[Music]
what do you do when you want to observe
somewhere so deep in space that you can
never reach it you send a space
observation station nasa has done
precisely that by sending the james webb
space telescope to deep space so that it
can help us see more of our universe
there are no limits to the human spirit
i thought i would see the end of physics
but now i think the wonder of discovery
will continue long after i am gone
one of the places the space telescope
will be pointed at is the very edge of
the universe the findings at the edge of
the universe promises to be scary what
will the first telescope see at the edge
of the universe how does it affect you
personally join us as we explore the
terrifying discovery by the james webb
space telescope at the edge of the
universe that changes everything now
that the james webb space telescope has
made it to its orbit and work to get it
up and running has started how capable
exactly is it how powerful is this new
eye in space well according to nasa the
jwst is so sensitive to infrared light
it would be able to detect even the
slightest heat of a bumblebee at the
distance of the moon to quantify it
better this telescope is 100 times more
powerful than the iconic hubble
telescope that has been serving as great
pictures of the universe for more than
three decades the jwst is intended to
take baby pictures of the universe
literally sure the hubble can take
breathtaking photos of space but it has
its limits for instance it hasn't
allowed scientists to see the first
galaxy is formed after the big bang webb
will change that because it will be
acting like a giant time machine it's
like we have this 14 billion year old
story of the universe but we're missing
that first chapter the jwst will capture
light that has been traversing the
cosmos for as long as 13.5 billion years
extending our views of the universe
several hundred million years earlier
than the hubble what makes the webb
telescope so powerful part of it is the
giant primary mirror 6.4 meters in
diameter it comprises 18 smaller
segments that must align perfectly the
segments are covered in a gold coating
so thin that a single strand of human
hair is 1 000 times thicker the less
than 2 ounces of 24 karat gold reflect
infrared light better than other metals
infrared is just outside the visible
spectrum of what humans can see
actually the mirrors are not solid gold
they are made of beryllium to function
correctly the webbed telescope needs to
be kept cool it does that thanks to a
five-layer sunshield the size of a
tennis court this mechanism was folded
up when web launched on christmas day
but less than two weeks later the
extremely thin layers of the shield were
successfully deployed without the shield
the immense heat from the sun would
overwhelm the telescope's sensors the
side facing the sun will experience
about 260 degrees fahrenheit while the
other side will be chilled to some 370
degrees below zero a nearly 600 degree
difference the sunshield gives web the
equivalent sun protection factor or spf
of 1 million
one thing that makes scientists nervous
about the web telescope is that they
won't be able to fix any issues that
arise both during the launch and
operation for comparison in hubble's
lifetime five space shuttle crews have
made service calls to correct the
telescope's initial blurry vision and
perform maintenance and upgrades but
that is because the hubble is only 340
miles away the webb telescope is much
farther away nearly a million miles away
this is far beyond the reach of
spacewalking repair groups so nasa only
got one chance to get it right however
if the proper technology is developed
scientists could someday send a robot to
refuel web extending its life speaking
of fuel nasa initially thought the
telescope would last only 10 years but
thanks to an efficient launch there is
enough fuel left to power the jwst for
20 years for now scientists are eagerly
awaiting webb's first photos which will
arrive this summer after that the jwst
will settle down to work it will help to
investigate the nature of dark energy in
the universe and understand the nature
of these very old objects it will also
help to search if there is another earth
out there among the distant exoplanets
that litter the universe interestingly
the jwst has started proving its worth
almost 10 billion
even before taking its first photos
northrop grumman which built the
telescope's mirrors had to cover new
ground because a precise mirror had
never been created the technology the
company invented is now being used by
eye surgeons they also develop stuff on
the computer level the company made huge
advances in understanding how to deploy
big things like how to take a giant sun
shield the size of a tennis court and
fold it up neatly and deploy it
now when astronomers try to see the edge
of the universe with the jwst what will
they see
humans have always been interested in
what surrounds us but traveling across
the universe isn't just traveling
through space but through time as well
but before we get on we need to
establish something the dimension of the
universe because to find the edge we
should first know the dimensions of the
