Supernovas are the violent death of giant stars, and new discoveries reveal that these cataclysmic events create the elements that are essential to all life in the universe.
Thanks for watching. Follow for more videos.
#cosmosspacescience
#howtheuniverseworks
#season7
#episode2
#cosmology
#astronomy
#spacescience
#spacetime
#space
#nasa
#supernova
#exposionofstar
#cataclysmiceventsinspace
#newdiscoveriesofspace
#deathofstar
Thanks for watching. Follow for more videos.
#cosmosspacescience
#howtheuniverseworks
#season7
#episode2
#cosmology
#astronomy
#spacescience
#spacetime
#space
#nasa
#supernova
#exposionofstar
#cataclysmiceventsinspace
#newdiscoveriesofspace
#deathofstar
Category
📚
LearningTranscript
00:00supernovas gigantic explosions that light up the cosmos one of the most spectacular things in the
00:15universe is the death of a giant star they live fast and they die young inside the stars core
00:24temperature and pressures are immense we're talking about a billion degrees in the center
00:32of one of these stars a ticking time bomb that explodes with indescribable energy the last
00:40minutes of a giant star's life are the most cataclysmic events that we see in the universe
00:47dramatic finales blazing across space that one supernova is brighter than the hundreds of
01:00billions of stars that constitute the galaxy how amazing is that but these stellar deaths
01:06also hold the key to life itself understanding supernovas is understanding our story we owe our
01:15existence to them right now somewhere in the universe a giant star is detonating creating a
01:38huge cosmic explosion called a supernova supernovas are a big giant dramatic end to a star's life
01:54all stars die but only the biggest go out with a bang
02:03for a star to go supernova we think it has to be at least eight times more massive than our sun
02:10it's so easy to think of our sun as this incredibly gigantic thing but our sun is absolutely tiny
02:17compared to some of the giant stars in the sky
02:19we can see some of these giant stars with the naked eye
02:28and the 10th brightest in the night sky is a red supergiant around 15 times the mass of the sun
02:37betelgeuse
02:40betelgeuse is so big that if you were to place it in our own solar system it would stretch to the orbit
02:49of jupiter this is one of the biggest beasts in the galaxy it's a star also that is on the verge of death
02:58betelgeuse is less than 10 million years old but this huge star's days are numbered it's ready to blow
03:09and when it does we'll see a region of sky brighten for 14 days until it's nearly as bright as a full moon
03:21it is going to be one of the most spectacular shows in history
03:26and it could happen at any moment i mean this is the thing i often stand outside in my yard in the wintertime
03:34i look up at orion and i see betelgeuse i'm like explode
03:38so what will make betelgeuse goes supernova
03:44to understand a giant star's death we need to understand its life
03:49from the day it's born until the day it dies
03:55a star's life is a constant battle
03:58gravity is pulling in and energy pushing out
04:05the interior of a star is fusing countless atomic nuclei together
04:10atoms are ramming into each other getting very very close
04:14and if they get close enough they'll actually stick and form a larger atom
04:19every second a giant star fuses seven and a half billion tons of hydrogen
04:27that amount of energy is roughly equivalent to about 100 billion atomic bombs per second
04:32that's a big-ass explosion
04:35this explosive energy threatens to blow the star apart
04:42but the star's own massive gravity keeps the lid on
04:47everything in the universe is a fight between the inward force of gravity
04:52and the outward force of pressure or energy
04:55every single star in the sky even our own sun is an incredibly dynamic battleground
05:01in many ways stars are an explosion that are actually too big to explode
05:04gravity holds it together
05:06this battle between these two opposing forces
05:12determines the life and death of the star
05:15and this is where size matters
05:18the more massive the star the more gravity pushes inward
05:22and the harder the star has to push outward to keep itself alive
05:28very massive stars are like stars on steroids
05:33they have a lot of fuel to burn
05:37they're so powerful that they use up their fuel at a rapid rate
05:42massive stars like beetlejuice are giant factories
05:49fusing lighter elements into heavier ones
05:52but the hard work doesn't start until their final years
05:56for around 90 percent of their life they fuse hydrogen into helium
06:02but eventually the hydrogen starts running out
06:05in the core of a supergiant star
06:09there's a sequence of fusion that goes from lighter elements to heavier elements
06:13and it gets faster and faster every step of the way
06:16the countdown to death begins
06:20the inward push from gravity takes over
06:24raising the temperature in the core
06:26helium starts fusing into carbon
06:29there's enough helium to last about a million years
06:33but it too runs out
06:36and things start speeding up
06:38carbon gets fused into neon
06:41that takes about a thousand years
06:43neon fusing into silicon that takes about one year
06:46once it starts fusing silicon into iron
06:49that takes one day
06:51it gets more and more frantic
