I wanted to say that we live in this
amazing time that for the first time in
human history we actually have the means
the technological means part of them
developed here the museum - to figure
out whether we're alone in the universe
and I know there's a lot of things that
are going wrong in our times and a lot
of things that going through the news
that you're not proud of that I'm not
proud of but this is something that's
who me is astonishing that our
generation could be rebuilding these
telescopes right now and I show you what
we found so far that generation that
figures out if when you look up in the
sky that there are other planets like
ours with signs of life out there and I
think that to me is one of the most
fascinating question in humankind has
asked for thousands of years are we
alone so what I want to do today is I
would like to us to change your view of
our sky and I'm a little bit cheeky I'm
saying 4.6 billion years of Solitude it
could be more
we haven't found life on other planets
yet but as I said we have the means and
we are building the telescopes to
actually be able to spot science of life
on other worlds planets orbiting alien
Suns right now and here this is just my
graphical expertise this is the earth in
different colors so this is not images
we get from anywhere if you ever see an
exoplanet image at planet an image of a
planet around another star we have no
idea what its surface look like we have
no idea if there's any planes we have
not much idea if there's any colors okay
artist's impression so a lot of the
things that I'll show you is our
imagination leading us on to discover
these
and glimpse into what they're made out
of but so are we alone in the universe
the sky is really our new horizon
because we discovered other continents
we discovered other worlds but now our
next horizon is actually the sky out
there and when you go out at night and I
know it's a little hard to do in New
York City but when you go out at night
and in New York
I think somebody say you can spot two
stars if you're lucky there are
thousands of stars that you would see in
a nice dark place like it's a canoe York
having said that there's not much else
happening it's very pretty
but we do see the sky you know that's
like it's a trade off right there and so
when you go out in a darker place just
go and do one two three four five
science has told us we have found that
one out of five alien sons those stars
that you see up there are other sons our
son is a star one out of five of these
alien sons that you see in the night sky
actually have a planet that could
potentially be like ours what it means
is that it's at the right distance where
it's not too hot and not too cold so you
could have liquid water on the surface
and we could pick up signs of life if
they exist just by looking at the light
from that planet and that the planet is
small enough that it's a rock like the
earth and so if you had a huge cosmic
bathtub you throw the earth in it would
actually sink you throw Saturn in Saturn
would actually swim because the mean
density of Saturn a gas giant a very
different kind of planet than the earth
is less than water while the mean
density of the earth is actually more
than water so you'd say so our view at
the night sky is our view to other alien
Suns
and even so we can spot them yet it's
also our view to unseen other worlds
where somebody could ask themselves a
similar question are we alone in this
universe let me just give you a bit of
an overview how we fit in this universe
this is an image of our galaxy you are
here this is where we are about half way
out from the center where there's a big
black hole and the whole galaxy is about
a hundred thousand light-years across
what that means is that light needs a
hundred thousand years to get from this
side to this side it's like when you're
driving a car it's four and a half hours
to get to it took up so if you don't
have any cell phone reception when you
get to it's a car the message that you
have the news that you have is
four-and-a-half hours old right and so
all these sorry so then all of the youth
stars that you see out in the night sky
what they also are there are our few
back in time our closest star is four
light-years away so we see it today like
it was four years ago and anybody who
wants a nice birthday present let's say
somebody turns twenty google a star 20
light-years away find it bring your
friend and say I give you this star the
light that is arriving right now was
sent out when you were born works every
year it's a beautiful present really
only cost Internet access that's mostly
free you do learn stuff in grad school
so one of the things that I wanted to
point out all of these thousands of
other worlds that we already have
discovered and we above three thousand
now are actually in this tiny region
around our Sun in about a
I was in lightyears so in our solar
neighborhood and as I said before in our
solar system we were used to these
planets the inner ones are rocky because
it's very hot close to the Sun so gas
and ice evaporated only left rocky
material here and the outer ones are
have much more gas and ice as I said a
cosmic bathtub Jupiter or Saturn would
