[Music]
the end of this talk I wanna convince
all of you that aliens do exist and it’s
only a matter of time before we find
them but first we must understand just
how large the universes why because of
the near infinite scales of the universe
aliens are almost guaranteed the
universe is so large that there is true
scale we can’t even begin to comprehend
its size so I’m gonna change skills on
the slide is a star the Sun it is so
massive that you could fit a million
earths into it now I’m going to compress
the size of the Sun into this Janus ball
how big would it have to be for a
million of them to fit in this tennis
ball the earth would be a grain of sand
pause for a moment and picture that
earth a mere grain of sand orbiting our
Sun a tennis ball from 10 metres away
being held by nothing but gravity if
that doesn’t blow your mind I don’t know
what will if we move a kilometer away
from this tennis ball we will arrive at
the agreed-upon edge of the solar system
this is also where you’d find Voyager 1
now yj1
is the man-made object that is farthest
from Earth at this scale a mere
kilometer is the furthest human creation
has ever been we still have a long way
to go a next big landmark is Alpha
Centauri the nearest visible star at
this scale Alpha Centauri would be
another tennis ball of whopping 2000
kilometers away here’s a map for
reference with the circle of radius
2,000 kilometers
sent it at this room humans going to
Alpha Centauri would be like tiny people
living on a grain of sand in this room
going all the way to the edges of the
circle it would be how hard would it be
for those people to leave their grain of
sand and leave this room and go all the
way to China now you may think you’re
begin to understand just how large the
universe
and just how hard it is to travel across
it but we can get even bigger this is a
galaxy the Milky Way it spans a hundred
thousand light-years in diameter
now if the term Lightyear confuse you
don’t worry because when I first heard
it I was confused to a Lightyear is not
a unit of time but the unit of distance
it’s the distance traveled by light the
fastest thing there is is in an entire
year
it’s about nine trillion kilometers now
if we wanted this picture to be at scale
to a tennis ball son this picture would
have to be 46 million kilometers while
that is huge compared to how small this
tennis ball is and in this huge circle
there are over a trillion stars and our
galaxy is just one of many in the
observable universe
what is the observable universe this is
an artist’s representation of the
observable universe it’s a solid bubble
we cannot see beyond this bubble because
there hasn’t been enough time since the
beginning of the universe for light have
reaches from out there now there is
stuff beyond the observable universe but
we just can’t see it now this bubble
that spans 90 billion light-years in
diameter that distance is so large that
even if we were to compress it to this
tennis ball scale would it be too large
for us to think of but we can think
about how many there are in the
observable universe this is the Hubble
Deep Field image now this is a patch of
sky that you could cover with the nail
of your pinky finger of an outstretched
arm like this
now that small patch of sky was observed
by the Hubble Space Telescope for 11
days and it took 400 pictures of it this
pictures the culmination of all of those
pictures now the amazing thing about
this picture is that except for two
points of light every single point is an
entire galaxy there are galaxies
everywhere even the dark areas if we
look hard enough
we’ll see something like this and each
of these galaxies have trillions of
stars and scientists have just begun to
find planets around these stars how so
when a planet orbits a star the star
wobbles in its place slightly now we can
analyze this bauble by looking at its
light now it’s light seems to be
shifting to the right into the left
periodically using this shift we can
deduce that there must be a planet
around the star and use using that we
can find planets around other stars but
the problem with this is that the planet
must be huge like Jupiter if it’s small
like the earth the wobbles wouldn’t be
big enough for us to detect but when we
are looking for life we’re looking for
earth-like planets in a specific area
around the star this area is called the
habitable zone the habitable zone is the
area around the star red is not too hot
and not too cold but just right for the
secret ingredient of life to form liquid
water now everywhere we look on earth
the one thing that is necessary for any
life seems to be water so and due to
what is unique properties we believe
that water is essential for life
everywhere so we’re looking for planets
where water can form on the surface now
to find these planets we have another
method it’s called the transit method
now as you can see on the slide when the
planet passes in front of a star the
brightness dips ever so slightly now we
can analyze this dip in brightness and
figure out how big the planet is and how
far away from the star the planet is and
this method is sensitive enough to find
earth-like planets in the habitable zone
the plan is just right for life as we
know it but the thing is if the planet
happens to be orbiting a bit too higher
a bit too low from the star we will not
detect this because it will because the
brightness dip will not be seen so we
missed most planets of interest with
this method now although they we have so
many limitations and with
few decades of data we were able to find
3500 exoplanets planets around other
stars now if we extrapolate this data to
every single star in the universe we can
deduce that almost every star has one if
not more planets around it