06:54it's kind of like a cooking contest show
06:56where as the clock is running down
06:57they're trying to do more and more things
06:58and they get more and more frantic
07:00until ding
07:01time's up
07:02the star is now in its death throes
07:09once iron production has started
07:11the clock is ticking towards the cataclysmic end of this star
07:17a giant ball of incredibly dense iron forms in the middle of the dying star's core
07:26this iron sphere is several thousand miles across
07:31and unbelievably hot
07:33it gets so hot there
07:36the temperature almost becomes meaningless
07:38i mean we're talking about a billion degrees in the center of one of these stars
07:42this extreme heat is caused by fusion reactions
07:50more and more reactions create heavier and heavier elements
07:54and with each step
07:56less and less energy is produced
07:58until iron is created
08:01when you try to fuse iron nuclei together
08:04that takes energy
08:06it doesn't generate energy
08:07so once the core starts to fuse iron
08:09it's basically stealing its own energy
08:12the growing iron core sucks more and more energy from the star
08:17gravity continues pulling in
08:20overwhelming the outward pressure
08:22from inside the star
08:24everything gets crushed to unimaginable degrees
08:30all of a sudden there's no nuclear reaction to support the star
08:34against the crush of gravity
08:35with nothing left holding it up
08:41the star
08:42is doomed
08:43gravity wins
08:45the edges of the iron core collapse
08:48trillions of tons of dense iron fall inward
08:52at a quarter of the speed of light
08:54the star has now less than one second left to live
08:58things start to fall apart
09:00really quickly
09:02the core collapse is so fast
09:05that the outer layers of the star
09:07don't even have time to react
09:08they're just hanging there
09:09it's kind of like wily coyote
09:10when a cliff collapses underneath him
09:12and he doesn't even fall
09:13until he notices
09:14the rest of the star collapses
09:19a trillion
09:20trillion
09:21trillion tons of gas
09:23hurtle inwards
09:24following the iron
09:26think about the entire mass of the star
09:28that has been held up by nuclear reactions inside
09:31all of a sudden those nuclear reactions go away
09:33in a split second
09:35everything rushes into the middle
09:36and that sets off the most dramatic explosion in the universe
09:42the spectacular death blow can outshine all of the stars in the galaxy
09:54but there's a problem
09:59we still don't fully understand
10:01how a collapsing ball of iron
10:03and tons of falling gas
10:06create a giant fireball
10:08how this collapsing core triggers a massive explosion
10:13is one of the biggest mysteries in astrophysics
10:16a supernova
10:39one of the most powerful eruptions in the cosmos
10:42triggered by the collapse of a massive star
10:46how do you go from a violent collapse
10:49to an incredibly dramatic explosion
10:51this involves some of the most complex astrophysics
10:55known to humanity
10:57and we don't fully understand the details of the process
11:01we're missing something
11:03because we nearly always spot supernovas too late
11:06what you're seeing is you're seeing the star brightening
11:09and that's really happening after the fact
11:12so now the magic key
11:14is not finding a supernova
11:16but finding the moment that we call the breakout
11:19the breakout is a giant star's death rattle
11:27it's the moment after the core has collapsed
11:30when the star blows apart
11:32in a huge flash of visible light
11:35but in the entire history of astronomy
11:40this moment has only been caught twice
11:44once by nasa's multi-million dollar space telescope
11:47kepler
11:48and once by a very lucky argentinian amateur
11:53i love this story there's an amateur astronomer named victor busso
11:57he has a very nice telescope in an observatory in his yard
12:00and he was taking photographs repeatedly of the same galaxy
12:04that happened to be overhead
12:05and he just happened to be looking at the right region of the sky
12:09and he luckily caught the shock breakout of a supernova
12:12the chances of catching this moment
12:18one in ten million
12:20what victor caught was the moment the shockwave reaches the surface
12:25victor noticed this spot appearing in his photographs
12:31realizing he'd captured the first flash of light from an exploding star
12:36he alerted professional astronomers across the globe
12:39when i heard of his discovery
12:43i was like no way
12:46how could the sky using a camera on his telescope
12:50for the very first time
12:51pointing at a single random galaxy in the sky
12:55have found this exploding star
12:58in the first hour of its explosion
13:00it's almost too good to be true
13:02alex filipinko and his team
13:05monitored the brightening light from the star
13:08what we found when studying the light from busso's supernova
13:13is that the object brightened very quickly
13:16for a short time
13:18when a shockwave
13:20a supersonic wave
13:21going through the star
13:23burst out through the surface
13:26and when it gets right to the edge
13:28that huge amount of energy is released
13:30as a tremendous flash
13:32that is the moment of shock breakout
13:35the monstrous shockwave travels at nearly 30,000 miles per hour
13:42bursting through the surface of the star
13:45and ripping it to pieces
13:47fire!
