In the beginning there was darkness and then
BANG!
giving birth to endless expanding existence of time, space and matter.
Now see futher that we ever imagined
beyond the limits of ours existence
in the place that we called the Universe.
The Universe is vast
wonderous, electrified.
But for space travellers that looking for thrill ride
it could be a one way ticket
It is a place from which you cannot return.
Or at least, not in the form that you went in.
go and no one has dare to venture.
take a virtual tour of the deadiest placies of our galaxy
and beyond
most dangerous places
It is the ultimate frontier adventure, Space Travel
But when trekking through the galactic jungles
One must steer clear of the cosmic, hot zones
Places teeming with violence and intrigue.
There are dangerous places certainly very energetic phenomena
That are a lot more powerful than atomic bombs being detonated
Infinitely more powerful.
The universe does seem to be a very violent place.
It seems to have been born in a violent explosion called "The Big Bang"
And there is also violent processes going on.
On december 27, 2004
Satellites picked up the greatest cosmic explosion ever recorded
A blast 30,000 light-years away
Which had the power to briefly alter our planet's upper atmosphere.
The blast was caused by a magnetar
The densest and one of the most dangerous stars in space.
The magnetic field strength of a magnetar is about
A thousand trillion times the magnetic field energy of the Earth.
And for reference
This would wipe the information off a credit card
At a distance of about 100,000 miles away.
Now, this distance is sort of half the distance of the moon
So it's very nearby by astronomical standards.
These mischievous stars have the strongest magnetic field in the Universe.
Scientists have confirmed 12 of these rare stars in our galaxy
And there may be more.
Caltech's Brian Cameron
Scans the milky way for these strange stars.
Magnetars are a special class of neutron stars
With ultra strong magnetic fields
The densest form of matter in the Universe.
The first magnetar showed itself in the form of a high-energy event
That was detected in the late'70s
Although at the time
We didn't know that it was a magnetar.
It wasn't until the early'90s
That researchers suggested that
these objects were dominated by magnetic fields
And that the magnetar theory was actually confirmed.
Magnetars are born out of the death throes of massive stars.
When a star dies
It begins to collapse and go supernova.
Sometimes, a dense neutron star
Forms from the centers of that supernova explosion.
During the process
A few neutron stars become magnetars
Which possess a strong magnetic field.
These stars eject high-energy emissions of x-rays and gamma rays.
We think that normal neutron stars are born from regular stars
That are something like 10 or 20 times the mass of the Sun.
But there's evidence that
magnetars are born from possibly even more massive stars
Than this, something like 40 times the mass of the S un.
Typically
A star of such mass would be too heavy to form a neutron star.
Instead, its mass would collapse into a black hole.
Black holes are formed
From cramming a certain amount of mass in a certain volume.
And for whatever reason
These stars are unable to do that.
One theory is that some massive stars
Undergo a weight loss program right before exploding as a supernova
Losing 90 percent of their mass.
So instead of collapsing into a black hole
The emaciated star becomes a neutron star
With extreme magnetic powers.
When the magnetic force gets incredibly strong
It deforms the magnetar's crust
Creating seismic events called "starquakes" on its surface.
Eventually, if this crust breaks under the stress
And the magnetic field reconfigures itself into a lower energy state
And when this happens
A fireball is launched off the side of the star.
So starquakes on neutron stars' surfaces are thought to
give rise to these giant flares that we see.
After a magnetar undergoes one of these flares
It outshines all the stars in the galaxy
For a few--For the few tenths of a second that it's taking place.
Within these giant flares
Are short bursts of gamma rays, which move at the speed of light.
The giant flares from magnetars are gamma ray bursts.
They're very short in duration£¬Less than a second
And have very hard x-ray spectra
Compared to another class of gamma ray bursts.
If a deep space traveler veered off course
And was unlucky enough
To pass within 700 miles of one of these massive objects
The consequences would be horrific.
