[Applause] so are we alone those three simple words
so are we alone those three simple words
so are we alone those three simple words when you put them together in that order
when you put them together in that order
when you put them together in that order forms perhaps the most compelling
forms perhaps the most compelling
forms perhaps the most compelling unanswered place question facing
unanswered place question facing
unanswered place question facing humanity today I wish I could say at the
humanity today I wish I could say at the
humanity today I wish I could say at the end of the 15 minutes that you will walk
end of the 15 minutes that you will walk
end of the 15 minutes that you will walk away with a positive answer to that
away with a positive answer to that
away with a positive answer to that question but I’d be lying if I told you
question but I’d be lying if I told you
question but I’d be lying if I told you that instead what I hope at least that
that instead what I hope at least that
that instead what I hope at least that you walk away with is an appreciation
you walk away with is an appreciation
you walk away with is an appreciation for why the answer to this question may
for why the answer to this question may
for why the answer to this question may not be the positive uplifting answer
not be the positive uplifting answer
not be the positive uplifting answer that I think most of us in the room
that I think most of us in the room
that I think most of us in the room would hope it to be now before I get
would hope it to be now before I get
would hope it to be now before I get into the topic just a bit of geography
into the topic just a bit of geography
into the topic just a bit of geography bit of homework if you were an
bit of homework if you were an
bit of homework if you were an omnipotent being and you could remove
omnipotent being and you could remove
omnipotent being and you could remove yourself from the Milky Way galaxy in
yourself from the Milky Way galaxy in
yourself from the Milky Way galaxy in which we live and float above it and
which we live and float above it and
which we live and float above it and look down this is what you would see
look down this is what you would see
look down this is what you would see spanning roughly a hundred thousand
spanning roughly a hundred thousand
spanning roughly a hundred thousand light-years across
light-years across
light-years across there’s a hundred billion stars in that
there’s a hundred billion stars in that
there’s a hundred billion stars in that picture these hundred billion stars are
picture these hundred billion stars are
picture these hundred billion stars are rotating around in circular orbits
rotating around in circular orbits
rotating around in circular orbits around the galactic center each one
around the galactic center each one
around the galactic center each one moving at around half a million miles
moving at around half a million miles
moving at around half a million miles per hour amongst these hundred billion
per hour amongst these hundred billion
per hour amongst these hundred billion stars there’s maybe a billion ten
stars there’s maybe a billion ten
stars there’s maybe a billion ten billion or so rocky planets sort of the
billion or so rocky planets sort of the
billion or so rocky planets sort of the sites that we might hope that complex
sites that we might hope that complex
sites that we might hope that complex intelligent life might evolve upon our
intelligent life might evolve upon our
intelligent life might evolve upon our Sun sits in a rather nondescript suburb
Sun sits in a rather nondescript suburb
Sun sits in a rather nondescript suburb of the Milky Way sort of halfway between
of the Milky Way sort of halfway between
of the Milky Way sort of halfway between the edge of the disk in the center of
the edge of the disk in the center of
the edge of the disk in the center of the galaxy we do sit on a tiny little
the galaxy we do sit on a tiny little
the galaxy we do sit on a tiny little spur that’s in between two very dense
spur that’s in between two very dense
spur that’s in between two very dense bright spiral arms as you can see here
bright spiral arms as you can see here
bright spiral arms as you can see here and I want you to just sort of take a
and I want you to just sort of take a
and I want you to just sort of take a mental snapshot of this because we’re
mental snapshot of this because we’re
mental snapshot of this because we’re going to come back and see these spiral
going to come back and see these spiral
going to come back and see these spiral arms repeatedly throughout the rest of
arms repeatedly throughout the rest of
arms repeatedly throughout the rest of the presentation they’re going to come
the presentation they’re going to come
the presentation they’re going to come back to haunt us when I talk about the
back to haunt us when I talk about the
back to haunt us when I talk about the development of complex life but the nice
development of complex life but the nice
development of complex life but the nice thing to take from that as we sit in a
thing to take from that as we sit in a
thing to take from that as we sit in a very under dense sedate quiet region of
very under dense sedate quiet region of
very under dense sedate quiet region of the Milky Way right now if you step
the Milky Way right now if you step
the Milky Way right now if you step outside the city this picture perhaps
outside the city this picture perhaps
outside the city this picture perhaps doesn’t do it justice you’re in a dark
doesn’t do it justice you’re in a dark
doesn’t do it justice you’re in a dark sight and you look up into the night sky
sight and you look up into the night sky
sight and you look up into the night sky you can see thousands upon thousands of
you can see thousands upon thousands of
you can see thousands upon thousands of stars with the naked eye if you’re in a
stars with the naked eye if you’re in a
stars with the naked eye if you’re in a particularly dark sight you may see the
particularly dark sight you may see the
particularly dark sight you may see the Milky Way cutting across the sky just
Milky Way cutting across the sky just
Milky Way cutting across the sky just like this and there’s a reason why
