Oh my goodness. Yes.

[00:03:04] Dan: Can you imagine a more nerve-racking occasion – strapping a $10 billion telescope onto the pointy end of a rocket and launching it to space? It was nerve-racking to say the least.

[00:03:17] Jacinta: Oh, it was hectic. It was so cool. It was on the 25th of December. So Christmas Day. And, well, down here in Australia in my time zone, that was in the evening. So I came back after a full Christmas Day, stuffed full of food and yeah, I managed to watch JWST successfully launch. You and I were kind of chatting to each other on WhatsApp while that was happening, being like, oh my gosh, can we relax yet? Is it done?

[00:03:46] Dan: Yeah. I had to interrupt our Christmas lunch with our family, which we were hosting. We ate lunch and then I told everyone to come inside and they can eat their dessert in front of the TV because there was no way I was missing it.

[00:03:58] Jacinta: Yeah. And it was all successful. And, as of a couple of days ago, JWST has now arrived at its new home, in orbit at the Lagrange 2 point.

[00:04:07] Dan: Yeah. So it’s reached its parking spot, wheeled into place. And now it can start beginning its work. I think that the first pictures will only be coming out June or July though.

[00:04:17] Jacinta: Yeah, if you missed it, we spoke all about the JWST, the James Webb Space Telescope in episode 45, when we chatted with Christy Tremonti. And this is basically a new, very big, very powerful space telescope, sort of marketed as Hubble 2.0. But actually, it’s a bit different and observes in the optical and the infrared wavelengths, whereas Hubble observes at the optical and UV wavelengths. And it was a big deal. It’s been in the planning and construction for about three decades. Delayed delayed, delayed. And then, now, it’s finally launched and there are many, many astronomers all over the world who are very excited to see what this shows us. And we’re hoping that it will be able to peer so far away, so deep into space, that we’re looking back in time at basically the first stars and galaxies forming after the Big Bang. I don’t need to say the word ‘exciting’ too many times, but needless to say, it’s extremely exciting.

[00:05:09] Dan: The new era of astrophysics, potentially.

[00:05:12] Jacinta: Well, yes, exactly. Kind of just like MeerKAT and the SKA are new-era radio astronomy, JWST is a new era of optical and infrared astronomy. But actually, speaking of previous episodes, I would like to correct myself. In the last episode that we did in 2021, that was episode 46 with Dr. Kenda Knowles, we spoke all about clusters. And remember Dan, I made you go through the whole exercise of collective nouns. We wanted to know what a group of clusters would be called. So a group of galaxies is called a group, a group of groups is called a cluster. But then what’s a group of clusters called? And I said, we should call it a crash of clusters or a clash of clusters, forgetting that there’s actually already a term for that, which is supercluster. And so thank you to Dr. Nathan Deg for pointing that out. And we spoke to Nathan in episode 9 if you want to go and hear from Nathan. So, that’s a correction. A group of clusters is called a supercluster.

[00:06:10] Dan: We had an argument about it last time. I still hold firm on my side of the argument, even with the supercluster, Nathan if you’re listening. I mean a supercluster is a larger cluster, right? So it’s a collection of clusters, which are all gravitationally bound or they’re one big supercluster. But what if you have clusters on other sides of the universe and you’re just referring to them. A whole lot of clusters, which aren’t necessarily related. Then we need a collective noun, I mean –

[00:06:40] Jacinta: Then you’re kind of like, what’s the collective term for a group of superclusters?

[00:06:44] Dan: You don’t have to have all the rhinos in one place for them to be a group of rhinos.

[00:06:48] Jacinta: Yes you do, that’s the whole point.

[00:06:52] Dan: I don’t think that’s how collective nouns work. Anyway, we’re delving beyond our areas of expertise here.

[00:07:02] Jacinta: Completely getting off track.

[00:07:04] Dan: We’ll move back to astronomy and see where that ends us.

[00:07:08] Jacinta: All the way close to us with near-Earth objects.

[00:07:11] Dan: Yes. So if you did catch our recent rerun of the first episode, where we were very green to the whole podcasting thing, apologies for that. So very exciting developments with the ATLAS telescope, the Asteroid Terrestrial-impact Last Alert System, which is as cool as it sounds. The ATLAS system has now been deployed both in Chile and in South Africa. And that happened just before Christmas last year. ATLAS is now functional and is able to observe the night sky 24/7. So the setup is that there are two telescopes in Hawaii. Hawaii, being on the opposite side of the Earth to South Africa, means that when it’s daytime in Hawaii, we can observe, and when it’s daytime here, they can observe. So we have constant coverage across the Southern Hemisphere and also around the world, for looking for these near-Earth asteroids, things which will potentially impact. So that’s been deployed and we have a press release, which has just come out about this, announcing it and announcing the first discovery of a new asteroid, by the Sutherland-ATLAS telescope. So very exciting.

