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i would like for humans to take a
picture of an exoplanet i mean we can
image them by which i mean you can see
the little points of light that are
planets in other solar systems so that's
kind of a picture but i really want to
see one you know like we're flying up to
it in a sci-fi movie i'm gonna see the
clouds and the continents and that of
course
is impossible except it's not we just
need bigger batter telescopes and you'd
be surprised how creative astronomers
can get when it comes to coming up with
them a telescope is really just two
things some way of focusing light and
some way of detecting light this can be
as simple as say a lens and galileo's
eyeball these days it's more along the
lines of mirrors and tons of different
cameras and detectors in theory though
to get better and better photographs of
distant objects you just need a bigger
lens or a bigger mirror just a system to
collect more light galileo's telescope
had a 38 millimeter lens and from there
we've scaled up to the james webb space
telescope 6.5 meters up in space with
even larger mirrors down here on the
ground like currently under construction
in chile the appropriately named
extremely large telescope will have a 39
meter mirror but those are just peanuts
compared to some telescopes we're
already using see there's no reason the
detector and the lens of a telescope
have to be in one piece in theory you
could have a telescope that is very very
very long with a detector literally
light years away from the lens and
indeed those telescopes exist thanks to
gravity gravity warps space specifically
very massive objects distort space
around them and warping space causes
light passing through it to bend as well
and bending light is what the lens of a
telescope does and in very particular
situations this effect creates an
accidental telescope this is an einstein
ring a weird ring around a massive
object in the sky the stuff you can see
around the star is not actually there
it's behind the star
way behind it the light coming from
those extremely distant objects is being
warped by the divot the star makes in
space allowing us to see stuff that is
very very far away as if it were much
closer gravity is warping the space so
we call this gravitational lensing these
accidental telescopes are how we know a
ton of stuff about our universe
including seeing some of the most
far-off and therefore earliest stuff out
there in 2022 for example astronomers
wrote that they'd actually used
gravitational lensing to spot the oldest
star ever seen the james webb space
telescope will be able to use
gravitational lensing effectively
pointing a telescope at another
telescope to make some seriously
superpowered images potentially seeing
some of the very first stars to ever
exist in the universe many objects such
as stars galaxies and even black holes
can create a gravitational lensing
effect but almost none of them are
useful because we can't control these
telescopes the detector which is us and
the lens which is the star have to line
up perfectly with the object we're
observing and all by pure astronomical
chance luckily even though space is very
empty it's also very big which means
there are lots of opportunities to get
lucky we've identified thousands of
these alignments that have allowed us to
discover all kinds of cool things but we
really don't have a choice about what's
being lensed except here's the cool part
in the future
we might that kind of control would let
us use gravitational lensing to do all
kinds of things including taking an
actual photograph of an exoplanet
photographs could show us if they have
continents clouds oceans who knows in
2021 an article called image recovery
with the solar gravitational lens was
published in the journal physical review
d and by solar they don't mean any old
star out there they mean our sun this is
just the latest proposal for a solar
gravitational lens an idea that goes
back decades what's different about this
one is that it considers what is
possible with current technology and
draws the conclusion that we already
have the computing capacity to take
pictures with solar gravitational
lensing
if not the spacecraft all you'd have to
do is launch a detector of some sort and
line it up with the sun and whatever it
is you want to see of course this is not
without its challenges let's hit some of
the big ones the authors identified
first the sun doesn't have a perfectly
sharp edge it has an atmosphere called
the corona and the corona would block a
lot of what we'd like to see so we would
need sophisticated ways to correct for
that second we need to put our detector
far enough away from the sun to actually
use it as a gravitational lens this is
far away around 550 astronomical units
from the sun that's 550 times the
distance between the sun and the earth
for context voyager 1 the most distant
craft we've ever sent into space is a
bit more than 150 au from the sun and
finally these telescopes would in effect
be single use you need them to be
perfectly aligned with whatever they're
observing so if we want to observe the
alpha centauri system we need to send
out a telescope specifically for the
alpha centauri system if we want to
observe the trappist-1 system we'd need
a totally different mission but the big
win of this study was that they actually
offered a simulation of what the earth
would look like if it was about 4.3
light years away and we were able to
take a picture of it this way this is
what we would get before correcting for
any fuzziness from the sun's corona and
the fact that it's not a perfect sphere
this is what we would get after
correction it seems impossible but this
is likely a thing that humanity really
could do probably not super soon though
there are a lot of challenges to
overcome and probably a number that are
yet to be uncovered and even if a solar
gravitational lens was built it would
take with current technology at minimum
17 years to arrive at the proper focal
distance to start doing astronomy but i
really want to see those pictures so
tick-tock astronomers thanks for
watching this episode of scishow space
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