What do you do when you want to see something so far into space that you'll never be able
to reach it? You send a space telescope into orbit. NASA has done just that by deploying
the James Webb space telescope into outer space to enable us to see more of our cosmos.
The very edge of the universe will be one of the targets of the space telescope. The
discoveries at the universe's edge promise to be terrifying. What will the first telescope observe
at the universe's edge? How does it affect you? Join us as we investigate the startling
discovery made by the James Web space telescope at the universe's edge that shakes everything.
Humans have long been intrigued by what lies underneath our feet, but as our
research equipment becomes more advanced, our fascination has grown to include deep space.
The invention of the telescope was critical in furthering our understanding of the cosmos;
while the concepts of telescopes were known in the late 16th century, the first telescopes
were not made until 1608 in the Netherlands. The story of Galileo and his telescopic views
demonstrates how powerful a tool for seeing and collecting information can be in changing our
understanding of the universe. Early telescopes were largely used for making observations on Earth
and assisting with activities such as surveying and military tactics, but Galileo Galilei became
one of a small bunch of astronomers who aimed telescopes towards the heavens.
Galileo created his own telescope after learning about the Danish perspective glass in 1609,
and the exhibition of the telescope secured him a lifetime lectureship at the university
following his initial success. Galileo spent his time improving the instrument;
his initial telescope could magnify objects three diameters, making them appear three times larger
than they were; but, with further refinement of the design, Galileo built an instrument that could
magnify eight times, and eventually 30 times. Space and telescopes go hand in hand. This is
due to the vastness of space; for example, the nearest star to us is Proxima Centauri,
which is around 4.2 light years away; one light year is approximately 5.88 trillion miles or
9.6 trillion kilometers. This means that the distance between Proxima Centauri and us is 25
trillion miles. Even though the Mars planet that Elon Musk is attempting to colonize is close by,
volunteers will have to undertake months and months of journey across space before touching
down on Mars to start living their lives. When the distance is great enough,
we deploy telescopes. We've been able to study these celestial bodies in greater depth thanks to
the extraordinary power of magnification. Several of these telescopes are positioned in orbit around
the body, such as the sun's or Earth's orbit, from where it peeps into space. One such telescope is
the Hubble, which has for years returned stunning images of the universe. Even so, a better and
more powerful eye has been installed in space, and this eye will assist us in comprehending
what goes on at the edge of the universe. This is the James Webb Space Telescope.
Galileo would never have anticipated that a telescope manufacturer would have such a
vast budget or a workforce from all over the world, but supporters claim it is worth it.
Thousands of astronomers from all around the world will use the JWST, which will be the
prime observatory of the next decade. The history of our universe will be examined at every point,
from the first light after the big bang through the emergence of solar systems
that may support life on planets like Earth and the evolution of our own solar system.
The telescope cameras and spectrometers all contain detectors capable of recording
extremely faint signals. One instrument, NIRSPEC includes configurable micro shutters that allow
it to see up to 100 objects at the same time. Webb also features a cryocooler for cooling
another instrument's mid-infrared detectors to a very cold seven kelvin so they can work.
How do we know what exists beyond the observable universe? We can draw conclusions based on known
physical principles and the things we can measure within our observable universe, for example,
we observe that the universe is spatially flat on the greatest scales and is neither positively nor
negatively curved to a precision of 0.25%. If our existing law of physics are right,
we can establish boundaries on how big the universe must be before it curves back on itself.
The observations from the SLOAN digital sky survey and the Planck satellite provide the
best data for our extrapolation. According to the two sources, if the cosmos does circle back
in on itself and close, the part we can see must be at least 250 times the radius
of the observable region. This leads to the conclusion that the unobservable universe,
assuming no topological oddities, must have a diameter of at least 23 trillion light years and
a volume of space that is more than 15 million times larger than the volume we can observe.
There are, nevertheless, convincing arguments that the unobservable
universe should be much larger than that. What is the most distant astronomical object
that humans can see? One thing is that we might never see some objects in the universe. Why?
About 16 billion light years away from earth marks the current cosmic event horizon of the
universe. Are we almost there? No way, not yet. This is the maximum distance at which light can
ever reach us if it began at that distance today. This indicates that beyond 16 billion light years,
the expansion of space is faster than the speed of light itself. Since light must
travel through an expanding universe, it will never reach us. This also means that we will
never be able to see any event that may have occurred today beyond the cosmic event horizon.
