Signs of Life on Mars? NASA's Discovery, Explained

NASA’s Perseverance rover may have found the clearest signs of ancient life on Mars yet.
Billions of years ago, Mars’ Jezero Crater held a lake fed by rivers that could have carried minerals and maybe even organic matter. On Earth, places like that are teeming with microbial life.
Signs of Life on Mars? NASA&#x27;s Discovery, ExplainedPublished: September 23, 2025NARRATOR: This speckled rock could be evidence of ancient life on Mars. NASA called it,SEAN DUFFY: The clearest sign of life that we have ever found.NARRATOR: Scientists say that traces of minerals here could have been left behind by ancient microbial life, maybe after a meal, about three and a half billion years ago, a time when primitive life was thriving on Earth.Using tools on the Perseverance Mars Rover, scientists were able to analyze the chemical makeup of the rock. These teeny tiny dark specks, NASA are calling them poppy seeds, contain vivianite, an iron phosphate mineral. And these areas, nicknamed leopard spots, have vivianite in the dark ring, but in the center contain greigite, an iron sulfide mineral.The rock itself is also rich in organic carbon, sulfur, oxidized iron, which is rust, and phosphorus. And the combination of these could have been a rich energy source for microbes. But there is a possibility the minerals in this martian rock were created by non-living sources.To know for sure, NASA will have to rule out all other geological and chemical processes. And to do that, researchers hope to one day bring the samples from Mars to Earth to study them more closely.So far, the Perseverance Rover has collected more than 20 rock samples from the red planet. Further analysis here on Earth could bring us closer to answering one of the most fundamental questions for humanity: are we alone?Believe it or not, Mars was not always the cold inhospitable desert it is today. Several billion years ago, there were flowing rivers and lakes, and even an atmosphere, but over time, that atmosphere was lost, transforming the climate and the red planet&#x27;s ability to sustain life on its surface.But this area in the northern hemisphere of Mars, called Jezero Crater, has the tell-tale geographic signs of water, fan-shaped deltas. Scientists think rivers once spilled over the crater wall and created a lake. Billions of years ago, active rivers could have deposited minerals and organic molecules here. If Mars ever hosted microbial life, this was the place to look.In 2021, the Perseverance Mars Rover landed in Jezero crater. This crater has some of the oldest rocks in the solar system. And in 2024, the rover found this speckled rock in an ancient river valley called Neretva Vallis in an area known as the Bright Angel Rock formation. But notably, this rock outcrop is younger than most of the other samples the rover has taken, possibly suggesting that the conditions for life could have lasted longer than we thought.Since then, scientists have been trying to understand more about this area of Jezero Crater, and rule out all the possible origins of these minerals. It&#x27;s possible these minerals did not come from microbes, but researchers haven&#x27;t been able to find any evidence of that yet. The rock doesn&#x27;t show signs of extreme heat or acidity that could have been responsible for the compounds.Past missions have found hints of life before, like methane spikes or hints of organic molecules. But the standard of proof for a major discovery like this, life on another planet, is high. NASA actually has a scale to assess confidence. The CoLD scale, which stands for &quot;Confidence of Life Detection,&quot; and this discovery sits at about a two out of seven.So has Perseverance definitely found life on Mars? No, not yet. But this discovery is one of the strongest clues so far. Bits of chemistry and context that supports habitability. It doesn&#x27;t settle the question, but it pushes us one step closer, reminding us that the story of life on Mars isn&#x27;t totally fictional. It may be written in stone.

NASA’s Perseverance rover may have found the clearest signs of ancient life on Mars yet.

How Algorithms Decide Who Gets a Kidney

Clinical algorithms are meant to guide doctors toward better care – but do they?
Algorithms are designed to make medicine more accurate. But when race is factored in, they can worsen inequality.
How Algorithms Decide Who Gets a KidneyPublished: September 9, 2025NARRATOR: For decisions like who should get a kidney transplant, doctors across many medical fields routinely use calculations that combine a patient’s medical history with additional data. These calculations are called “clinical algorithms.”MICHELLE MORSE, M.D. (Acting Commissioner, New York City Health Department): A clinical algorithm is a tool that clinicians would use to really best understand their patient’s specific diagnosis or treatment.NARRATOR: According to the clinical algorithm that Gregory’s doctors used, if Gregory had the same test results but was white, he would’ve immediately qualified for a kidney transplant evaluation. But why would race be a variable in determining kidney function?MICHELLE MORSE: There should be no reason why the physiological function of someone who’s Black would look different than the physiological function of someone who’s white.

