Instant Genius - How to harness the healing power of the body’s largest nerve

Episode Date: June 5, 2025

It’s a little-known fact that we all have two long networks of nerves that run down either side of our necks that pass signals from our brains to all of the organs in our bodies. This is known as the vagus nerve, and cutting-edge research is now uncovering how stimulating this vital part of our anatomy can help us combat a whole range of damaging health conditions. In this episode, we speak to neurosurgeon and researcher Dr Kevin J Tracey about his latest book The Great Nerve: The New Science of the Vagus Nerve and How to Harness its Healing Reflexes. He tells us how this nerve network acts as a vital conduit for communication between our brains and organs, talks us through the exciting new therapies being developed using electronic implants that stimulate the vagus nerve, and why we’re only just scratching the surface of the therapeutic potential of this understudied part of our bodies. Learn more about your ad choices. Visit podcastchoices.com/adchoices

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So you can experience exceptional sound at home. Music just as the artist intended. Visit name audio.com to learn more. Hello and welcome to Instant Genius, a bite-sized masterclass in podcast form. Every Monday and Friday, you'll hear world-leading scientists and experts talking about the most fascinating ideas in science and technology today. I'm Jason Goodyear, commissioning editor at BBC Science Focus. It's a little known fact that we all have two long networks of nerves

that run down either side of our necks and pass signals from our brains to all of the organs in our bodies. This is known as the vagus nerve. And cutting-edge research is now uncovering how stimulating this vital part of our anatomy can help us combat a whole range of debilitating health conditions. In this episode, we speak to neurosurgeon and researcher Dr. Kevin J. Tracy about his latest book, The Great Nerve, the new science of the vagus nerve and how to harness its healing reflexes. He tells us how this nerve network acts as a vital

conduit for communication between our brains and organs, talks through the exciting new therapies being developed using electronic implants that stimulate the vagus nerve, and why we're only just scratching the surface of the therapeutic potential of this understudied part of our bodies. So welcome to the podcast. Thanks so much for joining us. Thanks for having me on. It's great to be here. So today we're talking about your book, The Great Nerve, the new science of the Vagus nerve and how to harness its healing reflexes. So the first obvious question is, what is the Vagus nerve? Well, you actually have two Vegas nerves, one on each side, like you have two thumbs

and two kidneys. We call it the vagus nerve, but it's even more complicated than one versus two, because in each of these vagus nerves, which run on each side of your neck, you have 100,000 fibers in each side. So I like to say, when someone asks me how to stimulate their vagus nerve,

I say, well, you have 200,000 to choose from. Which ones do you want to stimulate first? Now, these fibers originate in the brain at about the level of your ear, deep down in your brain called your brain stem right above the top of your spinal cord. And they run from, as I say, about the level of your ears across your neck on both sides, down across your chest and into the abdomen. And in the abdomen, as well as in the chest, the branches, the fibers, the extensions of these vagus nerves touch all the organs that you never think about

all day long. So the importance of this nerve lies in its ability to send communicating signals about the status of all your organs, your heart, your lungs, your pancreas, your kidneys, your liver, everything. Back up into your brain. Every second your brain is being filled with information, traveling up the fibers of the vagus nerve, telling it what's going on in these organs. And the brain reacts. The brain responds to this incoming information with reflex signals that travel back down the fibers of the vagus nerve, back to those organs to adjust.

organs in a harmonious function, like the conductor of the orchestra keeps all of the instruments and performers playing in harmony, the signals traveling in your vagus nerve balance the function of your organs. This is what we call health when all of your organs are in balance. So as you state, though, it's an incredibly important part of our bodies. And I understand it's something, you know, if you chop off my hand, okay, it wouldn't be great. but I can still live. But without these nerves, I'm done.

