When Earth Was Bombarded by Asteroids

What studying the surface of the Moon revealed about Earth’s apocalyptic youth.
Four and a half billion years ago, Earth was battered by relentless asteroid impacts powerful enough to vaporize oceans and melt its crust. Despite the chaos, life emerged anyway.
When Earth Was Bombarded by AsteroidsPublished: January 30, 2025NARRATOR: Craters are a reminder of our solar system&#x27;s formation around 4.56 billion years ago. It began as a disc of dust and gas in orbit around the young sun. The solid materials collided and clumped together to gradually form the rocky planets.SIMONE MARCHI: As a result of the formation of the earth, there were still lots of debris and asteroids and other smaller objects flying around the sun. Those objects kept colliding with the surface of the earth.NARRATOR: About four and a half billion years ago, a single object the size of Mars or even bigger may have crashed into the young earth. This high resolution simulation reveals how the collision flung enough molten and vaporized debris into space to create the moon.SIMONE MARCHI: I&#x27;m trying to understand the early evolution of the earth and the effects of all those impacts that were taking place during the idea on the earth. So we do this by building models.NARRATOR: One of the most important sources of data comes from NASA&#x27;s lunar reconnaissance mission. This robotic spacecraft has made a 3D map of the moon&#x27;s surface at extremely high resolution.SIMONE MARCHI: The first thing that we do is to look at the surface of the moon. It is much older than the surface of the earth. The surface of the moon is full of impact graters, all the impact graters, and so we can use that information by mapping how many there are and their sizes and their ages, and that will provide us the primary information that we need to build our models.NARRATOR: It took an international team decades to collect the data. But they finally created a computer model that took what happened on the moon during the Hadean and simulated the asteroids that would&#x27;ve hit the earth during the same stretch of time.SIMONE MARCHI: And the outcome of that, our first modeling was staggering. We are seeing the entire surface of the earth that is strongly affected by impact. Every single circle that you see here is an impact, is a collision.The prediction was that there were a tremendous number of impacts, even large one. Imagine an object the size of the moon that could have collided with the earth. That would have basically wiped out almost entirely perhaps the oceans, vaporized the oceans and melted a large portion of the crust of the earth.NARRATOR: This series of apocalyptic bombardments might look like it created a chaotic hellscape on earth. Even during asteroid impacts, there must have been enough habitable conditions somewhere on the planet for life to get a foothold.

What studying the surface of the Moon revealed about Earth’s apocalyptic youth.

This Discovery Rewrote Human History

In a remote cave, in North West Africa, a chance discovery uncovered some mysterious human remains.
For the longest time, we thought we knew the origins of our species. We thought we began 200,000 years ago in East Africa. But new revelations from out here in Morocco, from a part of Africa that people weren’t really considering, are forcing us to rethink our very first steps on this planet.
This Discovery Rewrote Human HistoryPublished: December 11, 2025ELLA AL-SHAMAHI: Several decades after the initial discoveries came a breakthrough. Archaeologists uncovered another 16 fossils, all with the same blend of features. And taken together with the old finds, a fuller picture started to emerge.ABDELOUAHED BEN-NCER: (Translated from Arabic) This is another fossil we excavated. It’s part of the lower jaw.ELLA AL-SHAMAHI: (Translated from Arabic) From this skull?ABDELOUAHED BEN-NCER: (Translated from Arabic) No, no, from a child.And this one from another adult.ELLA AL-SHAMAHI: (Translated from Arabic) And how old?ABDELOUAHED BEN-NCER: (Translated from Arabic) Around eight years old.ELLA AL-SHAMAHI: (Translated from Arabic) So, between the old and new discoveries?ABDELOUAHED BEN-NCER: (Translated from Arabic) Yes, collectively a group of young and old were found at the site.ELLA AL-SHAMAHI: With each new find the evidence grew. These were not some other species, but Homo sapiens, with hints of an earlier ancestor. But it wasn’t until archaeologists were able to more accurately date the remains that the final piece of the puzzle fell into place.The archaeologists, using new and improved dating techniques, were able to give us dates for these fossils. And they tell us that these individuals lived about 300,000 years ago. And that is mind-boggling, because we thought our species was only about 200,000 years old. What these fossils tells us is that our species, Homo sapiens, is 100,000 years older than we thought.We are much older than we realized. This fossil went from being enigmatic and a, basically a mystery, to being one of the most important fossils in our whole field.Thousands of miles from East Africa, where many anthropologists thought we began, and far older than expected, these are the earliest Homo sapiens ever found. And they have forced us to re-think other finds across Africa, which are painting an entirely new picture of our origins, suggesting Jebel Irhoud was just one of many emerging Homo sapiens populations.

