Cosmic Coffee Time with Andrew Prestage
Cosmic Coffee Time with Andrew Prestage
#49 The new Mars meteorite impact. NASA Insight has detected a new meteorite impact on Mars! Meteorite expert Greg Brennecka returns to talk about this breathtaking new discovery.
Friend of Cosmic Coffee Time and expert meteoriticist Greg Brennecka returns to talk about the breathtaking detection of a new meteorite impact on Mars. Greg tells us how the impact was detected, and then confirmed with detailed imagery from Mars orbit. What does this tell us about the subsurface geology of Mars, and what does it mean for astrobiology and the future exploration of Mars and beyond?
It's a fascinating chat.
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This is Cosmic Coffee Time, the place where we take a look at what's happening somewhere in the universe in about the time it takes to have a coffee. It's cosmology in a cup. I'm Andrew Prestage, and join me and join meteoriticist Greg Brennecka for a coffee as we welcome Greg back to talk about a new and unusual meteorite impact. He joined me from the Lawrence Livermore National Laboratory in California. Welcome back, Greg Brennecka. It's great to talk to you again. You're becoming a regular on cosmic coffee time.
Greg Brennecka:That's great. This is my favorite podcast, so I'm happy to be here.
Andrew Prestage:And there's been some interesting things happening in the world of meteorites and we mostly talk about meteorites impacting the earth, but obviously they impact other bodies as well. We're familiar with the craters on the moon, uh, being caused by meteorite impacts, but there's been an amazing discovery on Mars. Greg, what happened?
Greg Brennecka:Well, I think this is really good evidence of, of just how dynamic of a place the solar system is. Uh, so recently there were some papers that came out that showed that, uh, scientists had had really kind of discovered, uh, a large meteorite impact on the surface of Mars. Um, you know, so this is, this is something I I think we, we knew was happening, but this was the first real evidence of it. Uh, we saw it in real time.
Andrew Prestage:And what was that first evidence?
Greg Brennecka:Yeah, there was a seismic profile basically that was, uh, recognized looking for Mars quakes. So basically an earthquake only on Mars. And, uh, this has a slightly different signature than, you know, what, maybe a deeper, a deeper Mars quake. And so they, they recognized this, I think it was on Christmas day, and, uh, and, and realized it was kind of a different signature than they'd been seeing in the Mars quakes. Uh, and then later on they were able to kind of, uh, find what that, what caused that. And, and it was actually a meteorite impact on the surface of Mars.
Andrew Prestage:And I understand it could be seen, the impact could be seen from Mars orbit. Um, did we get some images from the Mars Reconnaissance Orbiter?
Greg Brennecka:Yeah, we actually, uh, got some really spectacular images. So you can, you can, you know, Mars Orbiter is taking pictures of, of the surface of Mars. Uh, and then over a time series you're able to see this, this crater appear. And what's really cool is that it was, you were able to see the objective from this, uh, from this crater. And I think we learned an awful lot about the interior of Mars from this, or, or at least, uh, you know, the subsurface of Mars.
Andrew Prestage:And we expect a lot of meteorite impacts on other, other bodies in the solar system. And you heard some interesting information about Mars and meteorites from one of the Mars Rover drivers about how common meteorites are on the surface of Mars.
Greg Brennecka:Yeah, so while they were driving around the surface of Mars, we've had a lot of rovers that have, you know, kind of traversed Mars over the years. Uh, they found multiple meteorites on the surface of Mars while they're driving around, uh, you know, over over 10, I believe, uh, you know, of, of just meteorites that are laying around, uh, on the surface of Mars.
Andrew Prestage:To me, the most interesting aspect of this is what the impact can teach us about what lies under the surface of Mars. We've got the Perseverance rover drilling tiny holes around Jezero Crater, which is amazing to do that on another planet, but this is a huge 150 meter wide crater. What can that teach us?
Greg Brennecka:Well, it teaches us a ton about, like you said, what's at the subsurface. And, and while we've got instrumentation that's trying to do this at the small scale, uh, you know, nature can do this for us at the big scale. And, uh, what it did is it excavated this large hole. And what we find is that there's a lot of water, ice, basically that's not just at the poles, but it's also at the equator of Mars. And that's really significant find, uh, because there's a lot more water on Mars maybe than people who have, have thought in the past.
Andrew Prestage:And what could that mean for the study of astrobiology or even the future exploration of Mars?
Greg Brennecka:Well, it's obviously quite important for biology because, you know, as we know what life needs water, um, so if there's more water on Mars, there may be a higher chance that life existed in the past or, or maybe even present if we're really lucky. Um, but if you look at it from a perspective of exploring space, it's really important because water is a very critical resource for being able to not just sustain, you know, astronauts or something like that on the surface of, of, of Mars, but it presents a resource, uh, to where you can make fuel and other things out of the hydrogen and the oxygen that exists. So it's a really, really important resource if we are to explore deep space.