[00:08:32] Jacinta: Yes, incredibly cool. I’ve been wondering what’s been going on with the ATLAS project because, of course, we spoke with Nic about it originally in 2019, when the building hadn’t been built – there was no telescope yet, it was all just a plan, which sounded very exciting. And now it has been – it’s installed. And so, yeah, let’s hear from Nic and hear what he has to say.

[00:08:55] Dan: Alright, Nic. Welcome back to The Cosmic Savannah.

[00:09:04] Nic: Thanks for having me back in almost two years now.

[00:09:08] Dan: Yeah, I think, yeah, it must be that long. You were our very first guest, or one of our very first guests, first episode.

[00:09:16] Nic: I didn’t know that until you told me a few minutes ago.

[00:09:20] Dan: We’re honored and honored to have you back. A lot has obviously happened since then. And, in particular, what we want to talk to about today was the ATLAS telescope, which is now operational. So maybe you can just talk us through what’s gone on.

[00:09:34] Nic: So I think last time we spoke, so for those of you don’t know, ATLAS is this near-Earth discovery network. There are two telescopes in Hawaii, and we’ve just built two now in the Southern Hemisphere, one in South Africa and one in Chile. And I think the last time we spoke, we were sort of in the planning phase of, not even the telescope, just the building. So during COVID, we completed that building construction that was initially going to be contractors flying out from the US to do that. But because of COVID, they couldn’t. So SAAO staff constructed that all by themselves. So that took us about two weeks. And so we’re quite proud of that.

[00:10:07] Dan: That only took you two weeks to build?

[00:10:09] Nic: Yes.

[00:10:09] Dan: What does it entail? What does the telescope housing require?

[00:10:12] Nic: Yeah. Okay. So when I talk about a dome, this is the telescope building. This is sort of a round building, so just a round wall. And then on top of that is a dome that can move around with a slit. So only the slit opens and the telescope points through this slit. And this is for, sort of, so that you don’t have the whole telescope exposed to the wind and the elements. A small patch of the sky is open that you want to look through. Yeah. Two weeks sounds like a short time, but this is almost like a kit that we got. So a container arrived and inside was just a bunch of timber and the kit for the dome part. And so yeah, we just had to follow instructions and put it together.

[00:10:46] Dan: So it’s like a huge LEGO set?

[00:10:48] Nic: Exactly. It was actually a really fun project. And I learned a few carpentry skills and I’ve actually applied some of them at home, in the door, and so forth.

[00:10:56] Dan: And so your wife will be happy too then?

[00:10:59] Nic: I’m not advertising it too much. I don’t want to have too many projects.

[00:11:02] Dan: Okay. Great. So, I mean, so the SAAO constructed that dome and then you have to ship the telescope here. Right?

[00:11:10] Nic: We rushed to finish the dome, I think in November 2019, in the hopes that the telescope would arrive in March the next year. And then COVID struck and you know, it was so many delays in delivery of all manufacturing on that side of the telescope and the optics, that actually the telescope only arrived about six months later. So the dome was empty for almost a year. But slowly but surely, the stuff started arriving, crate after crate with the telescope in it, the mount in it, the optics, the camera. They sort of just trickled in. And so in October 2021, so a few months ago, everything was in place. And then the ATLAS guys book their tickets to come and do the final installation. And just as they were about to get on the plane, we find out about this new variant and literally three days after they booked their tickets, they cancelled their tickets. And so we were wondering, are we going to go ahead with the ATLAS installation? We had a long Zoom session and we said we’ve got everything in place. I cleared my schedule for three weeks to do the installation with them. Let’s just try and do this. Let’s just do it with them helping remotely. Yeah. And that’s what we did. So we started, I think, on the 6th of December and ten days later, we were on sky, taking the first images.

[00:12:26] Dan: Wow. Yeah, that’s very impressive. So you’ve built a telescope now from scratch.

[00:12:31] Nic: So I can say that I’ve tightened every single screw on that building and every screw on the telescope. So, yeah.

