SciTech Now Episode 406

In this episode of SciTech Now, a look at the topography of teeth; a dwindling supply of plutonium threatens deep space exploration; meet the Kootenai tribe of Idaho who are saving the white sturgeon; and a speed-dating science competition.


Coming up, the scientific topography of teeth...

Teeth are basically fossils in your mouth.

A lot of what we know about evolution of organisms is based on the teeth.

Is the future of deep-space exploration at risk?

Plutonium-238 emerged as the best option study after study that NASA has looked at, and there is about 35, 36 pounds of this stuff left.

...saving the white sturgeon...

Sediment moving through a river can promote natural changes in the movement and formation of a river, but on the other hand, for the sturgeon, it's covering up a lot of the eggs that they're laying.

...Science Speed Dating...

Three, two, one.


Aside from technical prowess, technical background, we find communication skills are critically important.'s all ahead.

Funding for this program is made possible by...


I'm Hari Sreenivasan.

Welcome to 'SciTech Now,' our weekly program bringing you the latest breakthroughs in science, technology, and innovation.

Let's get started.

Ancient human teeth can tell us a lot.

Hidden inside each set of teeth are clues about their owner's behavior and ancestry, as well as what really made up the Paleo diet.

Shara Bailey, Associate Professor of Anthropology at New York University, reads the topography of teeth to better understand the origins and lineages of humans.

Our partner, 'Science Friday,' brings us the story.

Who are we?

Where do we come from?

What makes us human?

Shara Bailey looks to answer those questions by peering into the mouths of ancient humans.

My specialty is in the dental morphology or the bumps and the grooves and the shape of teeth.

I'm interested in when we get the teeth that we recognize as being distinctly Homo sapiens.

Locked inside our teeth are secrets of our past.

Teeth are 98 percent mineral in content already.

Teeth are basically fossils in your mouth.

A lot of what we know about evolution of organisms is based on the teeth.

Sometimes, it's the only thing that preserves.

And the information Bailey and other researchers uncover from looking at pearly whites pieces together the origins of early humans going back to when humans and chimpanzees split from a common ancestor around 6 to 8 million years ago.

One key difference is recorded in the fangs or canines.

They become more diamond-shaped.

Other clues are more subtle.

In reading the topography of teeth, Bailey can reconstruct details of their owners' lives like behavior, location, and even their last meals.

If you run your tongue along your molar teeth, you'll feel little bumps.

Those are called cusps.

In leaf-eating primates, their cusps are very high, and they shear against one another, right, like scissors.

Flat cusps work more like a mortar and pestle, and pointed teeth used for grinding nuts or seeds.

Counting cusps can give indication about origin.

Most people have five cusps on the lower molars.

Four cusps point to places with a long history of agriculture like Europe and India.

Six cusps are often counted people with Asian ancestry, and an extra cusp on the tongue side, cusp seven, may point to Sub-Saharan African ancestry.

Now move your tongue behind your top two front teeth.

Do you feel deep ridges?

That could indicate northeast Asian or Native American ancestry and could also be accompanied by ridges on the front of the teeth.

That's called double shoveling because it looks like a coal shovel, and that's where they get the name.

And a link between Native Americans and Northeast Asians is very clear when you look at the teeth.

Zooming in closer, a scanning electron microscope reveals fine scratches and gives clues on a month of meals.

And going deeper, you can look at the growth lines of the enamel, which researchers can read like tree rings.

You can tell how fast an individual grew their teeth, which some people think reflects how fast they grew in general.

Bailey looks at how all the bumps, scratches, and features combine to piece together information about early humans, and her work can put her in the middle of debates about our origins.

We like to think that we're really special, and so it's like... Because we're here, and Neanderthals aren't, right?

So why is that?

Was it diet?

Was it that we killed them off?

Were we smarter?

When archaeologists discovered a site in Southern Italy from 41,000 years ago, around the time Neanderthals went extinct, containing some of the earliest art and tools, there was a debate about the culture that created them.

Was it Neanderthals or modern humans?

It's, like, one of these transitional tool industries, and so the question is -- what were Neanderthals capable of?

What were their minds like?

And the only way you can get in a Neanderthal mind, because we don't have brains, is by what they left behind, what they were doing.

Scientists didn't have many remains to go by, just a few teeth.

We looked at all the teeth, and they're all, you know, they're modern human.

Not Neanderthals.

The cultures that created the earliest art and tools represent a shift in human evolution and likely led to the demise of Neanderthals in the area.