13:54we see shockwaves from explosions on earth
13:57they can travel through gas
13:59liquid and solid
14:01including the layers
14:03of a collapsing star
14:04this observation of the shockwave
14:09reaching the surface of the star
14:11was incredibly important
14:12because victor managed to catch a star
14:14the moment it actually went supernova
14:16that is something that is a scientific treasure
14:19the shock breakout
14:22is like cosmic gold dust
14:24a flash in the pan
14:26that lasts 20 minutes
14:27just a blink of the eye
14:31on astronomical timescales
14:33but what sets
14:36the shockwave off
14:37is it just a question of bounce
14:40a supernova shockwave
14:42can be explained
14:43with the help
14:44of a basketball
14:45the thing about an exploding star
14:48is that the nuclear reactions
14:49go out in the core
14:50and then the outer layers
14:52fall in
14:52at incredibly high speeds
14:54toward the inner core
14:55and then
14:56it rebounds
14:58and bounces out
14:59and what gives it so much energy
15:00is the structure of the star
15:02as the dying star
15:05burns through its fuel
15:07it creates layers
15:08of different elements
15:10heavy iron at the core
15:12with layers
15:13and layers
15:13of lighter elements above
15:15so let's say
15:16there was only one layer
15:17and there was a rebound
15:18like dropping this ball
15:20it doesn't bounce very high
15:22but let's say
15:23it's organized like a star
15:24where the heavy thing
15:25is at the bottom
15:26the lighter thing
15:27is at the top
15:27and let's see
15:28how this rebound goes
15:30now that was a rebound
15:38the tennis ball
15:40launches off the basketball
15:42because energy
15:43from the basketball's bounce
15:45is transferred upwards
15:47the same thing happens
15:49in a collapsing star
15:50but with many more layers
15:52all the different elements
15:54collapse inwards
15:56the heavier layers
15:57hit the dense core first
15:59passing energy
16:00to the lighter ones
16:01and this
16:02creates the shock wave
16:04but this energy
16:07isn't enough
16:08to propel the shock wave
16:09all the way
16:10out of the star
16:11the problem is
16:13when we looked at this
16:14in detail
16:15using computer models
16:16it didn't work
16:17the shock wave
16:18seemed to stall
16:19we couldn't get the star
16:20to explode
16:21for 50 years
16:22we couldn't figure out
16:23what we were missing
16:24scientists suspect
16:27something else is involved
16:29something that's almost
16:30impossible to detect
16:32could there be
16:33a ghost
16:34in the supernova machine
16:41when stars as big
16:55as beetlejuice die
16:56there are explosive deaths
16:58and shock waves
16:59that travel trillions
17:01of miles through space
17:02but how these shock waves
17:04are created
17:04has puzzled scientists
17:06for decades
17:07time and time again
17:10when we actually went back
17:11to our computers
17:11and our theories
17:12and looked at how
17:13supernova should work
17:14they just didn't
17:15they shouldn't actually explode
17:17in computer models
17:20the bounce from falling gas
17:22and the collapsing core
17:23can't drive the shock wave
17:25all the way
17:25out of the star
17:26something crucial
17:28is missing
17:29what we needed
17:31from inside the core
17:32of the star
17:33was a completely new
17:34source of energy
17:35something to actually
17:36make that final push
17:37to get the star
17:38to rip itself apart
17:39scientists suspect
17:42this energy comes
17:43from an enigmatic particle
17:45called a neutrino
17:47neutrinos are a type
17:49of fundamental
17:50physical particle
17:51that are still
17:52a little bit mysterious
17:52to us
17:53they're almost like
17:55ghost particles
17:56they travel through us
17:57without touching us
17:57at all
17:58like particles of light
18:04photons
18:04neutrinos
18:06carry no electrical charge
18:08but
18:08unlike photons
18:10they can pass through stars
18:12planets
18:13and us
18:14so
18:15where do they come from
18:16scientists predict
18:18the source
18:19is the star itself
18:21in the middle
18:23of the core
18:24of the star
18:24you're producing
18:25something called
18:26a neutron star
18:27an amazing
18:28super compressed
18:29ball of matter
