Science Friday
Hosted by Flora Lichtman and Ira Flatow
A new book charts the millennia-old history of our fascination with aliens, and how myth transformed into research.
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This is Science Friday. I am Ira Flatow. This week, NASA reported that a sample collected by the Perseverance rover on Mars contains chemicals that could, and I underline could, be a sign of ancient life. Seems like I've heard that kind of claim somewhere before. Here with more on that and other stories from the week in science is Omer Irfan, senior correspondent at Vox in Washington, DC. Welcome back.
Hi, Ira. Thanks for having me.
Considering the history of false alarms about finding evidence of life on Mars rocks, it almost feels like deja vu all over again here.
It does, but this time NASA scientists say it's one of the strongest signs of life on Mars that they've found to date. The sample was actually collected last year, and it was very tantalizing at the time, but they really wanted to make sure that they ruled out all the other possibilities as best as they could. And so they spent the past year analyzing the sample. It was collected from a region in Mars that was known to likely have water in the past and also some of the important minerals that we need for life. And the sample, it's called Sapphire Canyon. They analyzed it and they found that it does show like it has biosignatures, basically that it has patterns on it that seem consistent with processes of life.
And crucially, they look a lot like what we see in sediment samples here on Earth. Now, the scientists do know and they do caution that this is not a confirmation that there are other potential inorganic mechanisms that can cause this pattern that they saw on the rock, these leopard spots. But it's, again, what they say is the most suggestive sign of life on Mars that we've seen to date.
Right, okay, we'll wait to see how that turns out. Back here on Earth, there is a long-running study about the science of decision-making in the brain. Tell me about this, please.
Well, 22 labs over the last seven years have been working together to map out brain activity. Now, they're looking at mice, but they're a useful model organism, and they basically pieced together the largest data set at this resolution of brain activity ever made. Now, typically, when we talk about brain activity, we're looking at individual neurons or clusters of neurons, but in this case, they would be able to look at and image thousands of neurons working at the same time and image them across an entire brain. So what they did was they put these mice in essentially these helmets that had sensors in them that could monitor their brain activity, and they gave them this task of essentially moving a circle on a screen into a specific region, and if they did that correctly, they
were rewarded with sugar water. Now, previously, you know, we used to think that the brain had distinct regions, discrete areas where certain functions were located. There's a visual cortex, there's an auditory cortex. Parts of the brain were assigned to specific tasks, but what they found was when it came to making a decision, the whole brain lights up. This is something that the whole brain has to work together when it comes to deciding what you want to do and how you respond to stimuli.
This was a mouse study, right?
Yes, we do want to be clear that these are mice, and you know, mice are not people, but there's a lot that we can learn from them, that this kind of points in the direction that while there may be specific regions of our brains that are assigned to certain tasks, decision-making is actually very complicated, and things that may be affecting the way we think about things and how we decide things in our brains may be afflicted in ways that we are only beginning to understand.
Cool, cool. I know you have a big article this week about vector-borne illnesses on the rise. Is that like mosquito-carrying diseases? Tell us more about that.
Yeah, that's exactly right. So over the past 20 years in the United States, the rates of vector-borne disease have actually doubled, and it seems to be a simmering threat. Now, the US has a long history with diseases like malaria and yellow fever and has successfully pushed them back. But a lot of factors are changing now that are bringing these threats back and introducing new ones. A big one is that people are traveling back and forth between regions that these diseases are actually more common. But also, the mosquitoes themselves are moving to new areas because the average temperatures are rising and mosquitoes are creatures of the heat. They reproduce faster when it's warm out. They also like these pools of standing water that are common during severe rainstorms. And even the pathogens,
the viruses inside the mosquitoes, they replicate faster. And so increasingly, we're seeing diseases moving to areas that have never seen them before, and health departments are now scrambling to try to figure out what they're dealing with.
Well, I know that you actually went to look at one of these big hotspots for this kind of disease.
