Space's Deepest Secrets

A mysterious object

the size and shape of a skyscraper

hurtling through the solar system

at over 100,000 miles per hour,

fast enough to level a city if it hits the earth.

As the data came in, everybody's jaws began to drop

and you realize, no, this is something different.

This is something we've never seen before.

This bizarre object

comes from outside our solar system.

It's our first interstellar visitor.

Astronomers call it "'Oumuamua," the messenger from afar.

'Oumuamua is our galaxy coming to us.

This is the first time in history

we encountered something legit alien.

Astronomers around the world

scramble to unlock its deepest secrets.

How did 'Oumuamua get here?

Does it pose a threat to the earth?

Could it even be an alien spaceship?

'Oumuamua was so strange, so different,

that everything was on the table.

We had no idea what it was.

This is the inside story

of the race to solve the mystery of the alien asteroid.

captions paid for by discovery communications

The summit of Maunakea,

the giant volcano on Hawaii's big island.

Home to some of the earth's most powerful telescopes.

This is where astronomers keep watch on the night skies

looking for asteroids and comets that threaten the earth.

Astronomer Rob Weryk

is part of this vitally important search.

At the end of my e-mail signature,

I just write "guardian of earth."

It's kind of a joke between my colleagues and me.

My official title is planetary defense researcher.

But we're basically looking to protect the planet

from hazardous asteroids and comets.

On October 19th, 2017,

Rob spots a mysterious object

streaking through space like a rogue missile.

We actually had a new candidate detection.

It was moving very fast.

It appeared as a streak in the image.

The object is moving so fast,

that it appears as a faint, gray line.

At this speed, it will hit the earth

with more force than a nuclear bomb...

Powerful enough to destroy a city.

Rob and the team set up camp

at the Canada-France-Hawaii telescope,

to plot the object's trajectory.

The data they capture confirms

that this object is heading away from our planet.

The earth is safe... For now.

But the object's orbit

is unlike anything Rob has seen before.

Everything that belongs in our solar system

travels in closed loops around the sun.

The sun holds the planets in near circular orbits.

Smaller bodies, like comets, move in vast, elliptical orbits

that take them to the edges of the solar system,

before looping back towards the sun.

But Rob's data reveals

that this mysterious object is different.

Its orbit is open, not closed.

This means that it must come from outside the solar system,

from interstellar space.

It's our first confirmed alien visitor.

Astronomers named it "'Oumuamua,"

Hawaiian for "messenger."

It's an incredible discovery.

And that's what really told us, right then,

that this object came from outside the solar system.

'Oumuamua was like nothing we had ever seen before.

And think about that. That's literally true.

This was actually a completely alien object.

And, you know, that day, I kind of got shivers, right?

But 'Oumuamua travels so fast,

that astronomers have just weeks to study it

before it disappears beyond the reach of earth's telescopes.

The best assessment we had,

we would see it for about two or three weeks,

so we had to get as much data as we could

as soon as we could on as many telescopes as we could.

It's now a race against time,

to learn as much about 'Oumuamua as possible.

Astronomers start with the most important question.

What is 'Oumuamua?

The main candidates are two forms of space debris

routinely hurled out of developing solar systems.

When our solar system first formed,

we think that a huge number of comets and asteroids

were ejected away by Jupiter, its gravity.

This must've happened around other stars, as well.

In all likelihood,

'Oumuamua is an interstellar asteroid or a comet.

Could 'Oumuamua be an asteroid or comet,

tossed into interstellar space

during the birth of an alien solar system?

Astronomer Meg Schwamb studies asteroids and comets

in our solar system.

She and her team race to observe the object

using the Gemini north telescope in Hawaii.

Astronomers hope to get an idea

of 'Oumuamua's shape and size,

a vital clue as to what it is.

It was exciting.

I really wanted to know where it would fit in.

Would it look like an asteroid?

Would it look like a comet?

But it looked completely different.

There are no telescopes powerful enough

to determine the size and shape directly.

All they have to go on is the fact

that 'Oumuamua's dimensions

affect how much light it reflects back towards earth.

This is actually data from many, many telescopes

from around the world watching 'Oumuamua.

So, this is brightness over time.

It gets brighter and fainter and brighter again.

What could make the light from 'Oumuamua brighten and dim?

Rob thinks it's because of the object's shape,

and the way it's moving.

If you can imagine this shape here,

you're looking on the longest edge,

it has the greater surface area.

This reflects more light.

But when you look at the smaller end,

it doesn't reflect as much light,

therefore it's not gonna appear as bright.

So, this is similar to 'Oumuamua,

where we think it's a very elongated object.

And as it's tumbling through space,

the different size of the reflective surface

gives you the variation of brightness you see.

Astronomers use this difference in light

to determine exactly how elongated

and how big 'Oumuamua is.

Based on the variation in the light curve of 'Oumuamua,

we know that it's approximately a length-to-width ratio

of 6 to 1.

'Oumuamua is six times longer than it is wide.

This makes it exceptionally tall and thin.

It soars between 650 to 785 feet high.

It's a skyscraper that could be as big

as the empire state building,

tumbling through our solar system.

Determining 'Oumuamua's shape

is a fantastic bit of detective work,

but astronomers are no closer to saying

whether the alien visitor is an asteroid or a comet

because they've never seen anything with this shape before.

Astronomers scramble to explain what 'Oumuamua is.

First up, could it be an asteroid?

Investigators turn to lab experiments

to try to solve this mystery.

If it is a rocky asteroid,

what kind of cosmic process could carve out

such a long and thin shard of rock?

Planetary scientist Peter Schultz

has spent his career recreating violent collisions in space.

He wants to know if an almighty collision

can make a rocky splinter the size and shape of 'Oumuamua.

'Oumuamua is really interesting,

'cause we've never seen an asteroid that is shaped

like a cigar.

That's just strange.

And so, we have to figure out why.

Could an epic collision create a similar asteroid?

Or is there an even more incredible explanation

behind 'Oumuamua's strange shape?

Could this interstellar visitor be an alien spaceship?

At the NASA AMES vertical gun range,

planetary scientist Peter Schultz

uses a giant, hypervelocity gun to recreate

some of the most violent collisions in the solar system,

to understand the forces at work.

Here we are, at the NASA AMES vertical gun range.

This allows us to fire projectiles

at 22 times the speeds of sound.

Over the last 40 years,

Peter's investigated everything

from moon shaping collisions...

To determining what type of impact killed the dinosaurs.

Most of Peter's epic collisions

create short and lumpy debris, shaped like

most of the asteroids seen in our solar system.

But drawing on his experience, Peter believes

that one very specific type of collision

might just generate something

that looks long and thin like 'Oumuamua,

the first interstellar visitor to our solar system.

Right now, we are in the impact chamber.

This is where we slam into things.

This is our projectile, which represents an asteroid.

And today we're going to be slamming into this cylinder.

Now, imagine that this is a planet or another asteroid.

It will be coming in, slamming in at an oblique angle,