18:30only about
18:30ten miles across
18:32as the iron core
18:34of a star
18:34collapses
18:35the atoms
18:36are crushed together
18:37protons
18:39and electrons
18:40are forced to combine
18:41to form neutrons
18:43this process
18:44releases
18:45vast quantities
18:46of neutrinos
18:48despite being
18:52one of the most
18:52abundant particles
18:53in the universe
18:54neutrinos
18:56are notoriously
18:57difficult to detect
18:58but in 1987
19:04scientists
19:05got lucky
19:06a massive star
19:09went supernova
19:10in a nearby galaxy
19:12in 1987
19:16astronomers got
19:17a wonderful gift
19:19it was the first
19:20naked eye
19:22supernova
19:22in about
19:23400 years
19:25and we had
19:26lots and lots
19:27of telescopes
19:27with which to study it
19:29throughout the
19:30electromagnetic spectrum
19:32but the 1987A
19:36supernova
19:37set off
19:38another
19:39scientific instrument
19:40a neutrino
19:43detector
19:43hidden deep
19:45below a mountain
19:45in Japan
19:46there was a burst
19:48of neutrinos
19:49associated
19:50with a supernova
19:51this was just
19:52a fantastic surprise
19:53a wonderful
19:55added bonus
19:56when you're trying
19:57to capture
19:58and measure
19:58elusive particles
20:00that you don't even know
20:01if you're going to get
20:02a signal or not
20:03and you're just sitting there
20:03waiting at your detector
20:04and then suddenly
20:06this thing just lights up
20:07how exciting is that
20:08this was definitive proof
20:12that supernovas emit
20:14neutrinos
20:15neutrinos may be ghostly
20:20but they don't gently drift out
20:21from the collapsing core of the star
20:23they have to burst out
20:25the amazing thing about the inside
20:28of a supernova explosion
20:29is that it's getting dense enough
20:31to trap neutrinos
20:32all of a sudden now there's pressure
20:35when scientists
20:39add neutrino pressure
20:40to the computer models
20:41the shockwave
20:43gets farther away
20:44from the core
20:44but the supernova
20:46still doesn't explode
20:48one more ingredient
20:49is needed
20:51disorder
20:52because stars
20:55are round
20:55it's tempting
20:57to think
20:57that a supernova
20:58explosion
20:59too
21:00will be round
21:01but supernova
21:03aren't perfectly symmetric
21:05energy
21:08from the shockwave
21:09and the neutrinos
21:10heats up the gas
21:11in chaotic
21:12unpredictable ways
21:14they cause
21:15hot bubbles
21:16to rise
21:17and then come back down
21:18and rise
21:19and come back down
21:20it's sort of a boiling motion
21:21this imparts
21:22a lot of turbulence
21:24into the gas
21:24researchers
21:26add all the ingredients
21:27to a supercomputer
21:28and let it run
21:30the result
21:33is this simulation
21:35when the shockwave
21:38stalls on its way
21:39out of the core
21:40it creates tiny ripples
21:42in the falling elements
21:43above
21:43the ripples
21:45become giant
21:46sloshing waves
21:47neutrinos
21:49bursting out
21:50from the neutron star
21:51heat the layers
21:52of elements above it
21:53causing them
21:55to bubble
21:55and rise
21:56eventually
22:00the intense heat
22:01combines
22:02with the pressure
22:03of these violent motions
22:05driving the shockwave
22:07out
22:07like an interstellar tsunami
22:10smashing the star
22:11to pieces
22:12it turns out
22:22stars do explode
22:24nature knows
22:24what it's doing
22:25it was the computer models
22:27they were too simple
22:28once the models
22:29became more complex
22:30started taking into account
22:31all the dimensions
22:32of a star
22:33the supernova models
22:34started to explode
22:35we think of supernova
22:37as effectively
22:38simple events
22:39very violent events
22:40but simple
22:41and this is just
22:42a beautiful
22:43illustration of the fact
22:44that when you dig
22:45deep down
22:45these are really
22:47exquisitely complex
22:48and elegant
22:49fluid dynamics problems
22:50the shockwave travels
22:54through all the layers
22:55of elements
22:56that make up
22:57the massive star
22:57it takes hours
22:59for it to reach
23:00the outer edge
23:01and trigger
23:02the first flash
23:03of light
23:04but this flash
23:05is just the start
23:06of the supernova
23:07the spectacular light show
23:09is just beginning
