everything in it seems so spread out.

But some objects are closer

than you might realize.

Every now and then,

a random interstellar asteroid

passes through the Oort cloud,

the wall of icy debris at the very edge

of our Solar System.

But what if a rogue star

unceremoniously rampaged

right through the Oort cloud?

How bad would it be, if it brought

other planets along for the ride?

What if I told you that a rogue star

has already invaded our Sun's territory?

A dim red dwarf, dubbed Scholz's star,

crossed the Oort cloud some 70,000 years ago.

It passed just 0.8 light-years

away from the Sun.

And then it made a turn in the opposite direction,

without causing much trouble.

Right now, another rogue star

is moving in our direction.

Gliese 710 has about 60%

of the mass of our Sun,

and it's traveling across the galaxy

at 52,000 km/h (32,000 mph).

If another star rampaged

through the Solar System,

the extent of the chaos it would cause

would depend on the size of that star,

and its trajectory.

When Scholz's star passed through the Oort cloud,

it came five times closer

than Proxima Centauri,

the closest star to our Solar System.

Scholz's star didn't have much effect on Earth,

although around the same time,

early humans almost got wiped out

by a massive volcanic eruption.

But that was pure coincidence, right?

In any case, before Scholz's star

turned away minding its own business,

it did change the orbits of about 10%

of comets and asteroids in the Solar System.

But, what if it was a bigger incoming star,

like Gliese 710, that's currently making its way towards us?

Gliese 710 isn't scheduled to make

its first contact with the Solar System

for another 1.29 million years.

But when it does, it could shake the Earth quite a bit.

At first, the rogue star would

make its way into the Oort cloud.

At this point, it wouldn't affect us directly.

But it would send massive chunks of space rock

showering the Solar System.

About 170 meteors, comets and asteroids

would hit the Earth every day.

That's ten times more

than what's bombarding our planet right now.

Comets and meteors might not seem like a big deal,

since most of them are small,

and they often fall in unpopulated regions. But...

Back in 1908, in Siberia,

it only took one asteroid to obliterate 80,000 trees,

and blow out windows 60 km (37 mi) away.

If the same asteroid were to hit New York,

the entire city would be in the impact zone.

And that's if just a single star smaller than the Sun

slightly made it just inside our Solar System.

If a star larger than our Sun

entered the Oort cloud,

it would disrupt the orbital cycle

for every planet it passed.

Since there are such large distances within the Solar System,

this disruption would happen

over the span of millions of years.

It would be an almost slow-motion

chaos of debris waves.

It might even set some planets on a collision course.

And that's not the worst it could get.

If the rogue star had other planets and moons following it,

our Solar System would turn into a galactic soup,

with stars and planets

being pulled out of their orbits.

Massive collisions would create a rippling effect,

disrupting planetary orbits even more.

Eventually, the Earth would be

knocked out of its orbit too,

if it wasn't already destroyed by meteor storms

and the remnants of other planets.

Not to sound too dramatic, but there are estimates that

40,000 stars have entered the Oort cloud,

at some point in the history of the Solar System. But...

They all came here on "just visiting" trips.

Chances that any of those rogue stars

will ever make it past the Oort cloud

are close to zero.

Let's just hope that we'll never have to deal

with anything like a black hole

coming too close to the Solar System.

But that's a story for another WHAT IF.