In a remote cave, in North West Africa, a chance discovery uncovered some mysterious human remains.

This Was One of the First Known Human Ritual Sites

Early humans may have brought offerings to this enormous stone snake.
In a secluded Botswana cave, a natural stone outcropping was carved to resemble a python. Archaeologists think this could be one of the world’s earliest ritual sites.
This Was One of the First Known Human Ritual SitesPublished: December 11, 2025SHEILA COULSON: The front has a natural slit for a mouth and a natural depression for an eye. And even if you want to go that far, a nostril up at the front. With the head rearing up, it does in modern eyes look like a snake.The overall form has been altered to make it look even more snake-like. There are over 300 indentations that have been ground into the surface over what is obviously an extended period of time. When the initial excavations were conducted, they absolutely revealed a number of questions. One of the things found was an extremely large number of tools that appeared to be manufactured and then just left there in pristine condition.ELLA AL-SHAMAHI: These look gorgeous. I mean, they&#x27;re absolutely stunning.SHEILA COULSON: Once they were manufactured, then you did one of three things with it. You either manufactured it perfectly and just left it. Or more interestingly, you burnt it. But not burnt to just like throwing it in a bonfire. It&#x27;s controlled burning. And the third and most bizarre thing that they did with them is they made it, manufactured it perfectly, and when they were finished, turned it over, smashed it in the middle.ELLA AL-SHAMAHI: This behavior suggests that people were likely coming here to make offerings, which tells us something about how their minds worked.SHEILA COULSON: Although it&#x27;s absolutely magnificent during the daytime, it comes to life at night. You make an offering and hope for something back.ELLA AL-SHAMAHI: Asking for probably some of the things that we would ask for, food, health, children, et cetera, et cetera. And you just think, &quot;Oh my gosh, that&#x27;s some of the earliest behavior that we know so well.&quot;

Early humans may have brought offerings to this enormous stone snake.

How Did Early Humans Hunt Monkeys?

These monkey bones showed that early humans could thrive in the rainforest.
Bones and tools found in a Sri Lankan cave show how Homo sapiens adapted to dense rainforest environments as early as 45,000 years ago.
How Did Early Humans Hunt Monkeys?Published: December 11, 2025OSHAN WEDAGE: So here you can see a monkey bone. We can clearly see that the V-shape. This V-shaped cut marks only can produced by the stone tools.ELLA AL-SHAMAHI: Yeah. So this here, that&#x27;s where somebody is cutting?OSHAN WEDAGE: Because yeah, they are cutting or the skinning also can be possible. Whatever is stuck with the bones, they tried to remove.ELLA AL-SHAMAHI: It&#x27;s funny because I think buttery marks often need to look at it through a magnifying glass, but not always. And actually, this one is quite clear. And this is not the kind of thing that you would see if an animal killed it. This is an indication that this was killed by a human.OSHAN WEDAGE: This is definitely Homo Sapiens.ELLA AL-SHAMAHI: And so the question is how they killed them.OSHAN WEDAGE: It is remarkable, Ella, because there are lots of trees very tall. In second, they can climb them up to the top. So therefore, it is very difficult to catch them. The prehistoric people or our ancestors should need to develop their own technology to get them down.So I would like to show you some earliest, which goes back to 48,000 years old. They developed this bone point technology and they made bone-tipped arrows. They identified the monkey bones are really special to make arrowheads because those are light in weight to hunt these fast-moving animal. So here you can see it is a little bit chipped because it&#x27;s hit, it contact with something.ELLA AL-SHAMAHI: Right.OSHAN WEDAGE: So that is why at the end it&#x27;s very small.ELLA AL-SHAMAHI: So that chip mark there-OSHAN WEDAGE: Yeah.ELLA AL-SHAMAHI: ... shows us that it was actually used.OSHAN WEDAGE: Yes.ELLA AL-SHAMAHI: I mean, it&#x27;s amazing because this is obviously, I&#x27;ve got in my hands right now, something that was used 48,000 years ago.OSHAN WEDAGE: Of course, of course.ELLA AL-SHAMAHI: And it was absolutely revolutionary.These bone points are only the tips of the full arrowheads. Many are chipped from actually hitting prey. And each one would have been attached to the end of a long wooden arrow. These hunters didn&#x27;t invent a brand new technology. They adapted an old one. These are some of the earliest examples of bow and arrows found outside of Africa, enabling Homo sapiens to hunt with exceptional skill and efficiency within the forest.