The magnetic field of the magnetar
Can literally warp the atoms in human flesh
And its gravitational forces would tear a person apart.
So then, how close would a magnetar have to be
To wreak havoc in our solar system?
Some suggest
That a blast from a magnetar even 10 light-years away
Could produce cosmic chaos
That would destroy our ozone layer
And cause mass extinctions.
The chances of that happening are so low that, you know
They're completely implausible.
It would be no different than
a regular star passing through the solar system.
And we know that a regular star
Has not passed through the solar system
Since this solar system was formed.
Scientists think
That magnetars are only a few thousand years old
And will become dim after 10,000 years.
We're just now starting to understand
The life cycle of magnetars.
We think that they're very young
But how young is still uncertain.
In addition to magnetars
Satellites and ground-based observatories
Have been picking up other violent things in space.
Scientists have now confirmed
The existence of a phantom-like force
That's so strong
That it might very well be the most vicious phenomenon in the Universe.
Stealthy villains haunt each and every galaxy.
One particular beast tears up anything in its path
And gobbles it down like a cocktail hors d'oeuvre.
It's one of the most bizarre and destructive phenomenon
In the Universe
A black hole.
I think a black hole
Is the place which is more violent than anywhere else in our Universe.
It's like going over the edge
And you can't get back.
It's fatal attraction, I suppose.
A black hole is a region of space
Where the pull of gravity is so immense
That nothing can escape it not even light.
Astrophysicist and triathlete
Feryal Ozel
Is attempting to unlock
The mysteries surrounding this elusive cosmic force.
In a black hole
The gravity is so strong
That no other force can compete with it
So everything collapses to a single point.
Ozel says
Whatever has a close encounter with a black hole
Will fall victim to its relentless tidal force of gravity.
Imagine you're swimming in a pool
And there is no current
You can go whichever direction you want.
Now, imagine, you're taken out of this pool
And you're in a river.
Imagine a current that is much, much, much stronger
That the only direction that you could go
Would be with this current.
The space around a black hole acts like this wild river.
You could never fight this enormous drag that you feel.
As an object approaches the edge of a black hole
Called the "event horizon,"
It reaches the point of no return.
As you come closer and closer to this event horizon
You would already be approaching
This extremely fast motion of space under you
And your only future direction is now into the black hole.
The idea of the black hole
As a hole sometimes can be a little bit confusing.
What it really is
In some sense
It's a place from which you can't return
Or at least, not in the form in which you went in.
Black holes are difficult to detect
Because as the name suggests
You cannot see one by itself because it's black.
But scientists
Have spotted a black hole
When its gravity affects something else in space
Such as a passing star.
A completely isolated black hole would not be visible.
What we really see from a black hole
Is actually the hot material that's swirling around it
And that's being sucked into it.
So, in the neighborhood of these powerful black holes
You'll get a lot of radiation
Resulting from the black hole
Pulling in material - And stretching it - And twisting it
As it's falling in black holes
Black holes consuming anything in close range
And there are billions upon billions of them prowling the Universe.
Astrophysicist Andrea Ghez
Is one of the world's leading black hole hunters.
Black holes are not picky eaters.
They'll dine on whatever get nearby
So they will happily eat gas
They will happily consume a star or a planet.
When a black hole dines on a star
It does so first by tearing it apart.
And you might think of silly putty being stretched out
And then it just streams on in sort of like water
Going down a drain.
It's completely pulverized.
Black holes are produced, we believe
By the collapse of the core of a massive star
Something like 25 or 30 times the mass of the Sun or more.
When it comes to the end of its lifetime
A massive star burns its core
All the way past helium, carbon, nitrogen, oxygen
All the way to iron which has no more nuclear fuel.
And when that iron core builds up to a certain mass
There comes a point where it can no longer support itself
And the core will collapse
All the way to a black hole
Producing at the same time a supernova.
The supernova sends out explosive amounts of energy
So anything in its vicinity will get obliterated.
Then, the remnants of the explosion
fall into a newly formed black hole.
