Who are you?
We are from Mars, don't be afraid.
We have children just like you on Mars.
Human beings have contemplated
whether life exists beyond Earth for thousands of years.
Ancient one of Mars I call upon you.
It's thought that there's a possibility
that simple microbial life might exist
within our solar system,
but not advanced complex life.
Doesn't mean it doesn't exist,
it just means we don't expect to find it,
largely because the conditions for life
elsewhere in the solar system appear
to be extremely hostile to such life.
But since the early 90s,
technology has allowed us to locate planets
outside of our solar system.
They're known as exoplanets and planet-hunting telescopes
like Kepler and TESS,
have discovered roughly 4,000 of them and counting.
So we now understand that majority of stars
will have planets.
So planets are ubiquitous.
And because we just reach that sensitivity
that is allowing us to detect those exoplanets,
this field is evolving very rapidly.
And while they're too far away
to send a probe to even the closest exoplanets,
a team at NASA's Jet Propulsion Laboratory
has been developing a method more powerful
than any telescope ever built.
It'll be able to give us a close-up look at planets
and other objects thousands of light-years away,
find worlds that are similar to Earth,
and maybe even discover signs of intelligent life.
So that's what the Earth people call a city?
How primitive.
Look at all those buildings above ground.
And it will be amazing discovery,
first of all to see that we are not alone
and how life evolved in that system.
So it's an enormous step
in our sort of philosophical understanding
who we are and where we go.
Powerful telescopes, like the Hubble Space Telescope,
Spitzer, Herschel and Keck Observatory
have photographed objects very far away.
This galaxy called The Sombrero Galaxy
is 28 million light-years from Earth.
But even though known exoplanets are as close
as four light-years, these are the best images we have.
All we really get are just these tiny little blobs.
They just look like fuzzy, little points
of light orbiting some distance from the star.
So we don't really see anything that looks like a planet.
In fact, if we didn't know any better we might think
that it was just a very very faint star,
when in fact it's a very very large planet reflecting
the starlight off of it.
And of the 4,000 discovered exoplanets,
only about 50 of them have been imaged.
So basically it's really really hard
to image an exoplanet?
It's really hard, but not impossible.
And that's why we're aiming to do that, you know,
that's why we're trying to make that happen,
but you're right, it's very difficult,
it's certainly is not beyond our capabilities
or won't be beyond our capabilities.
The majority of exoplanets
are found using the transit method,
a tiny dip in a star's brightness when a planet passes
or transits in front of it.
And it's that telltale drop off in light,
especially when it repeats over several cycles
that tells us that this is caused by a planet,
orbiting the star making regular transits
across its surface.
Another common method
is looking at slight shifts in the motion of a star
when there's a planet orbiting it.
This is known as the radial velocity or wobble method.
The planet exerts gravity on the star.
So what happens is that as the planet comes around the star,
the star also kind of comes around
the system's center of mass.
And so the star has to move.
Although both of these methods
allow planetary scientists to make predictions
like the basic mass, size, whether it's rocky or gaseous,
and distance to its host star,
it doesn't allow us to see it.
In the best case scenario,
the light can be analyzed with modern telescopes
to give hints as to whether the planet is habitable.
How can we even tell that a planet is habitable
just by a fuzzy blob?
We certainly cannot.
So the goal with these telescopes is not to actually show us
what the planet looks like,
but it would allow us to analyze the light coming
from the planet.
The spectrum of light
coming from the planet can be analyzed
to reveal the chemical components of its atmosphere,
a much easier feat than getting a real life image.
That's because in comparison to a galaxy,
exoplanets are dark and tiny.
Planets just reflect light from their host star.
So even though a planet
may only be a few dozen light-years down the road,
our chances of seeing it are much less
than seeing a bright star that's even farther
or a bright galaxy that's billions of light-years away.
It's just the nature of the luminosities involved.
Even with the upcoming
James Webb Space Telescope,
which will be the most powerful space telescope ever built,
the images won't give you much more than fuzzy blobs.
What we want is an image where you can see color variations
that distinguish oceans, continents, vegetation,
and even see lights at night.