Yeah, I went to this border town called Brownsville. It's a city in Texas that's basically right against the US-Mexico border. It has a favorable climate for mosquitoes year-round. It has sudden rainfall, downpours that lead to big bursts of mosquitoes, and they have a lot of movement back and forth across the border. So this tends to be one of the hotspots where we see some of the earliest outbreaks of vector-borne disease. This town saw, a few years ago, a big outbreak of Zika virus, which was transmitted locally rather than being among travelers. They saw dengue. And so they've invested a lot in actually surveilling and looking for mosquitoes actively, trying to find these diseases before they trigger outbreaks, and developing a response plan. And I think that this is something
that could be useful to other cities as they're contending with mosquito-borne disease outbreaks and could help prevent these outbreaks in the future.
Well, that does make a lot of sense. What does the surveillance look like? I mean, is it like a little mosquito trap I have on my deck?
It's a little bit more sophisticated than that. So like some of the traps I saw were called gravid traps, which are basically basins filled with water that smells like rotting vegetation. And that's apparently very attractive to female mosquitoes that are right about ready to lay eggs. And in order to lay eggs, a female mosquito has to drink blood. And so by capturing a mosquito right as it's about to lay eggs, you can get a sample of what it's been biting and potentially get a sense of what disease it's carrying.
Hmm. And then in other public health news, some positive news this time, and I'm talking about the US death rate is on the decline.
Yeah, that's right. The Centers for Disease Control and Prevention this week reported that in 2024, the death rate of the US declined by about 3.8%. And the big reason why is that the COVID-19 virus fell out of the top 10 leading causes of death for the first time in four years. And this also marks the lowest death rate recorded since 2020. So it shows that as COVID-19 has kind of moved down the list of priorities, it's helped drive the death rate down. But it's also interesting to note some of the other things that are on that list. So suicide has moved up the list as one of the 10 leading causes of death in the United States. And one of the big concerns now are sort of the diseases of lifestyle that we see, things like obesity
leading to things like diabetes, but also heart disease and cancer that tends to be associated with an aging population.
Uh huh. Yeah. Now you mentioned obesity. There's a new study out about the global obesity rise, right?
Yeah, that's right. UNICEF this week reported that for the very first time, there are more children around the world that are overweight than underweight. This is about 1 in 10 children around the world. The prevalence of underweight children has been declining since the year 2000, but now obesity is a larger portion of the population that's in the wrong direction in terms of nourishment in just about every region in the world, except for Sub-Saharan Africa and South Asia. Some of the Pacific Islands tend to have some of the highest rates of childhood obesity, but also in developed countries, places like the United States, the United Arab Emirates, and Chile tend to have very high obesity rates among children.
Let's pivot to something completely different. I'm talking about a kind of weird finding about ant queens and their offspring.
Yeah, so there are these ants in Europe called Iberian harvester ants. And they can interbreed with a species called Structur. So the Iberican species can interbreed and produce hybrids. But researchers found that there were ant colonies of just Ibericus ants, but they had hybrid offspring. And they were just like, where are they coming from? Where if they're not interbreeding, if the other population isn't around, what's going on? And when they studied them, they found that the queens were actually laying eggs with 100% Structur DNA. Basically, they were giving birth to a completely different species. And then using that different species to harvest their sperm to breed a colony of hybrid worker ants.
So they were basically operating as sexual parasites. And they were harvesting sperm from a completely different species in order to fill out their ant colonies.
You know, we think about royal jelly and bees, but this is not what's going on here, right?
Yeah, this is something a lot different. Basically, you know, ants, they have a lot of different roles in the ant colony. There are the workers, there are the drones, and there are the queens. And there's a lot of sub roles as well. And so what this is really interesting is that these two species that diverged almost five million years ago are still able to interbreed. But also that one species has figured out how to essentially domesticate the other and to basically give birth to a completely different species. This is not something that has been really documented before.
Hmm. Finally, we wanted to recognize the passing this week of a major figure in science, Dr. David Baltimore, who who I covered for many, many years, going back to the 1970s. He was an incredible guy. Tell us a little bit about him.
