The Human Obsession With Aliens Goes Way, Way Back

IRA FLATOW: This is Science Friday. I’m 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 Umair Irfan, senior correspondent at Vox in Washington, DC. Welcome back.

UMAIR IRFAN: Hi, Ira. Thanks for having me.

IRA FLATOW: Considering the history of false alarms about finding evidence of life on Mars rocks, it almost feels like deja vu all over again here.

UMAIR IRFAN: 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– 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 note, 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 in 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.

IRA FLATOW: Right. OK. 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.

UMAIR IRFAN: 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 were able to look at an 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, 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.

IRA FLATOW: This was a mouse study right?

UMAIR IRFAN: Yes, we do want to be clear that these are mice, and 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.

IRA FLATOW: 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.

UMAIR IRFAN: 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.

IRA FLATOW: Wow. I know that you actually went to look at one of these big hotspots for this kind of disease.

UMAIR IRFAN: 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.

IRA FLATOW: 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?

UMAIR IRFAN: 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 diseases it’s carrying.

IRA FLATOW: In other public health news, some positive news this time, and I’m talking about the US death rate is on the decline.

UMAIR IRFAN: 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 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.

IRA FLATOW: Yeah, now you mentioned obesity. There’s a new study out about the global obesity rise, right?

UMAIR IRFAN: 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 one 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.

IRA FLATOW: Let’s pivot to something completely different. I’m talking about a kind of weird finding about ant queens and their offspring.

UMAIR IRFAN: Yeah, so there are these ants in Europe called Iberian harvester ants, and they can interbreed with a species called structor. 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? 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% structor 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.

IRA FLATOW: We think about royal jelly and bees, but this is not what’s going on here, right?

UMAIR IRFAN: Yeah, this is something a lot different. Basically, ants, they have a lot of different roles in the ant colony. There are the workers, there are the drones, and then there are the queens. And there’s a lot of sub-roles as well. And so what is really interesting is that these two species that diverged almost 5 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.

IRA FLATOW: Finally, we wanted to recognize the passing this week of a major figure in science, Dr. David Baltimore, who I covered for many, many years going back to the 1970s. He was an incredible guy. Tell us a little bit about him.

UMAIR IRFAN: 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.

IRA FLATOW: 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.

DAVID BALTIMORE: The Human Genome Project is almost the 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.

IRA FLATOW: 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.

Umair, thanks for talking with us today.

UMAIR IRFAN: Thank you, Ira, for having me.

IRA FLATOW: Umair Irfan, senior correspondent at Vox in Washington, DC.

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After the break, you know our fascination with finding alien life? Well, it’s not a new thing.

BECKY FERREIRA: 2,500 years ago 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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SPEAKER 2: This video is of an MQ-9 drone tracking an orb, or this object, off the coast of Yemen. You’ll see–

IRA FLATOW: 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 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 has 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 Ferreira, 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.

BECKY FERREIRA: Thank you so much for having me.

IRA FLATOW: You’re welcome. First, let me ask you for your reaction to that hearing at the House Oversight Subcommittee on that UFO video showing the Hellfire missile bouncing off of the UAP, which just zipped away.

BECKY FERREIRA: First of all, not sure we should be firing missiles at the UAP.

[LAUGHTER]

But 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.

IRA FLATOW: Well, were you thinking about these kinds of things when you were writing this book?

BECKY FERREIRA: 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 how a lot of these pivotal moments, like the Roswell story or the stories of early experimental spycraft being seen by people and the CIA kind of trying to make them feel like they hadn’t seen anything– those kinds of stories that helped me to understand why this adversarial relationship sort of developed between people who have these sightings and the authorities on this.

IRA FLATOW: And how far back could you trace people sighting UFOs, or–

BECKY FERREIRA: Yes. Oh, it’s fascinating. It has a very long history. There are some really interesting anecdotes 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 sound 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 spheres. 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.

IRA FLATOW: Was there a time when we moved beyond myth to ancient people wondering if aliens do actually exist?

BECKY FERREIRA: Yes, it’s such a nebulous thing, because 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 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, Anaxagoras, 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.

IRA FLATOW: Well, to believe that there are aliens out there, you have to believe that we’re not the center of the universe, right? I mean, you had to get to more modern scientists.