You're exactly right. As it turns out, the vagus nerve is the only nerve in the body, which when cut on both sides, is lethal. We know this from experiments across the animal kingdom and virtually all mammals. When you cut the vagus nerve on both sides, breathing and heart rate is severely affected to the point of death. Now, why does that happen? Well, the signals traveling up and down are maintaining, as I said, a balanced organ function and balanced organ function of heart and lungs, heartbeat and breathing, is crucial for survival. You also have fibers to the vagus nerve controlling your voice box, your larynx, the atoms apple in the front of your throat. And this is very important for regulating

airflow in and out of your lungs. You also have fibers of the vagus nerve control, the ability to inhale and exhale. And you have fibers of the vagus nerve controlling your blood pressure and your heart rate. So significant damage to both vagus nerves at the same time is incompatible with survival. Fortunately, it's incredibly unusual, uncommon. It's rare to ever happen to humans. So we're talking about nerves here. So another thing I think we should sort of lay down the foundation for is people will say nerves,

Well, that's the nervous system, the parasympathetic and the sympathetic. So can you just give us a brief sort of Cliff's notes version of what that is? The nervous system is comprised in your body of your brain, your spinal cord, and the other nerves that connect the brain and spinal cord to all of your organs, including your fingers so you can play the piano and your feet and legs so that you can walk, and your mouth so that you can walk and chew gum at the same time. But this is possible because of the incredible specialization of the signals in the individual nerve fibers, which are extremely small. You can see large nerves like the vagus nerve in each side of your neck.

If you're having surgery on the carotid artery, you can easily see the vagus nerve. But what you can't see are the 100,000 individual fibers deep inside that vagus nerve. Now, millions of years of evolution of this mammalian human nervous system have enabled incredible specialization. So a very small number of fibers to your heart, for instance, maybe a few hundred. If traveling in the vagus nerve can slow your heart, this fact, combined with knowledge that other fibers to your intestines can speed up your intestines that these fibers also run in the vagus nerve, leads to the expression rest and digest, which is the functions commonly associated with increased neural signals in the vagus nerve. And maybe later we can talk about what a neural signal actually is. But for now, increased signals in the vagus nerve tend to slow the heart and

enhance digestion. The vagus nerve is therefore the rest and digest nerve and it's part of what we call the parasympathetic nervous system. On the flip side, you have the sympathetic nervous system. The sympathetic nervous system, the fibers to the heart tend to increase heart rate, and the fibers to your adrenal gland tend to increase the release of stress hormones and steroids, which raise blood sugar. This is, of course, the classic fight or flight response, which you experience during intense exercise or intense fear or surprise. The sympathetic nervous system and the parasympathetic nervous system, are not under your voluntary control. So this part of the nervous system is called the involuntary nervous system.

And that's, of course, as opposed to the voluntary nervous system, which enables you to play the piano and walk and chew gum. So understanding this gives a window into why it is that we can walk around, we can play golf, we can study, we can play the piano, and all in the background, your brain at a level that you're not thinking about is producing a balanced, harmonious

output of your organs that keeps you healthy. And that, of course, requires the involuntary nervous system, the sympathetic and parasympathetic, of which the vagus nerve is attributed to being the principal nerve of the parasympathetic nervous system. So you mentioned there the signaling process. So you often hear people say that the brain will communicate to the organs in the body via the vagus nerve and in other ways. But so how does it do that? Nerves propagate electrical signals from the place that the signal begins. In this case, in your example, beginning with the brain, nerve cells in the brain would be

activated to start sending electrical signals down the chain, down the nerve fiber in the vagus nerve to the organ under the control of the vagus nerve. Now, there tends to be an oversimplification of what the electrical signals are. People know from high school or middle school that flipping on a light switch leads to a flow of electrons through a copper wire, and this leads to the light coming on almost instantaneously. And without diving into any more physics than absolutely necessary, the speed of the electrons traveling through the vagus nerve is on the order of the speed of light. It's very, very fast. Nerves don't operate that way. When a nerve fires, it activates an opening in the nerve cell membrane, which allows a rushing in of ions from

outside the cell to inside the cell, like sodium and calcium, and a rushing out of other ions like chloride, chloride and potassium. And when these things happen, when there's this flow of charged ions in and out of the cell through this opening called a voltage-gated ion channel, you get a voltage spike in the area of that opening. This actually starts another nearby voltage-gated ion channel to open. And the opening of that now causes another spike, which causes the next one down the chain to open. and it's almost like watching a dominoes fall, one after the other. A voltage spike activates another voltage spike, and this can travel all the way from your brain at the level of your ears,

down the vagus nerve all the way into your heart or your lungs or your abdomen. Now, it gets perhaps even more interesting because at the end of the line, these voltage spikes run into the nerve terminus, the nerve ending at what's called a synapse. And at that place, at the very end of the nerve, the arrival of the voltage spikes causes the release of chemicals, neurotransmitters, that have names like acetylcholine and norapherin. Those neurotransmitters float across this very narrow space between the nerve ending and the cell that's being controlled by the nerve. And the arrival of the neurotransmitter at the other side of the synapse is what actually activates the response and the respondent. cell. So this is all really fascinating in and of itself like physiology and the way that the human body works. But you mentioned a really key word to our conversation today earlier, which is health.