swim the earth would sink this is a size
comparison this is our earth and this is
Jupiter the gas giant and yes our earth
fits into the storm that is the Red Spot
on Jupiter surface but how have we found
these thousands of planets we found so
far well actually we don't find the
planets per se but the star gives a way
that the planet exists and so think
about it this way you go through Central
Park and you see somebody walking like
this right and this is the person who
doesn't want to go to direction-- the
dog wants to go right you don't have to
see the dog to know that somebody is
actually pulling this person and the
further they go back
the bigger the dog in a way it's the
same for stars a planet pulls the star
leans back they're really going around
the center of mass but it's an analogy
the star leans back and so even so I
don't see the planet here I see that the
star goes this direction when the planet
is behind int now this is not working
this direction when the planet is here
so by the wobble of the star I can
actually tell that somebody's tugging on
it something is tugging on it and it's
not a dog in this case it's actually a
planet and that's what you see here and
so sometimes the viewing geometry is
right so that when this timing occurs or
this planning goes in front of the star
it actually blocks part of the stellar
surface of the hot stellar surface that
makes the star bright
from our few and so the star for a
little amount of time a couple of hours
appears a little bit darker than it used
to be and that tells you that something
blocks its surface light from your view
and that's something if it's small
enough is a planet so it's bright bright
bright then it's less bright because we
don't see all the hot surface and then
when the planet goes out of our point of
view we see the full brightness of the
star again and that's what's called the
transit method this is what Kepler used
to find thousands of planets out there
in the sky and if you look very closely
at this animation and this is an
animation again you see that when this
star when the planets in front of the
star part of the light from the star
gets filtered through the atmosphere of
the planet allowing us to read the
chemical composition off the air of this
other planet just by looking at the
light that we get and if you draw how
many planets we've actually found it's
about 3,600 in current count think it's
3691 but who can keep up luckily I
usually tell my grad students don't
worry there's more than one planet for
everyone and then we have a lot of
signals that we still look at but
basically if this is the size of the
planet 11 is the size of Jupiter and one
is the size of the earth then this is
how many there are so we have many many
many more of the small planets then of
the big vennett's what's really exciting
for me because I like the small planets
because I would like to find life in our
lifetime and I said most of the stars we
see indirectly by the movement of their
stars most of these planets we actually
don't see directly but we already have a
handful off these planets and there's a
brown dwarf just over there on this
image where this the planet is far
enough away from the star or we can
block out the stellar light with a mask
so we can see this dot
off a planet and of course to me
personally the ones that are most
interesting are the ones that are in
this temperate zone where it's not too
hot and not too cold for there to be
liquid water on the surface so liquid
water is one of the key ingredients for
life and it also allows us to actually
see the gases that life breathes in and
out in the air if you have a huge layer
of ice and Enceladus with the example we
had before this icy moon you actually
have to go drill a hole and see if
there's a fish could be fish could be
something else could be no life at all
this is what we have to go and look but
if you can't get there with a spacecraft
and we don't have any of the star trekky
ones let unfortunately then we have
light that we can actually look at to
figure out what is in the air of these
planets and one of the things I wanted
to point out is that our Sun like every
other star is becoming brighter and
bigger with time and so in a couple of
billion years so don't worry we have a
couple of billion years
we'd better be a spacefaring nation
international nation because this is how
big our Sun is gonna get this is how big
it is now this is how big it's gonna be
and this is the orbit the distance of
Mercury Venus and Earth so the good news
is in a couple of years billions of
years so lots of time a couple of
billion years you can touch the Sun the
bad news is it's probably a smidgen hot
while you do that but we have one one
object that has left our solar system
Voyager 1 Voyager 1 is the only
human-made object human touched object
that ever left our own solar system and
before it did that it actually had a
look back and looked at the earth and
this is what it saw this is the earth
this tiny pale blue dot that Carl Sagan
wrote an amazing beautiful beautiful
poem about and this tiny dot still tells
you a lot of information so you have
this tiny dot and you really can see
continents or oceans but if you split
