ln the history of our planet, few things have been as deadly as earthquakes and volcanoes.
A huge volcanic eruption produced the biggest extinction that life has ever suffered.
And no-one knows when Mother Nature will unleash her fury again.
These largest volcanic eruptions have happened repeatedly...
..and they're truly catastrophic.
But Earth isn't alone.
Planets, moons and stars are all at risk of violent upheaval.
This is an immense amount of energy released.
lt is a million, million times the energy released
in the most powerful earthquake ever recorded on the Earth.
Get ready because we're shaking the universe to its foundations.
Over the next hour,
we're going deep underground to witness the violent underbelly of the cosmos.
We'll start by investigating quakes and volcanoes here on Earth.
We'll reveal their smouldering pasts and cataclysmic futures,
including a deadly super volcano sitting right in the middle of the United states
that's overdue to blow.
But even our biggest eruptions don't compare to what we see elsewhere in the cosmos..
volcanoes that spew hot gas and magma hundreds of kilometres into the air,.
quakes that measure 32 on the Richter scale.
The violence unleashed on these worlds provides a frightening blueprint
of what could happen closer to home.
Because no matter how hard we try,
there's no way to prepare for nature's cosmic fury.
We've become so technologically advanced that we can rule our environment.
lf there's a mountain in front of us, we just slice through it.
lf we're blocked by a body of water, we just bridge across it.
There isn't an obstacle our planet can throw at us that we can't overcome.
Humans like to think that we're masters of our domain and that we control it,
and that's not true at all.
Every so often, we're reminded who's boss.
Volcanoes and earthquakes are among the deadliest catastrophes on the planet.
lt's estimated they've killed as many as 75 million people in recorded history.
These are some of the most energetic, powerful events
that ever occur on the surface of the planet.
Earthquakes are a daily reminder of the powers at work beneath our feet.
Every day, there are numerous quakes around the world that people can feel,
and there are plenty more that they can't.
so what's going on?
Why does the ground sometimes shake?
The motion that we feel on the crust, those little shakes and murmurs,
even though they might be big to us, they're small on a planetary scale.
lt's just like having a noisy tenant down below turning a stereo up.
There's something going on down there. l can feel the vibrations.
We have a noisy, hot, moving-about tenant just below our feet.
Most of the time, the energy released in quakes is fairly minor.
But sometimes the energy amounts rise to dangerous levels.
The energy released in an earthquake, we use the Richter scale to measure.
Each level of the Richter scale is much more powerful than the one before it.
The Richter scale grades the strength of a quake from 0 to 1 0 or above,
where each number is a tenfold increase in amplitude compared to the one before it.
That means that a magnitude 9.0 quake
is a million times stronger than a magnitude 3.0 quake.
A magnitude 4 is enough to shake you up a little bit.
A magnitude 5 might be enough to knock plants off tables.
A magnitude 6 certainly can do that.
And when you're talking 7 and 8,
it's enough to tear down buildings.
To understand earthquakes and why some tremors are more powerful than others,
you have to understand the architecture of our planet.
lf you were to take a cosmic meat cleaver to the Earth and just slice it in half,
you'd find that most of our planet really is a hot, almost molten ball of rock.
The Earth's inner core is 1,200 kilometres thick, made of solid iron and nickel.
But on top of that, the majority of the remaining Earth is made of super-heated metal and rock.
Most of it is found in the mantle, 2,900 kilometres of molten rock
that can reach more than 1,900 degrees Celsius.
Then there's the tiny sliver that we live on, the crust,
a skin of solid rock that can be as little as 6.5 kilometres thick.
The part of the Earth we live on, the crust,
is a thin layer that makes up less than one per cent of the Earth's mass.
Now, if l were to take the Earth and shrink it down to the size of this apple,
the crust would be about as thick as this peel and the molten centre we know very little about.
Except that it's good.
Very good.
The hot molten middle of Earth is constantly on the move.
Hotter rock from the centre bubbles up towards the surface while cooler rock trickles back down.
The mantle is a fluid. lt's basically molten rock.