So let's talk about how this affects our health. So there's something known as vagal tone. What do we mean by that? Vagal tone is a word that's commonly used to describe the amount of vagus nerve signals descending from the brain to the heart. And it's measured by looking at things such as resting heart rate or heart rate variability. And the idea is, as vagus nerve signals to the heart increase, heart rate tends to slow. And we know this from many years of study, physiology study, in laboratories and in human clinical research. The slowing of the heart rate occurs because the signals arrive at the conduction system in the heart and cause it to prolong the time to the next heartbeat. And the distance in time, if you will, the amount of time between individual heartbeats is

called instantaneous heart rate. And if you make averages of instantaneous heart rates over blocks of time, say an hour or half an hour, you can score this and stratify subjects who have more variability in their instantaneous heart rate and less. And as it turns out, increasing vagus activity to the heart increases heart rate variability. That's what we refer to as vagal tone. It's important to think about this for a second in the context of the 100,000 fibers on each side. Because some assume, and there are billions of web impressions and a tremendous amount of information online about the vagus nerve. And I personally find some of it helpful and much of it very confusing.

And I think one thing I find confusing is the assumption by many that vagal tone corresponds to all 200,000 fibers of the vagus nerve. We don't know that. What we know when we measure instantaneous heart rate variability is the activity of the vagus nerve fibers to the heart. My colleagues and I at the Feinstein Institute in New York for many years now, going on 25 years, have been interested in the fibers that travel in the heart. the vagus nerve from the brain to the immune system. And the activity of those fibers can switch off inflammation. Now, it's possible that maneuvers that increased vagal tone measured by looking at the signals to the heart also increases the signals to the immune system to suppress inflammation, but that's not proved by any stretch of the imagination. That's an idea that's not scientifically proven. So while it's intriguing and perhaps oversimplified to talk about vagal tone as it refers to all vagus nerve activity, I revert back to the simple concept that the nervous system is arranged around highly discrete signals in highly specific fibers that are very complicated, and it enables people to walk and chew gum at the same time.

So there's no proof that the same fibers that go to the heart that you're measuring with vagal tone, heart rate variability are the same ones that do other important functions like turn off inflammation. Yeah, so I think a lot of people will have heard of terms like heart health, gut health. Should we be thinking more about vagal health? Perhaps. I mean, I understand why that idea is passed around. Let's start with the most simple of reasons. The things that your grandmother and hopefully your primary care physician and primary health care providers ask you to do, encourage you to do, you know, eat a balanced diet, maintain a healthy body weight, exercise regularly, get enough sleep, avoid excess anxiety or stress,

and or have methods to deal with that, whether it's meditation or cognitive behavioral therapy or other relaxation techniques, and maintaining strong social ties and commitments and healthy use of learning and cognition. I mean, all of these well-known practices, strategies, life strategies, are all associated with decreasing heart rate and increasing vagal tone. So you have an interesting association there, an interesting relationship, but your listeners will know as well as anyone. They've probably heard it a thousand times on your podcast. Causality is not proved by correlation. It's certainly interesting. Where I think confusion arises when trying to explain all these things on the basis of the Vegas nerve

is that the Vegas nerve is the transatlantic cable. It's the massive conduit transmitting the information. It's not the server. In this analogy, if there's a submarine under the ocean, listening to the transatlantic cable, and there's a movie being transmitted on a server in New York to viewers in Paris, and the submarine decides to watch the movie,

and the submariners hack into the transatlantic cable and project the movie on the screen in the submarine. The movie's not originating in the Vegas nerve in the transatlantic cable. The movie is on the server in New York. So in these analogies, when you meditate, for instance, and induce a state of relaxation, your brain centers accommodate that relaxation by sending signals down. down your vagus nerve to slow your heart rate. And even casual meditators, simple meditative strategies with simple apps online, you can slow your heart rate very quickly by a few minutes of meditative practice. And technically, you have stimulated your vagus nerve by meditating. But it's all happening in your brain and the vagus nerve is transmitting the signal. That's where