[00:12:37] Dan: And now that’s on record in case anything goes wrong.

[00:12:38] Nic: Nothing is going to go wrong, touch wood. The telescope is performing really well.

[00:12:38] Dan: Okay, great. So, I mean, before we talk about the telescope and its performance, you mentioned that we’re looking for near-Earth objects with this. So how does the ATLAS system work? You know, you mentioned that they’re in Hawaii and now they’re in Southern Africa. Why are they in both places? Why Chile and what is the goal of ATLAS?

[00:12:38] Nic: Let’s just go back one step. So the way that these telescopes discover asteroids is they take images of the same patch of the skies with a certain interval between, so say fifteen or twenty minutes interval between the two. Several images, four images, in fact. And then it uses a reference image that it’s taken on other nights to see if anything has changed in that image. So if anything’s moving or was different to the image that it took on that night, relative to the reference, then it knows that something’s changed. Either that’s an object that’s appeared, like a transient supernova or something like that, or it’s moved, which is either an asteroid or satellites. And so that’s how it discovers asteroids. Now, obviously it can only do that if it’s taking images of the sky and it can only do that during the night. And also, depending on where the telescope is located on the globe, it can only – for instance if the telescope is located in the Northern Hemisphere, it can only point in the Northern part of the sky. So there’s a blind spot. The Southern part of the sky is not reachable by those telescopes. So that was sort of the weakness of ATLAS. They could scan whichever part of the sky we could see from Hawaii, but they couldn’t see anything in the south. So the obvious thing was to expand into the Southern Hemisphere. Which is exactly what they did. They picked two sites, namely South Africa and Chile. And then, of course, you don’t want to go south in the same time zone because then it’s nighttime at the same time there. So it’s advantageous to go into a different time zone. And that’s why South Africa is ideally placed because, not only are we south, but we’re exactly twelve hours difference in time. So when it’s nighttime there, it’s daytime here and vice versa. So we can essentially monitor the entire sky 24/7 now. Yeah. So that’s the reason for the two new telescopes.

[00:14:40] Dan: I mean is there somewhere in a different time zone in the Northern Hemisphere to Hawaii where they’re doing this?

[00:14:46] Nic: Yeah. So that’s a good point. So ATLAS is a program on its own. So they’ve got the four telescopes now, but they also have other programs that are also trying to do this. Catalina Sky Survey, Pan-STARRS and I believe the European Space Agency also have a few programs. So in Italy, I think there are a few programs. But each one has its strengths and weaknesses. So they sort of work together. We’re not in competition to each other. We work together and all our data is submitted to one central location. So even if we discover something, they might follow up. They might rediscover it on the same night, we just beat them to it, discovered it before them. And vice versa, they might discover something before we do. But our observations go to one central point and they all add up together to determine the position of this asteroid better.

[00:15:30] Dan: And there’s never been anything like this in South Africa before?

[00:15:34] Nic: Not directly. There are surveys running. So, I mean, for instance, the MeerLICHT telescope does semi-survey work, KMTNet does semi-survey work. Of course that data is available to try and look for asteroids in there, but just taking the observations and taking the images of the sky is one part; the whole data processing of trying to detect what has changed in the images is a whole other ball game. The survey is geared for trying to find asteroids and also the data pipeline that analyzes the images is also specifically tuned for finding asteroids. So, of course, you can find asteroids in other astronomical images from all other telescopes. But this is purely dedicated for finding asteroids.

[00:16:13] Dan: And it’s doing that regular revisit of the same –

[00:16:16] Nic: Exactly. And then, it’s specifically designed to optimize its likelihood of finding an asteroid, that cadence. So, I mean, there’s a playoff. So either you visit the same spot in the sky many times or a few times and you cover more of the sky. So there’s a sweet spot of everything to try and optimize finding as many asteroids as possible.

[00:16:35] Dan: And then, you mentioned you see other things like supernova and satellites, presumably satellites, as more and more satellites going up is problematic.

[00:16:43] Nic: That’s true in a sense. But the nice thing about these satellites is you know exactly where they are. And there is also a database for that. So as soon as we find something, we check it to a known database. If it pops up as a satellite, then we say, okay, we know about this guy. Just ignore it. So, it’s annoying, but it’s not detrimental to the project.

[00:17:02] Dan: I gather from your colleagues that you were able to spot the James Webb Space Telescope, which was launched on Christmas Day.