And if you take something that's hot on the bottom and cooler on the top, it'll convect.
And so you get these patterns of circulation
where the stuff goes up and falls back down,
and that pushes on the crust.
The forces produced by the convection currents on the solid crust are enormous.
lt's broken the crust into sheets of rock, called plates.
These plates are on the move,
riding the currents of molten rock in the mantle like leaves in a stream.
They're drifting and moving, and sometimes they rub against each other.
sometimes one goes under another one or one goes over the other one,
and when that happens, we here on the surface feel an earthquake.
Friction keeps the plates from moving continuously,
but that means that tremendous stresses build up
as billions of tons of rock smash into one another.
sooner or later that stress gets to be too much and the fault ruptures, triggering an earthquake.
What happens during an earthquake is basically something l can demonstrate here on the table.
What we've got are two tectonic plates,
landmasses that are pressed against one another under great pressure.
Now, they want to slide along one another, but friction holds them together.
However, as the stress increases, friction may not be enough.
And that's an earthquake.
Quakes are evidence that those tectonic plates are always on the move.
ln fact, every tremor is a sign that our planet's changing.
lt's always been changing.
One place we can see direct evidence of this is on New York's staten lsland.
staten lsland is kind of a microcosm of the dynamic Earth.
On staten lsland, we have evidence of an ancient divergent plate boundary,
as we have here, where plates are spreading apart.
Underneath the graffiti are rocks that tell the story of Earth's dynamic past.
400 million years ago,
there wasjust one continent, Pangaea.
The same forces that power earthquakes broke this giant landmass into pieces
and sent them going in all different directions.
At one time, Africa was connected to the North American continent,
and, at that time, we didn't have an Atlantic Ocean.
Pangaea broke apart.
Africa went one way, we went the other way,
and the present-day Atlantic started to open around 200 million years ago.
Like the strands of encoded information that make up our DNA,
geologists can look at the make-up of rocks to determine their origins.
Alan Benimoff and his team are seeing that the same rocks from staten lsland
are showing up in different areas all over the globe.
The rock here is called diabase. That's the name of the rock.
Over in Africa, we'll find similar rocks.
Now separated by thousands of kilometres,
these rocks were once part of the same landmass,
but tectonics separated them and moved them across the globe.
This shows us that the Earth is in a constant state of change.
ln fact, our planet looked like this for less than one per cent of its history,
and is changing even today.
so what will Earth look like a million, 1 0 million, 1 00 million years from now?
Assuming things continue on their current path,
Africa will slam into southern Europe
as North America slides west.
Antarctica will head north as Australia sideswipes southeast Asia.
We're always gonna have oceans and continents, but we know one thing:
the continental configuration and oceanic configuration
won't look like it looks now in the future.
When Earth flexes its muscles, the ground shakes...
..and continents break apart or smash together.
But the titanic forces at work inside our planet also power Earth's most explosive events,
some of which can be so large
they threaten our very existence.
Below these oceans and continents, there's an Earth we don't see,
one that's home to enormous forces
that sometimes wreak havoc here on the surface.
These forces are what's behind catastrophic earthquakes,
but they're also what power volcanoes.
When a volcano erupts, we're really seeing energy
that's built up over hundreds or thousands of years
suddenly getting released all in one instant.
And so it actually becomes some of the most active, explosive events
that ever occur on the surface.
No-one knows exactly how many volcanoes there are on Earth,
but at any given time, there are about a dozen of them erupting.
Most volcanoes pop up among plate boundaries,
where one plate is sliding beneath another and melts.
As it melts, the hot rock and gases dissolved within it bubble up to the surface.
ln 1 980, Mount st Helens in Washington blew itself apart in an epic explosion.
lt sent a column of ash 24 kilometres up into the atmosphere.
ln 1 991, Mount Pinatubo blew its top and sent a column of hot ash and gas up 35 kilometres.
so why are some volcanoes so explosive?
lt has to do with gas trapped in the magma.
To demonstrate, l've got a trashcan filled with water - that's our magma -
and a gas bubble is represented by this bottle
with two ounces of liquid nitrogen in it.
l'm gonna screw on the cap and drop it in and watch what happens.