some of these analogies get very, and the same argument can be made for exercise and for the gut, Vegas brain connection and for on down the list. So first off, that's the really fantastic explanation of what's going on there, really, really fascinating stuff. So as we've established, when the vagus nerve is working as this, I don't know, conduit or whatever you want to call it, and our health's in good shape. But what happens when it starts going wrong, you know, what effects does that have? If the vagus nerve is damaged, infection, we saw this in COVID. If it's damaged by chronic inflammation, as we've seen in patients with autoimmune conditions, if it's damaged by injury, which can happen, a unilateral

vagus nerve injury can happen with certain kinds of trauma, then those patients manifest signs of dysfunction or imbalance in some of their organs. Where we have probably the most data is in looking at what happens to the control of inflammation. So the signals in the vagus nerve to your immune system act like the brakes on your car. They tend to slow inflammation from progressing and from developing in your body. Now, what is inflammation? Inflammation is the immune system response, the white blood cell response to injury and infection.

And inflammation at the site of an infection can be very good for you. It can kill the invading bacteria and it can accelerate wound healing. So that's all good. Inflammation at the site of an injury participates in slowing the potential for infection, but also accelerates stem cells to repair the tissue. And so the right amount of inflammation is absolutely crucial. In fact, we know this because immunosuppressed patients have serious complications from serious infection and other problems.

So the break function of the vagus nerve, the slowing function on inflammation in the vagus nerve prevents inflammation from becoming excessive. When does inflammation become excessive during conditions like rheumatite arthritis or inflammatory bowel disease or other. autoimmune conditions. In those patients, the inflammation in the joints or in the intestines acts as if it's uncontrolled. It's as if the brakes on the car were cut. And the car is now barreling down the mountain and the inflammation is actually causing more damage than good to the joints and the intestines. If the signals in the vagus nerve are depleted in those patients,

how can we find that out? You can actually go back to measuring vagal tone. And we and others have done this. And as it turns out, there is evidence of decreased vagal tone. Now, these are the fibers that control instantaneous heart rate, but there's evidence of a decreased vagal tone, in other words, impaired vagus nerve signaling to the heart in patients with serious inflammatory conditions. So it makes sense. It's intuitive. It's a reasonable hypothesis that the damage, to the vagus nerve, like the damaging brakes to your car, is enabling or accelerating the amount of inflammation that's occurring in the body and contributing to the arthritis. But again, that's a correlation at this time. It hasn't been proved as cause and effect.

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So let's have a look at that. Because I know you've been doing work on implants that stimulate the vagus nerve. Can you explain how that works? The vagus nerve fibers that we talked about, 100,000 on each side, carries signals either up into the brain or down from the brain into the body. If you implant a computer chip with an electrode, a lead, a rechargeable battery, and target the fibers in the vagus nerve that carry signals to the, immune system, we and others now around the world have showed it's possible to stimulate those fibers,

stimulate the brakes on inflammation, and stop or reverse inflammation that's causing severe damage in rheumatoid arthritis and an inflammatory bowel disease. And this gives a tremendous opportunity to use a computer chip that delivers electric current into the vagus nerve for one minute a day in the most recent study, one minute a day by activating those sick. signals was sufficient to significantly benefit patients in a major clinical trial reported out in the United States last November at the American College of Rheumatology. The study was done by a company that I co-founded Setpoint Medical. In 40 medical centers across the United States, it was a controlled study. In order to do a controlled study in a situation like that, all 242

patients received this chip implanted on their left Vegas nerve. It was about the size of of a multivitamin or a fish oil pill. It's implanted deep in the neck under the strap muscles at about the level of a voice box, Adams apple. And by activating the current one half of the subjects,

not the other half, so the cohort was divided in half, the investigators saw a significant clinical improvement in the patients that had received the therapy. Then, after some number of weeks, I believe it was 12 weeks. All the subjects were treated with the electric current for a minute a day. And the previous group, the control group, now actually caught up to the therapeutic benefit of the treated group. So a remarkable finding in patients who had exhausted all of their therapeutic options.