And it seems
The key to the black holes' allure is gravity.
Gravity will pull things around
Just like the Sun's gravity pulls the planets around.
In fact
Stars will happily orbit the black hole for most of its life
And won't actually be sucked in.
These stars are actually safe
From the fatal attraction of the black hole
But if you do venture too close
Like extremely close to the edge
Then you do get sucked in.
Scientists believe there are
Millions of wayward black holes throughout our galaxy, the milky way.
And because we can't readily see them
One could be right next door.
So how close does something have to be
To get sucked into a black hole?
Too close to a black hole is about the distance
Between the sun and the earth
But that is certainly too close.
For future space travelers, death by a black hole
Would be a violent way to go.
The method by which a black hole could kill you
Depends on how big the black hole is.
They come in two categories.
Most of them are the stellar-mass black holes
Which are five to 30 times the mass of our sun.
If the black hole is stellar-sized
Then the tidal forces near the black hole is strong enough
That it will tear you apart tidily
Even well outside the event horizon.
If you wanted to fall into a black hole
You certainly wouldn't want to fall into one of those.
It will spaghettify you.
But in addition to the stellar-sized black holes
There are others that are mammoth
Millions to a billion times the mass of the sun.
And now, scientists believe
That these monsters hold center court in every galaxy including our own.
Black holes
They're one
Of the most mysterious and potentially dangerous oddities in space.
A black hole has a ravenous appetite.
It sucks in everything in its path
And spits out what it doesn't devour.
And now, scientists have discovered
There are supermassive black holes
Which are millions of times bigger than their stellar mass cousins.
And evidence suggests
That supermassive black holes were born after the big bang
When the Universe was first created.
The leading idea is that they would have formed
Just like the stellar black holes from the collapse
Of the core of a massive star.
But then they grew by feeding grossly
From the gas from other galaxies which collided with them.
Scientists have discovered
That these black ogres
Wield their power in the center of galaxies.
The supermassive black holes are at the center of the galaxy
Most likely because
They are the most massive object within the galaxy.
Massive objects tend to sink to the middle
So you'll always find them at the center of a galaxy.
For a long time, scientists didn't think
A supermassive black hole existed in our neck of the Universe
The milky way.
But in 1995
Astrophysicist Andrea Ghez
Set out to prove one exists.
We've done an experiment over the last 10 years
To ask the question
is there a supermassive black hole at the center of our galaxy
And the way we did this experiment
Is to use the motions of stars at the center of our galaxy
To test whether or not there's a large amount of mass
Inside a very small volume.
And that's the proof of a black hole.
At the Keck Observatory in Hawaii
Which houses one of the largest telescopes in the world
Ghez began using
A groundbreaking technology called "adaptive optics"
Which brings into focus far away objects.
So this is without adaptive optics.
This is what you would see.
In this big square, there's nothing.
We turn adaptive optics on
And you see the stars.
This region contains the stars
That provide the keys to our experiment.
So we wanna watch how these stars move.
Ghez noticed that there was a large cluster of stars
Orbiting around an invisible object at the center of our galaxy
And they were moving at an unusually rapid rate.
So we can actually see these stars
That are really close to the center
And we can watch them go around.
Those stars go around the black hole
Just the way the planets orbit the Sun.
The orbits tell us
Where the black hole is
So it's located right where the star is.
That's the center of our galaxy.
And the details
Of exactly how fast these stars are going around
And how tight the orbits are
Tells us the mass of the black hole
Which we think today
Is four million times the mass of our Sun.
For Ghez
Confirming that a supermassive black hole indeed exists
At the heart of our galaxy
Was like summiting Mount Everest.
It was incredibly exciting to discover
The supermassive black hole at the center of our galaxy
Simply because it was a question we had set out to address.
The question, "is there a supermassive black hole?"
And we could design an experiment that actually got at it.
Astrophysicist Andrew Hamilton says
"death by a supermassive black hole
would be much different than by a smaller stellar mass relative.