[00:17:07] Nic: Yeah. So, I mean, that’s one of the cool things. That’s because we scan the entire sky. We basically see anything that’s moving out there. And so, I mean, ATLAS was one of the programs, but pretty much all these surveys, in some way or another, spotted the James Webb Space Telescope. So everyone had a Twitter post about “Hey, we saw this thing going up here.” So that was pretty cool.

[00:17:26] Dan: It’s the big thing at the moment. Okay, great. So you’re all set up now and everything’s operational, you’re fully commissioned and then you’ve found one?

[00:17:37] Nic: Yes. So what, three days ago, on Saturday, ATLAS was doing its thing, as it does, it scans the entire sky. And, of course, it observes thousands of asteroids and the software picks up asteroids in the images. So since we’ve been commissioned two or three weeks ago, we’ve seen many, many asteroids. But all of them have been known ones or someone has beat us to it and discovered them just before we saw them. But on Saturday night, we saw the first one where we were the first people to see it. So we’ve submitted that to the Minor Planet Center. A few minutes later, they said this is something that’s not in the database. No-one submitted this before. And the following nights, many people observed it and it was confirmed. And yeah. So by Sunday night, it was confirmed as 2022 KB. So that’s ATLAS-Sutherland’s first asteroid discovery.

[00:18:27] Dan: So a slight deviation. You actually have a comet named after you?

[00:18:32] Nic: Yes. Comet, let me get it right now, 2020 S3.

[00:18:36] Dan: Erasmus.

[00:18:38] Nic: Yes.

[00:18:39] Dan: Yeah. So you discovered that in one of your asteroid hunts too, right?

[00:18:43] Nic: Yeah. So, again, ATLAS doesn’t just discover asteroids or satellites, supernova, it discovers comets as well. It’s actually the same – in a similar way, discovers those. But one thing that is very tricky to automate is, it might see something moving, but something that’s a little bit tricky to automate is seeing if there’s moving things, a point source like a star or an asteroid, or if it’s a little bit fuzzy which might indicate that it’s a comet. And so what we still have is actually, physically, people monitoring the discoveries as they’re coming in. You can imagine, ATLAS discovers thousands of things that it thinks as an asteroid. But still, it’s like a human eye. There’s nothing better than a human eye to verify that. I was monitoring the page to see all the ones that were flagged as a new discovery. And I said, “Hey, this guy looks a little bit fuzzy. What’s going on here?” And that happens pretty regularly. It happens maybe once a month or so. So I just happened to be on duty that night. And so we submitted it as a new discovery. And then, on top of that, we send an email to the Minor Planet Center and say this is a new discovery, but in the images we see things a little bit fuzzy. We think it’s a comet. And if you happen to be the person on duty that night, then you get the credit for that discovery. And so I think I was the last ATLAS person to get a credit. I mean, all the other guys got theirs many months before me and I was just unlucky and you know, every time. So in fact, some of the ATLAS people would have discovered their fourth or fifth comment, but you only get the name of the first one you discovered. So they were already on their fifth discovery and I still hadn’t discovered my first one.

[00:20:13] Dan: Maybe I should come spend the night with you and see if I can get a comet.

[00:20:16] Nic: Yeah. But you first have to build a telescope to get that on there.

[00:20:21] Dan: Okay, great. So, I mean, that was a little aside. So that was discovered on the ATLAS telescopes too, but with the Hawaii telescope right?

[00:20:29] Nic: Yes, so what happens is, because we are in a different time zone, ideally it’s that human checking is perfectly suited for us because when they’re observing at night, it’s daytime for me. So during my lunchtime, I can just – while I’m having my lunch – I just have it on the background. And I just monitor these things and vice versa. They will do the same for us now. Yeah. So that’s how that happened.

[00:20:48] Dan: Okay, cool. And then, back to this new asteroid, which you’ve discovered, you don’t get to name an asteroid, right?

[00:20:53] Nic: No. So there are just so many discoveries now that they just get their automated designation. So, for instance, 2022 KB, the discovery we made. So 2022 was the year it was discovered. And then the numbers afterwards indicate the month that it was discovered. I’m a little bit confused why it’s KB.

[00:21:14] Dan: 2022 BK.

[00:21:14] Nic: BK. Sorry. That makes more sense because asteroids discovered in the beginning of the year will have A’s and B’s, and then it’ll go to Z. That’s why I was confused. KB didn’t sound right to me.