BECKY FERREIRA: Yes, absolutely. And that’s a really interesting history as well. Copernicism, in the 1400s and the 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 Copernicism, an early– 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 Copernicism was such a threat to the theological kind of worldview that Bruno sort of became the martyr and the scapegoat for that.

IRA FLATOW: Right, right. So you’re entering the Scientific Revolution where people are gathering facts.

BECKY FERREIRA: Yeah, it’s a fascinating transition. And it was a very popular subject by the 1700s. I think another important revolution that happens at the same time is Galileo is looking at the moon’s surface and seeing the moons of Jupiter orbiting Jupiter, which is another thread that supports Copernicism, 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 microbial revolution of being able to realize that there’s this whole other ecosystem of organisms that are invisible. And Christiaan Huygens, 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 is no life forms on other planets. And he kind of had a very early Star Trek kind of view. I think he would have been a Trekkie, because he believed that if we’re not even discovering everything that’s on Earth, then other worlds must be also inhabited.

IRA FLATOW: Well, considering the scientific skepticism we have and the famous Carl Sagan “extraordinary claims require extraordinary evidence,” there must have been pushback even in those days, right?

BECKY FERREIRA: Yes, there was a lot of pushback. And there’s always been alien pessimists. There’s a really interesting one in the 1800s, an Anglican priest called William Whewell, who actually made a very good case. His argument was pointing out, look, we’re not seeing these beings come into focus as telescopes get better in our own solar system. So it must be pretty rare if we’re not finding them. He kind of had 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 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.

IRA FLATOW: Yeah. OK, let’s turn to more recent times. Where are we right now on the search for extraterrestrial life, especially intelligent life?

BECKY FERREIRA: 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 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 I think it is strange– we haven’t searched most of the sky, of course. We have lots of sky left to search for technosignatures and things like that.

But we’ve really only had a couple possible, maybe that’s a technosignature. I’m thinking of the Wow 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 technosignatures, 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?

IRA FLATOW: Yeah, well, 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.

BECKY FERREIRA: 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 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, OK, there’s a lot of these worlds that have a particular signature that is associated with life. Maybe some of them do have life, maybe some of them have geological explanations, but it’s more of an odds game rather than, I think, what we’ve been set up to expect from movies where it’s kind of unambiguous if an alien invades Earth, right? You’re not going to be like, ooh, this is a technosignature.

IRA FLATOW: Do you have your favorite alien movie or series?

BECKY FERREIRA: Oh, yeah, yeah. Well, I do love Story of Your Life by Ted Chiang. It’s the story that Arrival is based on. I like Solaris as well. I like stories where the alien is very alien. I really enjoy when it’s hard to talk to them, because I think– I am a Trekkie as well, but I want a lot more stories and speculative fiction that might resemble what we actually end up with, which is an inability to communicate even if we do have a contact moment.

IRA FLATOW: 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.

BECKY FERREIRA: Why do you say that?

IRA FLATOW: Because you have the character– Klaatu goes around Washington trying to find smart people to talk to.

BECKY FERREIRA: Yeah, absolutely. Yeah. I refer to that movie in my book under the saviors kind of archetype, 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.

IRA FLATOW: Well, that brings me to the end of our conversation. I haven’t got anything more to say to you than Klaatu barada nikto, Becky.

BECKY FERREIRA: [LAUGHS] And I’ll say, live long and prosper.

IRA FLATOW: Live long and prosper. Thank you very much for taking the time to talk with us today.

BECKY FERREIRA: Thank you so much. It was a pleasure, Ira.

IRA FLATOW: Becky Ferreira, science reporter and author of the upcoming book First Contact– The Story of Our Obsession With Aliens. It’s out September 30, and you can get a sneak peek of it on our website, sciencefriday.com/aliens.

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Hey, thanks for listening. If you have a comment or question or a story idea, our listener line, it’s always open. Call 877-4-SCIFRI. 8-7-7, the number four, SciFri. This episode was produced by Charles Bergquist and Dee Peterschmidt. Lots of folks helped make this show happen this week, including–

SANTIAGO FLOREZ: Santiago Florez.

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EMMA GOMETZ: Emma Gometz.

ROBIN KAZMIER: Robin Kazmier.

IRA FLATOW: I’m Ira Flatow. Thanks for listening.