the most important bridge that we will
ever build it’s not one that connects
two points in space but rather two
points in time every day we’re building
this bridge together connecting our
present to our future but unlike most
bridges we can always change where this
one leads as an astronomer I’ve often
wondered if there are other
civilizations out there somewhere in the
cosmos
all their species like ours building
their own bridges to their futures like
we are today there definitely should be
our universe is a big enough place and
our cosmic neighborhood alone
there should be trillions of other
worlds around hundreds of billions of
other Suns other stars many of these
alien solar system should be younger
than our Shore but many still should be
older there should be other
civilizations out there ahead of ours
ones that have already built the same
bridges for themselves that we are
building for ourselves now but here’s
the question that keeps me up at night
what if we never find that what if we
never find any evidence that there are
civilizations out there ahead of us ones
who have already crossed these bridges
to their futures same as we’re trying to
cross ours now was that tell us about
the path that were on this past on this
bridge that we’re building behind us is
already set by our history but moving
forward our path this bridge is paved by
the choices we make every day and the
things that we value an essential
measure of this is our use of energy we
need energy to do whatever it is we want
to do both as individuals and
collectively as a species it’s at the
center of everything in our lives it’s
at the center of everything that we see
all around us now responsible for or a
product of everything from growing our
food and transporting it around the
globe to growing our population and
transporting that around the globe from
running our economy day-to-day to
developing the technology that we
take Korea and it all around us now our
axis and our use of energy defines the
tempo of our daily lives and the things
that we value in ways that we only
rarely think about since the 1800s or so
we’ve been using roughly 2.6 percent
more energy per year than the years
before now this may not seem like much
but overall this catches up to you over
time we’re using more and more energy
faster and faster so now here we are in
the present day using somewhere between
15 and 20 trillion watts of power to
fuel our ambitions enough for a presence
to be seen from space a lot but if we
keep going down this bridge that we’re
building using more and more energy with
each passing year
in just a few human lifetimes we’ll have
to use a thousand times more energy than
we’re using now imagine that by then how
we obtain energy our ways that we can
use it our additional resources will be
somewhat limited there only be one game
in town left and that’s the giant star
sized nuclear reactor the Sun sitting
right in the middle of our solar system
give me off much much much more free
energy free power in all directions
without any effort from us and we want
to keep going down this bridge as we
have been we’re gonna have to harness
that energy there’s one good way to do
that too here’s the Sun from a distance
now now I want you to think of a solar
panel or something similar now imagine a
whole swarm of solar panels surrounding
the Sun a swarm that collects absorbs
the sun’s light and turns it into energy
that we can use such a swarm of solar
collectors would ideally be about the
size of the Earth’s orbit around the Sun
the astronomer Freeman Dyson is
considered the first to think of this so
we appropriately enough tell us the
Dyson swarm how I I know this idea
sounds fantastic
but believe it or not building such a
thing
is technically feasible that’s good
because again this is our bridge this is
where it’s pointing this is where our
insatiable hunger for energy is leading
us now I think if there are other
civilizations that have already crossed
this bridge into their own futures then
that mean there should be Dyson swarms
somewhere out there in the universe
right now we just have to find them
the trick is yeah you know knowing how
to look because Dyson storms are big
right sure but the space between stars
is much much bigger than that
Dyson swarms are so far away stars are
so far away that we won’t be able to
pick them out individually or see them
directly luckily we don’t have to we can
get creative you see regardless of what
a civilization would choose to do with
all of its energy it’s got to obey the
laws of physics these rules that are
sewn into the very fabric of the cosmos
around us tell us that energy can’t be
created or destroyed I’ve been saying
this whole time we use energy but really
what I mean is that we transform energy
from one type to another to another and
through all these transformations we get
something useful for us in the process
and you’re familiar with this in your
daily lives too and we take energy we
use that energy to produce food and
generate electricity you take food you
eat that food and you turn that energy
into energy of motion and energy of
thought meanwhile all the devices around
us right now take energy from
electricity and turn that into energy of
