When you think about archeologists,

you might imagine people who spend

years in the dirt, digging around to learn

about old cultures and civilizations.

But while field work is important,

there's also a lot more going on these days.

In fact, in the last few years, archeologists

have even started borrowing and adapting

methods from other fields to advance their own work.

So today, while you will find some researchers

knee-deep in dust, you'll find others using techniques

from computer science, meteorology, and even

astronomy to learn about people who used to

walk the Earth.

First, satellites.

These things are often associated with militaries

and tech companies, but recently, they've been

used to help archaeologists, too.

Satellites might not spot ancient bones

or pottery, but they can see

a whole region at once.

That lets us find larger patterns and big-picture

details we can't pick up from the ground.

And by studying areas using different kinds

of light, satellites can also reveal hidden structures.

For example, in 2011, the BBC announced that

researchers studying Egypt had used infrared

satellite images to spot mud walls underneath the sand.

According to those researchers,

the walls absorbed water,

so they looked different in infrared

than the drier sand over them.

Further analysis of these images revealed

that there could be previously unknown

cities down there, too — including thousands

of buried homes and buildings,

and possibly a dozen or so new pyramids.

If they exist, these sites are likely around

three or four thousand years old,

and they could teach us more about how

your average Egyptian lived backed them.

Also: New pyramids!

Outside of Egypt, satellites have also helped us

discover Viking settlements in Canada

and map sites throughout Peru.

They've even shown traces left by those

who stole from archaeological sites.

Which is less fun, but is a major problem

in the field and something to keep track of.

Satellites can only do so much, though,

because you don't always have

a clear view of the ground.

For example, places like Peru, Guatemala,

Belize, and even New England have pretty dense

forests that satellites can't see through.

They're also hard for archeologists

to reach in person.

So lately, scientists have started mapping

beneath the canopy with a method used

in everything from meteorology to self-driving cars.

It's called LiDAR, which is short for

Light Detection and Ranging.

In this method, they fly a plane overhead

and point a laser at the ground.

Then, some of that laser light sneaks

through the leaves and gets reflected

by whatever is down there.

By measuring how long it takes for the

light to return to the plane, scientists can

calculate the distance to the canopy,

the ground, and whatever structures might

be hidden on the forest floor.

That gives them a complete

3-D map of the area.

In the last decade, LiDAR has revealed

ancient Spanish gold mines,

sunken Roman villas, and in 2018, a huge,

densely-populated network of Maya

settlements in Guatemala.

The settlements involve hundreds of

square kilometers of cities, towns, roads —

and over a thousand years ago,

more than ten million people likely lived there!

And we found it all without a single archaeologist

coming face-to-face with a jaguar.

If you think about it, satellites and LiDAR

feel like pretty intuitive technologies

for archeologists to adopt.

But this last method is a lot stranger

because it takes a page out of astronomers' playbooks.

It involves some of the most powerful things

in the universe: supernovas.

These are huge explosions some stars

undergo at the end of their lives,

and they're one source of high-energy particles

called cosmic rays.

These rays aren't harmful to us on the ground,

but researchers pay a lot of attention to them

for other reasons: Physicists, for example,

use them to understand the subatomic realm.

But in 2017, cosmic rays revealed something

new in archeology, when physicists used them

to discover a huge new room inside

the Great Pyramid at Giza.

They went inside the pyramid and used detectors

to measure how many cosmic rays

there were in various spots.

Specifically, they were looking for one

type of particle called muons.

The idea was that fewer muons can get through

something dense — like enormous sandstone blocks.

So if they saw an area with more muons

than normal, that would suggest there was

a room somewhere above them.

And that's what they saw.

They noticed more muons than expected coming

from just above the Grand Gallery —

the largest room in the pyramid.

And after doing some follow-up tests,

they concluded that there was a huge,

completely unexpected room up there.

No one is quite sure why it exists,

but this was still significant, considering

that the Great Pyramid is one of the most

famous archaeological sites in the world.

It was the first new room anyone had

discovered there in more than a century,

and the researchers found it without

breaking any ancient walls.

Scientists are currently on the lookout

for more places to turn their cosmic ray detectors.

But finding a new room inside one of

the Seven Wonders of the World is

impressive enough for now.

And it's just one more way that archaeology

is changing and embracing new technologies.

Never fear, though:

The field still hasn't lost its roots.

After all, when something like a satellite

reveals an ancient city, someone still

has to go explore it in person.

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