23:10a light show
23:12that will create
23:13elements
23:13essential
23:14for life
23:15we see the light
23:41from supernovas
23:42all the way
23:43across the cosmos
23:45but what we're seeing
23:48isn't the explosive
23:49first flash
23:50that's just
23:51the opening act
23:52before the main event
23:54supernova are some
23:58of the most energetic
23:58events in the universe
24:00the galaxy has hundreds
24:03of billions of stars
24:04in it
24:04and yet the death
24:05of this one star
24:06can outshine
24:07those hundred billions
24:08of stars
24:09one of the interesting
24:10things about supernovas
24:11is that
24:12when the star explodes
24:14it's not at its maximum
24:16brightness immediately
24:17it takes days
24:18and weeks
24:19the first flash
24:27is the explosive
24:28parts of a supernova
24:30blasting tons of matter
24:32into space
24:33around the dying star
24:35but it's this ejected debris
24:37that makes supernovas shine
24:39often glowing brighter
24:41than the explosion itself
24:43heavy elements
24:47are formed inside the cores of massive stars
24:51and even heavier elements
24:53are formed during the explosion event itself
24:57as the star rips apart
25:02temperatures and pressures
25:03are immense
25:04the elements that once made up
25:06the layers of the star
25:08fuse together
25:09creating heavier elements
25:11and some of these
25:12are radioactive
25:14the decay of these radioactive elements
25:17actually produces light
25:19that gives it more brightness
25:20over a longer period of time
25:22than it otherwise would have
25:23this cloud of brightly shining matter
25:29can last for months
25:31and sometimes years
25:32these supernova remnants
25:37light up the universe
25:38like cosmic fireworks
25:40these are oftentimes
25:44beautiful
25:45beautiful things
25:46in the night sky
25:47because they are
25:48you see remnants of
25:50everything that this supernova
25:51has generated
25:52in its explosion
25:53but these are more than
25:57pretty light shows
25:59they're crucial
26:00for the evolution of galaxies
26:02and solar systems
26:03necessary ingredients
26:08things like sulfur
26:09things like phosphorus
26:11things like carbon
26:13and oxygen
26:14and even the elements
26:16necessary to build
26:17a rocky planet
26:18like the earth itself
26:19can only be formed
26:21inside of massive stars
26:22and can only be spread
26:24through supernova explosions
26:26NASA's Chandra Space Telescope
26:34studies one of the most famous objects
26:36in the Milky Way
26:37supernova remnants
26:43Cassiopeia A
26:44Cassiopeia A
26:49is a relatively young
26:50supernova remnant
26:51not even 400 years old
26:53ever since its star exploded
26:56Cassiopeia A
26:57has been expanding
26:59it's now
27:0029 light years across
27:02using x-rays
27:04the Chandra Space Telescope
27:06has looked inside
27:08this massive cloud
27:09new observations
27:11of Cassiopeia A
27:12have shown us
27:13that the ejecta
27:14from this event
27:15has created
27:16tens of thousands
27:17of times
27:18the earth mass
27:20of really important
27:21materials
27:2270,000 earth masses
27:27worth of iron
27:28and a whopping
27:291 million
27:30earth masses
27:31worth of oxygen
27:33now these are elements
27:34that are important
27:35to life
27:36to earth
27:36to us
27:37the iron in your blood
27:39the calcium
27:40in your bones
27:40these were forged
27:42in supernova explosions
27:44billions of years ago
27:46the new study reveals
27:49something
27:49even more extraordinary
27:51Cassiopeia A
27:55also holds
27:56the building blocks
27:58of life
27:59we see every single atom
28:01necessary for DNA
28:02in that one
28:03supernova remnant
28:04one of the really cool
28:06things about supernovas
28:07is that our very existence
28:09depends on them
28:10our DNA molecules
28:13are made up
28:14of material
28:15that was once
28:16in the core
28:17of a massive star
28:18so somewhere out there
28:19some unnamed supernova
28:21eons ago
28:21led to you
28:23watching me
28:24talking about supernovas
28:26that's awesome
28:27supernovas create
28:32all the elements
28:33needed to build
28:34everything
28:34from planets
28:36to humans
28:37dying stars
28:38give us life
28:40it's a cosmic
28:41recycling process