If you wanna go and be a tourist
And have the ultimate experience of falling inside a black hole
And finding out what's really there
Go visit a supermassive black hole
Much better idea , Unlike a stellar black hole
Which would rip you to shreds, before entering its deadly vortex
A space explorer could actually experience
Free falling inside a supermassive black hole.
Inside of a supermassive black hole
it turns out that even though the black hole is more massive
It's also much larger in size.
And that means
That the type of forces are weak enough
That you could pass through the event horizon
And fall deep inside the black hole
Without being tidily torn apart.
But, deep down inside the black hole
The centrifugal force of the rotation of the black hole
Provides effectively a repulsion.
If there's any matter at all inside it
Then stuff that's falling in
Will tend to collide with stuff that's trying to get out.
And the result of that collision of energies
Is an unimaginably chaotic maelstrom of super hot dense plasma.
And in that case
Your fate is that it can roast you.
So how close would space travelers have to be to get sucked
Into a supermassive black hole in the center of a galaxy?
For a supermassive black hole
You would have to be about a million to a billion miles
From the black hole to feel its influence.
Over the years
The Chandra x-ray Observatory
Has caught our galaxy's
Supermassive black hole nibbling on cosmic matter
Not bingeing like other supermassive black holes.
Our black hole is, today, inactive, compared to other black holes.
Our galaxy has very little gas at the center
And so, there's nothing really for the black hole to feed on.
It's not eating very much.
It's going on a bit of starvation diet.
Our galaxy's supermassive black hole appears to be fasting.
This is partly due to the fact
That as a galaxy ages
Less and less matter is present for it to gorge on.
But, in the future
It might be quite a bit more active
If it ever gets a fresh supply of gas at its center to feed off of
One way to rejuvenate our supermassive black hole's appetite
Is to collide with another galaxy.
Sound implausible?
Two million light-years away
Our closest neighbor, the Andromeda galaxy
Is charging toward us at almost 75 miles per second
Or 270,000 miles per hour.
In the future
Scientists predict the two galaxies will collide
And upon impact
The larger galaxy may engage in
one of the most primitive acts known in the Universe.
It's one of the most barbaric rituals in space
A larger galaxy eats a smaller one.
The scenario isn't a science fiction writer's fantasy
It's a cosmic reality.
It's called "galactic cannibalism."
The ghastly event can occur on the celestial highway
When two galaxies have a head-on collision
Both eventually melt together in a less than harmonious merger.
If you're a galaxy, it's very violent.
You're torn to shreds.
Joshua Barnes studies galaxy mergers.
Acting like a crime scene investigator
He admits his research is a bit like inspecting a car crash.
Imagine that you come across the scene of a car crash
Two wrecked vehicles but no witnesses
Nobody to tell you what happened
All you have is the physical evidence.
That's basically what we have to do
When we study colliding galaxies.
So there are no witnesses to a galactic collision.
All that you have is the present state of the wreckage.
So you have to conduct a sort of forensic investigation
To try and figure out
what happened on the basis of what you have today.
If they collided head on , You would know
Because the fronts were squashed up.
And if they, say, side-swiped each other
Which is actually more likely in galactic collisions
That would leave you a completely different pattern of wreckage
And you could interpret that.
So what causes galaxy mergers?
It's gravity.
Everything in the universe is falling freely through space
And when you've got two large objects like galaxies
Their mutual gravity pulls them together
So they fall into each other.
So it's really just the force of gravity pulling things around.
The galaxies that we're seeing colliding today
Most of them have been bound and destined to collide
For upwards of 10--15 billion years
And they're only now just making it to that first collision.
Our own galaxy, the Milky Way
Is moving toward our neighbor, Andromeda.
Both galaxies are spiral in shape
But andromeda is about twice as massive with a supermassive black hole
The mass of 30 million suns.
It'll look a lot like a dance.
