Original subtitles

from the drama of our planets origins

and the birth of our solar system comes

one of the most startling revelations of

modern science

the solar system we see today quiet

stable was once a battlefield

[Applause]

newborn planets blasted through space

competing for stable circularized orbits

inside a grunge style mosh pit of gas

and dust for those that find the right

balance the prize is survival for the

rest world shattering destruction a new

look at the chaos of creation and a

frightening possibility in our distant

future

[Music]

Mars

[Music]

the Curiosity rover is searching for

clues about the origins of the Red

Planet it confirms the presence of

oxygen and nitrogen isotopes hidden in

the rocks and soil we use isotopes to

try to figure out the history of planets

partly because they are immune to many

of the changes the chemical changes that

occur when you have things like

collisions and so forth isotopes the

relative abundances of these isotopes

are like fingerprints curiosity confirms

a unique mix of isotope fingerprints the

isotopes indicate that Mars formed

elsewhere in the solar system and moved

into our neighborhood our solar system

is full of oddities pointing to an

imperfect birth and a malformed

evolution all of our planets go around

the Sun in the same direction that the

Sun is spinning this is the same

direction that the clouds within our

original nebula began to rotate six

planets spin around their poles in the

same direction for them the Sun rises in

the east

and sets in the west

yet two planets spin the opposite

direction for Venus and Uranus the Sun

rises in the West and sets in the east

Uranus not only has a retrograde spin it

rolls on its side like a bowling ball at

Neptune the icy moon Triton orbits

backwards opposite from the direction of

Neptune spin do these planets spin

backwards because they were rocked by

Titanic collisions in the past so we see

evidence in the architecture of the

solar system for not only collisions

like Earth's moon and the fact that

Venus is is rotating in the wrong

direction and you're innocent sightings

before all these things are attributed

to collisions we also see in the

asteroid belt and in the Kuiper belt the

outer asteroid belt if you like we see

that the orbits of these things look

like they've been disturbed closer to

home our own earth has an inexplicable

23 and 1/2 degree tilt it's spin axis is

radically misaligned from its magnetic

pole and our moon is comparatively large

for a planet our size

now a new theory may be able to explain

many of these oddities it is called the

grand tack hypothesis

four and a half to five billion years

ago a gas giant planet arose inside a

primordial disk of gas and dust

Jupiter didn't just form where it is but

formed then moved inward towards the Sun

as it spirals toward the Sun Jupiter

herds asteroids and rubble

[Music]