They had tried steroids and methotrexate and even biologic drugs, which have to be injected, cost in the U.S., cost upwards of $100,000 a year per drug and only work in about half the patients and also carry significant side effect warnings called black box warnings in the United States. So putting all this together, the understanding of how to put a computer chip on the vagus nerve in patients with impaired vagus nerve signals because they have severe autoimmune disease is a new way of thinking about treating these serious conditions. And my hope is that, in the coming weeks or months, perhaps, that the US FDA will approve this as a therapeutic option in the US and that this will prompt a lot of interest and similar approval processes in other

countries, including the UK. So these implants, you called it a computer chip. So the managing physician can sort of tap into it externally without any need for further surgical procedures. Monitor what's going on. You sort of turn it up and down. Is that right? 100% correct. And that's a very important point. So a lot of work was done with focus groups talking to not only the patients to find out what their preferences are, but also the physicians to find out what their preferences

for interfacing with these devices would be. And the consensus from both groups, physicians and patients, is that for carrying a chronic condition like rheumatoid arthritis or inflammatory bowel disease, an interaction between doctor and patient every six or eight weeks is preferred. So currently, the interaction is the checkup and perhaps some blood tests and physical examination, maybe other tests depending on the severity of the condition, followed by the physician adjusting the medications by changing the prescriptions. And the patient taking a different number of pills or a different kind of injection. The idea going forward is that the interaction between the patient and the patient,

the physician will continue to happen every six or eight weeks. But now the adjustment of therapy will be the doctor, the physician, or the practitioner typing into a tablet, which is communicating with the device. The clinical trial, most recently, the one I referred to that reported out last November in the 242 patients, used a therapy of about one minute a day, usually around 4.30 in the morning, many of the patients slept through the therapy. They didn't even wake up when it was going on because it's a very low amount of current. But it's possible someday with additional work, we may learn. Clinical trials may show that some patients would benefit from two minutes a day, once in the morning and once at night, or three minutes a day at different times of the day,

or a little more current, or a little less current. And those adjustments will all be made by the physician communicating with the device through a tablet. So you also talk about something really fascinating that you call the ear brain body connection. So that's an entirely new one on me. So can probably as to most other people as well, can you explain what that means? The ear Vegas access has gained tremendous attention on social media, actually in the peer-reviewed medical literature and in the press, the classic media. And the reason is that there's a branch of the vagus nerve that travels to the cartilage of the external ear.

So if you put your finger in your ear and you feel the flat space adjacent to that, that is cartilage, that's called the simba concha. It is innervated by a branch of the vagus nerve. Why? Well, because in evolutionary time scales, fish have gills, of cartilage, and that cartilage is innervated by the branch of a vagus nerve in fish. That cartilage, over hundreds of millions of years of evolutionary time, that cartilage

moved laterally in developing embryos as they evolved and ended up as the cartilage of your ear and it dragged a branch of the vagus nerve with it. Now, it's a sensory branch. What does that mean? That means if you

put a tens unit or a cue tip onto your Simba Concha and stimulate those sensory fibers, you are technically stimulating the vagus nerve. It's the reason why if you clean your child's ear at bath time and they start coughing, that's why. It's because you've stimulated the vagus nerve branch in the ear and activated a coughing reflex because of that incoming signals in the vagus nerve branch. Now, something happens after that, which is fascinating, and we don't completely understand. My colleagues and I have done clinical trials at the Feinstein Institute and collaborated with clinical trials elsewhere in the world. Many, many other centers have published clinical trials of placing a tens unit device in the ear and gently stimulating the simba concha to activate, quote-unquote, the vagus nerve.

and they call that vagus nerve stimulation. Now, I back up from that a bit because perhaps you are stimulating that branch of the vagus nerve depending on where the device is placed in the ear, depending on the anatomy of the specific patient, and depending upon the settings on the DENs unit. However, it's not the only nerve to your ear. There are many other nerves to your ear that can take separate roots of carrying information or sensory signals into the brain. And once these signals arrive in the brain,

now they're connected to 100 billion neurons in the brain that are all ultimately connected in one way or another. And so what we've seen clinically is that some of these interventions do decrease inflammation in some patients. And that's fascinating. It is possible some of these interventions are activating what we call the inflammatory reflex, which is the vagus nerve signals that turn off inflammation like the brakes on your car. But we also know for certain that it's not the same as putting a device on the vagus nerve in your neck

when we know exactly what we're doing to activate that inflammatory reflex. So I think what you're seeing is a lot of interest in this because people can try these things at home and there are over-the-counter products from dozens of companies now worldwide that are pushing this. And I understand the interest and I understand the need for additional study of this. I wish some companies particularly would exert more restraint in their promise, in their marketing of outcomes, when in fact we truly don't understand the underlying neuroscience or physiology. And we do know it's not the same thing as stimulating the vagus nerve with a device implanted in the neck. So we've covered an awful lot there, really fascinating conversation, lots to think about.

