In the year 1609, Galileo pointed one of the first telescopes ever created
up at the heavens and what he observed sparked a revolution of curiosity
that has been central to every single human generation since.
Galileo saw mountains and craters on the surface of the Moon, the arm of our Milky Way galaxy
arching across the sky, and an endless Universe riddled with countless stars. The mysteries of
outer space were boundless, and the journey toward discovering them had only just begun.
Over 400 years later and our obsession with the enigma that is space
has only managed to intensify, fueling many great technological advancements
that have made our ever-expanding Universe seem smaller and its boundaries closer than ever.
On the 25th of December, 2021, NASA launched humanity’s most powerful telescope yet.
More than 30 years in the making, $10 billion spent, a successful launch,
50 intricate outer space deployments, and a distance of over 1.5 million
kilometers (932,000 mi) traveled from Earth, the James Webb Space Telescope has finally delivered
its first full-size images of our Universe, marking a new era of space discovery that promises
unique and unprecedented views from across our own Solar System to the very heart of the Universe.
The James Webb Space Telescope, JWST for short, has been designed to look more than 13.5 billion
years into the past to study the farthest and oldest regions of space, peering back into the
early days of the Universe. Its aim is to look at the first galaxies that started forming and
emitting light right after the big bang. It’s no wonder that scientists often refer to telescopes
as time machines. In them lies the power to see what our Universe once was and perhaps
answer one of humanity’s most perplexing existential questions, how did we get here?
And right now, Webb is our best chance at finding an answer to that question.
However, to fully understand what makes Webb so special,
we have to travel back in time to the year 1990 when the Hubble Space Telescope was launched.
The Hubble Space Telescope embarked on a mission similar to Webb’s.
Its purpose, just like Webb’s, was to study the Universe like it’s never been studied before
and to bring us closer to understanding our existence and our place among the stars.
Over the past 30 years, Hubble has brought us images of galaxies we never knew existed,
star clusters, and nebulae like we’ve never seen before.
These images helped illustrate how in the early days of our Universe,
just millions of years after the big bang, cold clouds of gas and dust evolved into swirling,
coalescing galaxies teeming with stars. Sadly, that was how far Hubble could see.
In order to observe how these first galaxies were born, we needed a bigger telescope,
one that wasn’t just more powerful, but that could also operate in the infrared.
So just a few years after Hubble was launched into space,
scientists began working on the next big telescope.
Today, Webb is 100 times more powerful than Hubble, and its ability to observe infrared
light opens up a new universe of possibilities. Ever since Edwin Hubble discovered that the
Universe is expanding, we’ve known that galaxies have been receding at faster and faster speeds.
Light from these galaxies is stretched to longer wavelengths as it travels through space,
which is why they’re only visible through infrared.
Hubble, the telescope, is only able to see light on the visible spectrum, which means it’s limited
in the amount of information it can fetch us about these earliest galaxies. But with Webb,
we finally have the ability to observe them. To detect these infrared waves, Webb traveled
more than 1.5 million kilometers (932,000 mi) away from the Earth’s warm atmosphere,
to a very cold region in space that is protected from our planet’s infrared radiation.
Built into this telescope are huge Sun shields as big as a tennis court that protect it from the
rays of the Sun and help keep its temperature at minus 233 degrees Celsius (- 387 °F), so
it can be cool enough to detect infrared radiation from the early days of the Universe.
This is the first time in the history of our species that we’ve been able to
look at our Universe with such depth and detail.
And the first images NASA released on July 12 are proof that we’ve entered a new space frontier that
is bound to bring us closer to understanding our place in this ever-expanding Universe.
Let’s begin our journey back in time with the closest image Webb has taken. This is called the
Southern Ring nebula. It’s a planetary nebula in our own Milky Way galaxy, 2,000 light years away.
Despite its name, a planetary nebula does not have any planets. The name is simply inspired by its
round structure. A nebula is clouds of dust that are thrown out by the explosion of a dying star.
You can see the enormous clouds of gas thrown out by this red giant in the center of the image.