Clinical algorithms are meant to guide doctors toward better care – but do they?

The Surprising Power of a Bird Brain

Bird brains may be tiny, but they pack in as many—or more—neurons as much larger animals.
Similar to humans and other animals with higher intelligence, the executive center of a bird&#x27;s brain allows them to strategize and organize ideas.
The Surprising Power of a Bird BrainPublished: August 28, 2025NARRATOR: Compared to other birds, parrots and crows have large brains in relation to their body size. And scientists believe that may be one reason why they can work out solutions to problems they don&#x27;t encounter in the wild. Most bird brains are small, but they have one critical area in common with humans and other animals with higher intelligence.JOHN MARZLUFF: The executive center of the bird&#x27;s brain really allows them to make plans and strategies and organize ideas.NARRATOR: Bird brains may be tiny, but for their size they seem to contain more brain cells or neurons than many other animals.JOHN MARZLUFF: The number of neurons is a better indication of brain power than the physical size of the brain. And this is an interesting thing we&#x27;ve learned recently that bird brains actually pack a lot more neurons into a particular area than do mammal brains. So even though they&#x27;re physically very small in size, they have a lot of punch in that size.

Bird brains may be tiny, but they pack in as many—or more—neurons as much larger animals.

These Birds Are Smarter Than You Think

Can these birds solve the puzzle and claim their prize?
When birds crack a puzzle in more than one way, they’re showing the kind of flexible problem-solving once thought uniquely human. Could intelligence be more widespread in nature than we realized?
These Birds Are Smarter Than You ThinkPublished: August 19, 2025NARRATOR: This experiment is designed to compare how New Caledonian crows and kea solve problems. Wek represents the crows, and for the kea parrots, this is Kermit. Their reward: a peanut. Their challenge is called a multi-access box. The first time both birds see the puzzle, they make the same choice. They just pull the string. Then the researchers take that solution away to see what they&#x27;ll do next. Wek uses the stick to poke the nut free, but this isn&#x27;t a surprise.AUGUSTE VON BAYERN: New Caledonian crows are very special because they&#x27;re the only crow species that use tools in the wild. They obtain a lot of their diet by using tools.NARRATOR: Kea parrots don&#x27;t use tools in the wild, but Kermit figures out a solution with the ball and chute. Again, the researchers remove the option that&#x27;s been used. For Wek, the hole for the stick is taped over. Wek has to try something else, so she tries the ball and chute. With two choices left, Kermit just opens the door, reaches inside, and takes the peanut. But Wek won&#x27;t take this approach.JOHN MARZLUFF: The last thing a crow wants to ever do is stick its head in something. They&#x27;re extremely vulnerable if they do that and to stick their head inside that box, it could trap them in it.NARRATOR: Wek still opens the door, but rather than put her head inside, she pokes the nut free with a stick. Kermit&#x27;s last option is the stick. His curved beak makes it very hard to hold, but he still sees this as a potential solution, even though it&#x27;s not easy. Both birds found four different solutions to the puzzle, showing they&#x27;re able to think flexibly.

Can these birds solve the puzzle and claim their prize?