28:43but
28:44what if some stars
28:46are faking
28:47their own deaths
28:48for thousands of years
29:08humans have wondered
29:09about bright new stars
29:11appearing in the sky
29:12and supernovas
29:14continue to surprise us
29:16our fascination
29:17with supernova
29:18has grown
29:19with each discovery
29:20of a new event
29:23the study of supernovas
29:24is really going
29:26through a revolution
29:27we're learning
29:27more and more
29:28we're better able
29:29to find them
29:30and observe them
29:31as it turns out
29:34not all supernovas
29:36are the same
29:37some are the result
29:38of white dwarf stars
29:40stealing matter
29:41from a twin
29:42and growing so big
29:43they explode
29:44all other supernovas
29:54are massive stars
29:55collapsing under
29:56their own gravity
29:57but just to confuse
30:03things further
30:04scientists also
30:05categorize supernovas
30:07based on whether
30:08hydrogen is present
30:09type 1 are missing
30:11hydrogen
30:11type 2
30:13are not
30:14so astronomers
30:16have these categories
30:17for supernova
30:18and that might
30:19make you think
30:20that we've got them
30:20all figured out
30:21but here's a spoiler
30:22we don't
30:24September 2014
30:30a supernova
30:31appears in the
30:32great bear
30:33constellation
30:34and glows brightly
30:35for 600 days
30:37when scientists
30:38check the records
30:39they discover
30:41a supernova
30:42was sighted
30:42at the exact
30:43same spot
30:4460 years before
30:46a star
30:47seemed to be
30:49dying
30:49over and over
30:51again
30:51this particular star
30:54was something
30:55we had never
30:55seen before
30:56and it seemed
30:57so strange
30:58it was almost
30:58impossible
30:59it actually
31:00brightened
31:01and faded
31:01about 5 times
31:03over a
31:03several year
31:04time span
31:05and each
31:06of these
31:07brightenings
31:07would have
31:08qualified
31:09as a supernova
31:10in terms of
31:11its total
31:11energy
31:12it's the
31:13supernova
31:14that would
31:14never die
31:15so how could
31:18it happen
31:18with the same
31:19star
31:19again and
31:20again and
31:21again
31:21this really
31:22did seem
31:23to be
31:23a zombie
31:24star
31:25how can a star
31:27have multiple
31:28deaths
31:29the answer
31:31lies in its
31:32sheer size
31:33we're talking
31:35about a very
31:36massive star
31:37here
31:37about a hundred
31:38or more
31:38times the mass
31:39of the sun
31:39really the upper
31:41limit of what
31:41a star can be
31:42without tearing
31:43itself apart
31:43this star
31:48is so big
31:49that reactions
31:50in the core
31:51are off the charts
31:52and these
31:53energetic reactions
31:54produce more
31:55than just
31:56elements
31:57it can actually
31:58get so hot
31:59in the interior
32:00that you produce
32:01gamma rays
32:01this is the most
32:02energetic form
32:03of light
32:03imaginable
32:04the gamma rays
32:07extreme energy
32:08supports the
32:09dying star
32:10against the
32:11crushing forces
32:12of gravity
32:13pushing in
32:14but it also
32:15affects the
32:16gamma rays
32:16themselves
32:17gamma rays
32:19above a certain
32:19energy can do
32:20something weird
32:21they can transform
32:22themselves into
32:23matter
32:24this transformation
32:25affects the delicate
32:26balance between
32:27gravity and energy
32:29in the star's core
32:30the core starts
32:32to collapse
32:32when it collapses
32:34it generates
32:34more energy
32:35this energy leaks
32:37out of the outer
32:38layers of the star
32:38and we see a sudden
32:40brightening of the star
32:41a pulse
32:42and it brightens
32:45and fades
32:46a bunch of times
32:47each time
32:48releasing some
32:49material
32:50but not quite
32:51exploding
32:52it's almost
32:54supernova levels
32:55of energy
32:56that's what fooled
32:57the astronomers
32:57at first
32:58eventually
33:01the pulsations
33:02stop
33:03the star
33:04calms down
33:05ready to live
33:07another day
33:07astronomers
33:10still don't know
33:11if this
33:12zombie supernova
33:13has finally died
33:15we think
33:16that we've seen
33:17this final explosion
33:18of the zombie
33:19supernova
33:20but honestly
33:21we're not sure yet
33:22maybe it's currently
33:23fading
33:24but next year