heating cooling lighting powering our
journeys through the internet through
all the transformations of energy there
all the transformations that we put our
energy through invariably gets released
as heat just walk into an
air-conditioned room full of sweaty
people in technology and you kind of get
what I mean
over time the energy that we use gets
released into our an environment and
finds its way out into a space other
civilizations beholden to the same laws
of physics that we are would be no
different
civilizations with the Dyson swarm would
be no different they just use a lot of
energy from a star but they would have
to take that star’s worth of energy and
regardless of what transformations they
put that energy through they would have
to release that energy out as heat too
so a Dyson swarm should be warm and glow
with the heat that it gets off a special
kind of light that we call infrared
radiation light that’s redder than right
now a few years ago I joined a search a
hunt for Dyson swarms with some other
astronomers we knew that space
telescopes like wise Spitzer and IRS had
already surveyed the whole sky
specifically in infrared light we knew
that these surveys could be used the
hunt for Dyson swarms too so we looked
we scanned the whole infrared sky
hunting for distant points of light that
had just the right kinds and balance of
infrared light what you’d expect the
tail tell-tale signatures of a Dyson
swarm around another Sun but even though
the Eden we’re good enough to spot them
the data were good enough even in a sky
of billions stars and other objects not
one was a Dyson swarm our search found
nothing there’s no evidence that there
are advanced civilizations out there
using significant amounts of energy kind
of energy that we’re going to need just
to keep going down this bridge that
we’re building now so again I ask you no
one else could cross this bridge what
does this tell us about the path that
we’re on this question haunted me for
the last few years so I decided to do
some more research and look into this
further it seems that the search for
extraterrestrial intelligence implicitly
assumed
that more is always synonymous of
progress right that more advanced
civilizations use more energy just like
our path up until now would suggest but
what if that’s just not true
why if there’s a bottleneck somewhere we
just don’t see it where could be all the
while I was asking myself these
questions I couldn’t help but notice the
backdrop of the 21st century all around
us increased frequency of deadly storms
wildfires droughts floods rising
temperatures all mark the impacts were
having on our planet through climate
change and all of this is also because
of how we use our energy the fossil
fuels that we burn now release
greenhouse gases into the atmosphere and
these trap heat around the surface of
the earth like a blanket we’re using a
lot of energy now sure yeah that’s true
but we’re not using enough to directly
heat the planet all that much rather as
a side effect we trap more of the heat
that’s already here and that’s that’s
good actually believe it or not that’s a
good thing because that makes this a
solvable problem we could just not use
fossil fuels we could not release
greenhouse gases it’s a challenge
certainly but I think it’s one we can
solve and we’re working on it right now
but remember that bridge and where it
leads
just a few human lifetimes will have to
use a thousand times more energy than
we’re using now and that magnitude of
energy use will have significant
consequences much like a glowing Dyson
swarm using that much energy will be
enough to heat the earth directly based
on the laws of physics alone there’s no
getting around the laws of physics we
could try to be clever we could try to
be creative and I’ve looked into the
options believe me but it doesn’t change
if we keep building this bridge as we
have done if we keep using more and more
energy every year our energy use will
render the planet uninhabitable by the
end of the 24th century if not sooner
a bridge dangerous our thirst for energy
for more has consequences we’re starting
to register this consequences now with
the climate that we’re currently
changing and if we keep going down this
bridge these consequences will only be
worse other researchers in this
overlapping field that I’m in of
astronomy biology planetary science
climate science and more what we’re
calling astrobiology are all reaching
similar conclusions research is now
showing that unless civilizations are
careful as they’re developing if they
use too much if they consume too many
resources or grow too quickly that they
can inflict terrible damage on their
planetary environments developing
civilizations like ours unless we’re
careful can destroy themselves by
damaging their planetary cradles even
before they get all that far into the
cosmos or put it another way
astrobiology and the search for
extraterrestrial intelligence may be
telling us that our bridge is
unsustainable now I won’t pretend like
this is the only possible solution for
why we seem to be so alone out there
but even if we are alone or we are the
first civilization in this unimaginably
vast cosmos this doesn’t change anything