Yeah, he died this week at 87 from cancer. But his work was very remarkable because he kind of upended the conventional wisdom of how genetic information flows. So previously, the idea was that our cells use DNA to make RNA, and then that RNA is read to make protein, and that it only flows in one direction. But Baltimore discovered that there are actually some viruses that can work in the opposite direction. They use an enzyme called reverse transcriptase, and they can turn RNA back into DNA, and that DNA can actually reintegrate into the host genome. This is the mechanism that HIV uses, and that's part of why it's such a pernicious virus. But this could also be a potentially useful mechanism for genetic therapy, for
helping to correct genetic diseases. And this work helped him earn the 1975 Nobel Prize in Physiology with two other scientists.
Yeah, we've had him on the show a few times over the years. I want to play a bit of the time I spoke with him in 1996 about the coming genetic revolution. And you know, he was very prescient about the rise of computing and AI.
The Human Genome Project is almost a quintessential interdisciplinary project because the amounts of information that are coming in are so enormous that only computer scientists can organize that information in a form in which biologists can even have access to it. So combinations of computer scientists, engineers, biologists, geneticists are making the difference today and are allowing the human genome to be opened up to us in all of its glory.
Dr. David Baltimore, one of the icons of biology, always ready and eager to talk to the public about his work. Dr. Baltimore died this week at the age of 87. Umer, thanks for talking with us today. Thank you, Ira, for having me. Umer Afan, senior correspondent at Vox in Washington, DC. After the break, you know our fascination with finding alien life? Well, it's not a new thing.
2,500 years ago, you see this idea that all of these planets and stars and things, they might actually be physical places. They might not be divine entities.
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This video is of an MQ-9 drone tracking an orb, or this object, off the coast of Yemen. You'll see-
A video of a close encounter with an unidentified aerial phenomenon, the military's term for a UFO. That video was shown on Capitol Hill this week. It reportedly shows an American Hellfire missile attacking and bouncing off the UAP, apparently creating little damage. Senior defense leaders at the hearing did not offer comment. When videos like this one come out in congressional hearings, we can't seem to help ourselves but wonder if aliens were behind it. And if I asked you to think of the beginning of our modern obsession with aliens, or a little green men from Mars, flying saucers, you might think back to the '30s, Orson
Welles' fake War of the Worlds broadcast, or any of the alien invasion movies of the '50s, The Day the Earth Stood Still, my favorite. But as my next guest writes in her new book, humanity's been obsessed with the potential for alien life for about as long as we've been around. It is hard not to wonder what might be out there when you look up at the stars. So how have our views of beings from other worlds changed throughout the last few millennia? And where are we at now with our scientific exploration of life beyond our planet? Here to beam us up is Becky Ferreras, science reporter at 404 Media and author of the upcoming
book, First Contact: The Story of Our Obsession with Aliens. Welcome to Science Friday, Becky. Thank you so much for having me. You're welcome. My first, let me ask you for your reaction to that hearing at the House Oversight Subcommittee on UFO video showing the Hellfire missile bouncing off of the UAP which just zipped away.
First of all, not sure we should be firing missiles at the UAP. But, you know, it is, when these videos come out, it is incredibly tantalizing. I think even for people who are skeptical of alien origins, just to see these really strange objects and to not know their identity is incredibly tantalizing. So, this is the latest of so many strange videos. So, I certainly wish I knew what this strange metal orb is.
Were you thinking about these kinds of things when you were writing this book?
So, actually, UAP and UFOs, I hadn't really done much research into them. I was really focused more on the scientific side of life, and I saw this book as an opportunity to get into that world for the first time. But I was really interested in sort of how a lot of these pivotal moments, like the Roswell story, or the stories of early experimental spy craft being seen by people in the CIA, kind of like trying to make them feel like they hadn't seen anything. Those kinds of stories that, that helped me to understand why this adversarial relationship sort of developed between people who have these sightings and, and the authorities on this.
And how far back could you trace people sighting UFOs?