like this and there’s a reason why
like this and there’s a reason why philosophers scientists general public
philosophers scientists general public
philosophers scientists general public UI
UI
UI when we look up at things like this we
when we look up at things like this we
when we look up at things like this we want to believe that there is complex
want to believe that there is complex
want to believe that there is complex life out there there’s intelligent life
life out there there’s intelligent life
life out there there’s intelligent life out there the sheer vastness of space
out there the sheer vastness of space
out there the sheer vastness of space this your number of stars makes you want
this your number of stars makes you want
this your number of stars makes you want to believe we can’t be this unique
to believe we can’t be this unique
to believe we can’t be this unique intelligent entity sitting all by
intelligent entity sitting all by
intelligent entity sitting all by ourselves now and that’s that’s where
ourselves now and that’s that’s where
ourselves now and that’s that’s where that belief has underpinned the
that belief has underpinned the
that belief has underpinned the development of all kinds of genres of
development of all kinds of genres of
development of all kinds of genres of literature and television and film in
literature and television and film in
literature and television and film in fact if you go into the IMDB and you
fact if you go into the IMDB and you
fact if you go into the IMDB and you take a look at what are the top 20
take a look at what are the top 20
take a look at what are the top 20 grossing films of all time
grossing films of all time
grossing films of all time more than half of them are based around
more than half of them are based around
more than half of them are based around this premise that aliens exist out there
this premise that aliens exist out there
this premise that aliens exist out there the top grossing film each of the last
the top grossing film each of the last
the top grossing film each of the last seven years has been a film that
seven years has been a film that
seven years has been a film that involves the belief that aliens exist
involves the belief that aliens exist
involves the belief that aliens exist out there somewhere so we really do want
out there somewhere so we really do want
out there somewhere so we really do want to believe if you want further evidence
to believe if you want further evidence
to believe if you want further evidence of that you’re sitting out there phone
of that you’re sitting out there phone
of that you’re sitting out there phone you can go to Ted calm and do a search
you can go to Ted calm and do a search
you can go to Ted calm and do a search for how many TED Talks there have been
for how many TED Talks there have been
for how many TED Talks there have been in the topic of that are aimed at
in the topic of that are aimed at
in the topic of that are aimed at answering this question of whether we
answering this question of whether we
answering this question of whether we are alone this can be related to you
are alone this can be related to you
are alone this can be related to you know the search for extrasolar planets
know the search for extrasolar planets
know the search for extrasolar planets can be related to the search for
can be related to the search for
can be related to the search for extraterrestrial intelligence there’s
extraterrestrial intelligence there’s
extraterrestrial intelligence there’s about 2024 of them that I found on the
about 2024 of them that I found on the
about 2024 of them that I found on the database which is a remarkable number
database which is a remarkable number
database which is a remarkable number there’s a common thread that links all
there’s a common thread that links all
there’s a common thread that links all of these talks and that is they’re very
of these talks and that is they’re very
of these talks and that is they’re very inspirational they’re very optimistic
inspirational they’re very optimistic
inspirational they’re very optimistic they’re very uplifting and so in some
they’re very uplifting and so in some
they’re very uplifting and so in some ways it would’ve been very easy for me
ways it would’ve been very easy for me
ways it would’ve been very easy for me to stand here and deliver that same sort
to stand here and deliver that same sort
to stand here and deliver that same sort of uplifting message that we’re not
of uplifting message that we’re not
of uplifting message that we’re not alone but aside did I’d be a little bit
alone but aside did I’d be a little bit
alone but aside did I’d be a little bit contrary and maybe approach this in a
contrary and maybe approach this in a
contrary and maybe approach this in a slightly more pragmatic maybe maybe
slightly more pragmatic maybe maybe
slightly more pragmatic maybe maybe somber way and and talk a little bit
somber way and and talk a little bit
somber way and and talk a little bit about the galactic scale catastrophic
about the galactic scale catastrophic
about the galactic scale catastrophic events that surround us on our path
events that surround us on our path
events that surround us on our path around the Milky Way the sorts of things
around the Milky Way the sorts of things
around the Milky Way the sorts of things that at any given moment could wipe us
that at any given moment could wipe us
that at any given moment could wipe us out and something that not only that we
out and something that not only that we
out and something that not only that we have to face but any other alien life
have to face but any other alien life
have to face but any other alien life that may be trying to develop anywhere
that may be trying to develop anywhere
that may be trying to develop anywhere else in the Milky Way has to face as
else in the Milky Way has to face as
else in the Milky Way has to face as well
well
well some of these things are most of these
some of these things are most of these
some of these things are most of these things are unavoidable they’re
things are unavoidable they’re
things are unavoidable they’re inescapable they do happen and they will
inescapable they do happen and they will
inescapable they do happen and they will happen to us in the future and it’s just