That can determine not just if it's habitable,
but show proof of advanced life.
But to image an Earth-sized exoplanet,
that's a hundred light years away at a decent quality,
1000 by 1000 pixels,
you would need a telescope
that is 90,000 kilometers in diameter,
seven times larger than Earth.
And even if it were made of a super lightweight material,
it would still weigh about a trillion kilograms.
In other words, it's not possible.
What we need to do instead is rather than think
about even building a telescope,
we need to think about using nature itself
as a kind of telescope.
And luckily nature gives us a way to do that.
This was discovered by Albert Einstein,
and it's the idea that mass or gravity
can bend the path of light.
As long as that can happen, then we can in theory,
go to where all those light rays
that are being bent by a mass converges,
and we can take an image.
This is called gravitational lensing.
As long as we can choose the right place to put a telescope,
we could in principle, look back toward the sun,
image the gravitational lens from a distant exoplanet,
and for the first time,
we would actually be able to see continents.
We'd be able to see the oceans and map the coastlines
of a Earth-sized planet, maybe a hundred light-years away.
This is a very different approach to making images
with a telescope that we could build here on Earth,
but it may in fact be the only way that we'd be able
to directly image the surface of another planet.
It may sound like science fiction,
but we've actually observed this phenomenon before.
When light from a distant galaxy
is behind a massive foreground object,
from our perspective on Earth,
the mass of that foreground object bends space time,
creating gravity and bending the light around that object.
This forms a ring called an Einstein ring.
To visually demonstrate this,
you can use a wine glass to act as the lens
or a foreground object and a light bulb
that can act as the source.
If we the observer looked through the center
of the base of the wine glass, we see a ring of light.
And in theory, we could use computer software
to decode that ring of light back into its original state.
If you replace the wine glass with the sun to bend the light
and send a telescope, now the observer,
to the point where the light converges,
you could then take images of the ring
and put it back together using software.
The sun is massive enough
that it will amplify whatever you're pointing it at,
by a factor of a hundred billion,
just like an astronomically massive telescope.
That's why a team of scientists led by Slava Turyshev
at NASA's Jet Propulsion Laboratory
are proposing a solar gravitational lens mission.
Flying a small telescope to the solar gravitational lens
will allow us to study those objects in very fine details
and confirm the presence of life,
and study the evolution of life on that exoplanet.
There are a few challenges though, for this to work,
the telescope will need to be positioned
past the convergence point at around 650 astronomical units
or AU from the Sun.
One AU equals the distance from the Earth to the Sun.
Neptune is at 30 AU for example.
And Voyager 1, the farthest manmade object
that was launched in the 70s,
is currently at about 150 AU.
So we have thought about how we can reach those distances,
what technology do we have?
And essentially we realized that using chemical propulsion
is very challenging because the fastest velocity
we were able to achieve with chemical propulsion
was achieved with the New Horizons mission to Pluto
and New Horizons was able
to reach roughly three astronomical units per year.
With this velocity, it will take us a lot of time
to get to solar gravity lens.
So, we realized that solar sailing
offers a unique alternative.
With solar sailing we are using the solar photons,
solar light to gain a very significant momentum
that will push our sail craft to very high velocity.
Solar sailing has been successfully
demonstrated by The Planetary Society,
NASA and the Japanese Aerospace Exploration Agency.
If done in a way that Slava and his team are proposing,
which involves flying close to the Sun,
the telescope will reach speeds of roughly 25 AU per year.
So with those velocities,
we will be able to reach solar gravity lens
within I would say 20 to 25 years.
That's the only way to do this.
The next challenge is once you get to 650 AU,
there's no slowing down.
But this is where they get a lucky break.
It doesn't have just a single focal point,
it has a focal line.
If you fly a spacecraft towards the focal region
of the solar gravity lens, we don't have to stop.
Moving along that focal line will still benefit
from that large amplification.
Another challenge,
which current telescopes also face when imaging exoplanets,
is that you have to point the telescope
at a very bright object, in this case the Sun.
This creates a glare
which needs to somehow be blocked out
in order to see the planet.
We will use a very interesting technique
called a coronograph.