When you see the two galaxies come close together
So they kind of dance around each other
Getting closer and closer, moving faster and faster
Before they finally come together.
But at the point of impact,
These galactic dancers will do more than pirouette.
Each one has a spiral disc of stars
And then surrounding that,
A halo of dark matter, invisible material
That we can detect by its gravitational field.
These two dark halos, which are much larger
Will overlap as the galaxies pass by.
Eventually, as the two galaxies spiral around each other closer and closer
You can no longer distinguish them as separate systems
And finally, the nuclei merge.
When Andromeda and the Milky Way collide
That's going
To be the biggest collision that the Milky Way has seen
Something like five billion years' time.
The good news is that we, the solar system
Will have a grandstand view.
What will happen is the two galaxies
Their spiral discs
Are gonna get tidily torn apart into fantastical shapes.
When the discs start to get close to each other
They'll throw off long streamers of stars
So-called "tidal tails."
And what happens to the Sun and the solar system
Should we still be around
It really is hard to predict.
We could get lucky and be on one of those tidal tails
And get a sort of bird's eye view of the whole process as we fly out
Or we could get thrown into an orbit
Plunging towards the center of the merging galaxies.
There's basically no way to say.
During the merger
If our solar system moves through the suburbs or the edges of Andromeda
We might not notice anything.
On the other hand
Countless stars and space material
Could be propelled towards the planets
Potentially disrupting their orbits around the sun.
Moreover, the entire galaxy could face cosmic upheaval.
We could have consequences
Which would nonetheless be dangerous.
First of all, we could have
A lot of star formations as a consequence of the merger.
Currently, both the Milky Way and Andromeda galaxy
Have plenty of interstellar gas
The raw material from which stars are born.
Now, that would mean
A lot more evolved stars, supernova going off in our vicinity
And that could create shockwaves, blast waves
Or bursts of cosmic rays
Which would have nasty consequences.
After the merger
The fate of our solar system is uncertain
As the supermassive black holes of Andromeda and the Milky Way
Vie for power in the newly jumbled galaxy.
When they merge, they're gonna form a new galaxy
And these two supermassive black holes
Will gradually spiral into the middle of the new galaxy.
They will be a binary black hole for a short time.
And these black holes will start to swallow gas
As the collision stirs things up
Gas will fall into those black holes.
They're gonna turn on.
They're gonna start emitting radiation.
But the potential for fireworks, possibly for fueling the black holes
At the centers of the galaxies
Matter falling into them, possibilities like that do exist
And then the only safe place to watch the process
Would be on one of those tidal tails
Riding out and escaping the collision.
Some scientists think that
Andromeda's larger supermassive black hole
Will eventually consume the Milky Way's.
The two black holes will spiral in the center
And become a binary black hole
And ultimately, will merge with one another
To become yet an even bigger supermassive black hole.
So, a small galaxy colliding with a large galaxy
Is likely to be dominated by the larger galaxy.
It'll essentially have most of its material
Absorbed by that galaxy and becomes subsumed into it.
Scientists believe galaxy mergers
Are a way of life in the Universe.
Modern galaxies, including the Milky Way
Have grown larger by cannibalizing smaller galaxies.
Every galaxy that we see
Has probably been through many collisions.
The Milky Way has a central bulge of stars,
Which are, probably, the relic of a previous collision.
Most scientists agree that
the much anticipated merger between the Milky Way and Andromeda
Won't happen for at least three billion years.
But there may be more immediate dangers in space.
In cosmic neighborhoods, millions of light-years away
There are hyperactive galaxies
That have become the big bullies on the block.
At the heart of some galaxies lives a cosmic monster.
It transforms a run-of-the-mill galaxy into
one of the brightest and deadliest in space.
Quasars are peculiar objects.
Each powered by a supermassive black hole
That continually swallows large amounts of matter
10 to 20 stars every year.
At the core of these objects lives a very large black hole.
And the role of that black hole
Is to actually generate a huge amount of energy.