it doesn’t change the path that we’re on
doesn’t change the laws of physics if
anything it only raises the stakes even
higher and makes the choices that we
make now even more important so what
choices can we make
with this knowledge how can we build a
better bridge a bridge to our best
possible future remember it all comes
back to energy right we give that bridge
direction every day with how we use
energy to live our lives everything
comes down to energy everything we do
our growing population our
transportation how we work how we live
what we work and what we live for our
economic priorities our consumer habits
everything that we do gives direction to
our bridge I’ve just shown you a rough
idea of where this bridge is heading now
based on this paradigm that we live in
but only rarely question or think about
but that’s the great news because the
future is not set we can question this
paradigm you can make better choices we
can build a better bridge a bridge to
our best possible future using our
effects on our climate now is a clear
step one from there we’re gonna need to
take a hard look at our growth in energy
use and everything that contributes to
it it’s easy for me to come up here and
dream about a perfect world with a
stable population that cherishes and
takes careful stewardship of the earth
its resources and its ecosystem but
that’s gonna require a population that
really values those things over other
things that our economy set up to value
now things like the latest smartphone
free shipping and endless panoply of
consumer products that are always made
to break and never meant to last and the
underlying economic reality of it all
maximizing shareholder value for the
latest fiscal quarter we all need to
take a hard look at our path our
priorities the things that we value
personally as an astronomer I’ve always
dreamed of the day our species leaves
the planetary cradle for the cosmos
I believe we can get there I believe
that can be our future or any other
future that we choose but what I’ve
learned is we can only get there if we
take care of ourselves and the planet in
the process we can’t unthinkingly
slouched into our future let the future
happen to us no we need to choose our
future we need to make our choices
understand our priorities and understand
the consequences that go with them
our ultimate responsibility is to plan
for our future not just ours not just
our children’s or grandchildren’s future
but humanity’s future together on earth
even if we reach for the stars so where
will our Bri our bridge lead us now that choice is up to you thank you
ever build it’s not one that connects
two points in space but rather two
points in time every day we’re building
this bridge together connecting our
present to our future but unlike most
bridges we can always change where this
one leads as an astronomer I’ve often
wondered if there are other
civilizations out there somewhere in the
cosmos
all their species like ours building
their own bridges to their futures like
we are today there definitely should be
our universe is a big enough place and
our cosmic neighborhood alone
there should be trillions of other
worlds around hundreds of billions of
other Suns other stars many of these
alien solar system should be younger
than our Shore but many still should be
older there should be other
civilizations out there ahead of ours
ones that have already built the same
bridges for themselves that we are
building for ourselves now but here’s
the question that keeps me up at night
what if we never find that what if we
never find any evidence that there are
civilizations out there ahead of us ones
who have already crossed these bridges
to their futures same as we’re trying to
cross ours now was that tell us about
the path that were on this past on this
bridge that we’re building behind us is
already set by our history but moving
forward our path this bridge is paved by
the choices we make every day and the
things that we value an essential
measure of this is our use of energy we
need energy to do whatever it is we want
to do both as individuals and
collectively as a species it’s at the
center of everything in our lives it’s
at the center of everything that we see
all around us now responsible for or a
product of everything from growing our
food and transporting it around the
globe to growing our population and
transporting that around the globe from
running our economy day-to-day to
developing the technology that we
take Korea and it all around us now our
axis and our use of energy defines the
tempo of our daily lives and the things
that we value in ways that we only
rarely think about since the 1800s or so
we’ve been using roughly 2.6 percent
more energy per year than the years
before now this may not seem like much
but overall this catches up to you over
time we’re using more and more energy
faster and faster so now here we are in
the present day using somewhere between
15 and 20 trillion watts of power to
fuel our ambitions enough for a presence
to be seen from space a lot but if we
keep going down this bridge that we’re
building using more and more energy with
each passing year
in just a few human lifetimes we’ll have