happen to us in the future and it’s just
happen to us in the future and it’s just a matter of when this actually happens
a matter of when this actually happens
a matter of when this actually happens okay so where am I going to start this
okay so where am I going to start this
okay so where am I going to start this may not be where you thought a talk on
may not be where you thought a talk on
may not be where you thought a talk on the a lien life the evidence for alien
the a lien life the evidence for alien
the a lien life the evidence for alien life might have started but there is a
life might have started but there is a
life might have started but there is a method to my madness so just cut me some
method to my madness so just cut me some
method to my madness so just cut me some slack for for a minute if you finish
slack for for a minute if you finish
slack for for a minute if you finish searching the Ted database and you do a
searching the Ted database and you do a
searching the Ted database and you do a also then do a search for say the most
also then do a search for say the most
also then do a search for say the most complex
complex
complex difficult recipes out on the Internet
difficult recipes out on the Internet
difficult recipes out on the Internet there’s a number of things start to show
there’s a number of things start to show
there’s a number of things start to show up that you might recognize here souffle
up that you might recognize here souffle
up that you might recognize here souffle Baked Alaska macarons these things are
Baked Alaska macarons these things are
Baked Alaska macarons these things are very complex they’re very difficult but
very complex they’re very difficult but
very complex they’re very difficult but if you then take a look at what are the
if you then take a look at what are the
if you then take a look at what are the basic ingredients they’re very simple
basic ingredients they’re very simple
basic ingredients they’re very simple they’re very trivial they’re very
they’re very trivial they’re very
they’re very trivial they’re very commonplace ingredients you mix these
commonplace ingredients you mix these
commonplace ingredients you mix these things together and hopefully you come
things together and hopefully you come
things together and hopefully you come up with these sorts of things that I
up with these sorts of things that I
up with these sorts of things that I just showed you but if anyone in the
just showed you but if anyone in the
just showed you but if anyone in the room has actually tried doing some of
room has actually tried doing some of
room has actually tried doing some of these things you realize these things
these things you realize these things
these things you realize these things are very very finicky and it does
are very very finicky and it does
are very very finicky and it does require sort of a deft touch which hence
require sort of a deft touch which hence
require sort of a deft touch which hence the illusion to Jamie Oliver to actually
the illusion to Jamie Oliver to actually
the illusion to Jamie Oliver to actually bring these things together and have
bring these things together and have
bring these things together and have them come together create successfully
them come together create successfully
them come together create successfully and it requires you to actually have an
and it requires you to actually have an
and it requires you to actually have an understanding of some basic science that
understanding of some basic science that
understanding of some basic science that you may or may not be aware of when you
you may or may not be aware of when you
you may or may not be aware of when you say with a Baked Alaska you need to be
say with a Baked Alaska you need to be
say with a Baked Alaska you need to be aware of temperature gradients inside of
aware of temperature gradients inside of
aware of temperature gradients inside of your oven if you’re doing say a souffle
your oven if you’re doing say a souffle
your oven if you’re doing say a souffle maybe I have to worry about protein
maybe I have to worry about protein
maybe I have to worry about protein molecule contamination from egg yolk you
molecule contamination from egg yolk you
molecule contamination from egg yolk you have to worry about pressure gradients
have to worry about pressure gradients
have to worry about pressure gradients in the oven if you’re doing macarons you
in the oven if you’re doing macarons you
in the oven if you’re doing macarons you need to worry about the subtle effects
need to worry about the subtle effects
need to worry about the subtle effects of humidity and the ability to make
of humidity and the ability to make
of humidity and the ability to make these things these are things you may
these things these are things you may
these things these are things you may not be aware of but they’re all come
not be aware of but they’re all come
not be aware of but they’re all come together to demonstrate that it’s not a
together to demonstrate that it’s not a
together to demonstrate that it’s not a you know a trivial task to take simple
you know a trivial task to take simple
you know a trivial task to take simple ingredients and come up with some
ingredients and come up with some
ingredients and come up with some complex creation and that’s the message
complex creation and that’s the message
complex creation and that’s the message I want you to take from the first few
I want you to take from the first few
I want you to take from the first few minutes of this presentation now you may
minutes of this presentation now you may
minutes of this presentation now you may think that we already have found life on
think that we already have found life on
think that we already have found life on Mars of your Daily Mail Reader you can
Mars of your Daily Mail Reader you can
Mars of your Daily Mail Reader you can find lots of fascinating stories about
find lots of fascinating stories about
find lots of fascinating stories about this we have a number of Rovers that are
this we have a number of Rovers that are
this we have a number of Rovers that are walking their way across the surface of
walking their way across the surface of
walking their way across the surface of Mars and they found all kinds of