Jupiter's natural tendency is to drift

in slowly through this debris field but

that it's to traveling around

the inner solar system is also thick

with gas and dust the birth of our

planetary system is well underway

numerous worlds are born in this region

including the earth primordial skies are

ruled by chaos

Jupiter's approach destabilizes these

planets their orbits decay into wildly

swinging ellipses

some are tossed out others fall into the

Sun their numbers are unknowable these

are ghost worlds from a bygone age

Jupiter just causes all heck to break

out in the solar system and all that

debris in the outer solar system gets

flung inward towards the inner solar

system and it was a busy time in the

very early solar system and since we are

colliding with each other all the time

and then it stopped

Jupiter's invasion of the inner solar

system is mysteriously halted the planet

makes a turn or n sailors parlance a

grand tack lurking behind Jupiter is a

second gas giant Saturn so as Jupiter

was migrating inward Saturn was

following it and growing and as Saturn

was growing it came to have a size that

it had a gravitational impact on Jupiter

which became more important than the

gravitational interaction between the

gaseous disc and Jupiter

they reverse direction and in a sense

you can think of Saturn and Jupiter

feeding off one another and moving back

out gravity tugs each passing planet

this transfers orbital energy from one

world to another all you have to do is

exert a very subtle little periodic

force at the right time and you can have

amazing changes in the motion of the

object you're pushing on once enough

energy has been transferred the planets

synchronize their orbits they are said

to be in a resonance for planets

resonances are achieved and maintained

through the mutual push and pull of

gravity through the fabric of space

there a key factor in the continuing

evolution of our solar system this

effect can be duplicated in the lab we

have ten metronomes here set up on a

swinging platform they have little

weights on pendulums here but they've

all been set at the same frequency and

I'm going to try to start them as best I

can completely out of phase randomly so

their oscillation is going to transfer

energy by the swinging of this plastic

sheet to the other metronomes that are

out of phase to get into phase with the

majority it's inevitable that there's

going to be some majority group which

starts out swinging more or less

together and they are eventually going

to win out

aha

maybe in this corner I see four that are

pretty closely synced yes now it's more

like five six they have one that's

almost completely out of phase every

time the majority hits a beat it's going

to give a little impulse a little push

to the platform and that push is

transferred to the metronome that's not

in sync because the platform you can

actually see this platform vibrating

back and forth in sync with the majority

of these metronomes working on this one

pretty close to resonance right now as

the metronomes achieve resonance it's

important to notice how the platform

shakes now it doesn't have to just be

the force that's being transmitted by

the plastic platform it could be a force

at a great distance for example the

force of gravity just these small little

seemingly insignificant pushes building

up over multiple cycles can have

dramatic energy transfer that is how

planets do it like the metronomes the

two gas giants form a resonance

we don't know exactly how long that took

but we have some fiducial marks for

timing in the solar system formation and

that means that the grand tack had to

have occurred relatively quickly

talking hundreds of thousands of years

perhaps two million years the two

planets retreat until they've reached

their current positions the sequence of

planets as we find them today is based

on Jupiter and Saturn's orbits

the planets eventually achieve a

sequencing that many students learn

through a mnemonic such as my very

educated mother just served us nine

pizzas was there a time when the

mnemonic was scrambled seems very likely

the answers yes not to mention a lot of

additional letters were probably in

there as well

Jupiter's Menace of the inner solar

system is finally over

if Saturn had not formed at the right

time in the sufficient size Jupiter

would have continued migrating in

throwing out objects unfortunate objects

in the inner solar system and ending up

very close to the Sun where it would

stay yes the earth would be gone or the

earth would have had it a terrifying

encounter with Jupiter and would have

been it had its orbit changed

dramatically too gosh knows what

there is mounting evidence that earth

had a terrifying visitor not Jupiter but

another world fail

FEA was essentially another proto-earth

where there were a number of these

objects flying around and day it took

time to grow just like the earth did

they probably had rather similar

histories and for one reason or another

the orbit of theta was perturbed such

that it collided with the earth

saya was this planet everybody that was

roughly the size of Mars and through

this collision a lot of particles were

ejected probably completely destroyed we

don't really know how much of saya was

preserved earth is rocked off its axis

its surface liquefied

chunks of Earth's mantle are shoved into

space

as a planetary body FEA ceases to exist

its remains are absorbed by the earth

and intermingled with the debris field a

new planetary body is formed the moon

further evidence is found in rock

samples from the Apollo moon landings

Lisi is a sample from the moon if you

can sit this was collected by the Apollo

15 mission moon rocks contain isotopes

identical to those found on earth when

the moon arose it is first covered with

a magma ocean people imagine the you

know magma ocean to be like this

magnetic chamber I am describing but at

the surface and covering a whole planet

I see it as this ocean like the Pacific

but this has to be like completely

magnetic orange and like probably like

flexing around and probably moving

conditions in the lunar magma are as

hellish as we can imagine

but a microscopic treasure forms in the

magma crystal zircons these are the same

gemstones used in jewelry but the

zircons and the apollo moonrocks

yield a different treasure so the zircon

are very important because we know they

crystallize in this union magma ocean we

know roughly when they crystallize in

the renal that motion so they are one of

these old piece of the Moon that we are

looking for one of these old piece that

we can use to to date the origin of the

Moon zircons not only give the age of

the Moon they set a specific date for

the collision

the edge of the moon is 4.51 billion

years old

4.5 1 billion years ago fááá becomes

part of earth and forms the moon but the

story is not over space probes measure

the moon

slipping 3.8 centimeters further away

each year one day the moon will break

free when that day comes there will be

no more tides no more romantic moonlit

nights could planetary orbits be

inherently unstable could the chaos of

planetary migration return oh Tremont's

Observatory France it's here that a

discovery from a faraway star gives one

of the biggest revelations about our own

solar system the story begins when Swiss

astronomers DDA quello and michelle Maor

noticed something unusual about a star

50 light-years away in the constellation

of Pegasus everything about this star is

ordinary a main-sequence midlife yellow

dwarf just like our Sun but with one

strange difference the star at Pegasus

51 is rocking back and forth

it's a weird anomaly astronomers have

never seen before they check their

instruments everything is working

including their new spectrograph a

device that splits the starlight from

Pegasus into rainbow colors hidden

inside the colors are patterns of lines

by tracking the day-to-day movement of

these lines astronomers make a startling

discovery

Pegasus 51 has a planet but no one has

ever seen a world like this it's half

the mass of Jupiter yet it's extremely

close to its star nine times closer than

mercury is to the Sun the planet at 51

Pegasus must be inside the corona

broiling and temperatures over a million

degrees Fahrenheit soon another planet

is found around another star and then

another and another

astronomers have now confirmed over 3700

exoplanets beyond our solar system

nearly all of them are Jupiter class

planets grazing their host star there a

new previously unknown type called hot

Jupiters

they're so numerous hot Jupiters

challenged theories about the origins of

planetary systems it's very difficult to

make a planet close to the star because

there isn't enough mass to build a giant

planet very close to the star and

there's gravitational frustrations for

trying to build a planet very close to

start astronomy is shaken with a new

revelation

planets do not stay put where they're

born when they're big enough they

migrate it's a process called planetary

migration and yet our own solar system

has no hot Jupiter astronomers realize

the Jupiter in our solar system was once

on the move as well but its migration

was halted by a resonance with Saturn

Pegasus 51 shows where a planet lands

when its migration is not blocked the

strongest evidence for the grand tak

hypothesis comes not from our solar

system but from exo world's charted

around other stars planetary migration

is a universal concept we see it

evidence of it out there in extrasolar

planets other solar systems there's no

reason why planet migration shouldn't

have operated in our own solar system

[Music]