to use a thousand times more energy than
we’re using now imagine that by then how
we obtain energy our ways that we can
use it our additional resources will be
somewhat limited there only be one game
in town left and that’s the giant star
sized nuclear reactor the Sun sitting
right in the middle of our solar system
give me off much much much more free
energy free power in all directions
without any effort from us and we want
to keep going down this bridge as we
have been we’re gonna have to harness
that energy there’s one good way to do
that too here’s the Sun from a distance
now now I want you to think of a solar
panel or something similar now imagine a
whole swarm of solar panels surrounding
the Sun a swarm that collects absorbs
the sun’s light and turns it into energy
that we can use such a swarm of solar
collectors would ideally be about the
size of the Earth’s orbit around the Sun
the astronomer Freeman Dyson is
considered the first to think of this so
we appropriately enough tell us the
Dyson swarm how I I know this idea
sounds fantastic
but believe it or not building such a
thing
is technically feasible that’s good
because again this is our bridge this is
where it’s pointing this is where our
insatiable hunger for energy is leading
us now I think if there are other
civilizations that have already crossed
this bridge into their own futures then
that mean there should be Dyson swarms
somewhere out there in the universe
right now we just have to find them
the trick is yeah you know knowing how
to look because Dyson storms are big
right sure but the space between stars
is much much bigger than that
Dyson swarms are so far away stars are
so far away that we won’t be able to
pick them out individually or see them
directly luckily we don’t have to we can
get creative you see regardless of what
a civilization would choose to do with
all of its energy it’s got to obey the
laws of physics these rules that are
sewn into the very fabric of the cosmos
around us tell us that energy can’t be
created or destroyed I’ve been saying
this whole time we use energy but really
what I mean is that we transform energy
from one type to another to another and
through all these transformations we get
something useful for us in the process
and you’re familiar with this in your
daily lives too and we take energy we
use that energy to produce food and
generate electricity you take food you
eat that food and you turn that energy
into energy of motion and energy of
thought meanwhile all the devices around
us right now take energy from
electricity and turn that into energy of
heating cooling lighting powering our
journeys through the internet through
all the transformations of energy there
all the transformations that we put our
energy through invariably gets released
as heat just walk into an
air-conditioned room full of sweaty
people in technology and you kind of get
what I mean
over time the energy that we use gets
released into our an environment and
finds its way out into a space other
civilizations beholden to the same laws
of physics that we are would be no
different
civilizations with the Dyson swarm would
be no different they just use a lot of
energy from a star but they would have
to take that star’s worth of energy and
regardless of what transformations they
put that energy through they would have
to release that energy out as heat too
so a Dyson swarm should be warm and glow
with the heat that it gets off a special
kind of light that we call infrared
radiation light that’s redder than right
now a few years ago I joined a search a
hunt for Dyson swarms with some other
astronomers we knew that space
telescopes like wise Spitzer and IRS had
already surveyed the whole sky
specifically in infrared light we knew
that these surveys could be used the
hunt for Dyson swarms too so we looked
we scanned the whole infrared sky
hunting for distant points of light that
had just the right kinds and balance of
infrared light what you’d expect the
tail tell-tale signatures of a Dyson
swarm around another Sun but even though
the Eden we’re good enough to spot them
the data were good enough even in a sky
of billions stars and other objects not
one was a Dyson swarm our search found
nothing there’s no evidence that there
are advanced civilizations out there
using significant amounts of energy kind
of energy that we’re going to need just
to keep going down this bridge that
we’re building now so again I ask you no
one else could cross this bridge what
does this tell us about the path that
we’re on this question haunted me for
the last few years so I decided to do
some more research and look into this
further it seems that the search for
extraterrestrial intelligence implicitly
assumed
that more is always synonymous of
progress right that more advanced
civilizations use more energy just like
our path up until now would suggest but
what if that’s just not true
why if there’s a bottleneck somewhere we
just don’t see it where could be all the
while I was asking myself these
questions I couldn’t help but notice the
backdrop of the 21st century all around
us increased frequency of deadly storms
wildfires droughts floods rising
temperatures all mark the impacts were
having on our planet through climate