Whoa! Look at the can.
Now, what happened here?
As the liquid nitrogen expanded into a gas,
it threw the water up into the air,
and the same thing happens in a volcano.
As magma rises to the surface, the pressure decreases,
allowing the trapped gas within to expand explosively,
throwing magma up into the air, just like what we saw here.
The pressure from these gases is enough to blow mountains apart.
But as powerful as these eruptions are,
they're nothing compared to some others we see out there in the solar system.
Venus has some of the largest volcanoes anywhere in the solar system,
and furthermore, the lava flows are planet-wide.
Venus is a volcanic heavyweight.
lt has more volcanoes than anywhere else in the solar system.
Radar mappings of the planet identified more than 1,600 major volcanic structures
and maybe 1 00,000 smaller ones.
so what's behind all this fire and brimstone?
Venus apparently doesn't have plate tectonics of the kind that we're familiar with on Earth.
ln the case of Venus, the plates form,
they build up in thickness,
and then, when the interior heat gets to be too much,
the plates drop into the interior of the planet
and the surface of the planet is completely remade from volcanic rocks.
Like Earth, Venus has a molten mantle and hot inner core.
But its crust is a lot thicker, which means that Venus is like a pressure cooker.
On Earth, heat in the interior escapes through the constant movement of the plates.
But Venus doesn't have plate tectonics.
lts crust is solid and bottles up all the heat and pressure until it literally explodes.
There's a lava flow channel on the surface of Venus that's 22,000 miles long
that winds its way essentially from the North Pole of the planet to the south Pole.
While Venus may have the most volcanoes,
Earth's other neighbour, Mars, has the largest.
Mars is home to some of the solar system's most spectacular volcanoes.
ln fact, the largest volcano in the solar system is Olympus Mons.
Towering over the Martian landscape,
volcano Olympus Mons rises more than 25,000 kilometres high...
more than three times as high as Earth's tallest peak, Mount Everest.
When l was a kid, we used to joke
that we were gonna make a bumper sticker called ski Olympus Mons.
But it turns out you can't really do that.
Even though it's 1 6 miles high, it's so broad at the base that if you were standing on it,
in many cases, you wouldn't even notice that you're standing on a hill.
Like Venus, Mars has a thick, solid crust that doesn't move.
That means the molten rock just pushes out in the same spot
to build on itself for hundreds of millions of years.
When a weak spot emerged and the volcano started erupting,
nothing moved, so it just built up and built up and built up
and made this enormous feature on the surface of Mars.
When it comes to size and might,
volcanoes on Venus and Mars dwarf almost anything we find here on Earth.
But we do have a few volcanoes here that are powerful enough
to drive life to the brink of extinction.
They're called super volcanoes.
A super volcano is an eruption that ejects a minimum of 225 cubic miles,
mile by mile by mile,
of lava out onto the Earth's surface.
When we think of mass extinctions,
the asteroid that wiped out the dinosaurs 65 million years ago
is the first that comes to mind.
That impact killed 70 per cent of all species on Earth.
But 1 85 million years before that,
a super volcano erupted in siberia with enough fury
to change the environment so drastically that 95 per cent of all the species on Earth died.
That's the biggest extinction that life has ever suffered.
The eruption of Mount st Helens in 1 980
belched out four fifths of a cubic kilometre of ash.
Mt Pinatubo burped out a little over four cubic kilometres of material.
But this super volcano in siberia released hundreds of thousands of cubic kilometres
of lava and ash into the atmosphere.
scientists believe it was enough to blot out the sun.
lf the total amount of material blasted out of Mount st Helens in 1 980
were represented by this marble
and the 1 991 Mt Pinatubo eruption by this orange,
the super volcano would be the size of this giant balloon.
That's 240 cubic miles of ash and debris.
so are there super volcanoes left on Earth that could erupt?
lt turns out there are.
We know that Yellowstone has produced several super volcanic eruptions in the past
and we're pretty sure that it will produce another super eruption.
