SciShow

The Most Important Explosion in History

On February 23rd, 1987, an 
explosion rocked the sky

not just in living memory, but in centuries.

If you had a keen eye and lived 
in the southern hemisphere,

and witness a bright dot that wasn’t there before.

It was a supernova, one of the most violent events

And it was the first supernova to be visible

to the naked eye since the telescope was invented!

In the decades since, researchers 
have learned an astronomical

amount of new science by 
studying this one explosion.

I’m talking right up until 
2023, when they finally solved

Nothing lasts forever, including stars. And the reason they’re 
shining in the first place is

they’re using up a bunch of 
nuclear fuel inside of them.

And as anyone who has ever had to worry about

surging gas prices or getting hangry 
knows, fuel inevitably runs out.

But while some stars like our own Sun are content

to end their lives with a proverbial 
whimper, others go out with a bang.

A near-instant, massive explosion 
that tears the star apart.

Our galaxy is supposed to have two or three

But most of the time we can’t see them from Earth.

They’re often too far away, with too 
much interstellar dust in the way.

That’s why the previous great supernova,

one that an average person could step outside

and spot without a telescope, was 
seen all the way back in 1604!

But luckily for astronomers, 
there are super fancy telescopes

that let them look at millions of other galaxies

and hunt for supernovas that are 
way too dim to see otherwise.

And the one that happened in 1987 
did happen in another galaxy.

Sure, it’s the Large Magellanic 
Cloud, which is a dwarf galaxy

on the Milky Way’s back porch. But it counts!

And at roughly 160,000 light years away from us,

the light from this supernova had 160,000 years

to spread out as it traveled through space.

Which is why it was a lot less 
bright than that 1604 explosion.

it made up for as a brilliant bed-time story.

at Las Campanas Observatory 
high atop a Chilean mountain,

his final photographic plate of the night.

And as he scanned the image 
captured on that plate,

he saw a star that didn’t used to be there.

He rushed outside to check, and, to his surprise,

he could see this “new star” with 
his own eyes in the night sky.

Of course, Shelton hadn’t 
witnessed a star being born.

It was the opposite. And he 
and his colleagues scrambled

to get a message to the 
International Astronomical Union,

which involved a 100 kilometer 
drive to the nearest town.

Oh, and because astronomers are 
so amazing at naming things,

they eventually gave this once-in-many-lifetimes

Eventually, astronomers were able to pin down

It went by the name, um… this… and it was roughly

Now, being so massive, you might think it’d be

able to live a lot longer than our Sun will.

But for stars, it’s actually the opposite.

The more mass you’ve got, the 
faster you burn through your fuel.

So while our Sun is roughly halfway 
through its 10 billion year lifecycle,

the progenitor to SN1987A kicked the astronomical

bucket at the ripe old age 
of only 10 million years.

Of course, the supernova 
at the end of its life was

even more of a pinprick in the 
greater timeline of the universe.

million years before the actual explosion.

The star’s core ran out of its 
primary fuel source, hydrogen.

And with no way to spew out a bunch of energy,

it started collapsing under its own gravity.

But that near collapse actually helped the star

switch over to burning the next 
lightest thing available: Helium.

But eventually, it ran out of helium. 
So it switched to another fuel.

And this happened again and again until there was

nothing left that the star could use, 
and its nuclear furnace turned off.

And at that point, gravity 
took over one final time.

In just a few tenths of a second, 
the core collapsed down from being

roughly Earth-sized to a sphere 
the size of a small city,

creating a stupendously powerful 
shockwave that ripped the star apart.

And over the next few months, 
that explosion released

as much energy as our Sun does 
over a hundred million years.

In fact, it peaked in 
brightness a full three months

We’ll get back to why that happened later,

but 160,000 years after that initial explosion,

all that light finally reached the Earth,

including Dr. Shelton’s photographic plate.

But after that momentous night 
in the Chilean mountains,

astronomers realized there was 
another signal from the supernova

that had arrived just a bit 
earlier. And it was much weirder.

This episode is brought you by this months

Presidents of Science Mclaren 
Stanley and Charlie Stanley.

Article by AI based on youtube video transcript: The Most Important Explosion in History

Summary by AI based on youtube video transcript

Article by AI based on youtube video transcript

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