the light in its colors the light that
gets to you gets filtered through the
planet's atmosphere to you then you can
check if there's some energy missing
because light is energy you put your
hand out and you see that it gets warm
so light when it hits molecule in the
air all around us can actually hit them
so they start to swing and rotate and
that light is unique the one that's
missing - the molecule that it hits and
therefore the light that not that does
not get to my telescope tells you what
the composition the chemical composition
of the air on another world is and it
looks a little bit like you had an apple
and you took bites out of it and this is
how you can say which molecules are in
the air of a world that are really
really far away of course we also have
planets that don't have life like Venus
and they have their own light
fingerprint so we know how life light
fingerprint looks like that's oxygen
with the reducing gas like methane and
how other planets that don't have light
it look like and so the spectral
fingerprint of life for our own planet
is ozone with methane and water and
that's what we're trying to find in
other worlds and the last tiny point
that I wanted to make life of course
doesn't have to be like you and me life
can be very very different and then the
planet would also appear very different
if you think about a huge algae bloom
for example that could cover the whole
world it could be red or it could be
yellow it could be any color you really
want in life this is a really
interesting extremely file it's called a
water bear and it basically survives
anything you can radiate it you can even
put it into space they took it to space
open the door put it out without any
protection three days later they put it
back in put a little bit of water on it
and was like did it did it did it did it
it was fine so this is probably really
where astronauts go in the future or
something like this dehydrate them but a
bit a little bit of water on em I
actually gave a talk to about a hundred
astronauts they did not like that joke
at all you find this extreme forms of
life here in the here on our planet for
example in Yellowstone all these
different colors different forms of life
and so we're looking at that and we
making a color catalog of life of life
that's just not the flower you think of
or the tree but different forms of life
they can live in very very different
conditions and this is just a subsample
of the color code of a color catalog of
life we assembled and one of them is a
coral that biofluorescence so why I want
to bring that up is that in addition to
these other Earth's maybe not being pale
blue dot but red blue dots and green
blue dots in any other color you can
think of we could actually also have
really weird lifes
and some of the last planets that were
discovered orbiting small red Suns one
of them our closest star even our
closest neighboring star how closer
starts the Sun eight light minutes from
us the one after is four light-years
away from us Proxima Centauri so if you
shrink our solar system to the size of a
cookie and I want everybody to think
about cookies and astronomy together now
whenever you have a cookie then the next
star in the same scheme is two football
fields away and I was told not to use
soccer here even so the ladies team is
doing great
but the question is this star this red
Sun is very different because it has
flares so it hits its planet with huge
amounts of UVs but actually the coral I
just showed you before if you hit it
with huge amounts of UV what it does it
actually biofluorescence so maybe and
this is a big maybe on another world
this has worked at one of my postdocs
that in my lab on another world such a
huge flare of UV radiation that might be
really bad for life could actually lead
to a sign of life for us to be able to
TechEd it in the bio fluorescent flare
and of course to think about is this
this other system we discovered small
star seven earth sized planets the other
planets in your night sky if you were
standing on that planet would be as big
as the full moon
and then just imagine you'd see two of
them on each side of you and they might
actually flare in this beautiful
biofluorescent colors does it exist I
don't know but it's definitely something
that we should look for in the next with
the next telescopes and so our reach
towards the star is one that we just
starting and I sometimes like to think
about is like we making a travel list
for the coolest destinations around our
solar system and beyond we taking
together what we have and we're making
like a Lonely Planet top ten list for
travel bucket lists we don't have the
ships yet to get there but one of the
things we do have is the first
information of our travel destination
and in 2019 we'll start the follow-up of
Hubble it's a six point five meter
telescope so it's about four times me in
size that will be in space and for the
first time we'll be capable to
collecting enough light to actually find
signs of life when
world's close by if such lice exists and
so I think we live in an incredible
exciting time and we aren't the
generation that can actually transition
from are we alone to the universe - ooh
we figured it out
you
you