Right in the middle of the United states
is one of the Earth's biggest super volcanoes,
Yellowstone National Park.
This super volcano has erupted more than 1 00 times over the last 1 6 million years.
The last eruption was 640,000 years ago,
and no-one's quite sure when the next big one is coming.
Those tremendous catastrophes do not happen very often,
but they have happened repeatedly over millions of years.
And so ultimately, the question we're asking is where are we in the volcano's history?
When will the next magma erupt to the surface?
Beneath these postcard vistas is a 70-kilometre-wide chamber
full of molten rock under incredibly high pressure.
This magma is what powers Yellowstone's fantastic geysers and hot springs.
But within the beauty lies a beast.
lf Yellowstone blows, it will create an apocalyptic catastrophe.
A super eruption at Yellowstone would be a global event.
lt would produce what sometimes get called stone hurricanes,
lateral flows of solid rock,
molten magma, volcanic gases, and temperatures, searing temperatures,
moving maybe 1 00 miles an hour across the countryside.
An eruption would send millions of tons
of super-heated rock and ash kilometres into the atmosphere.
Blast waves of these fiery clouds would roll out from the volcano
and scour the surface of every living thing.
There will be ash and volcanic gas injected all the way into the stratosphere,
tens of miles above the surface.
That material will encircle the globe.
lt will alter global weather.
The global temperature would drop by degrees, probably for a period of at least years.
The Earth would be a very different place.
On our little planet, we're threatened with all sorts of apocalyptic scenarios..
asteroids smacking the Earth,.
gamma ray bursts frying the atmosphere,.
and black holes sucking us in.
Fortunately, those frightening events have a low probability of occurring any time soon.
But the Yellowstone volcano erupts roughly once every 600,000 years
and the last eruption was about 640,000 years ago.
Which is why volcanologist Dan Dzurisin is here monitoring the surface
to learn what's going on underground.
We're here studying it in between those eruptions,
so that we'll recognize the signals that undoubtedly will come before the next eruption.
Dzurisin is looking for any clue that could signal an impending eruption.
He uses GPs monitors at different points in the park to determine if the ground is rising.
We should expect the ground surface to move.
lt might go up by feet, for example, as magma begins to approach the surface.
We should expect earthquakes, some of them too big to stand up in.
And it's those signals, those changes,
that we want to study and interpret properly to give a warning.
And over the last few years, Dzurisin has noticed changes.
We've discovered that Yellowstone right now is going up faster
than we've ever measured it before.
lt's a tremendous rate, on the order of three inches a year,
seven to eight centimetres a year.
That's two to three times higher than any rate we've measured before.
No-one knows when Yellowstone will blow again,
but what would an eruption be like?
scientists don't have to imagine it.
There are hundreds of them erupting right now.
They just happen to be on a tiny world more than 800 million kilometres from Earth.
Earth's super volcanoes have rained down catastrophe on our planet in the past
and no-one's sure when the ticking time bomb that is Yellowstone will explode again.
But since we can't study a super volcano's eruptive fury here on Earth,
we can only hope to glean some clues from volcanoes out in the cosmos,
and there's no better display of the awesome power of eruptions
than on Jupiter's moon called lo.
Jupiter is orbited by a lot of moons.
One of them is called lo.
lt's roughly the same size as the Earth's moon,
but it really could not be any more different.
lt looks like a pizza.
lt's kind of orange and it's covered with yellow and red and black spots and white spots
and it doesn't look like anything else in the solar system.
lo's a hellish world brimming with rivers of molten rock and lakes of hot liquid sulphur.
lt has enormous volcanoes, and they're the hottest spots in the solar system,
with temperatures nearing 1 6,000 degrees Celsius.
And it's got explosive plumes rising so large,
they can be seen from Earth with the Hubble telescope.
On Earth, you'll get a volcanic explosion.
You might see a plume that goes up 1 0 miles, maybe even 1 5 or 20 miles. Very high up.
But on lo, the gravity is lower,
and so the plumes of these volcanoes can reach up hundreds of miles.