And Bailey was called again when researchers found a site with remains of a specimen nicknamed 'The Hobbit.'

The question was -- Is this a new species, Homo floresiensis?

I was called in to go look at the teeth.

I did, and be honest to you, I looked at the molars, and I'm like, 'They look kind of modern.'

I mean, they have four cusps.

You know, there's nothing really remarkable about the upper molars, but there's the lower-third free molar.

There's your first bicuspid.

That's what the dentist would call it.

It's like nothing I've ever seen in all, you know, all the modern humans I've looked at, even the fossil hominids.

It has, like, three roots.

It has an extra weird cusp.

The shape of it is, you know, kind of odd, but it's really just the whole way it's put together is completely unique.

The teeth support this as being a different species.

Recently, Bailey examined a set of baby teeth which helped determine that remains found in 2015 were from a new species, Homo naledi.

But despite so many differences, early human and Neanderthal teeth have one surprising thing in common.

They'd get a good report from dentists today.

You know, I look at all these fossil teeth, right?

There's no dentists back then, and they're perfect.

They're beautiful.

You start looking at teeth after agriculture gets adopted, and their teeth just, you know, go to hell in a handbasket.

There are cavities.

There's abscesses.

They're just... They're disgusting. [ Laughs ]

Now that's some history you can sink your teeth into.

Dave Mosher is a science and technology correspondent for Business Insider who's written for National Geographic News and

Throughout his career, he's watched humans and robots launch into space, flown over the North Pole to catch a total solar eclipse, and toured a cutting-edge nuclear reactor.

He joins us now to discuss how a dwindling supply of Plutonium threatens deep-space exploration.

Plutonium is the fuel that's powered some of these satellites that we've gotten amazing pictures from, but what is Plutonium-238?

Plutonium-238 is a by-product of Cold War weapons production.

So when you're trying to make Plutonium-239, which is the active ingredient in a nuclear bomb, you can do a little side project and make this Plutonium-238.

And it doesn't react, doesn't work like Plutonium-239.

All it does, it just sits there, and it gets hot.

So if you can convert that heat into energy through its basic radiation, which you could stop with a piece of paper, then you can make a battery, and you can put it up in a spacecraft and, you know, take pictures and send them all the way back to Earth, hundreds of millions or even billions of miles away.

How long have these batteries lasted?

That is a great question.

So Voyager, the Voyager twins, solar system, that battery is still going after its launch in 1977, when it was fueled.

So 40 years, and it's still going to keep kicking.

I mean, the half-life of Plutonium-238 is about 88 years, just about, so, you know, you lose half of it, half of the energy over 88 years.

So it should still power that craft long into the future, and we're using all sorts of fun tricks and antenna gadgets that pick up that incredibly weak signal from the satellite, but it can last decades.

So how much more is left to put into the next wave of satellites, or do we use a different fuel now?

So, there was a report that came out, I think, in 2010, 2012, something like that, looking at all of the options, and what they came back to was Plutonium-238 is the only option basically, given all these problems that the other fuel sources, you know, chemical fuel cells and solar.

Your panels get too big.

Plutonium-238 is still the best option.

How much of it's left?

There is about 35, 36 pounds of this stuff left, 16 and some kilograms.

That's all earmarked for future missions.

NASA doesn't really have anything beyond that.

However, they have an arrangement with the Department of Energy, which, after more than 2 decades, started to create Plutonium-238 again.

So the end of the Cold War ends production.

Now we're trying to start it back up.

We don't have the same facilities, we don't have the same personnel.

It's sort of kind of a mystery.

How do you make this stuff?

So they've been spending years doing this, and I visited some of the facilities where they're trying to do this work.

How hard is it to make, or how much time or energy or money does it cost to make a couple of pounds of this stuff that could power a satellite?

So per gram, Plutonium can cost you tens of thousands of dollars, and that was, again, a by-product of the Cold War.

So now we're talking about a whole different story where we have to earmark some nuclear reactor time, stick some stuff in there, irradiate it, wait a year, filter it out, six more in, wait.

So it takes a lot of time to make this stuff, and you can refresh your existing supply since it's always the king.

But it's a game, and it can get very expensive.

NASA, there's a big political battle over this, but NASA now is paying the Department of Energy.

The government is paying itself to make this stuff, and it's in the tens-of-millions- of-dollars-per-year range, probably.

They should be up to $100 million or so if they really want to hit the targets that they're talking about in terms of production.

Do we have a lot more satellites in the queue waiting to take off and that we're putting this fuel into?

So, the satellite question is a good one.