The Next Big Earthquake Could Sink Parts of the Pacific Northwest

A massive earthquake along the Cascadia Subduction Zone could unleash a tsunami and sink parts of the Pacific Northwest by several feet.
A 2025 study suggests that when the next &quot;Big One&quot; hits, coastal land could sink by up to 6 feet. That sudden drop could instantly double the number of people, homes, and roads exposed to flooding.
The Next Big Earthquake Could Sink Parts of the Pacific NorthwestPublished: August 4, 2025NARRATOR: In this region, a massive earthquake is pretty much inevitable. This is the Cascadia Subduction Zone. It&#x27;s one of the top hazards on the planet. Here, the ocean floor is slowly diving under North America. Massive earthquakes are expected here every 500 years or so, and the last one was in 1700.WENDY BOHON: So it&#x27;s not a matter of if, it&#x27;s just a matter of when.NARRATOR: A 2025 study suggests that the quake could suddenly sink part of the Pacific Northwest and climate driven sea level rise would only make it worse. So why is the Cascadia Subduction Zone so dangerous and when will the next big one happen? The Cascadia Subduction Zone is a major fault line that spans Vancouver Island in Canada to Northern California, but it&#x27;s not really a line at all. It&#x27;s a crack where two massive tectonic plates meet. It&#x27;s where one of the largest earthquakes in the history of North America happened more than 325 years ago. in January of 1700. The earthquake had an estimated magnitude of nine, and it caused a tsunami. A graveyard of trees that fell victim to flooding are still in the area. The subduction zone has been pretty quiet ever since. The last magnitude nine earthquake on Earth was caused by a subduction zone known as the Japan Trench in 2011. It spurred a tsunami and caused widespread devastation, including a nuclear disaster at the Fukushima Daiichi power plant. Subduction zones produce the biggest earthquakes in the world. They happen where one tectonic plate is sliding down another plate.WENDY BOHON: In Cascadia, you have one plate diving down beneath another. This section gets locked and it pushes this part up. When the fault ruptures, when the amount of stress overcomes the friction, it bounces back, which lifts up the water above it and causes that water to flow out in all directions. And that water flowing out in all directions is the tsunami.NARRATOR: The inevitable earthquake in the Pacific Northwest is what&#x27;s called &quot;the big one,&quot; and it would absolutely be devastating to a number of coastal communities. But the Cascadia Subduction Zone is not actually one continuous fault line. It has ruptures in it that form at least four major segments. It&#x27;s possible that an earthquake in one zone might not trigger an earthquake in the others, but the longer the segment, the bigger the quake. One segment runs from Vancouver Island to the Oregon border. Some scientists think that this is the most dangerous section and could spark the biggest earthquakes. So when will this happen? Unfortunately, earthquakes often happen without any clear warning signs, and scientists haven&#x27;t yet identified reliable predictors. The United States Geological Survey even says that, &quot;Neither the USGS nor any other scientists have ever predicted a major earthquake,&quot; and that they do not expect to know how to predict earthquakes in the foreseeable future. Whoa. Even if scientists can&#x27;t predict when an earthquake will strike, they can use analytical models to study the potential effects. Some researchers found that if the Cascadia earthquake were to strike today, the coastline could suddenly sink by up to six feet raising the sea level. And more than doubling the number of people, buildings, and roads currently exposed to coastal flooding risks. Sea levels are already rising across the globe. But the Pacific Northwest coast has seen much slower rise than other parts of the US coastline because of the subduction zone. It&#x27;s slowly pushing the coastline up almost as fast as the sea level is rising in some areas. But a massive earthquake could quickly reverse that. According to one projection, by the year 2100 sea levels along the Pacific Northwest could rise by almost three feet. Combined with a Cascadia quake, that&#x27;s a sea level difference of nearly nine feet compared to today. And don&#x27;t forget that when the earthquake strikes, it will trigger a tsunami, which could bring waves over 50 feet high in some locations. For now, some communities are taking action against these deadly threats by creating high ground. A tsunami could come only 15 minutes after an earthquake, and experts say it&#x27;s imperative to get to high ground ASAP. The thing is that in many low lying coastal communities, that isn&#x27;t an option. So vertical evacuation structures like towers and platforms where people can get to high ground without traveling, great distances are essential. Right now, there are three vertical evacuation towers in the Pacific Northwest, a tsunami evacuation tower built by the Shoalwater Bay Indian Tribe, an elementary school gym that was rebuilt with a fortified foundation to withstand massive earthquakes and a new roof built to hold more than a thousand people, and an Oregon State University marine sciences building. There are more vertical evacuation structures planned for the Pacific Northwest, but one study found that many more are needed. The trouble is we don&#x27;t know how much time we have until the next big one.

A massive earthquake along the Cascadia Subduction Zone could unleash a tsunami and sink parts of the Pacific Northwest by several feet.

Can Birds Recognize Faces?