33:25it'll surprise us
33:26and brighten
33:27once again
33:28but this isn't
33:31the only
33:32mysterious
33:33supernova
33:33that has
33:34scientists
33:35scratching their heads
33:36meet
33:37supernova
33:38SN
33:392014
33:40C
33:41supernova
33:422014
33:43C
33:44was a bit
33:45of a strange
33:45one
33:46it was initially
33:46classified
33:47as a type
33:481
33:48astronomers
33:53use
33:53type 1
33:54and
33:55type 2
33:56to identify
33:57whether a supernova
33:58contains hydrogen
33:59if you break
34:01the light up
34:02coming in
34:03from a supernova
34:03into its individual
34:04colors
34:05you take its spectrum
34:06if there's the
34:07signature of hydrogen
34:08in that spectrum
34:09that's a type 2
34:10supernova
34:11if the hydrogen
34:12is missing
34:12that's type 1
34:14when SN
34:162014 C
34:17was first discovered
34:18hydrogen
34:19was missing
34:20but then later on
34:22hydrogen suddenly
34:24appeared
34:24and we realized
34:25no this is actually
34:26a type 2
34:27it's sort of a
34:28chameleon supernova
34:29it went from being
34:30type 1
34:31free of hydrogen
34:33to type 2
34:34full of hydrogen
34:35how can a supernova
34:37change from
34:37not having hydrogen
34:39to having hydrogen
34:40the chameleon supernova
34:46baffled scientists
34:47until they looked
34:48around it
34:49with the
34:50new star
34:50x-ray telescope
34:51it revealed
34:55that the star
34:56had spewed out
34:57a huge amount
34:58of hydrogen
34:58but this didn't
35:00happen during
35:01the supernova
35:01event
35:02this happened
35:03many decades
35:04before
35:04this star
35:06is very massive
35:07and relatively
35:08unstable
35:09and it underwent
35:10an explosive event
35:11about a century ago
35:12not big enough
35:13to be a supernova
35:14but it expelled
35:15all the hydrogen
35:16in that star
35:17so it was a type 1
35:18then
35:21the star
35:21exploded again
35:22but this event
35:24was massive
35:26the ejected gases
35:28from the supernova
35:29smashed into
35:31the hydrogen
35:32that had been
35:33previously
35:34expelled by the star
35:36before exploding
35:37and once
35:39the ejected gases
35:40crashed in
35:41well that caused
35:43that hydrogen gas
35:44to glow
35:44and then we saw
35:46hydrogen in the
35:47spectrum
35:47and it became
35:48a type 2
35:48the more scientists
35:51learn about
35:52supernovas
35:53the more complicated
35:54they become
35:55so now it seems
36:02that we've seen
36:02every type of
36:03supernova
36:03that must be possible
36:04and we've seen
36:05some very very
36:06strange ones
36:07things that are
36:07zombies or
36:08chameleons
36:09but there has to be
36:10something out there
36:11that's stranger still
36:13there may be a whole
36:17zoo of undiscovered
36:18supernovas
36:19out there
36:20exciting
36:21perplexing
36:22deadly
36:23and they
36:24may have been
36:25shaping the solar
36:26system and earth
36:28since the beginning
36:29of time
36:30the death of a giant star
36:51it's more than just
36:53an epic explosion
36:54it unleashes
36:55a storm of elements
36:57that form the universe
36:59around us
36:59there's a wonderful cycle
37:01of death and life
37:02in the universe
37:03individual stars
37:05are born
37:05they live their lives
37:06and they die
37:07when they die
37:10they enrich
37:11the universe
37:11with new atoms
37:12and new chemicals
37:13those go on
37:15to form new stars
37:17and new planets
37:17dust blows out
37:20from the explosion
37:21forming spectacular
37:23interstellar clouds
37:25nebulas
37:26the nursery of stars
37:28including
37:29our own solar system
37:30one of the biggest
37:33pieces of evidence
37:34we have
37:34is that
37:35supernovae
37:36themselves
37:37produce
37:37some very rare
37:39radioactive elements
37:41radioactive elements
37:42that we can still
37:43see embedded
37:45in the solar system
37:46today
37:46it's sprinkled
37:48like radioactive salt
37:49these radioactive elements
37:54found right across
37:55our planet
37:55are only produced
37:56in supernovas
37:57proof that earth
37:59and the solar system
38:00were created
38:01from exploding stars
38:024.6 billion years ago
38:05but supernovas
38:08may have affected
38:09earth
38:10much more recently
38:11we do have some evidence
38:14that there was