These monkey bones showed that early humans could thrive in the rainforest.

Did Homo sapiens and Neanderthals Interbreed?

Ancient bones reveal that early Homo sapiens and Neanderthals didn’t just coexist.
For years, scientists argued about whether Homo sapiens interbred with Neanderthal groups in Europe. The Oase fossils show that the two species did mix.
Did Homo sapiens and Neanderthals Interbreed?Published: December 10, 2025ELLA AL-SHAMAHI: For thousands of years, Homo sapiens and Neanderthals lived in close proximity. But how close were we? For decades, most assumed interbreeding between our two species didn&#x27;t happen. But in the early 2000s, this was called into question by new finds in Romania, bone fragments dating back to around 40,000 years ago, which were painstakingly reassembled to reveal humans with a mysterious mix of features.It even smells like a fossil. This, I assume, is Oase 1?SILVIU CONSTANTIN: This one is Oase 1.ELLA AL-SHAMAHI: And that&#x27;s Oase 2?SILVIU CONSTANTIN: So that&#x27;s Oase 2.ELLA AL-SHAMAHI: This is quite special because I&#x27;ve read about them. I&#x27;ve studied them. They&#x27;re hugely significant fossils, but I&#x27;ve never seen the originals. I&#x27;ve never been this close to them.SILVIU CONSTANTIN: It looks and it is modern homo sapiens, but it has some features which are more like Neanderthal, like this one. It&#x27;s quite clear it&#x27;s a mandible of a modern human with this chin.ELLA AL-SHAMAHI: There&#x27;s a chin.SILVIU CONSTANTIN: There&#x27;s a chin, yeah.ELLA AL-SHAMAHI: And Neanderthals don&#x27;t have a chin. Neanderthal&#x27;s chin kind of recedes.SILVIU CONSTANTIN: But then you see the size of the molars, which are really huge.ELLA AL-SHAMAHI: More a Neanderthal feature.SILVIU CONSTANTIN: Modern sapiens, but with Neanderthal teeth. Yeah, Oase 2 has the same hybrid features, like if you look at the face.ELLA AL-SHAMAHI: You look at that and you do think that&#x27;s Homo sapiens. And then it has these features on it which are more Neanderthal, like this occipital bun here at the back, that bulge at the back of the skull here.SILVIU CONSTANTIN: Yeah. That&#x27;s kind of strange. It&#x27;s not a Neanderthal, but it has Neanderthal features which prompt us to think about some sort of interbreeding, Neanderthal, Homo sapiens interbreeding. It was pretty controversial. People were just not ready to accept that.ELLA AL-SHAMAHI: Around a decade after the bones were discovered came a revolutionary breakthrough. Advances in genetic analysis allowed scientists to extract DNA from ancient fossils, proving these two species could and did produce offspring.

Ancient bones reveal that early Homo sapiens and Neanderthals didn’t just coexist.