What do you think the future of this research looks like in the next, let's say, five, ten years? You know, where do you hope it would go? I think the first thing you're going to see is a major change in how patients and physicians approach the treatment of serious, chronic, acute and chronic inflammatory conditions, ranging from rheumatoid arthritis to inflammatory bowel disease, I think you're going to see clinical trials in multiple sclerosis, you're going to see clinical trials in diabetes, you're going to see clinical trials in Alzheimer's and in other Parkinson's

and in other inflammatory and neurodegenerative conditions. Because we already have laboratory-based evidence and early clinical suggestion that it may be. be possible to target the nervous system and the vagus nerve with devices to ameliorate, if not benefit some of these conditions significantly. There's a lot of work to do, so I guarantee you're going to see a lot more clinical trials. In the meantime, my hope is that the FDA will, in fact, approve the use of vagus nerve stimulation to treat rheumatoid arthritis in patients who are out of other therapeutic options from some of the most powerful

immunosuppressing drugs in the world. And I think that will push a sea change because patients in a focus groups would prefer to have a device implanted than to keep injecting themselves with drugs with black box warnings, which in the U.S. can also bankrupt you. So on the clinical side, I think you're going to see that we're at a tipping point and that this will be an amazing thing to watch as it's adopted into medical practice. And the reason I'm so confident is that we already have a three or four decades experience using vagus nerve stimulation to treat epilepsy and depression, and we know it can be very safely done, especially when you put those risks of a minor surgical procedure, which are less than 1% risks in the majority of large studies, up against the risks

of the available injectable drugs people are using already, which have much higher risks than 1%. So I think you're going to see a sea change on the clinical side. You asked specifically about the research side, and I think that there's an enormous opportunity in the field that we call neuroimmunology. Neuroimmunology, I think, is the fastest growing and most interesting field in all of the sciences, because it treats the immune system, which is capable of responding to foreign invaders like viruses and bacteria, and forming a memory of those events, like the nervous system responds to the appearance of a strange tiger in your backyard or other novel feature and creates a memory of that event. And so you have these two memory-producing systems

that are intimately involved in acute responses in order to increase the chances of survival and of having health, and they intersect completely, around stories like the inflammatory reflex of the vagus nerve controlling inflammation minute to minute and hour to hour. So the amount of research that's possible to do knowing that we have 100 billion neurons in the brain and 200,000 fibers in the vagus nerve, what that represents in the neuroimmunology story is the tip of the iceberg. We are rapidly learning about individual fibers in the sympathetic nervous system, the fight or flight nervous system that enhance inflammation in some conditions and inhibit it in others. There is a tremendous interest in what we

call cancer neuroscience, where we're looking at how signals from the nervous system to the tumor or to the immune system in the tumor or to the immune system generally, how these neural signals can influence the growth of the tumor, the spread, the metastasis of the tumor, and even the the lethality of the tumor. That's a rapidly growing field as well. So on the research side, I see growth and excitement, and I see that the basic research discoveries that will come will lay the groundwork for new therapies in the next 10 and 20 years. But in the next year or two, I fully expect vagus nerve stimulation will make its way into therapeutic armamentarium for acute and chronic inflammatory conditions. Thank you for listening to this episode of Instant Genius.

brought you from the team behind BBC Science Focus. That was Dr Kevin J. Tracy. To discover more about the topics we've just discussed, check out his book, The Greats Nerve, the new science of the Vegas nerve, and how to harness its healing reflexes. If you liked what you just heard, then please do consider subscribing to Instant Genius

on your preferred podcast platform. If you'd like to see our guests and hosts in person, then please also check out our YouTube channel, at Science Focus. The current issue of BBC Science Focus magazine is out now. Pick up a copy wherever you buy your favourite magazines or download us on your app store of choice. You can also find us on Apple News or online at sciencefocus.com.

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