[00:21:26] Dan: Yeah. Too early in the year for all the way down to K. But I mean, now that we’ve got new eyes on the sky, we’ll be discovering them even faster, presumably?

[00:21:34] Nic: Exactly. And the nice thing is there were asteroids that were zooming past us in the past that we never discovered, and we will never discover because they’ve already flown past us. And so, because we’re looking in the south now where there are not many people looking, we will most likely increase our discovery rate compared to what the guys in the ATLAS telescopes in the north are discovering now, because there’s a lot of competition there. So you sort of have to be quick on the trigger there. Otherwise someone else would discover it before you, whereas in the south, we don’t have that competition.

[00:22:02] Dan: Cool. So congratulations on your first new asteroid discovery with ATLAS south. And then what happens immediately after that is presumably all these other telescopes follow up and constrain its orbit? So extra information and try and work out where it’s going and how big it is?

[00:22:18] Nic: Exactly. So as soon as we make a discovery, immediately submit it to the Minor Planet Center. They post it on a public webpage. It’s called the NEOCP, the Near-Earth Object Confirmation Page. And on there are tools where, based on the few data points we have submitted, can predict where it will be in the sky for any given time in the future. So anyone can go on there. It doesn’t have to be professional astronomers. A lot of amateur astronomers monitor those pages. And they can use the tools to indicate where they are situated on the globe, where they can point in the sky, what time they’re going to point in the sky. And we’ll tell them exactly where that discovery is. So they can go there. If they also see it, where that prediction is, they then submit their data points and that sort of refines the orbit. And so those predictions become better and better and better. And once the prediction is shrunk down to a certain level where we really know where this asteroid is going to be far in the future years, many years, then it gets MPEC and it gets an official designation. And then that gets permanently put on the database.

[00:23:15] Dan: And we can look out for it in 300 years or whatever.

[00:23:18] Nic: Exactly. So, for instance, 2022 BK is making its close approach on the 28th of January 2022 and already with the orbit that we have now, we can predict that it’s going to make another close by in the year 2110, I think. And even I think the dates are within a few hours accuracy already.

[00:23:38] Dan: And its close approach, so the 28th of January. This may not even come up by then. And how close is it coming?

[00:23:46] Nic: Yeah, it’s something like – what was the number – twenty or thirty lunar distances. So still pretty far away, but bear in mind, this is a hundred-meter object. So, you know, a hundred meters doesn’t sound big, but if that were to impact us, it wouldn’t be globally catastrophic, but it would cause a fair amount of damage. And twenty lunar distances, that’s still pretty far away. It’s a couple of million kilometers, but in the solar system scheme, that’s a close shave, right? I mean, you could call a close shave twenty lunar distances. The close approach in 2110 is a little bit further. 200 lunar distances or something like that.

[00:24:22] Dan: How often do we get a close approach? Like within the lunar distance?

[00:24:26] Nic: Within a lunar distance, every day. Just depends on the size, right. You know, I mean, we get hit by stuff every day, small, granular size asteroids, in inverted commas. Something really big, like a hundred meters within a lunar distance, to thumbsuck, maybe once a week or so, once a month.

[00:24:43] Dan: Okay. Wow. Okay. And then how far in advance do you detect those?

[00:24:50] Nic: A typical example. So we discovered 2022 BK on Saturday. So what was the date then? It was sort of the 20th of January, right?

[00:24:59] Dan: Yeah. Eight days.

[00:25:01] Nic: Yeah, 28th of January. So that gives you about a week notice. So I would say that’s about average. A hundred-meter object, we will discover about a week out. This is now with an ATLAS-sized telescope, which is only half a meter in diameter, the mirror size. So, obviously, the larger the mirror is, the more light you are collecting, the fainter you can see it so the further out you can see it. ATLAS is a smaller telescope, but it’s more nimble. So it scans more of the sky with a smaller aperture, whereas the larger telescopes might scan a smaller part of the sky, but can see further away. And that’s why I said all these discovery programs are complementary. Some guys are not looking at the entire sky, but they can look further out. ATLAS was specifically designed, sort of, to catch those that slipped through the finger, as you can say.

[00:25:44] Dan: The conversation when you’re talking about asteroids, inevitably goes to everybody fearing for their lives. It would be remiss of me to not mention Don’t Look Up, the recent movie. I’m sure you watched it the night it came out.

[00:25:57] Nic: Yeah. It’s a little bit cringe, but it’s pretty accurate, to be honest. At least the first few minutes.

