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[ ♪ 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.
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[ ♪ Outro]