Mars and they found all kinds of
Mars and they found all kinds of fascinating interesting jaw-dropping
fascinating interesting jaw-dropping
fascinating interesting jaw-dropping things there’s an enormous database of
things there’s an enormous database of
things there’s an enormous database of things that you can go and find on the
things that you can go and find on the
things that you can go and find on the web it looks like there’s evidence for
web it looks like there’s evidence for
web it looks like there’s evidence for iguanas in the on the surface there’s a
iguanas in the on the surface there’s a
iguanas in the on the surface there’s a woman sitting on there on a Ridge
woman sitting on there on a Ridge
woman sitting on there on a Ridge contemplating things there’s a floating
contemplating things there’s a floating
contemplating things there’s a floating spoon in the bottom left we’ve got
spoon in the bottom left we’ve got
spoon in the bottom left we’ve got bowler hat in the bottom right there’s
bowler hat in the bottom right there’s
bowler hat in the bottom right there’s any number of these sorts of things now
any number of these sorts of things now
any number of these sorts of things now being like interesting to note you know
being like interesting to note you know
being like interesting to note you know to believe that this is evidence of
to believe that this is evidence of
to believe that this is evidence of extraterrestrial life but the reality is
extraterrestrial life but the reality is
extraterrestrial life but the reality is either just really fascinating rock
either just really fascinating rock
either just really fascinating rock formations there’s many many many many
formations there’s many many many many
formations there’s many many many many more of them out there there’s entire
more of them out there there’s entire
more of them out there there’s entire gallery on the web which I encourage you
gallery on the web which I encourage you
gallery on the web which I encourage you to go through is it is it is actually
to go through is it is it is actually
to go through is it is it is actually really fascinating what are the sort of
really fascinating what are the sort of
really fascinating what are the sort of ingredients that we need to think about
ingredients that we need to think about
ingredients that we need to think about in terms of terms of life there are
in terms of terms of life there are
in terms of terms of life there are three building blocks
three building blocks
three building blocks is the ingredients that come together
is the ingredients that come together
is the ingredients that come together there is also the oven in which you do
there is also the oven in which you do
there is also the oven in which you do the cooking and there’s the amount of
the cooking and there’s the amount of
the cooking and there’s the amount of time that you do the cooking for so I’m
time that you do the cooking for so I’m
time that you do the cooking for so I’m going to come back and address each of
going to come back and address each of
going to come back and address each of those one by one but in relation to
those one by one but in relation to
those one by one but in relation to where we sit on the on this Milky Way
where we sit on the on this Milky Way
where we sit on the on this Milky Way galaxy plot I want to come back to that
galaxy plot I want to come back to that
galaxy plot I want to come back to that point that I said at the beginning that
point that I said at the beginning that
point that I said at the beginning that we sit in a very nice quiet under dense
we sit in a very nice quiet under dense
we sit in a very nice quiet under dense region we’re surrounded by these dense
region we’re surrounded by these dense
region we’re surrounded by these dense spiral arms what’s also unique about
spiral arms what’s also unique about
spiral arms what’s also unique about this area as we move it around half a
this area as we move it around half a
this area as we move it around half a million miles an hour around the galaxy
million miles an hour around the galaxy
million miles an hour around the galaxy at the same time the spiral arms are
at the same time the spiral arms are
at the same time the spiral arms are winding at half a million roughly half a
winding at half a million roughly half a
winding at half a million roughly half a million miles an hour
million miles an hour
million miles an hour so we don’t run into anything for a
so we don’t run into anything for a
so we don’t run into anything for a large chunk of time we just happily move
large chunk of time we just happily move
large chunk of time we just happily move in this under dense region but we don’t
in this under dense region but we don’t
in this under dense region but we don’t move it exactly the same speed of the
move it exactly the same speed of the
move it exactly the same speed of the spiral arms what that means is that
spiral arms what that means is that
spiral arms what that means is that every hundred million years or so we run
every hundred million years or so we run
every hundred million years or so we run into one of these spiral arms when we
into one of these spiral arms when we
into one of these spiral arms when we run into these one of these spiral arms
run into these one of these spiral arms
run into these one of these spiral arms it gives us what we call a gravitational
it gives us what we call a gravitational
it gives us what we call a gravitational shock you get slapped a little bit this
shock you get slapped a little bit this
shock you get slapped a little bit this lasts for about a million years or so
lasts for about a million years or so
lasts for about a million years or so this is not a not a good thing and I’ll
this is not a not a good thing and I’ll
this is not a not a good thing and I’ll show you why in in just a second at the
show you why in in just a second at the
show you why in in just a second at the same time that we are getting this
same time that we are getting this
same time that we are getting this gravitation shock from the spiral arms
gravitation shock from the spiral arms
gravitation shock from the spiral arms because the spiral arms is a few times
because the spiral arms is a few times