At the Edge of Extinction, These Neanderthals Were Cannibalized

Inside the Tunnel of Bones, a macabre Neanderthal mystery unfolds.
In life, this Neanderthal family from Northern Spain struggled as their species declined. In death, bone evidence shows they became food for another Neanderthal group.
At the Edge of Extinction, These Neanderthals Were CannibalizedPublished: December 10, 2025ELLA AL-SHAMAHI: The Neanderthals were failing to cope with the changing conditions. A struggle uncovered in a cave known as the Tunnel of Bones.Oh, wow. This is the famous El Sidron Cave?MARCO DE LA RASILLA VIVES: Yes.ELLA AL-SHAMAHI: It&#x27;s got more character than I was expecting actually.MARCO DE LA RASILLA VIVES: Yeah. Here is where we found 2,500 neanderthal bones. We found 13 neanderthal individuals of different ages and sexes.ELLA AL-SHAMAHI: Such a diverse group in terms of individuals all found in one spot.MARCO DE LA RASILLA VIVES: Genetic studies told us that they are related, so it&#x27;s a family group. We know, for example, that one female, we are not completely sure, genetic information said was red hair.ELLA AL-SHAMAHI: And you know when you say that one of those people had red hair, it suddenly brings just fossils really, to life. It&#x27;s a cave that&#x27;s filled with ghosts.MARCO DE LA RASILLA VIVES: We think these people were killed by other group.ELLA AL-SHAMAHI: This was not a natural death. Cracked skulls and precise cuts on the bones suggest that this was a brutal massacre. 13 people killed by another Neanderthal group. But closer analysis of their remains revealed an even darker truth.What do the bones actually tell us?MARCO DE LA RASILLA VIVES: The first thing the bones tell us is that a neanderthal group cannibalized another group.ELLA AL-SHAMAHI: They were really eating these 13 individuals?MARCO DE LA RASILLA VIVES: Yeah. Yeah.ELLA AL-SHAMAHI: How do we know that this was cannibalism as opposed to just straight-up murder, or for that matter, an animal coming?MARCO DE LA RASILLA VIVES: Well, because we have seen in the bones what we call cut marks. And also we have found a lot of bones broken just to get the marrow.ELLA AL-SHAMAHI: Yeah. Oh.MARCO DE LA RASILLA VIVES: There are both things. We have cut marks and then they broke the bones to get the marrow.ELLA AL-SHAMAHI: Yeah. If you&#x27;re getting bone marrow, that is an indication of cannibalism, sure.MARCO DE LA RASILLA VIVES: Yes it is.

Inside the Tunnel of Bones, a macabre Neanderthal mystery unfolds.

Would You Face a Bear With a Spear? Ancient Humans Might Have

This form of bear hunting took nerves of steel.
Archaeologists unearth traces of a 14,000-year-old struggle for survival — when early humans risked everything to hunt bears.
Would You Face a Bear With a Spear? Ancient Humans Might HavePublished: December 10, 2025ELLA AL-SHAMAHI: Here, archeologists sift through the muddy layers of time to find out more about the risks these early people took to survive.You know when people talk about archeology?DUNCAN MCLAREN: Yes.ELLA AL-SHAMAHI: The back of a cave digging mud, this is the hard stuff.DUNCAN MCLAREN: One thing that has been found in a number of caves on the northwest coast is spear points in association with bare bones. And these date as far back as 13,000 years.ELLA AL-SHAMAHI: So is this one of these spear points?DUNCAN MCLAREN: This is a fragment of a spear point that was found in a cave not too far from here. We have uncovered a bone in the wall of this unit and it&#x27;s 20 centimeters below the surface. And so I&#x27;m going to pull it and we&#x27;ll see if it moves.ELLA AL-SHAMAHI: And we don&#x27;t know what species it is or what bit of bone it is.DUNCAN MCLAREN: There&#x27;s not enough here to know for sure, but it is a pretty big mammal.ELLA AL-SHAMAHI: It&#x27;s a rib, isn&#x27;t it?DUNCAN MCLAREN: So that could be a bear rib. It&#x27;s probably most likely what it is because it&#x27;s quite robust.ELLA AL-SHAMAHI: Oh, amazing. What age do you think it is?DUNCAN MCLAREN: Well, we have some other samples from above where this bone is, and they&#x27;re coming back around 14,000 years old.ELLA AL-SHAMAHI: Okay, so it&#x27;s old.DUNCAN MCLAREN: So it could be the same age or olderELLA AL-SHAMAHI: Yeah. One of the most wonderful things about archeology is that sometimes you uncover something that hasn&#x27;t seen the light of day in thousands of years, and in this case, well, maybe 14,000 years.DUNCAN MCLAREN: Well, we&#x27;re interested in where bears were hunted in the past. And in the winter when there&#x27;s not as many resources around and people are feeling a bit hungry, knowing where there is a bear den is quite a valuable thing because you can come up there and dispatch the bear, you&#x27;ll have a load of meat, fur, as well as bones.ELLA AL-SHAMAHI: One theory of how they hunted bears comes from studies of the native peoples of this region and North Asia in past centuries.DUNCAN MCLAREN: Essentially, a hunter would go with a party to a cave, smoke the bear out of the cave, and entice that bear to attack a single hunter. That hunter would be armed with a bracing spear. And a bear would come to take the hunter up in a bear hug, which is a common thing that they do. And the idea is a bear would take that hunter and essentially give them a good crushing. The hunter at the same time would brace the spear on the ground and aim it at the bear&#x27;s heart. And so essentially the bear would take the hunter and the spear into the bear hug, thereby spearing itself through the heart.

This form of bear hunting took nerves of steel.