Thanks to Linode Cloud Computing for supporting this episode of SciShow.

Head to linode.com/scishow to learn more and get a $100 60-day credit on a new Linode account. [ ♪ Intro] Science is at it’s best when it’s raising questions. I mean, yes, technically it’s a method of searching for answers.

But understanding one thing tends to lead to way more questions than it answers. Which is exciting! We are never going to reach a point where we know everything about the universe and just stop doing science.

And sometimes the questions science raises are especially tricky or fascinating, and it might take a long time to find some answers. So here are 5 mysteries that science started, and eventually managed to solve, in some fascinating ways. Evolution is generally a pretty gradual process where one life form adapts until it’s changed enough for us to consider it something different.

But the fossil record doesn’t preserve everything. Sometimes we have so little evidence documenting an evolutionary transition that it can be tricky to draw an unbroken line from ancient animals to those we see today. One of those mysteries is the European bison, which seems to have sprung out of nowhere around 12 thousand years ago.

And yes, they are still around in small numbers today. Prior to the European bison, there are two main bovine groups known in

Europe: ancestors of modern cattle, and ancestors of North American bison. But the closest relatives of the European bison remain elusive. So much so that this ancient creature has been dubbed the “Higgs Bison”, after the Higgs Boson that physicists spent years searching for. This mystery persisted until a 2016 study was able to find this ancient creature using a combination of DNA analysis and cave paintings.

Looking at cave paintings of bison, mostly from France, researchers noticed that many depictions from around 12 to 17 thousand years ago looked a little more like European bison than North American. They were drawn with thinner horns and a smaller hump on their back. So they hypothesized that these paintings could be depictions of the mysterious ancestors of European bison.

To figure this out, they sequenced DNA from 64 preserved bones and teeth from across Europe, dating from more than 50,000 to 14,000 years old. The goal was to figure out if the change in cave paintings correspond to a change in bison populations. And indeed, some of the samples from this period were from a previously unknown species.

Genetic analysis revealed this ancestor of European bison was a hybrid between steppe bison, ancestors of North American bison, and aurochs, ancestors of modern cattle. These hybrids were more abundant during large-scale climate change between glaciations, suggesting their population waxed and waned relative to other ancient species of bison. So even though we don’t have complete fossils of them, thanks to modern genetics, we can pinpoint the Higgs bison.

And thanks to ancient artists, we have a sense of what this creature looked like! Scientists are still figuring out the details of this mystery, and not everyone agrees with this interpretation of the genetic evidence. So as we gather more clues, we will get a clearer picture of where the European bison came from.

Klerksdorp spheres are bizarre-looking rocks found in South Africa, often nearly perfectly symmetrical with uniform grooves around them. They kind of look too perfect to be natural, which leads to the understandable conclusion that humans must have manufactured them. But the catch is the rock around them is more than 3 billion years old, long before people, or any animals for that matter, roamed the planet.

The more outlandish explanations have included previously unknown ancient civilizations or extraterrestrial visitors. Some have called them “cosmic cannonballs”. These ideas have come along with bizarre claims of them being able to spontaneously rotate on their own and being so perfectly balanced that they could only form in zero gravity.

But geologists have said not so fast. They are very sure there’s a natural, earth-based explanation. It just took a while to find that explanation, or at least rediscover it.

First of all, there is no evidence to the claims of spontaneous rotation. Seems pretty unlikely, turns out it is. And if you look at a bunch of them, you see that while some look like perfect spheres, they actually come in a wide range of shapes.

It’s just that the more round ones that get the most attention. See, these spheres are a beautiful example of what geologists call concretions, which slowly crystallize out of fluids flowing through the surrounding sediments. Crystals tend to grow from a starting point, called a point of nucleation.

This is commonly a little bit of something different than the surrounding sediment. So once this begins, the growth of the minerals happens evenly outwards, forming a sphere or something close to it. It’s the smooth exterior and bands around the Klerksdorp spheres make them particularly unnatural looking compared to many other concretions.

Originally the spheres were likely made of pyrite, but then over time chemical reactions altered their composition to a variety of minerals, still mostly quite rich in iron. That just leaves the grooves around the outside of the spheres to explain. The surrounding rock is made of layers of sediments and volcanic ash, so the grooves are likely an imprint of layers from the surrounding rock.

Geologists actually proposed pretty much the same explanation as early as the 1930s, but magazine articles and TV shows from the 70s to the 90s seem to have ignored that and perpetuated the mystery. Luckily geologists were able to clear things up again! So it’s pretty unlikely that aliens are to blame here.

But similar spheres have been seen on other planets. In 2004, the Mars rover Opportunity found similar objects dubbed “Martian blueberries”. And they could provide clues to the history of water on the red planet.

But, of course, since we haven't been able to take a sample of them directly, we will have to wait a bit longer for those insights. So, life in Antarctica is tough no matter who you are or where you are living. But scientists have discovered that the soils of the Antarctic deserts are filled with microbes!

In fact, the levels of microbial life are comparable to much more mild environments. This discovery has come as a bit of a surprise. And it’s sparked an even bigger question: how are these communities surviving?