the New Horizons probe finds evidence

for roving planets within our solar

system

while charting ancient craters on Pluto

and on the surfaces of its moons

the science team discovered many craters

are the same age this suggests that they

were formed by a single event even way

out here tiny Pluto was smashed by a

wandering planet the Pluto catastrophe

may be related to other planetary

migrations in the outer solar system

[Music]

it was noticed that the exact orbits of

the giant planets particularly the outer

giant planets the icy planets Uranus and

Neptune can be explained by their

migration outward there's a point in

time about 3.8 billion years ago or a

year nasa neptune trait and it's because

of what some of these mean motion

resonance interactions that we were

talking about earlier so this mean

motion resonance involving Jupiter and

Saturn and so forth just causes all heck

to break out in the solar system you're

innocent Neptune all of a sudden in 3.8

million years they they literally swap

places and all that debris in the outer

solar system gets flung inward towards

the inner solar system the disruption in

the outer solar system causes a new wave

of violence astronomers call this epoch

the late heavy bombardment

much of the cratering we see on our moon

today is from this period

it may be possible that swapping orbits

with Uranus is how Neptune got its moon

today the epic of planetary migration

appears to be over the solar system

seems stable but what does the future

hold computer simulations reveal what

may be the greatest threat to the solar

system in over 4 billion years it comes

from a very special relationship between

Jupiter and Mercury Mercury's orbit is

slowly perturbed thanks to a subtle but

constant gravitational nudge from

Jupiter a new resonance like the one

between Saturn and Jupiter that saved

the inner solar system is forming

between Jupiter and Mercury in 2001

computer models for the solar system

were run 2,500 times they plug in the

positions and the orbits of all the

planets in the solar system in a

computer and they just rillette it run

through time through millions of years

hundreds of millions of years billions

of years to find out whether or not

these orbits are stable change the

location of one planet say mercury by

one millimeter and you find that that

change will give completely different

predictions about where everything is

going to be millions of years in the

future

[Music]

to see how quickly and easily things can

change we have only to go back to our

metronomes all I have to do is stop this

platform from moving so that cannot

swing freely now there's no way for the

metronomes to influence each other

they're good metronomes but they're not

perfect they can't be going at exactly

the same frequency in the same phase and

they're just going to fall apart because

they have no way of forcing the others

to go to resonance

the same applies to planets any small

change can disrupt their harmony or

restore it now that the platform is free

to swing again it can again transfer

energy and sync them up just like we saw

it the first time scientists want to

understand the consequences of a

destabilized planet mercury in one case

mercury leaves the solar system the loss

of its gravitational pull disrupts the

balance of both Venus and the earth

Earth and Venus swap orbits

the superheated atmosphere of Venus cool

massive rains pour onto the face of the

desert planet oceans arise the land

cools and the air thins even the remains

of an ancient visitor begin to cool off

[Music]

Venus becomes like Earth but the reverse

happens to the earth as Earth settles

into Venus's orbit temperatures rise the

air becomes unbreathable glaciers melt

oceans boil the Sun looms larger in the

sky only to be obscured by a thickening

cloud cover suffering will be great but

brief the entire four billion year

pageant of life is cooked in a matter of

days

complete and utter destruction and

elimination of all life on earth not

judging in that higher life much talking

about civilization but everything a

sterilization of the planet is something

that I would want to think about a bit

sterilized uninhabitable and quiet there

is another possibility

equally dark and apocalyptic

a runaway mercury is deflected by the

gravity of Venus and barrels toward the

earth it may be a frightening encore to

the opening act of our solar system

the equilibrium of the ages is over

if this scenario is correct mercury

crashes into the earth just as fááá did

four billion years ago the question is

could it happen today

or is it a fate far away in the future

at a time when mankind itself is but a

distant memory

the problem is that even with a perfect

computer that understands all of the

laws of motion perfectly not just

gravity but all the other subtle forces

that go into it you cannot give it

accurate enough initial information

about the locations the masses the sizes

the speeds of all of the objects in the

solar system

odds are we may never see such a

calamity and yet among the billions of

stars in our galaxy how many worlds are

on the move how many will share this faint