there are more planets than there are
stars this allows for a vast arena
worlds where life can potentially evolve
into things we could never imagine now
the thing about these methods is that
they help us find planets where they
could potentially be water which means
that they could potentially be life on
it but we still cannot detect life for
certain around another planet there’s
one proposed method for this it’s a take
a picture of the atmosphere of the
planet now if something strange is
happening in the atmosphere that no
physical and natural phenomena can
explain a seeming violation of the laws
of physics this is probably best
explained by the existence of life on
that planet now we cannot the problem
with this is that we cannot take a
picture of another planet atmosphere yet
but we did this with earth this is a
real picture of Earth taken from space
by the Galileo spacecraft and using this
picture and only this scientists were
able to deduce that the earth is
probably teeming with life now this may
not seem like a big deal to all of you
because when you walk outside and look
there is life everywhere but the fact
that we were able to do this with only
one picture and no sample from the
planet means that we can apply the same
method to other planets and use that to
detect life on them now
as I said before the problem is that
stars are usually a million times
brighter than the planet so we cannot
take a picture of another planet yet but
there is one proposed method this is
called the star shape this technology
blocks out the light from the star but
not the planet so we can take a picture
of the planet without the glare from the
star now this technology will be in the
telescopes to follow Hubble in Kepler
and when they are in space
we will probably hear the first news of
detection of life now this shouldn’t
come as a surprise given the sheer
number of planets out there and this
life will probably be an intelligent
life the kind of life that does not use
technology but simply survives on the
surface but in this talk we’re
interested in the kind of life we could
communicate with intelligent life now in
theory intelligent life should be much
easier to detect because they would be
broadcasting some sort of signal of
their existence but the problem is
intelligent life is also much rarer to
find how much rarer is it we don’t know
the problem is we only have one form of
life to work with earth life and we do
not have enough data to understand how
intelligence itself grows fundamentally
so this is why finding life around
another planet even if it’s
unintelligent is so important because we
could learn something fundamental of
life about life that we could not have
from Earth life and using this we could
come up with better methods to find
intelligent life now the astronomer
Frank Drake came up with an equation for
the number of alien civilizations there
should be in a given area of space this
is the Drake Equation now although it
looks complicated don’t worry you don’t
have to understand it to follow the talk
you all you have to know is that
scientists don’t know the values of all
of these variables they make guesses for
the possible ranges for these values now
even in the most pessimistic case where
life evolves into intelligence only one
in a million times there should be over
300,000 alien civilizations in our
galaxy alone but when we go to the
countryside and look up at the stars we
see no signs of intelligence no
intergalactic was no empires trying to
destroy the earth because when they
burned aware of their highway and most
importantly knowing I need no sign of
interstellar signals now although we are
pretty stupid we seem to be the only
sign of in
since there is in the universe where are
the aliens a science says there should
be everywhere but they aren’t this is a
great problem in the search for life and
it is so important it even has a name
it’s called the Fermi question now there
are many possible explanations to this
apparent lack of life from intergalactic
conspiracies to empires ruling the
galaxy in hiding destroying any
civilization that comes in their way but
I’m going to talk about the few most
probable explanations to this we started
communicating at the fastest speed
allowed by physics the speed of light
about a century ago when we first
discovered radio waves this is when we
were broadcasting signals of our
existence into space at the speed of
light a mere 50 years later we detonated
our first nuclear bomb for the first
time in human history we had the ability
to destroy every last one of us now the
first explanation to the Fermi question
goes something like this every time an
intelligent civilization arises it will
destroy itself faster than it can move
out of its planet and communicate its
existence
now the second explanation is that
aliens are probably far more advanced in
us and have come up with technologies
and discovered physics we haven’t yet so
even if they’re communicating in signals
using that physics even if they’re
passing earth every single day we would
not detect them because we don’t know
they exist but my favorite explanation
is the limitation in space and time now
the universe is very large and time is
very long but there hasn’t been enough
time since the potential existence of
life for any signal to have reached us
yet this is best demonstrated by our own
signals that tiny yellow dot which is
magnified in that rectangle is our radio
bubble this is how far her radio waves
have traveled into space this is the
extent of human influence beyond that
bubble any alien civilization would not
know we exist
as you can see we have
even began to reach the ends of the
galaxy forget the universe this could be
the case with other alien civilizations