So the, or star shade,
the large instrument that is, has to be flown
in front of our telescope in space,
and that coronagraph will allow us
to block the light from the parent star.
And suddenly the very faint light from the exoplanet
may present itself.
So it's a challenging technique
because the brightness mismatch.
Fortunately,
coronagraphs are being developed and in use
on many planet-hunting telescopes,
including the upcoming James Webb Space Telescope.
Finally, the telescope will be limited
to choosing a single target
since changing the angle by just a degree,
could mean propelling it billions of kilometers
in the lateral direction.
Usually people when talking about solar gravity lens
there is a significant limit,
because we currently are limited by propulsion capability.
So we can think that we can fly
only towards one target essentially.
And so, I think about solar gravity lens mission,
it's like any planetary exploration.
If you fly towards a Saturn,
we're studying the whole set of satellites,
the whole formula of satellites around Saturn with Cassini.
If you fly around Jupiter with Galileo,
we're studying multiple satellites of Jupiter.
With the solar gravity lens, flying towards a Trappist
we can study every planet in that system.
The Trappist system
is a star with seven planets orbiting it,
three of which are in the theoretical habitable zone.
The sweet spot for a planet to possess liquid water
on its surface and possibly support life.
Pointing the telescope at the Trappist system
could be a solution for looking at multiple planets
since they orbit the same star.
Another way they're looking to solve this is to build
the telescopes cheaply and send many of them.
These are just a few of the hurdles
that Slava and his team face,
but none of them are out of reach.
And what we realize is that most of those technologies
already exist.
Some of them in a very high technology readiness level,
some of them are yet
to reach a very reasonable technology readiness level,
but all of them exist in one form or another.
Most of this technology
is being developed alongside other projects
that need to get far out into interstellar space cheaply,
and in a reasonable amount of time.
So ultimately we will transfer
those engineering developments to allow us
to explore further, more, at a very affordable cost.
Solar gravity lens is our ultimate goal so far,
but looking at this we realize
that there are plenty of synergistic efforts
within exploration community and who benefits from them,
who benefit from those efforts and we invite our colleagues
and friends to join us to look at those technologies,
how we can use those technologies in the near term,
how those technologies will benefit us
in the next, five, 10 years.
Slava and his team received phase III funding
from the NASA Innovative Advanced Concepts Program,
and are developing methods to reconstruct the image
from an Einstein ring,
as well as building instrument prototypes.
They hope to launch their technology demonstration mission
in the next three to five years.
So as of now, if you could choose one target
for the solar gravitational lens,
what would you choose and why?
Oh man, only one?
Let's take a picture of our closest neighbor,
so the Proxima, right?
So Proxima b, it's our neighbor.
The closer the exoplanet is, the larger its image
and therefore the more detail we will be able to see.
The closest star to our solar system, Proxima Centauri
is only 4.2 light years away,
and it has at least one,
but probably two planets orbiting it.
I would love to use the SGL on that to see
what the planetary system next door looks like.
It's possible that once we get a close-up look
at our nearest neighboring solar system,
we'll be able to find out once and for all,
whether we're alone or at the very least,
get a detailed image of an exoplanet for the first time.
Slava and his team hope to launch their first mission
to image an exoplanet in the next 12 to 15 years.
So it's only in a short 40 years from today,
you and I may discuss the images of, you know,
life present on a different exoplanet.
And this is how the childhood dream
may realize for many of us.
So now we will have a clear understanding,
yes we are not alone and oh by the way,
our life is excellent.
Or maybe we just have a confirmation that those aliens use,
you know, carbon fuel as stupidly as we do.
Or maybe they come up with something excellent
and we'll learn from them.
But anyway, I think it's exciting opportunity for us
to step above our daily lives and think about
what our universe will tell us about ourselves.
So, while we're never gonna solve
every problem on Earth, we can solve most of them.
And in addition to reducing the pain of life on Earth,
we can also increase the excitement
of being alive in the first place.
And that's what missions like the solar gravitational lens
and these next generation of space telescopes
are allowing us to do.
And there's something just fundamentally essential
about learning about our real true place in the cosmos
and understanding how it works.