[00:26:02] Dan: I mean, I think it was particularly accurate as to how people might behave if such a thing happened. You might have a hard time convincing people that this really is gonna happen.

[00:26:14] Nic: I would really hope that it’s not going to be as bad. I think we would be able to convince people better than in the movie. I don’t know. What do you think?

[00:26:24] Dan: Well, yeah, I mean, it was like maybe a bit cringey, but also maybe a little bit close to home. Okay. So yeah, eight days for a hundred meter, and a hundred meter that’s country killer size?

[00:26:36] Nic: Probably not quite country killer. A hundred-meter object will – to give you an idea, the asteroid that exploded over Chelyabinsk, Russia in – I can’t remember the date – 2010 or something like that, that was in the news, that shattered a bunch of windows. That was something like 20 meters. Of course, it doesn’t necessarily scale linearly. So a hundred-meter object might not be five times worse, it might be a little bit worse than that because more of it will reach the ground. But I don’t think quite country killer. And then you also have to remember 70% of the earth is ocean. So if it lands in the ocean, I mean, there are a lot of people doing simulations. What will happen then? Will you have a big tsunami or not? Who knows? Say we discovered something of a fifty-meter diameter with a one week notice and that’s heading straight for a city. One week is plenty of time to at least make an attempt of an evacuation, right?

[00:27:23] Dan: So you obviously get more and more telescopes on it the more threatening it? You work out that this 2022 BK it’s not coming that close to us, so everywhere kind of gives up and keeps looking at other things. If there was one which looked dangerously close, presumably you’re going to get huge telescopes on it, more and more telescopes trying to really refine it?

[00:27:43] Nic: Yeah, exactly.

[00:27:44] Dan: How accurately can you do that?

[00:27:46] Nic: Yeah. So, so this page that I told you that was publicly available, there’s another page run by JPL, Scout, which predicts impact likelihoods. So as soon as something is posted on that page, they immediately, with what data is available, calculate an impact rating. And if this is above a certain level, I can promise you every telescope available out there is going to jump on this and try and observe it. And the more people jump on it and observe it and submit data, the uncertainty of the orbit decreases and the more accurately we can predict how close it’s going to shave. And if it’s going to hit, where it’s going to hit. But you are right, after the first days of discovery, we’re probably just going to know that it’s going to hit us and we’re not going to know where it’s going to hit us. So that might only be known closer to the time, you know? And there are every, I think it’s every two years, they have this big conference where they do these exercises, where they come up with hypothetical asteroids that are going to hit us and they fully simulate it. They say, okay, on day one of the conference, we discovered this guy. On day two of the conference, X amount of people did follow up and now the uncertainty has shrunk down. They fully simulate it. They even have different branches for people dealing with how will we politically deal with it? How would we scientifically deal with it? So I haven’t actually been to one of these conferences, but I’ve heard it’s actually a pretty cool exercise.

[00:29:02] Dan: Oh, well hopefully you go to the next one.

[00:29:04] Nic: I’ve definitely had an opportunity to go. It’s just the past two years has been ATLAS-building stuff and COVID and yeah, I should just bite the bullet and go to one of these.

[00:29:13] Dan: Yeah, absolutely. It sounds like fun. And maybe you’ll learn something which will benefit all of humankind. So I encourage you to go there. Okay, cool. So in terms of ATLAS going forward, it just runs robotically, correct? And then now, because it’s an international consortium, Chile’s involved now in Hawaii and there’s this team. How big is the team monitoring?

[00:29:36] Nic: The ATLAS team, I think, compared to other asteroid discovery programs, is fairly small. I mean, it’s John and Larry are the co-PIs. They have one engineer and a few junior researchers slash postdocs. So we’re talking about a handful of people on the Hawaiian side. And then they have, sort of, contact people in either Chile and South Africa. But then they have a whole another side project, Queen’s University, Belfast. They are looking closely at the data, but not necessarily asteroid stuff, so the whole transient discovery of supernova and things. So there’s another group there looking at the data. There are many people involved, but the core ATLAS team in Hawaii is actually fairly small. It’s surprising, it’s impressive actually what they do with a small team.

[00:30:22] Dan: So you mentioned supernova earlier and there are huge surveys going up now looking primarily for supernova. The LSST, the Large Synoptic Survey Telescope, I’ll confirm that at the end of the podcast, that’s built almost exclusively to detect transients. Is that gonna like put you guys out of business?