Andrew Prestage:We are talking with meteoriticist Greg Brennecka, the Insight Lander has been operating on Mars since late 2018 with its seismometer listening for Mars quakes and for meteorite impacts. I understand they're easy to tell apart with quakes emanating from deep below the surface, but the impacts are right on top of the surface.
Greg Brennecka:Yeah, you've got a slightly different signature and you kind of think of this as, as different types of, of waves that are happening. And when you've got an impact on the surface, you have a surface wave, uh, and you don't have that kind of deeper signature of, of an interior wave that is happening that you would have with a Mars quake. So you can tell these types of, uh, impact, you can tell an impact apart from a Mars quake.
Andrew Prestage:Something that surprised me was that this was the first time that surface waves had been detected by insight. Well, the first meteorite impact that'd been recorded in the three years that Insight had been there, and scientists expected at least a few per year. I mean, the body waves seem fairly common. Um, they've been detected over a thousand times. Is there any explanation for the absence of meteorite impacts prior to this one?
Greg Brennecka:Well, there's certainly some luck to it. You, you need to be somewhat near the location, location of the meteorite strike. Uh, the surface of Mars is quite varied. So if you have a large layer of dust and you have an impact into dust, it's not gonna transmit the wave like you would be if it's in solid rock. Uh, so there's definitely some aspect of, of luck. And then, you know, how many large impacts do you get, you know, per year. Uh, it's not, uh, a huge number. Um, so, so that's, that's also part of
Andrew Prestage:It. And just on that, are we more likely to detect impacts on Mars given the atmosphere is so much less dense than Earth would meteorites, maybe meteorites that would burn up harmlessly in Earth's atmosphere? Are those size meteorites more likely to reach the surface on Mars?
Greg Brennecka:Yeah, you're much less likely to burn up a meteorite, of course, because Mars has such a almost non-existent atmosphere. It's, it's so much thinner compared to, to Earth's. Um, so you, you should be having quite a few impacts on Mars. But, uh, you know, maybe, maybe because we haven't had as many larger ones near where Insight was, uh, they just weren't recorded.
Andrew Prestage:And what's Insight taught us about the possibility of ancient oceans on Mars?
Greg Brennecka:Well, I think, I think the fact that, you know, we do see that water, ice excavated when you have this impact, uh, it tells us quite a bit about how much water was there to start with. And, you know, that's a really, you know, as we talked about earlier, that's a really important aspect to understanding Mars's evolution as a planet. Uh, if there was a lot of water there to start with, uh, then, you know, the possibility of having, you know, standing water in in the form of oceans is, is quite high.
Andrew Prestage:It seems. We were lucky to get this seismic data insights lasted well beyond its expected working life as NASA spacecraft tend to do. Uh, the Prime mission was scheduled for two years, but now we're coming up on four years of service for insights and insights. Ground team think we're only expecting another couple of months from it. What's gonna be the cause of death for Insight. And do you think this meteorite might be its signature discovery?
Greg Brennecka:It certainly might be. There's been a lot of cool science that has come from insight. Uh, unfortunately it is gonna be losing its life, I guess, uh, due to its solar panels being covered by dust. Uh, and this is something that, that certainly was, was well documented with the original rovers spirit and opportunity, uh, that were able to outlive their, you know, kind of planned existence as well. Um, they had the fortune of, of having their panels cleaned off occasionally by different storms. Uh, and maybe that'll happen with insight. Um, but, but right now they're not, not planning on that at the moment.
Andrew Prestage:And just before we wrap up, Greg, can we get one final thought from you? So when Insight finally does give up the chase, we won't have any working seismometers beyond Earth. We heard about the Apollo seismometers on the moon in a recent episode that worked for several years through the 1970s. Now it seems there's plans to send seismometers to the far side of the moon in the next few years, and we also heard that NASA's dragonfly mission to Saturn's moon Titan is gonna carry a seismometer. Greg, you are a geologist. Does it give you a good feeling to know that seismometers are gonna be included on those future missions, that the rocks and that seismic activity that seems such an important part of the storytelling of those other worlds?
Greg Brennecka:Absolutely. And you know, I think we have to really look at these things as systems, uh, and to understand the planet or a planetary body, we have to be able to look at it from a lot of different ways, whether that's spectral data from, you know, uh, satellites that are covering it with high resolution imagery, uh, or if it's, you know, seismometers on the ground, things like that. We need to look at these as, as entire systems if we're gonna try to understand these things. So it, it does, it does make me feel good that we're sending out a lot, a variety of, of different instrumentation for these, these planetary missions.
Andrew Prestage:Well, this, uh, meteorite on Mars, Greg, it's another exciting discovery and it's been great to have you back on Cosmic Coffee Time.
Greg Brennecka:Thanks a lot, Andrew.
Andrew Prestage:Check out Greg's book Impact published by Harper Collins. There's a link in the show notes or go to harper collins.com. If there's something in the universe that you want us to take a closer look at on the podcast, send us an email at cosmiccoffeetime@gmail.com. Thanks for joining us. I'm Andrew Prestage, and I'll see you again soon for another cosmic Coffee Time.