See, this soil has very little organic carbon or other nutrients. And there’s little to no light for much of the winter, so photosynthesis is tough. On top of all that, everything is constantly getting frozen and rethawed, so exactly how these tiny creatures survive has been quite a mystery.

But a 2017 paper found they might simply be living on air. Trace atmospheric gases are their main source of energy. The researchers sequenced DNA from two spots in Antarctica to figure out what types of microbes were living there.

Not surprisingly, only 0.28% of the microbes were known photosynthesizers, so clearly the community as a whole was not relying on sunlight. But using all of this genetic information, researchers were able to infer what sort of energy source the microbes were relying on. They found lots of genes that can take the carbon from carbon dioxide in the atmosphere, as well as enzymes that assist in using hydrogen gas and carbon monoxide as energy sources.

Carbon monoxide can, of course, be fatal to humans, so it’s pretty amazing these little microbes can essentially breathe it. To confirm this is what was actually going on, the researchers put samples of the soils inside sealed bottles and measured the consumption of hydrogen and carbon monoxide. They were even able to tag the carbon in the carbon dioxide and see it showing up in the microbes from the soils.

That demonstrates that there’s enough carbon and other nutrients in the air for these microbial communities to sustain themselves. Now that we know this happens on Earth, it even opens up the possibility to look for similar types of life on other planets. Tanystropheus is an extinct reptile that lived around 240 million years ago.

First discovered in 1852, along the border between Switzerland and Italy, this giant was 20 feet long and boasted a neck three times as long as its torso. And it took us more than a century and a half to work out some of the most basic things about it. Scientists weren’t sure if it lived on land, in the water, or even flew through the skies!

These kinds of mysteries aren’t that rare in paleontology. Fossils are often incomplete skeletons, and frequently smushed or scattered compared to how they were in life, so it can be easy to misinterpret what creatures looked like or how they lived. Over time, as more specimens were discovered, we realized that bones that were thought to be part of the creature's wings were actually vertebrae, and this creature had a very long neck.

So flying through the air was ruled out. But it wasn’t until 2020 that we were able to figure out it lived underwater and not on land. Researchers used high-resolution CT scans of fossil fragments to reconstruct a Tanystropheus skull.

This revealed that their nostrils were similar to crocodiles, and their teeth were positioned to catch fish. This is similar to the teeth seen in other prehistoric underwater predators. The researchers made another startling discovery as well.

They were looking at two species, not one. They examined small and large specimens of Tanystropheus. In the past these were thought to be juvenile and mature members of the same species.

But markings on the bones of the small species indicate that their growth had slowed by the time they died, suggesting they had reached maturity. So it’s most likely these two species coexisted by hunting different prey, each having its own role in the aquatic ecosystem. The Explorer’s Club is an organization surrounded by myth and legend.

It’s an exclusive group of scientists and adventurers, and members have included astronauts, presidents, and billionaires. But one story in particular also created a tricky scientific mystery that lasted for decades. Though maybe this one is more of a hoax.

Rumor has it that at a dinner in 1951, members of the club dined on wooly mammoth meat that was preserved in Alaskan ice. This meal began the club’s tradition of serving exotic meats. Menus since then have included polar bears, termites and tarantulas, and goat eyeballs.

Out of the ordinary for sure, but nothing like an ice age giant that has been extinct for thousands of years. Luckily a small sample of the cooked meat in question was preserved as a souvenir. So in 2015 researchers decided to solve this mystery once and for all!

Their first discovery was the menu claimed the meat was in fact from something rarer than a woolly mammoth: an extinct giant ground sloth from South America called Megatherium. If this were true, the scientific impact would be enormous, since these sloths have never been found anywhere near Alaska, and it’s uncertain if humans, ancient or modern, ever ate them. So the researchers performed a careful DNA analysis on the preserved sample and found it was actually neither of these species.

It turns out it was from a green sea turtle. Turtle soup was also on the menu that evening, so the researchers theorize one member of the club had the idea to take some of the meat from that dish and pass it off as something much more exotic. In an article published after the dinner, one member more or less admitted to doing just that.

But the power of a good story is hard to overcome, and the admission was pretty much completely ignored. Even though this meal was an elaborate prank, there are other tales of paleontologists sampling mammoth meat that the researchers think could be credible. Apparently, tasting your specimens was once much more common than it is now!

There you go, 5 mysterious puzzles, both sparked and solved by science! But these stories aren’t over yet. As methods improve and clever researchers try new things, we will surely learn lots more about the tiny creatures in the harshest environments, the giants of the prehistoric oceans, and which ancient animals taste the best.

Well, on second thought, possibly we should avoid eating the discoveries. All of that science is the result of tons of data that researchers had to sift through and organize. And when you have that much data, you need a solid organizational system.

This video’s sponsor, Linode, is a company that helps people manage and process giant data sets through cloud computing and database products. Working with Linode gives researchers quick access to all of their data in online databases from wherever they are in the world and keeps it secure. And Linode has handled a wide variety of data sets for years, like data from the National Institute for Risk and Resilience at the University of Oklahoma.

So you can click the link in the description or head to linode.com/scishow to check out Linode’s data solutions. That link gives you a $100 60-day credit on a new Linode account. Thank you to Linode for sponsoring this video, and thank you for watching! [ ♪ Outro]