38:15a particular
38:16supernova explosion
38:17that rained down
38:19on the earth
38:19about 2.5 million years ago
38:21and deposit
38:22a specific kind of iron
38:23iron 60
38:27is a radioactive element
38:29made during
38:30a supernova
38:31it's found
38:32in fossils
38:32from around this time
38:34we see it
38:37embedded
38:37in the crust
38:38of the earth
38:39itself
38:40we see
38:40pieces of evidence
38:41two and a half
38:44million years ago
38:45life on earth
38:46changed
38:48dramatically
38:48Africa
38:50lost much
38:51of its forests
38:52to grasslands
38:53various plants
38:54and animals
38:55went extinct
38:56and many new
38:57species
38:58appeared
38:58but how
39:01could a supernova
39:02change life
39:03on earth
39:04so dramatically
39:05without
39:06destroying it
39:07completely
39:08when a supernova
39:12explodes
39:12it produces
39:13a tremendous
39:13amount
39:14of gamma rays
39:14and if that
39:16supernova
39:16is close enough
39:17to the earth
39:17you could imagine
39:18it really doing
39:19damage to our
39:19atmosphere
39:20some of the
39:23incredible amounts
39:24of energy
39:24found in a supernova
39:26leave the star
39:27in gamma ray
39:28beams
39:29if that beam
39:31were to be
39:32pointing at earth
39:33then the ozone
39:34layer could be
39:35harmed
39:35it affects
39:53our ozone
39:54layer
39:54which affects
39:55the amount
39:56of UV
39:56radiation
39:57that can hit
39:58the surface
39:58which can
39:59trigger
39:59mutations
40:00which can
40:01trigger
40:01different forms
40:02of vegetation
40:03which can
40:04kill off
40:04algae
40:05in the oceans
40:05there's a lot
40:06of potential
40:07effects
40:07mutations
40:10drive evolution
40:11in all forms
40:12of life
40:13from the
40:13simplest
40:14to the
40:14most complex
40:15so it's
40:18conceivable
40:18that as a
40:19result of
40:20a relatively
40:21nearby supernova
40:22the mutations
40:24led to
40:25early hominids
40:26and then
40:26homo sapiens
40:27that actually
40:29affected the
40:30evolution
40:31of life
40:31on earth
40:32and humans
40:33in particular
40:34is it just
40:38coincidence
40:39that ancient
40:40humans
40:40started to
40:41appear
40:41at around
40:42this time
40:43or
40:44was our
40:45humanity
40:45sparked
40:46by a
40:47supernova
40:48supernova
40:50seem to be
40:51an example
40:52of violent
40:52death
40:53but there
40:53were so
40:53many steps
40:54in the
40:55formation
40:56of our
40:56solar system
40:56the formation
40:57of you
40:57that are
40:58intimately
40:59related to
40:59supernova
41:00they created
41:01the chemical
41:01elements
41:01and maybe
41:02even drove
41:02our evolution
41:03we very likely
41:04would not exist
41:05if it were not
41:06for exploding
41:06stars
41:07from the elements
41:09in our dna
41:10to the solar
41:11system
41:12and the world
41:12we live in
41:13supernovas
41:14have made us
41:16the reason we
41:17study astronomy
41:18at all
41:18is to actually
41:19answer the question
41:20as to who
41:20we are
41:21where we came
41:22from
41:22and where
41:22we're going
41:23and with
41:24supernovas
41:24that's all
41:25wrapped up
41:25into this
41:26amazing story
41:27literally
41:28you are
41:29the death
41:29of a star
41:30these epic
41:33explosions
41:33are unlocking
41:35the biggest
41:36mysteries
41:36of our
41:37existence
41:37the story
41:39of supernova
41:39have become
41:40more interesting
41:41and more complex
41:42with every
41:42discovery
41:43so as we
41:43learn more
41:44we discover
41:45what it is
41:45that we don't
41:46understand yet
41:46the cosmos
41:48is something
41:48that can seem
41:49so distant
41:50and so
41:51unreachable
41:51but stars
41:53are the things
41:54the brilliant
41:54light to the cosmos
41:55with which we
41:56have the most
41:57strong connection
41:58there are so many
42:01things to love
42:01about exploding
42:02stars
42:03they are what
42:04give rise
42:05to the elements
42:06of life
42:07from the most
42:10intimate
42:11to the most
42:11gigantic scales
42:12imaginable
42:13supernovas
42:14are the key
42:15to all of that
42:16so thank
42:19you supernova
42:20hats off
42:21to you
42:21now please
42:22stay very
42:23very far away
42:24thank you
42:26thank you
42:28thank you
Comments