[00:30:46] Nic: Yes. But again, each system has its strengths and weaknesses. For instance, LSST is only going to visit the same patch of the sky, once, maybe I think it does it twice in a night. But then it only comes back to that patch in the sky three days later. So the cadence is completely different, so it’s true, they’re going to be able to see much, much fainter stuff. And so they might be able to give us much longer warning for something that’s going to hit us. But the likelihood of them missing an asteroid is very high because they’re not scanning the entire sky with a high enough cadence. So that remains to be seen what the data’s going to look like. And so, yeah, I don’t think that programs like ATLAS will fall away when LSST, because it’s just a different regime.

[00:31:27] Dan: Yeah. Commensurate. Yeah. Well, I mean, I think that it’s super exciting and as astronomers, we always just want more data. So the more telescopes the better, and wonderful to have South Africa involved. I think it’s a wonderful opportunity for all South African scientists to get into this kind of work. I think that it’s only you really at the moment.

[00:31:46] Nic: So that’s a good point. I mean, I’m just helping on the asteroid side, but I’m also the contact for data access for South African communities. So if anyone has interesting science ideas of what they can do with ATLAS-type survey data for other science, for instance, they more than welcome to contact me. And I can help them with data access. So that’s an important thing to put out there, is that we have access to the data as the South African community.

[00:32:12] Dan: Yeah, that’s great. I mean, that’s great that that’s part of the agreement. And also, we’ve spoken about it before on the podcast, is the Observatory is moving more towards the Intelligent Observatory idea where all of the telescopes up on the plateau are sharing information. And, I guess, to have something at this high cadence, if it does detect a transient, then we can put bigger telescopes on it quite quickly.

[00:32:34] Nic: Exactly. I mean, I think having a survey or discovery telescope on the same plateau is advantageous because, you know, another survey like LSST or an ATLAS-Hawaii discovers a transient, it’s daytime here so we just have to wait for a couple of hours, for it to become dark here again, before we can do follow-up. And who knows, it might be a very short transient, by that time it’s gone. So having something on the same plateau, you can really follow up on it within less than an hour of the discovery.

[00:33:04] Dan: Yeah. Well, I mean, I think that, as I said, very exciting and I think that we will hopefully have you on soon with even more exciting discoveries, hopefully nothing too life-threatening.

[00:33:15] Nic: Yeah, me too.

[00:33:17] Dan: If you see a fuzzy blob on your lunch break, like call me over and I’ll identify it for you.

[00:33:21] Nic: The ideal case is if we discovered a ten-meter object going to hit us, because that’ll just be a nice fireball in the sky.

[00:33:28] Dan: And we can predict it, like this evening, everyone go outside for some fireworks. Well, I look forward to that. Nic, thanks again for coming on The Cosmic Savannah. It was great to have you back. And hopefully we’ll have you again soon.

[00:33:43] Nic: Thanks. That was great.

[00:33:51] Jacinta: Thanks for that, Dan. Very interesting to hear from Nic again and so exciting that they’ve already found a new asteroid.

[00:33:58] Dan: Yeah. So I think that, I mean, there’s going to be so much more coming out of ATLAS, new asteroids, new comets – hopefully none of them too dangerous or threatening to us. But yeah, the constant coverage now means that the telescope is observing hundreds or thousands of asteroids every night. A lot of them are obviously pre-known, but some of them will be new, and having this coverage and excitement is awesome. And hopefully we get some of these small ones, which we can actually locate coming into Earth. I mean, I think that has happened twice before that the ATLAS telescopes have identified two to ten meter asteroids, which are going to impact. And then they’ve observed them coming in. So that’s been pretty exciting. And I think that the one that came in over Botswana, they even found remnants of it.

[00:34:52] Jacinta: Very cool. I must say Comet Erasmus is a really awesome name.

[00:34:57] Dan: I know, right? Like he didn’t seem that excited about it, but like, for me, I mean, imagine having a Comet Cunnama out there.

[00:35:06] Jacinta: Well Comet Delhaize. But I don’t know, there’s something about Comet Erasmus that sounds really good.

[00:35:11] Dan: It does fit, doesn’t it? Anyway, I do think I’ll offer some of my very limited free time to scroll through during next lunch break, just in case.

[00:35:22] Jacinta: Yeah. I was wondering like, as I was listening to Nic, I mean obviously you can’t, even though you’ve got telescopes in the Northern Hemisphere and the Southern Hemisphere, they can only observe at night. So you can’t see if asteroids or comets are coming from the direction of the sun. Do you think that’s a problem?