It's one that NASA likes to deflect on.

They say, 'Oh, well, we've got all of our things, our ducks in a row.

We're fine. We're mapped out.

We're planning fine.'

But I've spoken to scientists who had dreams of sending spacecraft into outer space, to do really unique missions, land on the lakes of Titan, a moon around Saturn, or go back to Pluto and orbit Pluto instead of just flying by it.

You can't do those missions unless you can count on Plutonium-238, and right now, they're years behind schedule in producing this stuff.

They need to speed it up.

They need to figure out how to get more funding.

Something has got to give for these missions that scientists are dreaming up and putting a lot of work into to make happen.

So while NASA's script is, 'Oh, we've got, you know, a couple more missions planned, and by that time, we'll have a production timeline ready,' there's a whole bunch of missions nobody is ever talking about that aren't happening and probably should happen because we just don't have this resource available to us in the quantities that we need it.

All right. Dave Mosher.

Thanks so much for joining us.

My pleasure.

Thanks for having me.

[ Baby crying ]

The Kootenai River, which crisscrosses the U.S.-Canada border, is home to the endangered white sturgeon and is in need of attention.

Now the Kootenai Tribe of Idaho is undertaking a massive habitat restoration project.

The tribe is teaming up with U.S. Geological Survey researchers and using acoustic monitoring equipment to figure out how much sediment is in the river and how to reshape the river to help the sturgeon.

Our environmental reporting partner EarthFix has the story.

Movement is a river's constant, always flowing, always going somewhere.

One of the biggest things that it meant to the tribe was it was kind of like a highway, and they traveled up and down the Kootenai River to get from one place to another.

And they moved around from area to area for hunting and fishing and gathering purposes.

[ Train whistle blows ]

The Kootenai Tribe lives along the Kootenai River.

They follow a covenant handed down by their ancestors.

We have created the Kootenai people to look after this beautiful land.

As long as you do that, all your needs will be met.

To this day, we've kind of honored that covenant, you know, and I guess that drives us forward.

White sturgeon are sacred to the Kootenai.

They're also endangered.

Only about 1,000 wild sturgeon are left in this stretch of the river.

The tribe is trying to increase that number.

U.S. Geological Survey is helping them by listening to the water.

Acoustic Doppler meters are installed on the side of the river, aiming across the flow.

They send sound waves through the water.

When those waves return to the meter, they sound different.

That's because of particles in the water.

I'm really excited about this concept and this technology.

This is sort of a new concept for monitoring sediment nationwide.

We collect sediment samples while that equipment is running so that we can actually send that to the lab, and it correlates with that returned signal.

And so there's a lot of analysis on what we do with our collections and then corresponding to that power signal that returns back.

Right now, across the nation, we've got about 40 sites, roughly, where we're implementing this kind of acoustic technology to try to estimate sediment.

The more material you've got in the water, so the more sediment you've got in the water, the stronger that reflection of the sound will be in the water.

So the instruments can measure that, and we can use that information to try to relate that to sediment concentration.

Every river has sediment.

It's the sand, gravel, and the general muck that rolls along with the current.

The issue with sediment in the Kootenai River is that it's interesting.

It's both good and bad for the system.

It's good in that sediment moving through a river can promote natural changes in the movement and formation of a river, but on the other hand, too much of it can impact a habitat.

And for the sturgeon, for example, it's covering up a lot of the eggs that they're laying as part of their spawning effort.

Too much sediment suffocates spawn.

Researchers monitor sediment by placing sticky mats in sturgeon-spawning beds.

The mats collect hundreds of eggs.

The eggs are so adhesive.

Rolling down the river, they adhere right to the mat, and we pull them up.

And just we call it reading the mat, and we go over it with a fine-tooth comb and look for eggs.

As you can see, there's plenty of sand stuck to them.

The Kootenai River's sediment load in Idaho has changed over decades.

In some places, there's too much sediment.

In other places, there's none.

That's due, in large part, to a hydroelectric dam.

The Kootenai River starts and ends in Canada.

It runs 485 miles with about a third of those miles dipping into Idaho and Montana.

Much of the river's water in the U.S. is held behind the 400-foot-tall, 3,000-foot-wide Libby Dam in Montana.

Idaho's 66-mile stretch of the Kootenai is downstream of that, which means those river miles are controlled by humans rather than nature.

We see this everywhere in the U.S., where changes are made to an environmental system in response to the biggest issue at the time, and that's, you know, no one person's fault.

It's just our human response to natural hazards and natural conditions, and so that's the reality of where we're at.