living in their own tiny radiobubble
scattered across the galaxy and it could
take centuries if not millennia before
we hear the first signal from aliens now
whatever the reason for this lack of
aliens were still very hopeful of
finding them we even have an
organization called SETI the search for
extraterrestrial intelligence now these
people use large arrays of very powerful
radio telescopes to gather petabytes of
data and search for any signal that
could potentially be from aliens yes you
heard me right people work full-time
jobs in search for aliens are they crazy
no the odds of finding aliens seem to be
so high that we’d be crazy not to try
the annual budget of SETI and NASA
combined in the alien searches is
slightly over a billion dollars this is
nothing compared to what he spend on
other things such as the military and
what we could potentially learn from a
detection of aliens a science could be
potentially ever advanced by a few
millennia imagine going back to the time
of the Romans and handing them the
smartphone how much more how much more
would they have benefited from this now
even not finding life would mean a great
deal for science because if we didn’t
find life anywhere outside of it it
would mean that there’s something
special about Earth that allows life to
form that is nowhere else in the
universe if you figure out what that is
we would learn something fundamental
about the origin of life which would
revolutionize biology and even medicine
now perhaps the most important reason to
look is their inherent curiosity to know
more
we cannot quench our thirst for
knowledge especially when we are this
close to knowing with that I’d like to
leave you with this picture
it was taken by Voyager 125 years ago
when Voyager 1 first looked back at
Earth for one last time and took this
picture that tiny dot is how our planet
looks out from there now Carl Sagan the
astronomer
thing very profound about this and I
could look again at that dot that’s here
that’s home that’s us on it everyone you
love everyone you know everyone you’ve
ever heard of every human being who ever
was and lived out their lives the
aggregate of our joy and suffering
thousands of confident religions
ideologies and economic doctrines every
hero and cupboard every King and peasant
every creator and destroyer of
civilization every superstar including
Rajnikant every Supreme Leader every
saint and sinner in the history of our
species lived there on a mote of dust
suspended in a sunbeam ladies and
gentlemen tonight after the Sun sets I
ask you to walk outside and look up even
if you can’t see them
think about the trillions of stars out
there many orbited by motes of dust just
like our own each with their own
histories ideologies and discoveries the
universe is filled with stories to tell
and all we have to do is listen thank
you
[Applause]
the end of this talk I wanna convince
all of you that aliens do exist and it’s
only a matter of time before we find
them but first we must understand just
how large the universes why because of
the near infinite scales of the universe
aliens are almost guaranteed the
universe is so large that there is true
scale we can’t even begin to comprehend
its size so I’m gonna change skills on
the slide is a star the Sun it is so
massive that you could fit a million
earths into it now I’m going to compress
the size of the Sun into this Janus ball
how big would it have to be for a
million of them to fit in this tennis
ball the earth would be a grain of sand
pause for a moment and picture that
earth a mere grain of sand orbiting our
Sun a tennis ball from 10 metres away
being held by nothing but gravity if
that doesn’t blow your mind I don’t know
what will if we move a kilometer away
from this tennis ball we will arrive at
the agreed-upon edge of the solar system
this is also where you’d find Voyager 1
now yj1
is the man-made object that is farthest
from Earth at this scale a mere
kilometer is the furthest human creation
has ever been we still have a long way
to go a next big landmark is Alpha
Centauri the nearest visible star at
this scale Alpha Centauri would be
another tennis ball of whopping 2000
kilometers away here’s a map for
reference with the circle of radius
2,000 kilometers
sent it at this room humans going to
Alpha Centauri would be like tiny people
living on a grain of sand in this room
going all the way to the edges of the
circle it would be how hard would it be
for those people to leave their grain of
sand and leave this room and go all the
way to China now you may think you’re
begin to understand just how large the
universe
and just how hard it is to travel across
it but we can get even bigger this is a
galaxy the Milky Way it spans a hundred
thousand light-years in diameter
now if the term Lightyear confuse you
don’t worry because when I first heard
it I was confused to a Lightyear is not
a unit of time but the unit of distance
it’s the distance traveled by light the
fastest thing there is is in an entire
year
it’s about nine trillion kilometers now
if we wanted this picture to be at scale
to a tennis ball son this picture would
have to be 46 million kilometers while
that is huge compared to how small this
tennis ball is and in this huge circle
there are over a trillion stars and our
galaxy is just one of many in the
observable universe
what is the observable universe this is
an artist’s representation of the
observable universe it’s a solid bubble
we cannot see beyond this bubble because
there hasn’t been enough time since the
beginning of the universe for light have
reaches from out there now there is
stuff beyond the observable universe but
we just can’t see it now this bubble
that spans 90 billion light-years in
diameter that distance is so large that