because the spiral arms is a few times denser than the region in between so we
denser than the region in between so we
denser than the region in between so we get this little shock at the same time
get this little shock at the same time
get this little shock at the same time as we’re getting this shock the star the
as we’re getting this shock the star the
as we’re getting this shock the star the Sun all the stars in the galaxy are
Sun all the stars in the galaxy are
Sun all the stars in the galaxy are going around and they’re bobbing up and
going around and they’re bobbing up and
going around and they’re bobbing up and down at the same time every 30 million
down at the same time every 30 million
down at the same time every 30 million years or so we pass through the middle
years or so we pass through the middle
years or so we pass through the middle of the plane of the Milky Way galaxy we
of the plane of the Milky Way galaxy we
of the plane of the Milky Way galaxy we also get another gravitational shock
also get another gravitational shock
also get another gravitational shock because it’s denser in the middle of the
because it’s denser in the middle of the
because it’s denser in the middle of the plane than it is above the plane so
plane than it is above the plane so
plane than it is above the plane so we’re constantly being buffeted both
we’re constantly being buffeted both
we’re constantly being buffeted both from up and down and from our side to
from up and down and from our side to
from up and down and from our side to side motions as we move around the
side motions as we move around the
side motions as we move around the galaxies and so why why are these sorts
galaxies and so why why are these sorts
galaxies and so why why are these sorts of gravitational shocks important well
of gravitational shocks important well
of gravitational shocks important well I’m going to use another analogy if
I’m going to use another analogy if
I’m going to use another analogy if you’ll indulge me so if you picture a an
you’ll indulge me so if you picture a an
you’ll indulge me so if you picture a an aerial swing at a theme park in nice
aerial swing at a theme park in nice
aerial swing at a theme park in nice calm conditions you see the swing going
calm conditions you see the swing going
calm conditions you see the swing going around the pillar
around the pillar
around the pillar it’s very symmetric and that’s great
it’s very symmetric and that’s great
it’s very symmetric and that’s great very stable very symmetric if you start
very stable very symmetric if you start
very stable very symmetric if you start to get little gusts of wind then that
to get little gusts of wind then that
to get little gusts of wind then that symmetry starts to break down and if
symmetry starts to break down and if
symmetry starts to break down and if those gusts a win are strong enough then
those gusts a win are strong enough then
those gusts a win are strong enough then you get something that’s more disastrous
you get something that’s more disastrous
you get something that’s more disastrous you can get the collision of
you can get the collision of
you can get the collision of of the actual cars of the swings this is
of the actual cars of the swings this is
of the actual cars of the swings this is exactly the same sort of thing that
exactly the same sort of thing that
exactly the same sort of thing that happens for our solar system as we get
happens for our solar system as we get
happens for our solar system as we get these gravitational shocks as we pass
these gravitational shocks as we pass
these gravitational shocks as we pass through spiral arms into the mid plane
through spiral arms into the mid plane
through spiral arms into the mid plane of the galaxy it’s not swings that we’re
of the galaxy it’s not swings that we’re
of the galaxy it’s not swings that we’re talking about but instead we’re talking
talking about but instead we’re talking
talking about but instead we’re talking about comets our solar system we think
about comets our solar system we think
about comets our solar system we think of it as these eight planets that are
of it as these eight planets that are
of it as these eight planets that are going around the Sun but in reality
going around the Sun but in reality
going around the Sun but in reality there is millions billions perhaps
there is millions billions perhaps
there is millions billions perhaps trillions of comets in the outer part of
trillions of comets in the outer part of
trillions of comets in the outer part of the solar system that are happily just
the solar system that are happily just
the solar system that are happily just orbiting around surrounding us so the
orbiting around surrounding us so the
orbiting around surrounding us so the cocoon around our solar system they’re
cocoon around our solar system they’re
cocoon around our solar system they’re fragile e balanced they’re every once in
fragile e balanced they’re every once in
fragile e balanced they’re every once in a while one gets dislodged and worked
a while one gets dislodged and worked
a while one gets dislodged and worked its way down into the inner solar system
its way down into the inner solar system
its way down into the inner solar system most of the comets that you see pictures
most of the comets that you see pictures
most of the comets that you see pictures of originated out there in the Oort
of originated out there in the Oort
of originated out there in the Oort cloud the problem is when you get one of
cloud the problem is when you get one of
cloud the problem is when you get one of these gravitational shocks it can
these gravitational shocks it can
these gravitational shocks it can dislodge more than just one randomly and
dislodge more than just one randomly and
dislodge more than just one randomly and can actually lead to thousands maybe
can actually lead to thousands maybe
can actually lead to thousands maybe millions of these comets they come
millions of these comets they come
millions of these comets they come funneling down into the inner part of
funneling down into the inner part of
funneling down into the inner part of the solar system and some fraction of
the solar system and some fraction of
the solar system and some fraction of those have the ability to collide with