At any given time, there are up to 300 volcanoes erupting on lo.
so what powers these alien super volcanoes?
We think that lo has such a high level of volcanism
because it's so close to the planet Jupiter.
Because of its proximity, it actually experiences tidal forces.
These tides on lo are exactly the same phenomenon
as the tides the moon raises on the Earth.
On lo, however, this is so extreme that the land tide is 330 feet tall.
so every time high tide comes around, the land bulges up
the height of a 30-story building and then relaxes back again.
These immense tides roll over lo
and the accompanying friction heats its interior to thousands of degrees.
You can imagine if you took something and stretched it over and over again,
you're going to heat it up.
To understand what these land tides do to lo's interior,
you simply need a ball of putty.
All of that gravitational stretching and squeezing is why lo is so hot.
lt's a classic example of a principle called mechanical equivalent of heat.
Now, l have a nice sized ball of putty here and it's temperature reads about 87 degrees.
l'm going to twist it and squeeze it and stretch it, and roll it out on this table.
l'm even going to hit it with this hammer,
and as l do, the molecules inside are banging into each other and sliding over each other,
releasing a lot of heat energy.
And even with that little bit of action that l did,
the temperature's gone up three degrees,
and that's exactly what happens on the surface of lo, but on a massive scale.
The interior of lo is very hot and so it's actually molten.
And when you have a molten interior and a solid exterior, what you get is tectonic activity.
What you get are volcanoes.
lo's largest volcano is the 1 90-kilometre-wide Loki.
That's a monster, nearly four times the size of Yellowstone's super volcano.
There are many volcanoes on the surface of lo
that we would consider super volcanoes were they to occur on Earth.
And that's what makes lo so interesting to scientists.
The problem is it's about 800 million kilometres away from Earth.
so beyond just looking at pretty pictures, how do scientists study lo?
They come here to Hawaii's Kilauea volcano.
lt's fun to come here
and try to see how volcanoes on Earth
can tell you about volcanoes on lo.
Rosaly Lopes is one of the world's foremost lo experts.
she's here looking for volcanic features similar to the ones she sees on lo.
By examining those features on Earth,
she gains insight into the processes that created them on lo.
l'm walking here at the bottom of Kilauea lki.
This had a spectacular eruption with a fire fountain that was about a third of a mile high.
On lo, we had an eruption where a fire fountain was shooting up about 1 .2 miles high.
This gives us an idea about the very violent processes that are going on in the interior of lo.
These processes, Lopes believes, are the same that power Kilauea.
On Earth, most volcanoes occur at plate boundaries,
but Kilauea is in the middle of a plate
and it's powered by a current of super-heated rock called a mantle plume.
The rock in a mantle plume is so hot and it rises so fast
that it punches into and burns through the hard crust,
creating a volcano, or even a series of volcanoes.
Now, if this flame were a mantle plume,
watch what happens to our crust.
The mantle plume is warming the underside of the crust,
and there it busts through and makes a volcano.
And if the crust moves a bit...
ah, there's another volcano.
And if the crust moves some more,
we get yet another volcano.
There are about 30 plumes here on Earth,
but on lo, there may be hundreds, even thousands.
That's because lo's insides are incredibly hot.
ln fact, some of the lava erupting from lo's volcanoes
is 500 degrees Celsius hotter than lava on Earth.
The volcanoes might be spewing out a type of lava
that has not erupted on Earth... for millions and mostly billions of years.
This means lo could provide scientists with a window into our planet's past
and the kinds of processes that created our planet's crust.
The forces that power alien super volcanoes are, in many respects,
the same that power those on Earth,
but knowing that these subterranean processes are universal hasn't made it any easier
to predict those events here on Earth.
But there's hope that we one day will
because scientists are getting an unprecedented look
at what's happening far beneath our feet.
ln the last century, quakes killed nearly two million people.
lt seems hard to believe, because the ground we stand on seems so solid.
But it turns out that's part of the problem.
lt's because the planet is so static,
the surface is very resistant to change.
When those changes occur, they tend to be very traumatic.
