This rogue star has been traveling the Universe.
And now,
it's finally entering our Solar System.
But this isn't just any regular star.
It's known as a quasi-star
and it's one of the biggest stars in existence.
Quasi-stars aren't just regular stars.
They're powered by black holes.
The theory is that
the original star would have been so massive
that the core started to collapse.
Normally a supernova would happen at this stage,
but instead, the explosion
is absorbed by the outer layers of the star,
and a black hole forms at its core.
The black hole then feeds on this star
for thousands of years, slowly absorbing it.
Now, what would happen
if this deadly star
came toward our Solar System?
First, let's understand
just how massive this star is.
To put it in perspective,
our Sun is the largest object in our Solar System
at 1.3 million km (865,000 mi) in diameter.
That may seem massive, but it's really nothing.
Just 5.2 light-years away from us,
there's another star known as UY Scuti
which is 1,700 times larger than our Sun.
Pretty big, right?
But this quasi-star
is even bigger than that.
This massive star has a diameter
of 10 billion km (6 billion mi).
More than 7,000 times the size of our Sun.
So yeah, this thing is an absolute unit,
and now it's coming for us.
If a quasi-star did enter our Solar System,
we'd start to notice it
much sooner than you might think.
This one star would be as bright
as an entire galaxy.
Not only that, but it would be as luminous
as at least 100,000 Suns.
So the closer the star would get,
the brighter everything would appear on Earth.
But unfortunately, this star wouldn't
just be giving us brighter days than we're used to. 
As soon as the star entered our Solar System,
planets, asteroids, and any other
objects would likely be thrown out of orbit.
This could cause epic meteor
showers for us on Earth.
Thousands of asteroids
could all end up crashing on our planet.
And if a planet were lucky enough
not to get thrown out of orbit,
it would eventually still get
engulfed by the quasi-star
The quasi-star would go all across our Solar System.
It might engulf Neptune,
and then even our massive
planets like Saturn and Jupiter.
It would continue this journey
until it reached Earth.
Humanity would be extinct by this point,
due to the incredible temperatures of the star.
And then, the planet would quickly heat up.
Once it hit 260 °C (500 °F),
the atmosphere would become
steam and carbon dioxide.
Getting hotter, at 760 °C (1,400 °F),
sulfur dioxide would be produced.
And Earth would continue to
heat up until the crust and mantle
were completely vaporized, 
and the entire planet was engulfed by the star.
And as if this star hasn't caused enough trouble,
it could eventually become a supermassive black hole.
This would be after its black hole core
finished swallowing the entire star.
Now that we have this supermassive black hole,
how 'bout we make it fight a white hole?
But we'll leave that story for another WHAT IF.