those have the ability to collide with
those have the ability to collide with ear and lead to cataclysmic extinctions
ear and lead to cataclysmic extinctions
ear and lead to cataclysmic extinctions at least over the last billion years of
at least over the last billion years of
at least over the last billion years of the earth we think this has happened
the earth we think this has happened
the earth we think this has happened probably about five times where we’ve
probably about five times where we’ve
probably about five times where we’ve had mass extinctions over this left for
had mass extinctions over this left for
had mass extinctions over this left for a billion years this has happened to us
a billion years this has happened to us
a billion years this has happened to us it’s unavoidable it’s inescapable
it’s unavoidable it’s inescapable
it’s unavoidable it’s inescapable there’s nothing you can do about it
there’s nothing you can do about it
there’s nothing you can do about it every every tens of millions of years we
every every tens of millions of years we
every every tens of millions of years we are going to get a gravitational shock
are going to get a gravitational shock
are going to get a gravitational shock and eventually one of these is going to
and eventually one of these is going to
and eventually one of these is going to lead to a cataclysmic infall of comets
lead to a cataclysmic infall of comets
lead to a cataclysmic infall of comets that is going to do the sort of damage
that is going to do the sort of damage
that is going to do the sort of damage that you see in a picture like this may
that you see in a picture like this may
that you see in a picture like this may not be tomorrow may not be next year may
not be tomorrow may not be next year may
not be tomorrow may not be next year may be millions of years from now but it is
be millions of years from now but it is
be millions of years from now but it is coming now stepping back again outside
coming now stepping back again outside
coming now stepping back again outside of the Milky Way and looking down on it
of the Milky Way and looking down on it
of the Milky Way and looking down on it from above I’m going to come back to
from above I’m going to come back to
from above I’m going to come back to these spiral arms one more time the
these spiral arms one more time the
these spiral arms one more time the spiral arms it you can see in that
spiral arms it you can see in that
spiral arms it you can see in that picture are brighter that’s because
picture are brighter that’s because
picture are brighter that’s because that’s where most of the stars in the
that’s where most of the stars in the
that’s where most of the stars in the galaxy are being formed where most of
galaxy are being formed where most of
galaxy are being formed where most of the stars are being formed that’s also
the stars are being formed that’s also
the stars are being formed that’s also where most of the stars are dying now
where most of the stars are dying now
where most of the stars are dying now when most stars die they explode in a
when most stars die they explode in a
when most stars die they explode in a very spectacular fashion called a
very spectacular fashion called a
very spectacular fashion called a supernova a supernova
supernova a supernova
supernova a supernova gives off on the order of a billion
gives off on the order of a billion
gives off on the order of a billion billion billion times the energy of the
billion billion times the energy of the
billion billion times the energy of the most powerful nuclear whip
most powerful nuclear whip
most powerful nuclear whip that’s ever been released on earth we
that’s ever been released on earth we
that’s ever been released on earth we have roughly in in our galaxy maybe one
have roughly in in our galaxy maybe one
have roughly in in our galaxy maybe one goes off every 10 years or so now the
goes off every 10 years or so now the
goes off every 10 years or so now the galaxy is really really big so if one
galaxy is really really big so if one
galaxy is really really big so if one explodes on the other side of the galaxy
explodes on the other side of the galaxy
explodes on the other side of the galaxy doesn’t have any effect on us because
doesn’t have any effect on us because
doesn’t have any effect on us because it’s really far away but you can’t start
it’s really far away but you can’t start
it’s really far away but you can’t start to ask the question how close would one
to ask the question how close would one
to ask the question how close would one of the supernovae have to be before
of the supernovae have to be before
of the supernovae have to be before would actually do some serious damage to
would actually do some serious damage to
would actually do some serious damage to the earth and we’ve worked through the
the earth and we’ve worked through the
the earth and we’ve worked through the numbers we know what that answer is
numbers we know what that answer is
numbers we know what that answer is it’s roughly about 30 light years or so
it’s roughly about 30 light years or so
it’s roughly about 30 light years or so so 30 light years that number might by
so 30 light years that number might by
so 30 light years that number might by itself may not seem like anything but
itself may not seem like anything but
itself may not seem like anything but there’s roughly about 100 stars within
there’s roughly about 100 stars within
there’s roughly about 100 stars within 30 light-years of where we sit today so
30 light-years of where we sit today so
30 light-years of where we sit today so if a one of those stars exploded within
if a one of those stars exploded within
if a one of those stars exploded within that lethal radius if you like of 30
that lethal radius if you like of 30
that lethal radius if you like of 30 light years the amount of energy that we
light years the amount of energy that we
light years the amount of energy that we would see on the earth would be the
would see on the earth would be the
would see on the earth would be the equivalent of about a hundred thousand
equivalent of about a hundred thousand
equivalent of about a hundred thousand of the most powerful nuclear weapons