A large earthquake, where suddenly two plates begin to shift against one another,
can have effects for hundreds or thousands of miles.
What makes quakes so deadly is that unlike hurricanes and tornadoes,
earthquakes don't announce their arrival.
They strike without warning.
There's nothing to really tell us that one's imminent.
so why are they so hard to predict?
This is my earthquake machine, which is going to allow me to demonstrate
why it's so difficult to predict exactly when an earthquake is going to occur.
The brick represents the crust, the solid rock of the Earth,
which is sliding on the molten material underneath.
And the crank represents the constant motion of the plates as they slide over the mantle.
Now, let's make an earthquake.
The force on the plates is constant.
Nothing's moving because of friction.
The tension's getting stronger and stronger...
bang! An earthquake!
Oh, another earthquake right after it.
But now it's quiet again. There's a little earthquake.
so the first one was big, the second one was sort of medium, the last one was small,
but l couldn't predict the timing or the size.
Here's a second experiment.
l'm gonna crank at exactly the same rate because the forces underneath don't change.
Oops, a little bit of a slip.
And then a big one.
Oh, and there's another one after that.
And another big one.
lt's exactly the same machine, l was cranking with exactly the same force
and yet l couldn't even predict when the brick was going to move.
lt's not surprising, then, that seismologists have trouble predicting earthquakes in the real world.
For as long as we humans have been around to feel quakes,
we've been looking for ways to predict them.
so far, that's basically been impossible
because forecasting quakes
means understanding processes going on far beneath the surface.
One of the big challenges we have in earthquake science
is actually knowing what the fault is made of.
What are the materials? What conditions do they operate under?
We don't know those things.
We can't see the fault because it's buried under miles of solid rock.
seismologist Bill Ellsworth of the Us Geological survey is leading a project
that's giving scientists a look inside one of the world's most active and dangerous faults,
the san Andreas.
We're standing right on the san Andreas fault. lt's right behind me here.
This line of monuments that we're looking at
were built in 1 986 and they were put in in a straight line.
And what you can see is that they have been shifted progressively
by the movement of the san Andreas fault.
This side moving to the left, that side moving to the right, relatively,
so that over two feet of motion has accumulated.
The san Andreas is a massive fault running 1,200 kilometres up the California coast,
where two massive plates, the Pacific Plate and the North American Plate, come together.
At least 1 6 miles underground,
the Pacific Plate grinds into the North American in a north-westerly direction.
Every year, there are tens of thousands of tremors along the san Andreas.
Most are tiny, but some grow into catastrophic quakes.
Ellsworth wants to know why.
We think that every earthquake starts small and then grows to an indeterminate size.
One of the key things we're looking at is a bridge between the very smallest events we see
and those of larger scale.
To explore the relationship between micro- and mega-quakes,
Ellsworth is dropping an extremely sensitive listening device
into a hole that goes down almost three kilometres into the Earth,
directly into the san Andreas fault.
The listening device will detect the fault's faintest rumblings.
The sensor is sitting about 200 feet from the actual trace of the san Andreas fault.
By getting very close and being in much harder rocks underground,
we see those very fine details that otherwise get lost.
so here we can look at what happens in just, say, the first yard of rupture of an earthquake,
as opposed to maybe the first hundred metres, as what we might see at the Earth's surface.
Being closer to the fault will allow Ellsworth to hear what happens
in the very first moments of an earthquake.
He's hoping to eventually decipher the differences between small and large tremors.
so a key question is whether all earthquakes begin the same way or not,
whether there are differences in the way larger earthquakes start.
There are some theories that suggest it should be,
but we don't really have those answers yet.
scientists may be able to predict quakes in the future
if they can understand the intricate processes that go on underground.
And looking closely at faults like the san Andreas
could help them find patterns or certain signs
that a devastating earthquake might be on the way.
That could lead to early predictions, potentially saving countless lives.
But as bad as earthquakes can be on our planet, we should consider ourselves lucky.
There are quakes out in the cosmos that, even if we knew they were coming,
would rock our world.