Decades of holding back water changed the watershed.

And when you have an alteration to the flow and the sediment transport, the river takes on a different character, and a lot of the natural hydrology is altered.

So one of the things that happens when you don't allow... In this case, the river is no longer allowed to kind of go out into the floodplain and kind of promote some natural changes and side channels and little points where the fish can hide and rest as they're moving upstream.

That's been one factor that has influenced the survival of the sturgeon.

The dam was built in 1975.

The white sturgeon population plummeted after that, putting the ancient fish on the endangered species list in 1994.

When the sturgeon went onto the endangered species list, there really wasn't any program that was, you know, being put into place, so we stepped in, says, 'Well, why don't we do something?'

That's where listening, rather than looking, comes in.

Researchers are working with the tribe and state and federal agencies to create an underwater map of the river for restoration work.

Having these instruments out there has really been a benefit to us to see what's going on all the time.

Without the acoustic meters, we'd have to just get up there and collect a sample when we could and when it was safe to do so.

Now that we have these instruments in there, we can see what's going on.

We can better target and time our sample collection.

It really gives us a more complete and more accurate picture of what's going on in the Kootenai River, in terms of sediment.

With that clearer picture, they'll be able to sculpt river channels to help fish.

Because sturgeon numbers are so low, researchers are also mapping spawning beds, so they can catch spawners and raise their eggs in a hatchery.

We have to move with the fish, figure out where they're at on any given day to hit those periods when they are active and they're actively feeding.

It certainly brightens everybody's spirits when we catch fish, bring it in, and it's a good fish for the program.

Just to bring a healthy, wild adult, you know, it's a fish that big that's still in the river, is pretty cool.

Yeah, it's the highlight of, probably, everybody's job.

The hope is all this hatchery work goes away once the river is restored.

The long-term goal is not to have a hatchery program.

It is for the fish to be able to find the appropriate habitat, survive through all their life stages, and self-propagate.

Sturgeon are the slow-growing, long-living giants of the water world.

It will be decades before recovery success is evident, but any jump in the population is worth listening for.

In this next segment, Pennsylvania State University students participate in a contest to condense years of research into a 2-minute pitch.

The competition helps students hone communication skills.

Take a look at the event dubbed Science Speed Dating.

The Millennium Science Complex at Penn State is home to some mind-blowing science, but if you don't live it and breathe it every day, trying to understand some of the work that happens here can leave you with a headache.

That's why these Penn State grad students are attempting to turn years' worth of research into a 2-minute pitch for the Millennium Café Pitch Competition.

It's a big draw, 36 contestants eyeing a $750 first-place prize, but to get the cash, they'll need to convince the judges by coming up with a clear message about the importance and impact of their research, something that doesn't come naturally.

On the fight against the evil society, greenhouse gases, got to stay tuned to find out.

In the sciences, you work from the smallest detail down to the biggest picture.

That's typically how you structure your scientific message, but in this type of pitch competition, it's just the opposite.

You start with the biggest picture, and then you kind of go into the nitty-gritty details.

The high-pressure speed-dating setup doesn't help either.

Three, two, one.


Take a quick look around.

You'll notice different styles, from the casual coffee chat to superheroes.

It may seem like fun and games, but a contest like this is all about molding the next generation of scientists and leaders.

It's a great opportunity for students to develop skill sets in communications.

Really, aside from technical prowess, technical background, we find communication skills are critically important.

You'll see some people that really rise to the top that have this natural talent that maybe was even unknownst to them.

Number one...

After the first round, scores are tallied, and the top five are announced.

Top five.

[ Applause ]

Nerves are high.

Please wait a second.

But this is the finals.

I'm a little bit nervous.


The pitches are finely tuned.

If you could have an invisibility cloak, what would you use it for?

And the best grab your attention from the very beginning.

It's estimated that over 600,000 people will die from cancer this year.

To fight this, I am creating personalized surgical tools to customize cancer treatment for each individual.

A clear message with a real-world impact front and center.

For that, Brad Hanks walked away with the top prize.

But like his pitch, he's focused on the big picture.

I have to contribute some, at least, to my wife.

She helped me practice a ton, and I have two little boys at home, so I'm sure some of it will go towards diapers and whatever else they need.

And that wraps it up for this time.

For more on science, technology, and innovation, visit our website.

Check us out on Facebook and Instagram and join the conversation on Twitter.

You can also subscribe to our YouTube channel.

Until next time, I'm Hari Sreenivasan.

Thanks for watching.

Funding for this program is made possible by...