even if we were to compress it to this
tennis ball scale would it be too large
for us to think of but we can think
about how many there are in the
observable universe this is the Hubble
Deep Field image now this is a patch of
sky that you could cover with the nail
of your pinky finger of an outstretched
arm like this
now that small patch of sky was observed
by the Hubble Space Telescope for 11
days and it took 400 pictures of it this
pictures the culmination of all of those
pictures now the amazing thing about
this picture is that except for two
points of light every single point is an
entire galaxy there are galaxies
everywhere even the dark areas if we
look hard enough
we’ll see something like this and each
of these galaxies have trillions of
stars and scientists have just begun to
find planets around these stars how so
when a planet orbits a star the star
wobbles in its place slightly now we can
analyze this bauble by looking at its
light now it’s light seems to be
shifting to the right into the left
periodically using this shift we can
deduce that there must be a planet
around the star and use using that we
can find planets around other stars but
the problem with this is that the planet
must be huge like Jupiter if it’s small
like the earth the wobbles wouldn’t be
big enough for us to detect but when we
are looking for life we’re looking for
earth-like planets in a specific area
around the star this area is called the
habitable zone the habitable zone is the
area around the star red is not too hot
and not too cold but just right for the
secret ingredient of life to form liquid
water now everywhere we look on earth
the one thing that is necessary for any
life seems to be water so and due to
what is unique properties we believe
that water is essential for life
everywhere so we’re looking for planets
where water can form on the surface now
to find these planets we have another
method it’s called the transit method
now as you can see on the slide when the
planet passes in front of a star the
brightness dips ever so slightly now we
can analyze this dip in brightness and
figure out how big the planet is and how
far away from the star the planet is and
this method is sensitive enough to find
earth-like planets in the habitable zone
the plan is just right for life as we
know it but the thing is if the planet
happens to be orbiting a bit too higher
a bit too low from the star we will not
detect this because it will because the
brightness dip will not be seen so we
missed most planets of interest with
this method now although they we have so
many limitations and with
few decades of data we were able to find
3500 exoplanets planets around other
stars now if we extrapolate this data to
every single star in the universe we can
deduce that almost every star has one if
not more planets around it
there are more planets than there are
stars this allows for a vast arena
worlds where life can potentially evolve
into things we could never imagine now
the thing about these methods is that
they help us find planets where they
could potentially be water which means
that they could potentially be life on
it but we still cannot detect life for
certain around another planet there’s
one proposed method for this it’s a take
a picture of the atmosphere of the
planet now if something strange is
happening in the atmosphere that no
physical and natural phenomena can
explain a seeming violation of the laws
of physics this is probably best
explained by the existence of life on
that planet now we cannot the problem
with this is that we cannot take a
picture of another planet atmosphere yet
but we did this with earth this is a
real picture of Earth taken from space
by the Galileo spacecraft and using this
picture and only this scientists were
able to deduce that the earth is
probably teeming with life now this may
not seem like a big deal to all of you
because when you walk outside and look
there is life everywhere but the fact
that we were able to do this with only
one picture and no sample from the
planet means that we can apply the same
method to other planets and use that to
detect life on them now
as I said before the problem is that
stars are usually a million times
brighter than the planet so we cannot
take a picture of another planet yet but
there is one proposed method this is
called the star shape this technology
blocks out the light from the star but
not the planet so we can take a picture
of the planet without the glare from the
star now this technology will be in the
telescopes to follow Hubble in Kepler
and when they are in space
we will probably hear the first news of
detection of life now this shouldn’t
come as a surprise given the sheer
number of planets out there and this
life will probably be an intelligent
life the kind of life that does not use
technology but simply survives on the
surface but in this talk we’re
interested in the kind of life we could
communicate with intelligent life now in
theory intelligent life should be much
easier to detect because they would be
broadcasting some sort of signal of
their existence but the problem is
intelligent life is also much rarer to
find how much rarer is it we don’t know
the problem is we only have one form of
life to work with earth life and we do
not have enough data to understand how
intelligence itself grows fundamentally
so this is why finding life around
another planet even if it’s
unintelligent is so important because we
could learn something fundamental of
life about life that we could not have
from Earth life and using this we could
come up with better methods to find
intelligent life now the astronomer
Frank Drake came up with an equation for
the number of alien civilizations there
should be in a given area of space this