of the most powerful nuclear weapons
of the most powerful nuclear weapons ever released ten times greater than you
ever released ten times greater than you
ever released ten times greater than you would need to completely decimate the
would need to completely decimate the
would need to completely decimate the earth so you can ask the question how
earth so you can ask the question how
earth so you can ask the question how how often statistically with one of
how often statistically with one of
how often statistically with one of these supernovae explode within that
these supernovae explode within that
these supernovae explode within that distance of the earth
distance of the earth
distance of the earth and the answer is again roughly around
and the answer is again roughly around
and the answer is again roughly around once every hundred million years or so
once every hundred million years or so
once every hundred million years or so and once again this is something that
and once again this is something that
and once again this is something that happens we know what happens it’s
happens we know what happens it’s
happens we know what happens it’s unavoidable it will happen we know what
unavoidable it will happen we know what
unavoidable it will happen we know what happens actually pretty regularly in
happens actually pretty regularly in
happens actually pretty regularly in fact if you go go back less than 10
fact if you go go back less than 10
fact if you go go back less than 10 million years ago a supernova exploded
million years ago a supernova exploded
million years ago a supernova exploded that was 100 light years away so 30
that was 100 light years away so 30
that was 100 light years away so 30 light years away is the lethal radius
light years away is the lethal radius
light years away is the lethal radius where you just wipe out the biosphere
where you just wipe out the biosphere
where you just wipe out the biosphere you would evaporate the atmosphere you’d
you would evaporate the atmosphere you’d
you would evaporate the atmosphere you’d wipe out everything on earth so one went
wipe out everything on earth so one went
wipe out everything on earth so one went off only a factor of 3 further away 100
off only a factor of 3 further away 100
off only a factor of 3 further away 100 light years so to put that into context
light years so to put that into context
light years so to put that into context this is a supernova that exploded about
this is a supernova that exploded about
this is a supernova that exploded about a thousand years ago the distance across
a thousand years ago the distance across
a thousand years ago the distance across that bubble is about 60 light years and
that bubble is about 60 light years and
that bubble is about 60 light years and I stuck the earth up in the corner there
I stuck the earth up in the corner there
I stuck the earth up in the corner there 100 light years away this was roughly
100 light years away this was roughly
100 light years away this was roughly what happened 10 million years ago we
what happened 10 million years ago we
what happened 10 million years ago we know what happened we can see
know what happened we can see
know what happened we can see radioactive isotopes in the bottom of
radioactive isotopes in the bottom of
radioactive isotopes in the bottom of the ocean that clearly came from the
the ocean that clearly came from the
the ocean that clearly came from the signature of an exploding supernova on
signature of an exploding supernova on
signature of an exploding supernova on that sort of timescale if that had
that sort of timescale if that had
that sort of timescale if that had exploded just a factor of three closer
exploded just a factor of three closer
exploded just a factor of three closer so near the edge of that bubble rather
so near the edge of that bubble rather
so near the edge of that bubble rather than where it actually where the earth
than where it actually where the earth
than where it actually where the earth actually is that would have wiped out
actually is that would have wiped out
actually is that would have wiped out life or eight or nine million years ago
life or eight or nine million years ago
life or eight or nine million years ago so again it’s just further evidence that
so again it’s just further evidence that
so again it’s just further evidence that this does happen
this does happen
this does happen it’s unavoidable it’s going to happen
it’s unavoidable it’s going to happen
it’s unavoidable it’s going to happen and again it may not be tomorrow may not
and again it may not be tomorrow may not
and again it may not be tomorrow may not be next year
be next year
be next year but it is coming and it’s coming on that
but it is coming and it’s coming on that
but it is coming and it’s coming on that sort of timescale of millions of years
now that’s sort of a fairly grim way to
now that’s sort of a fairly grim way to sort of wrap up a talk so if I wanted to
sort of wrap up a talk so if I wanted to
sort of wrap up a talk so if I wanted to put a positive spin a slightly positive
put a positive spin a slightly positive
put a positive spin a slightly positive spin on it
spin on it
spin on it I’d like that I would end with with this
I’d like that I would end with with this
I’d like that I would end with with this point if we are going to be successful
point if we are going to be successful
point if we are going to be successful in finding extraterrestrial life in my
in finding extraterrestrial life in my
in finding extraterrestrial life in my lifetime in your lifetime I don’t think
lifetime in your lifetime I don’t think
lifetime in your lifetime I don’t think it’s going to be looking at distant
it’s going to be looking at distant
it’s going to be looking at distant stars it’s something we should be
stars it’s something we should be
stars it’s something we should be pushing for it’s a it’s something we
pushing for it’s a it’s something we
pushing for it’s a it’s something we should aspire to we shouldn’t avoid the
should aspire to we shouldn’t avoid the
should aspire to we shouldn’t avoid the challenge of trying to find out if
challenge of trying to find out if
challenge of trying to find out if there’s a life out there my my personal
there’s a life out there my my personal