Yes. Oh, it's fascinating. It has a very long history. There are some really interesting anecdotes I, I put in my book. There's one from the Song Dynasty in China, where there was a number of strange sightings of a pearl that opened its door around the Yangtze River, like a thousand years ago. So, would love to know, maybe that was the same orb, you know? This could be, a pearl and an orb sounds similar to me. But, another famous one that is rendered beautifully in a woodcut illustration from the medieval period in Nuremberg, Germany.
It's very well documented, I believe the year is 1561. There's just an incredible display of spooky images coming out of the sun, black spears. And there have been some attempts to explain that with natural phenomenon like a sun dog or something like that. So it's possible that they saw something like that. But this is an event that was witnessed by hundreds of people. So it's not a new thing to be seeing strange things in the skies, for sure.
Was there a time when, when we moved beyond myth to ancient people wondering if aliens do actually exist?
Yes, it's such a nebulous thing because I really, I think that the intuition that there's something out there, that we're not alone, must go back very deep into our prehistory, like tens of thousands of years, because we, all cultures really personify the skies and tell stories about what might be there. But I think you really start to see the change into the more scientific idea of aliens. About 2,500 years ago, you see cosmic pluralism as an idea come into being, which is this idea that all of these planets and stars and things, they might actually be physical places, they might not be divine entities. And I highlight one person in the book, Anaxagris, who was the first to work out the mechanics
of eclipses, and he believed that these are just places and that if we're on a planet like Earth, then these other planets may also have life as well. And I think that's when you start seeing the more modern definition of aliens as actual living beings that are inhabiting environments similar to ours.
Well, to, to believe that there are aliens out there, you have to believe that we're not the center of the universe, right?
Yes.
I mean, you had to get to more modern scientists.
Yes, absolutely. And that's a really interesting history as well. Copernicanism in the 1400s and 1500s, that really leads to the explosion of alien speculation. And one figure that I think is very important for that is Giordano Bruno, who is most known for being very cantankerous and a very unique character, who was eventually executed by the Catholic Church in 1600, was burned at the stake. For lots of heretical theories that he had, but he was a big proponent of Copernicanism. An early, he, he believed that it was not a threat to the religious dogma. He thought that if we're orbiting the sun and lots of other planets are orbiting these distant stars that are also suns, then that means that God's power is actually immense.
But I think Copernicanism was such a threat to the theological kind of worldview that Bruno sort of became the, the martyr and the scapegoat for that.
Right, right. So you're entering the scientific revolution where people are gathering facts.
Yeah, it's a fascinating transition and you know, it was, it was a very popular subject by the 1700s. I think another important revolution that happens at the same time as, you know, Galileo's looking at, at the moon's surface and seeing the moons of Jupiter orbiting Jupiter, which is, you know, another thread that supports Copernicanism is if a planet can have its own moons, then obviously the earth is not the center of the universe. Another thing that was unfolding at the same time though, is the sort of microbial revolution of being able to realize that there's whole other ecosystem of organisms that are invisible. And Christen Hoijens, the, the Dutch polymath of the scientific revolution, kind of married these ideas and believed very strongly that it was very unlikely that if there's life forms on earth that we can't see, that there's no life forms on other planets.
And he kind of had a very early Star Trek kind of view. I, I think he would have been a Trekkie because he, he believed that if we're not even like discovering everything that's on earth and other worlds must be also inhabited.
Well, considering the scientific skepticism we have and the famous Carl Sagan, you know, extraordinary claims require extraordinary evidence, there must have been pushback even in those days, right?
Yes, there was a, there was a lot of pushback and there's always been alien pessimists. Uh, there's a really interesting one in the 1800s, an Anglican priest called William Weewell, who actually made a very good case. His argument was pointing out like, look, we're, we're not seeing these beings come into focus and as, as telescopes get better in our own solar system. So it must be pretty rare if we're not finding them. He's kind of have an early version of the Fermi paradox. And he also kind of intuited that the habitable zone around these distant stars must be very, very small, that, uh, most of these worlds would either be too hot, too cold, you wouldn't have a lot of Goldilocks planets. So there's always been that pushback as well.