Crows remembered the face of a person they considered a threat—even across generations.
Researchers caught, tagged, and released crows to see if they can recognize the face of a person who’s a threat. They discovered the crows were warning each other that the person in the mask was dangerous — even generations after it the initial capture.
Can Birds Recognize Faces?Published: July 30, 2025NARRATOR: John Marzluff went undercover to test the birds&#x27; reactions to being caught and tagged.JOHN MARZLUFF: When we first captured birds, we were wearing this mask, so the birds that were immobile under a net saw this person coming to them, grabbing them, stretching their wings out to measure them, applying rings to their legs to identify them, and then letting them go.NARRATOR: Crows don&#x27;t like being caught, even when they&#x27;re unharmed, so the question was: would they remember that the masked man was a threat? A few days after the initial tagging, Marzluff walked across the campus again. He kept the mask on, but he left the crows alone to see if he&#x27;d get any response.JOHN MARZLUFF: It was very striking. The first time after we did this experiment and we walked with the caveman mask, birds immediately responded to that. They scolded with harsh calls that are indicative of a predator, and they gathered around us. They attracted others in and they would even dive down at us.NARRATOR: Marzluff discovered that the crows were somehow telling each other that the person in the caveman mask was dangerous. And what&#x27;s more amazing, even though the team never again caught crows with the mask on, that reaction has been passed down through several generations.JOHN MARZLUFF: It&#x27;s been 11 years since we caught seven birds on our campus with this mask, and nearly half of all the birds we encounter on a given day respond strongly to that face, even though they weren&#x27;t even born at the time we first did our capture, the only experience they have with that caveman is hearsay.

Crows remembered the face of a person they considered a threat—even across generations.

Why Does This Mummy Have So Many Tattoos?

Otzi, a 5,000-year-old mummy, has 61 tattoos arranged in 19 groups across his body.
Researchers used a unique camera sensitive to invisible light to discover the exact number and location of all of Otzi’s tattoos — including a never before seen tattoo on the right side of his chest.
Why Does This Mummy Have So Many Tattoos?Published: July 28, 2025NARRATOR: These are Otzi&#x27;s tattoos. The iceman is the oldest tattooed mummy ever discovered. Researcher Marco Samadelli has been one of Otzi&#x27;s caretakers for nearly 20 years. Recently, Marco set out to inventory every tattoo on Otzi&#x27;s skin.MARCO SAMADELLI: We discovered exactly 61 tattoos.GARY STAAB: That&#x27;s a lot of ink.NARRATOR: Marco&#x27;s research revealed something no one had ever seen before, thanks to a unique camera, sensitive to invisible light.MARCO SAMADLLI: Multispectral imaging is a technique used to see what the eye can&#x27;t see. It&#x27;s with this technique we discovered every single detail, even under the surface of the mummy&#x27;s skin.NARRATOR: The exact number and location of all the tattoos was a mystery until now.MARCO SAMADLLI: We discovered a tattoo that had never been seen before, four parallel lines on the right side of his chest. We were able to see all his tattoos and obtain a complete mapping.AARON DETER-WOLF: 61 tattoos arranged in 19 groups across his body.NARRATOR: Archeologist Aaron Deter-Wolf studies the use of tattoos in ancient cultures.AARON DETER-WOLF: Tattooing has been practiced throughout a huge portion of human history going back at least 16 or 18,000 years before present. During that time period, people have been tattooed for all sorts of different reasons depending on their culture and the region in which they lived. We generally agree that Otzi&#x27;s tattoos don&#x27;t seem on the whole to be decorative or symbolic.NARRATOR: For Aaron and other experts, a key clue to understanding the purpose of the tattoos could be where they&#x27;ve been placed.AARON DETER-WOLF: A number of Otzi&#x27;s tattoos seem to correspond to areas where he suffered from ailments or injuries. He had arthritis in his lower back, and there are tattoos on his lower lumbar area. He had arthritis in his right knee, there are tattoos on the back of his right knee. He had arthritis in his ankles, there are a number of tattoos around both his right and left ankles. Most recently, this new set of tattoos is located on his lower right abdomen. Among the many ailments that he suffered from was gallstones and whipworms in his colon, and this is a place that is very close to those areas and could potentially have been used to treat the pains he was experiencing.NARRATOR: Tattooing the skin to alleviate pain has been the practice of many cultures.AARON DETER-WOLF: And there are therapeutic tattoo traditions that have been documented all across the world, and in India, in Southeast Asia, North America, in the American Arctic.NARRATOR: Otzi&#x27;s tattoos are the earliest direct evidence of this ancient tradition.

Otzi, a 5,000-year-old mummy, has 61 tattoos arranged in 19 groups across his body.