but the age of cartographers mapping our continents' shores and mountains has long since passed.

Well, I have good news: there are still places that remain uncharted. You may just have to

point your gaze upward to find them. And in fact, cosmographers recently revealed a massive

wall of galaxies shockingly close by that was hidden from our view until now.

That's right, there are scientists called cosmographers, and like cartographers mapping

out our planet, their goal is to map out the observable universe. From their findings we

can learn more about the structures that make up everything we can see and gain insights

into those features we can't see. You may think that stars and galaxies are

all scattered about randomly and in one sense you'd be right. On a large enough scale,

the universe is uniformly spread out, and this is what's known as the cosmological

principle. But as you zoom in, things start to become

more distinct. Stars, galaxies, and galaxy clusters bunch up and form enormous structures,

but the gravity of the stars is not what pulls them together. Rather it's that illusive

and invisible stuff called dark matter that gives shape to the universe, so as we map

it out, we'll be able to refine our understanding of the universe's makeup.

But cosmography isn't always as easy as pointing a telescope towards the sky and writing

down what you see. Sometimes, even massive structures are hidden from view.

Our own Milky Way's dusty center obscures whatever is behind it, an area of the sky

above the South Pole that has been dubbed the “Zone of Avoidance.” Which is funny,

because the Zone of Avoidance is also what I've been calling places with people during

the pandemic. Some cosmographers were undaunted by the zone

though, and they pulled out some clever tricks to peer into it. The universe is expanding

which means on the whole, galaxies should be moving away from us at a constant rate.

Using a catalog of the motions and distances of 18,000 galaxies called Cosmicflows-3, the

scientists noticed that some galaxies were moving faster or slower than expected, and

seemed to be drawn to something in the middle, something hidden in the Zone of Avoidance.

Something… big. Computer models revealed a wall made up of

thousands of galaxies at least 600 million light-years deep and 1.4 billion light-years

across, forming a bow shape over the southern hemisphere's sky.

They have creatively dubbed this wall-like structure above the south pole the South Pole

Wall, and not only is it enormous, it's one of the top-ten biggest structures ever observed,

it's also relatively close. It's 500 million light-years away, twice as close as a similarly

sized structure called the Sloan Great Wall. It's large enough and close enough that

it actually affects the velocity of our own galaxy, contributing about 40km/s to the movement

of the Milky Way. The South Pole Wall could in fact be even

larger than we think. It's curved shape allowed for a lot of it to fit within the

Cosmicflows-3 view, but it's possible that the wall extends beyond what we can see. We'd

need a bigger map to know just where it ends. It's incredible that something so enormous

was hiding just behind the dusty curtain of the Milky Way's center. Who knows what other

areas of the universe's map are obscured from view? It'll take better technology

and more research to see the unseeable, which means if you feel that itch to be one of the

next great explorers, now is the perfect time to look to the stars.

Since the universe is so enormous, mapping out the whole thing is an enormous challenge.

So, some researchers have turned to an unlikely place for guidance: slime mold. Check out

my video on how these communal creatures are showing us where to look for dark matter here.

Do you have that drive to explore the universe? Let us know down in the comments. Don't

forget to subscribe for more videos like this, and I'll see you next time on Seeker.