Earthquakes are one of the most dangerous natural phenomena on the planet.
Not only can they strike without warning,
but they've also got the power to spread disaster across hundreds
and even thousands of kilometres.
But would you believe that these events are, in fact, universal?
There are several other kinds of quakes in the solar system
beyond those that we experience on Earth.
The moon has quakes that are induced by the tidal stress of the Earth.
lnterestingly, the sun also has quakes.
sunquakes are without doubt the most powerful seismic events in the solar system.
They're caused by enormous explosions called solar flares.
lnside the sun, there are huge currents of gas,
and as they move, they generate magnetic fields
that rise up and loop over the surface of the sun.
When these massive loops break, they explode,
and the resulting explosions
can reach up to tens and even hundreds of thousands of kilometres high.
The amount of energy that's released in a solar flare is beyond human comprehension.
You could take all of the combined nuclear weapons on the entire planet
and a single solar flare would blow those out of the water.
The power of that explosion can cause the sun to shudder.
As the magnetic loops break and explode,
billions of tons of hot gas come crashing into the surface, causing a sunquake.
so it slams into the surface of the sun and can cause the sun's surface to ripple
and that's similar to an earthquake on Earth,
except, of course, on the sun this is a much larger and more violent event.
ln 1 998, scientists spotted a small solar flare
that triggered a sunquake that would have measured an 1 1.3 on the Richter scale.
That's almost 1 00 times more powerful than the largest earthquake ever recorded.
A similar thing happens on a magnetar.
But what is a magnetar?
They're neutron stars.
Neutron stars are the mass of a normal star
compressed into something the size of a small city, say, six miles or so across.
Magnetars are the most extreme of these objects.
These things are extreme in every sense of the word.
They're the densest objects in the universe. They have the highest gravity on their surface.
They can be spinning incredibly rapidly, sometimes thousands of times per second.
They also can have incredibly intense magnetic fields.
These stars are so dense that a teaspoon of material from one of them would weigh
as much as all the cars and trucks on Earth.
Neutron stars do have a solid crust.
Now, admittedly, this is a crust of pure neutronium, neutrons slammed together,
but it does have the properties of a solid.
The crust of the magnetar is like a giant crystal
and it's under huge stresses from this tremendous magnetic field.
And that stress builds up and the crust suddenly cracks.
The crust might only move a millimetre,
but because magnetars are such massive objects, the amount of energy released is titanic.
The release of energy when you have a crack on the surface of a neutron star
is far vaster than any kind of earthquake
you could ever imagine on the surface of the Earth.
lt's beyond comprehension.
The most powerful earthquake ever measured on Earth was roughly a magnitude nine.
A magnetar flare is generated by a seismic event
that has a measurement of roughly Richter 32.
32!
lt is a million, million times the energy released
in the most powerful earthquake ever recorded on the Earth.
A magnitude 32 earthquake would literally turn the crust of the Earth inside out.
ln 2004, scientists detected one of these quakes on a magnetar 50,000 light years away.
so much energy was released by the quake,
it sent out a pulse of hot energy gamma rays
that actually tampered with Earth's magnetic field.
lts crust must have slipped literally this much.
Just that much.
This object was halfway across the galaxy
and this explosion was violent enough to literally compress the Earth's magnetic field.
Luckily, that's all it did,
but given that, do magnetar quakes pose any danger for us here on Earth?
so if the solar system were cruising through the galaxy
and happened upon a magnetar, say, 1 00 light years away, that had one of these quakes,
the burst of radiation would ionise the atmosphere,
destroy the ozone layer and expose us to ultraviolet radiation.
The chances of Earth's atmosphere getting fried by a magnetar quake are pretty slim.
scientists know of only 1 0 in our galaxy,
but there may be millions more.
Whether we look to the celestial bodies in faraway space or deep under our own planet,
powerful forces shake things to their very core.
On Earth, quakes and volcanoes have killed millions in the past
and no doubt will cause mass destruction in the future.
so while we may think we're masters of our domain,
look below and you'll find that Mother Nature's cosmic fury
has a way of cutting us down to size.