Yeah, okay, let's turn to more recent times. We are, where are we right now on the search for extraterrestrial life, especially intelligent life?
Yeah, absolutely. I mean, I think it's really exciting. Just today, we had a finding from Perseverance on Mars of a possible biosignature there. So there certainly seems to be the, a growing flood of potential biosignatures that are discovered, not only on worlds around us, but increasingly, interesting atmospheric chemistry in exoplanets far from us. But as for your question specifically about intelligent life, I think that is the most difficult one, because so far, we're really just looking for signs of any kind of metabolic activity or respiration on the most basic level. And it, I think it is strange, we haven't searched most of the sky, of course, we have lots of sky left to search for techno-signatures and things like that. But we've really only had a couple possible, maybe that's a techno-signature. I'm thinking of the WAO signal that happened
50 years ago, but there was recently a paper that came out that provided a natural explanation for that one. So it really is a bit strange that we seem to have a very silent universe in terms of techno-signatures, even though you have to admit that we're very early on in this search. I think also, it's worth thinking about, we're the only species that appears to be interested in this question on our planet, despite this diversity of intelligent species here. Maybe aliens just aren't that interested, or if they're maybe in an interior ocean world like Europa or Enceladus, they might not know there's a galaxy out there, you know?
Yeah, well, this is, we live in interesting times about this, especially since more of these photos of who knows what are showing up in Congress and other places.
Yes. You know, for so many thousands of years, people have really been yearning for data on this question. And now we are in the age where we have the opposite problem. We're going to have way too much data, and it will be difficult to assess it all, because it's quite, it's quite a high bar to say that something is a conclusive sign of life. So I think we're going to have to move towards this idea of a cosmic mosaic, where perhaps we're looking at the atmospheric chemistry of many worlds and seeing if, well, okay, there's a lot of these worlds that have a particular signature that is associated with life. Um, maybe some of them do have life, maybe some of them have geological explanations, but it's sort of more of an odds game rather than I think what we've been set up to expect
from movies where it's kind of an ambiguous if an alien invades Earth, right? You're not going to be like, oh, this is a techno signature.
Do you have, do you have your favorite alien movie?
Oh, yeah, yeah. Well, I do love Story of Your Life by Ted Shanks. It's the story that Arrival is based on. I like Solaris as well. Uh, I like stories where the alien is very alien. Uh, I really enjoy when it's hard to talk to them because I think, you know, I am a Trekkie as well, but I, I want a lot more stories and speculative fiction that might resemble what we actually end up with, which is, uh, an inability to communicate, even if we do have a contact moment.
Well, I, I'll reiterate, my favorite film is the original, The Day the Earth Stood Still, because it's sort of the thinking person's alien movie, I think.
Why do you say that?
Because you have the, you have the character, uh, Klaatu goes around Washington trying to find smart people to talk to.
Yeah, absolutely. Yeah. I refer to that, that movie in my book, Under the Savior's kind of archetype, uh, because he's sort of got this messianic idea around him, which Superman also has, and that is a big strain in our alien fiction, that we do like a benevolent alien that will come and redeem us.
Well, that, that brings me to the end of our conversation. I haven't got anything more to say to you than Klaatu Barada Nikto, Becky, so.
And I'll say, live long and prosper.
Live long and prosper. Thank you very much for taking time to talk with us today.
Thank you so much. It was a pleasure, Ira.
Becky Ferrera, science reporter and author of the upcoming book, First Contact, The Story of Our Obsession with Aliens. It's out September 30th, and you can get a sneak peek of it on our website, sciencefriday.com slash aliens.
Hey, thanks for listening. If you have a comment or question or a story idea, our listener line, it's always open. Call 8774 Sci-Fry, 877-the-number-four-Sci-Fry. This episode was produced by Charles Berkowitz and Dee Peterschmidt. Lots of folks helped make this show happen this week, including... Santiago Flores.
Jordan Smudjic.
Emma Gomez. Robin Casmer.
I'm Ira Flatow. Thanks for listening.
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