universe our universe is expected to be
13.772
billion years old making it quite old so
how big is our universe really
scientists today estimate it to be 28.5
gigapass x in width getting a grasp of
how big that figure is requires some
basics of astronomical units how large
is a parsec to understand how a parsec
is defined you should first know what an
astronomical unit au is one au is
essentially the average distance between
the sun and the earth approximately 150
million kilometers so a parsec is
defined as the longest length of a
triangle whose shortest side is 1au and
which subtends an angle of one arc
second at the opposite vertex if you
calculate further you will see the one
parsec equals 3.26 light years or the
distance light travels in one year which
is about nine trillion four hundred
sixty billion kilometers and we're
talking about 28 gigapass x here which
is 93 billion light years that is 879
780 times 10 raised to the power of 18
kilometers that is just unimaginably
huge
for comparison the length of dna of all
humans on earth combined together when
stretched will be about 0.119
billion light years long now look at the
figures mentioned earlier carefully and
you will discover that something looks
inconsistent the speed of light is the
absolute maximum speed possible right so
if the universe is 13.7 billion years
old how come the width of the universe
is about 93 billion light years
technically if an object created just
after the big bang moved with the speed
of light it should by now have travelled
a maximum of what
13.7 billion light years nothing more
nothing less from where did all the mata
come from beyond this limit this is
where we turn to hubble's law the law
states that objects observed in deep
space are found to be red-shifted
redshift refers to the shifting of the
wavelength of light to the red end of
the spectrum that is an increase in the
wavelength of the light but why does the
wavelength expand one reason space is
expanding and this is not just that
objects are moving away from one another
but the fabric of space itself is
expanding here is where everything goes
crazy the expansion is accelerating it
is assumed that dark matter and dark
energy have a strong influence on this
behavior
so the extra distance due to the
expansion of space needs to be taken
into account when estimating the width
of the universe this is why the edge of
the universe is clearly not at some 13
billion light years from earth it is
estimated to be much beyond that what is
the furthest astronomical object humans
can see one thing is that there are some
objects in the universe that we might
never see why about 16 billion light
years from earth this marks the current
cosmic event horizon of the universe are
we there yet nope not yet this distance
is the upper limit of light ever
reaching us if it originated at that
distance today this implies beyond 16
billion light years the expansion of
space is faster than the speed of light
itself obviously the light will never
reach us as it will have to travel
through a relatively expanding space
this also signifies that any event that
may have happened today beyond the
cosmic event horizon will not be
observable by us no matter what but we
can see even further through telescopes
like the jwst the most distant galaxy
ever observed is the gnz11
located about 32 billion light years
away from earth mind you we calculate
this distance taking into account the
expansion of space as well at about 46
billion light years away from earth we
reach what is called the surface of last
scattering this is what you will observe
irrespective of the direction you look
at the surface of last scattering is
like a uniform sphere of fog from which
the first ever photons of cosmic
microwave background radiation came
after recombination and photon
decoupling contrary to the name it's the
origin of the very first scattering of
light but the last of what we can
observe
is this finally the edge of the universe
yes and no technically this is the
farthest point in space and the farthest
in time that we can observe that
essentially forms the edge of the
observable universe what lies even
beyond that is what is known as the
opaque universe this marks the limit of
what we can observe but not what we can
imagine let us now go even beyond the
edge of the observable universe what can
exist there all this time we have only
explored what existed at a point in
space in the distant past a more
unimaginable question would be what
could possibly exist there a present
the edge of the observable universe also
marks what is called the particle
horizon the maximum distance one can see
into the past everything we've seen so
far was from the perspective of keeping
earth at the center and scaling time to
the past with distance this brings us to
the question is the universe infinite
well from einstein's theory of
relativity it can be estimated directly
that a flat universe must be infinite
can we then conclude there is no edge or
end to the universe it is not so
straightforward we have not been able to
determine categorically if the universe
is finite or not let's hear what you
think of the edge of the universe in the
comment section