[00:35:38] Dan: Yeah, I think that that’s always the blind spot with these sorts of searches. The fact that if it comes almost directly from the sun, within a few degrees or maybe even 10 or 20 degrees of the sun, then we wouldn’t be able to see it coming. And I think that there’s not a lot we can do about that. I would say, given the orbits, it’s probably unlikely that something will come directly from the sun. The sun would like to hold onto it if it was that close to it. But yeah, I think, I think that’s the blind spot and hopefully one which we don’t have to find out about.

[00:36:12] Jacinta: Not too important. Yeah. I was also thinking sort of, why do we need another telescope? You know, there’s a lot of telescopes in Sutherland. Why do we need another one dedicated specifically to hunting for near-Earth objects, near like asteroids? But Nic explained it really well. You know, in terms of you need a telescope that’s dedicated to doing this all the time every night. Whereas the other telescopes are of course being used for other things, for other science. And even though it was only a half a meter mirror or something like that, that’s still big enough that you can detect the bigger and brighter asteroids that might cause problems. If they’re coming close to the Earth.

[00:36:52] Dan: Yeah. I mean, I was actually in ATLAS yesterday having a look at it. I mean a half a meter mirror doesn’t sound like much, but it’s a pretty hefty telescope. So yeah. Very, yeah. I mean, I think that it’s very important work and actually in Sutherland, we can talk about it at a later date, but we are also looking at installing some smaller telescopes, which will actually observe the meteorites and even smaller objects coming into the atmosphere. So constantly looking at the sky for shooting stars. We’ll have an episode about that in the future.

[00:37:23] Jacinta: And speaking of constantly looking at the sky, we get this wrong every time, but LSST stands for the Legacy Survey of Space and Time.

[00:37:32] Dan: Yep. Sorry about that.

[00:37:34] Jacinta: Yeah. And the telescope is now called the Vera C. Rubin Observatory.

[00:37:37] Dan: Which is going to be another game changer.

[00:37:40] Jacinta: Yes, indeed. And then of course, finally, you mentioned Don’t Look Up. Daniel messaged me and said “You have to watch this movie straight away.”

[00:37:48] Dan: And did you?

[00:37:50] Jacinta: I did well, not straight away, but I did watch it. And yeah, I thought it was, I mean, it was a little bit cheesy, but I think that was half the point of it, of it being like if there’s an absolute crisis coming, how that can be politicized and nothing to be actually done about it. And of course, I’m assuming this whole movie and actually an allegory for climate change, right?

[00:38:15] Dan: Yeah, for sure. And I mean, maybe even a bit of COVID. So I think that it’s just a sort of commentary on the state of the world right now. But seriousness aside, I mean just a fun movie, and I think required watching for astronomy fans.

[00:38:30] Jacinta: Yeah. It was quite funny in many parts.

[00:38:37] Dan: Okay, great. Well I think that’s it for episode 48. We’ll speak to you again soon. Thanks for listening. And we hope you’ll join us again on the next episode of The Cosmic Savannah.

[00:38:49] Jacinta: You can visit our website, thecosmicsavannah.com, where we’ll have the transcript, links, pictures and other stuff related to today’s episode.

[00:38:57] Dan: As always, you can follow us on Twitter, Facebook, Instagram, @cosmicsavannah, that’s savannah spelt S-A-V-A-N-N-A-H. You can also find us on YouTube, where audio-only episodes are uploaded with closed captions, and those can be auto translated into over a hundred different languages, including Afrikaans, isiXhosa and Zulu.

[00:39:18] Jacinta: Special thanks today to Dr. Nic Erasmus for speaking with us.

[00:39:23] Dan: Thanks to our social media manager, Sumari Hattingh and our audio editor, Jacob Fine.

[00:39:26] Jacinta: Also to Mark Allnut for music production, Michal Lyczek for photography, Carl Jones for astrophotography and Susie Caras for graphic design.

[00:39:42] Dan: We gratefully acknowledge support from the South African National Research Foundation, the South African Agency for Science and Technology Advancement, the South African Astronomical Observatory and the University of Cape Town Astronomy Department.

[00:39:47] Jacinta: You can subscribe on Apple Podcasts, Spotify, or wherever you get your podcasts. And we’d really appreciate it if you could rate and review us or recommend us to a friend.

[00:39:55] Dan: And we’ll speak to you next time on The Cosmic Savannah.