Quasars are the most energy-efficient mechanisms in the cosmos
They give off more power than a hundred normal galaxies.
And they're 10 trillion times brighter than our Sun.
So how are quasars created in the Universe?
There's a fairly good connection
Between the last stages of a galactic merger
And the so-called "quasar phenomenon."
If that really happens in the case of the Milky Way and Andromeda
We could have
For a period of some tens, even a hundred million years
A quasar active in the center of the merged galaxies.
And a quasar puts out about a hundred times
As much energy as a typical galaxy.
And if we were actually thrown into an orbit
Which took us towards the center of the galaxy
We could get very close to that quasar
And really get scorched.
The word "quasar" stands for "quasistellar radio source,"
Which means star-like emitters of radio waves.
The word was coined
When the quasar phenomena was still a mystery.
Now, we know they're not star-like at all.
In addition to emitting radio waves and visible light
Quasars also give off ultraviolet rays
Infrared waves, x-rays, and gamma rays
All deadlylf, something or someone gets too close.
A quasar is a supermassive black hole at large distance
but it's is active, it's powerful, it's emitting light
And we can observe it in many wave bands.
Quasars were first discovered in the 1960s
But as radio telescope imaging got better
Astronomers discovered that some of those quasars
Also have powerful jets beaming out of them.
These particular quasars are called "blazars"
Probably some of the most violent phenomena in the Universe.
Blazars are powered by black holes just like quasars.
But they're somewhat different in that all their energy
Is being focused
Or a large amount of their energy is being focused into
jets which are streaming out.
A blazar's aggressive plasma jets produce
radiation in the form of radio waves
All the way through the spectrum
Up to high-energy gamma rays.
Astrophysicist Glenn Piner
Had been investigating the physical conditions
At the centers of these exotic galaxies.
We can use this fountain to visualize the geometry of a blazar.
If that circular base of the fountain
Represents the accretion disc
Then the jet of water that's coming up
Represents the jet of plasma coming out from the blazar.
And if the earth is sitting up in the direction that water is going
Then we would see this object as a blazar.
For an astronomer, it's like looking down a fire hose.
It really gets you in the eye to see this bright
Blazing thing that we call a "blazar."
These blazar jets move exceptionally fast.
The fastest observed move at 99.9 percent the speed of light.
If you were to take a small object
Like this bowling ball
And you wanted to accelerate it
Up to 99.9 percent of the speed of light,
You would have to give this bowling ball
All the energy produced in the world
For an entire week to accelerate it to that speed.
And in these blazars
We're accelerating not just small objects like bowling balls
But large masses of the mass of the planet jupiter or larger
To those speeds
So they're being given incredible amounts of energy
By this efficient engine.
Blazars pose unimaginable consequences
To cosmic objects that get too close to its deadly jet.
If there was a planet relatively close
A few light-years from the actual jet
The radiation on that planet
Could be millions of times what it gets from the star.
It would be continually exposed to high levels of radiation.
So I don't think
We wanna look for life on a planet
That would be orbiting a star, that's in a blazar jet.
Scientists link radio telescopes all over the world
To achieve the magnification needed to zoom in on a blazar jet.
So to give you an analogy for what kind of magnification
That would be magnification sufficient to read a newspaper
That someone was holding in New York from Los Angeles.
We'd love to look as close to the central black hole as possible
So we could actually figure out how nature
Is accelerating these jets
And getting them up to such high speeds.
And we'd also like to know
What it is actually that the jets are made of
Because it turns out that's something
That's currently not known.
Until more is known about blazars
Astronomers will keep a neighborhood watch for them
As well as all the other dangerous places
In our uncontrollable Universe.
Definitely
There are violent events going on in the Universe
Much, much more energy than we can even imagine on Earth.
There are trillions of suns shining all at once.
Those are the kinds of energies that we're talking about.
But in that case the fact that we are far away from them
Helps the survival of our species.
If we're actually travelling through space
Then, definitely
We will have to be worrying about these events.