change and all of this is also because
of how we use our energy the fossil
fuels that we burn now release
greenhouse gases into the atmosphere and
these trap heat around the surface of
the earth like a blanket we’re using a
lot of energy now sure yeah that’s true
but we’re not using enough to directly
heat the planet all that much rather as
a side effect we trap more of the heat
that’s already here and that’s that’s
good actually believe it or not that’s a
good thing because that makes this a
solvable problem we could just not use
fossil fuels we could not release
greenhouse gases it’s a challenge
certainly but I think it’s one we can
solve and we’re working on it right now
but remember that bridge and where it
leads
just a few human lifetimes will have to
use a thousand times more energy than
we’re using now and that magnitude of
energy use will have significant
consequences much like a glowing Dyson
swarm using that much energy will be
enough to heat the earth directly based
on the laws of physics alone there’s no
getting around the laws of physics we
could try to be clever we could try to
be creative and I’ve looked into the
options believe me but it doesn’t change
if we keep building this bridge as we
have done if we keep using more and more
energy every year our energy use will
render the planet uninhabitable by the
end of the 24th century if not sooner
a bridge dangerous our thirst for energy
for more has consequences we’re starting
to register this consequences now with
the climate that we’re currently
changing and if we keep going down this
bridge these consequences will only be
worse other researchers in this
overlapping field that I’m in of
astronomy biology planetary science
climate science and more what we’re
calling astrobiology are all reaching
similar conclusions research is now
showing that unless civilizations are
careful as they’re developing if they
use too much if they consume too many
resources or grow too quickly that they
can inflict terrible damage on their
planetary environments developing
civilizations like ours unless we’re
careful can destroy themselves by
damaging their planetary cradles even
before they get all that far into the
cosmos or put it another way
astrobiology and the search for
extraterrestrial intelligence may be
telling us that our bridge is
unsustainable now I won’t pretend like
this is the only possible solution for
why we seem to be so alone out there
but even if we are alone or we are the
first civilization in this unimaginably
vast cosmos this doesn’t change anything
it doesn’t change the path that we’re on
doesn’t change the laws of physics if
anything it only raises the stakes even
higher and makes the choices that we
make now even more important so what
choices can we make
with this knowledge how can we build a
better bridge a bridge to our best
possible future remember it all comes
back to energy right we give that bridge
direction every day with how we use
energy to live our lives everything
comes down to energy everything we do
our growing population our
transportation how we work how we live
what we work and what we live for our
economic priorities our consumer habits
everything that we do gives direction to
our bridge I’ve just shown you a rough
idea of where this bridge is heading now
based on this paradigm that we live in
but only rarely question or think about
but that’s the great news because the
future is not set we can question this
paradigm you can make better choices we
can build a better bridge a bridge to
our best possible future using our
effects on our climate now is a clear
step one from there we’re gonna need to
take a hard look at our growth in energy
use and everything that contributes to
it it’s easy for me to come up here and
dream about a perfect world with a
stable population that cherishes and
takes careful stewardship of the earth
its resources and its ecosystem but
that’s gonna require a population that
really values those things over other
things that our economy set up to value
now things like the latest smartphone
free shipping and endless panoply of
consumer products that are always made
to break and never meant to last and the
underlying economic reality of it all
maximizing shareholder value for the
latest fiscal quarter we all need to
take a hard look at our path our
priorities the things that we value
personally as an astronomer I’ve always
dreamed of the day our species leaves
the planetary cradle for the cosmos
I believe we can get there I believe
that can be our future or any other
future that we choose but what I’ve
learned is we can only get there if we
take care of ourselves and the planet in
the process we can’t unthinkingly
slouched into our future let the future
happen to us no we need to choose our
future we need to make our choices
understand our priorities and understand
the consequences that go with them
our ultimate responsibility is to plan
for our future not just ours not just
our children’s or grandchildren’s future
but humanity’s future together on earth
even if we reach for the stars so where
will our Bri our bridge lead us now that choice is up to you thank you
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