is the Drake Equation now although it
looks complicated don’t worry you don’t
have to understand it to follow the talk
you all you have to know is that
scientists don’t know the values of all
of these variables they make guesses for
the possible ranges for these values now
even in the most pessimistic case where
life evolves into intelligence only one
in a million times there should be over
300,000 alien civilizations in our
galaxy alone but when we go to the
countryside and look up at the stars we
see no signs of intelligence no
intergalactic was no empires trying to
destroy the earth because when they
burned aware of their highway and most
importantly knowing I need no sign of
interstellar signals now although we are
pretty stupid we seem to be the only
sign of in
since there is in the universe where are
the aliens a science says there should
be everywhere but they aren’t this is a
great problem in the search for life and
it is so important it even has a name
it’s called the Fermi question now there
are many possible explanations to this
apparent lack of life from intergalactic
conspiracies to empires ruling the
galaxy in hiding destroying any
civilization that comes in their way but
I’m going to talk about the few most
probable explanations to this we started
communicating at the fastest speed
allowed by physics the speed of light
about a century ago when we first
discovered radio waves this is when we
were broadcasting signals of our
existence into space at the speed of
light a mere 50 years later we detonated
our first nuclear bomb for the first
time in human history we had the ability
to destroy every last one of us now the
first explanation to the Fermi question
goes something like this every time an
intelligent civilization arises it will
destroy itself faster than it can move
out of its planet and communicate its
existence
now the second explanation is that
aliens are probably far more advanced in
us and have come up with technologies
and discovered physics we haven’t yet so
even if they’re communicating in signals
using that physics even if they’re
passing earth every single day we would
not detect them because we don’t know
they exist but my favorite explanation
is the limitation in space and time now
the universe is very large and time is
very long but there hasn’t been enough
time since the potential existence of
life for any signal to have reached us
yet this is best demonstrated by our own
signals that tiny yellow dot which is
magnified in that rectangle is our radio
bubble this is how far her radio waves
have traveled into space this is the
extent of human influence beyond that
bubble any alien civilization would not
know we exist
as you can see we have
even began to reach the ends of the
galaxy forget the universe this could be
the case with other alien civilizations
living in their own tiny radiobubble
scattered across the galaxy and it could
take centuries if not millennia before
we hear the first signal from aliens now
whatever the reason for this lack of
aliens were still very hopeful of
finding them we even have an
organization called SETI the search for
extraterrestrial intelligence now these
people use large arrays of very powerful
radio telescopes to gather petabytes of
data and search for any signal that
could potentially be from aliens yes you
heard me right people work full-time
jobs in search for aliens are they crazy
no the odds of finding aliens seem to be
so high that we’d be crazy not to try
the annual budget of SETI and NASA
combined in the alien searches is
slightly over a billion dollars this is
nothing compared to what he spend on
other things such as the military and
what we could potentially learn from a
detection of aliens a science could be
potentially ever advanced by a few
millennia imagine going back to the time
of the Romans and handing them the
smartphone how much more how much more
would they have benefited from this now
even not finding life would mean a great
deal for science because if we didn’t
find life anywhere outside of it it
would mean that there’s something
special about Earth that allows life to
form that is nowhere else in the
universe if you figure out what that is
we would learn something fundamental
about the origin of life which would
revolutionize biology and even medicine
now perhaps the most important reason to
look is their inherent curiosity to know
more
we cannot quench our thirst for
knowledge especially when we are this
close to knowing with that I’d like to
leave you with this picture
it was taken by Voyager 125 years ago
when Voyager 1 first looked back at
Earth for one last time and took this
picture that tiny dot is how our planet
looks out from there now Carl Sagan the
astronomer
thing very profound about this and I
could look again at that dot that’s here
that’s home that’s us on it everyone you
love everyone you know everyone you’ve
ever heard of every human being who ever
was and lived out their lives the
aggregate of our joy and suffering
thousands of confident religions
ideologies and economic doctrines every
hero and cupboard every King and peasant
every creator and destroyer of
civilization every superstar including
Rajnikant every Supreme Leader every
saint and sinner in the history of our
species lived there on a mote of dust
suspended in a sunbeam ladies and
gentlemen tonight after the Sun sets I
ask you to walk outside and look up even
if you can’t see them
think about the trillions of stars out
there many orbited by motes of dust just
like our own each with their own
histories ideologies and discoveries the
universe is filled with stories to tell
and all we have to do is listen thank
you
[Applause]
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