there’s a life out there my my personal belief become more and more pragmatic as
belief become more and more pragmatic as
belief become more and more pragmatic as time goes by and I start to to think
time goes by and I start to to think
time goes by and I start to to think that maybe there isn’t someone out there
that maybe there isn’t someone out there
that maybe there isn’t someone out there that said if I do want to find evidence
that said if I do want to find evidence
that said if I do want to find evidence for extraterrestrial life if it’s going
for extraterrestrial life if it’s going
for extraterrestrial life if it’s going to happen I do think it will happen on
to happen I do think it will happen on
to happen I do think it will happen on our lifetime but it’s it’s going to
our lifetime but it’s it’s going to
our lifetime but it’s it’s going to happen much closer to home it’s not
happen much closer to home it’s not
happen much closer to home it’s not going to be Mars it’s not going to be
going to be Mars it’s not going to be
going to be Mars it’s not going to be Venus it’s going to be the icy moons of
Venus it’s going to be the icy moons of
Venus it’s going to be the icy moons of Jupiter and Saturn so Europa and
Jupiter and Saturn so Europa and
Jupiter and Saturn so Europa and Enceladus these moons are fantastic
Enceladus these moons are fantastic
Enceladus these moons are fantastic they’re covered in ice but beneath that
they’re covered in ice but beneath that
they’re covered in ice but beneath that ice is a massive ocean of seawater very
ice is a massive ocean of seawater very
ice is a massive ocean of seawater very salty seawater every once in a while the
salty seawater every once in a while the
salty seawater every once in a while the planets of Jupiter and Saturn torque and
planets of Jupiter and Saturn torque and
planets of Jupiter and Saturn torque and mess up these planets and cause the
mess up these planets and cause the
mess up these planets and cause the surface ice to fracture and then you get
surface ice to fracture and then you get
surface ice to fracture and then you get these enormous geysers of seewhat salt
these enormous geysers of seewhat salt
these enormous geysers of seewhat salt water that comes spewing out from
water that comes spewing out from
water that comes spewing out from underneath the icy surface we can see
underneath the icy surface we can see
underneath the icy surface we can see this on both of these moons there are
this on both of these moons there are
this on both of these moons there are missions that are planned to be launched
missions that are planned to be launched
missions that are planned to be launched in the next five years from NASA and the
in the next five years from NASA and the
in the next five years from NASA and the European Space Agency that are going to
European Space Agency that are going to
European Space Agency that are going to fly through and around these geysers of
fly through and around these geysers of
fly through and around these geysers of salt water hoping to find evidence of
salt water hoping to find evidence of
salt water hoping to find evidence of simple microbial life I think there’s a
simple microbial life I think there’s a
simple microbial life I think there’s a reasonable chance that that’s where
reasonable chance that that’s where
reasonable chance that that’s where we’re going to find it that’s where
we’re going to find it that’s where
we’re going to find it that’s where we’re going to find it if we don’t find
we’re going to find it if we don’t find
we’re going to find it if we don’t find it there then you can start to get
it there then you can start to get
it there then you can start to get really worried that maybe it isn’t out
really worried that maybe it isn’t out
really worried that maybe it isn’t out there at all because this is the ideal
there at all because this is the ideal
there at all because this is the ideal environment for a simple microbial life
environment for a simple microbial life
environment for a simple microbial life to develop so I guess the do the final
to develop so I guess the do the final
to develop so I guess the do the final summary it may be a little bit it may be
summary it may be a little bit it may be
summary it may be a little bit it may be a little bit grim it may be a little bit
a little bit grim it may be a little bit
a little bit grim it may be a little bit somber but I just want you to be aware
somber but I just want you to be aware
somber but I just want you to be aware that there are these galactic scale
that there are these galactic scale
that there are these galactic scale cosmic events that occur on millions of
cosmic events that occur on millions of
cosmic events that occur on millions of years timescales
years timescales
years timescales there’s nothing we can do to avoid them
there’s nothing we can do to avoid them
there’s nothing we can do to avoid them they’re out there they’re going to
they’re out there they’re going to
they’re out there they’re going to happen it’s going to hit us eventually
happen it’s going to hit us eventually
happen it’s going to hit us eventually not in our lifetime probably but it’s
not in our lifetime probably but it’s
not in our lifetime probably but it’s coming eventually this is something we
coming eventually this is something we
coming eventually this is something we have to face it’s something that every
have to face it’s something that every
have to face it’s something that every alien civilization would have to face in
alien civilization would have to face in
alien civilization would have to face in the future as well but even though the
the future as well but even though the
the future as well but even though the pragmatic part of me thinks that maybe
pragmatic part of me thinks that maybe
pragmatic part of me thinks that maybe life isn’t out there at all I still
life isn’t out there at all I still
life isn’t out there at all I still can’t help it I’m a romantic at heart
can’t help it I’m a romantic at heart
can’t help it I’m a romantic at heart part of me still wants to believe thank
part of me still wants to believe thank
part of me still wants to believe thank you
you
you [Applause]
”
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