However, telescopes such as the JWST allow us to look much farther. The GN-Z11 galaxy,
which is around 32 billion light years away from Earth, is the most distant galaxy ever detected.
Note that we calculate this distance while taking into account the expansion of space.
At about 46 billion light years away from earth we reach what is called the surface of
last scattering. Whatever direction you look at it from, this is what you will see. After
recombination and photon decoupling, the surface of last scattering looks like a homogeneous
sphere of fog from which the initial photons of cosmic microwave background radiation emerged.
Contrary to its name, it is the origin of the earliest light
scattering but the last of what we can observe. Is this the end of the universe at last? No and
yes. Technically, this represents the edge of the observable universe—the furthest point in
space and time that humans can observe—and what lies even further beyond is referred to as the
opaque universe. This represents the limit of what we can see, but not what we can imagine.
Let us now venture beyond the limits of the observable cosmos. What could
possibly exist there? We've only looked at what existed at a specific place in space
in the distant past. What might potentially exist there is a more inconceivable question.
The edge of the observable universe also represents the particle horizon, which is
the farthest distance one can look into the past. Everything we've observed thus far has been from
the standpoint of keeping Earth at the center and scaling time to the past with distance,
which begs the question, "Is the universe infinite?" Well, Einstein's theory of
relativity predicts that a flat universe must be endless, thus we can conclude that there is
no edge or end to the universe. However, we have not been able to determine conclusively
whether the universe is finite or not. How? It's like this: while the hot big
bang may signal the beginning of the observable universe as we know it, it does not signify the
birth of space and time. This is because, prior to the big bang, the universe went through a period
of cosmic inflation, throughout which it was filled with energy intrinsic to space itself,
expanding at a constant exponential rate and developing new space so rapidly that the smallest
physical length would be stretched to the size of the currently observable universe every 10
raised to the power of negative 32 seconds. While inflation has ceased in our part of
the universe, three key problems that directly affect the size of our universe
remain unsolved. These problems concern whether the universe is infinite or not.
They are, first, how large was the post-inflationary region of the
universe that produced our hot big bang? Second, is the concept of eternal inflation, in which the
universe inflates indefinitely into the future, correct? and three, how long did inflation last
before it ended, resulting in the hot big bang? It is probable that the universe where
inflation took place barely grew to a size larger than what we can see;
perhaps in a year the evidence for an edge to where inflation took place will materialize,
and we will have to adjust our perception of the universe once more. However, it is also
possible that there are many other universes out there that are similar to our own, adhering to
the same laws of physics and possessing the same kinds of physical cosmic structures.
This opens up the enticing prospect of complex life in one of the many worlds out there.
The bubble in which inflation ended should likewise have a finite size and scale, as well as
an exponentially enormous number of such bubbles trapped within the bigger inflating space-time.
So, what does the universe's edge look like? You've probably heard of flat earthers and
dismissed them, but if they could apply their flat surface hypothesis to the universe as a whole
rather than just the earth, they might be correct. If it's tough to visualize the cosmos as flat
terrain, Einstein's theory of general relativity says that the speed of light remains constant no
matter how distorted spacetime becomes owing to the gravitational influence of objects like
stars or black holes. As a result, it makes the most sense since the entire amount of universe in
existence is bounded by an event horizon, which is a boundary over which no light can escape and is
constantly expanding in all directions at a rate significantly faster than the speed of light.
The edge of the universe is defined by something called a particle horizon,
which is similar to the event horizon of a black hole but inverted. However, it's crucial
to acknowledge that the edge of the universe does not exist in the manner you might believe
it does. How? You might think that the edge of the universe is a place where you could turn
around and see a zoomed-out view of everything, including every galaxy, planet, star, and so on,
but this is probably not the best way to think about it, at least not in terms of space, which
explains that even if you were to catch up with the edge, there would simply be more universe.
According to the theory, this is not a problem that can be solved by envisioning the entire
universe as some kind of object or point of observation; it simply is. Instead,
imagine you could step outside of the universe and hold the entirety of its contents in your hands.
What would you have? Most likely, a sphere-shaped object that stays the same size in your hands
even as the components inside shift around, but because the universe is self-contained,
we could never truly become aware of an outside, at least not without interstellar travel.
Let us know in the comments what you think the edge of the universe looks like.