This image utilized Webb’s Near-Infrared Camera, or NIRCam,
which looks at the shortest infrared wavelengths. When we switch to its MIRI, or the mid-infrared
instrument that can observe longer wavelengths, you can see that it gives us an unprecedented look
into the heart of this nebula. Right here, you can actually see two stars at the center of the system
with the dimmer one being a white dwarf at the tail-end of its life, and the brighter one – a red
giant – at an earlier stage of its dying process. The pair of stars are locked in each other’s
orbit in a cosmic embrace which leads the dimmer star to spray ejected material like a sprinkler,
resulting in these jagged rings. Stars are critical to life as we know it.
With Webb’s powerful mirrors and its ability to peer behind the thickness of gas and dust,
we’ll be able to study the death of stars like we’ve never done before.
This could give us a greater understanding of the chemicals and the elements that are
discharged from stars as they evolve through time, and whether these components are
the building blocks that are needed to spawn life as we know it back on Earth.
But the birth of stars is just as important as their death. This image of the “Cosmic Cliffs” in
the Carina Nebula 7,500 light years away, offers a breathtaking view of the clouds of gas and dust
actively coming together to form new stars. This is one of the most active star-forming regions
in our galaxy, a star nursery that could give us tremendous information on this creation process.
When we switch to the MIRI once again, you can see the infant stars behind this ethereal cloud
of dust. Being able to see what is behind their cosmic clouds is incredibly important
when we look at galaxies as a whole. It can enable us to estimate the total
mass of stars in a galaxy with more accuracy. Speaking of galaxies, 300 million light years
away lies the tightest galaxy grouping we have ever discovered. These five galaxies are called
Stephan’s Quintet and they are all bound to crash into each other and eventually merge.
Actually, two of them are already in the process of doing exactly that.
This image of Stephan’s Quintet is the largest of Webb’s initial images. It might not look like it
at first glance, but what you’re seeing here is actually a composite of over 1,000 images
made up of over 150 million pixels when combined together. Zooming in on any part
of this picture will show you hundreds, if not thousands, of galaxies waiting to be discovered.
What’s even more fascinating is that when we switch to the mid-infrared instrument,
we can spot never before seen details of Stephan’s Quintet. That very bright structure
in the uppermost galaxy is actually a supermassive black hole, 24 million times the size of the Sun,
and actively increasing in density while emitting more energy than 40 billion Suns put together.
Just pause and think about that for a moment.
These new images provide us with valuable insights into galactic interactions that may have driven
galaxy evolution in the early universe. The early Universe… Webb’s primary mission.
This is what is called a deep field image. Deep field is a long-lasting observation
into a particular region of space, intended to collect light from the faintest, furthest objects.
Peering 4.6 billion years into the past, this image shows the galaxy cluster SMACS 0723
at its center alongside shimmering stars, warped light trails and thousands of
extremely distant jewel-like galaxies. It’s the deepest and sharpest infrared
image of the early Universe we’ve had so far. But despite its magnificence, what’s most interesting
about this deep field is the warped light trails around the galaxy cluster’s edges.
This galaxy cluster is so massive that it warps spacetime, and ultimately the light of stars and
galaxies located billions of light years behind it. This is called gravitational lensing and it
acts like a cosmic magnifying glass bringing us the light of galaxies almost 13 billion light
years away, potentially making them some of the oldest galaxies we’ve ever observed.
Without a doubt, these early images are breathtaking and already showcase
the huge capabilities of Webb, but taking pretty pictures is not the telescope’s only superpower.
It can also study the atmospheres of planets. You see, for a while now we’ve been searching for
exoplanets, which are planets outside our Solar System orbiting around a star similar to our Sun.
We’ve discovered around 5,000 of them so far, with our main goal being to find one that’s hospitable
to life, and ultimately finding some of that life. When analyzing the atmospheres of exoplanets,
we look for elements such as methane, oxygen or nitrogen; ingredients present
in our own atmosphere that could signify the presence of life on these planets.
So far, the Universe has not offered us any signs of life. However, this graph captured by Webb of
the hot gas giant exoplanet WASP-96 b could be our first step toward locating some extraterrestrials.
The observation reveals the presence of a very specific gas molecule, water vapor. While Hubble
analyzed numerous exoplanets’ atmospheres over the decades and detected water in 2013, Webb offers a
more detailed observation and a giant leap forward in tracking down habitable planets beyond Earth.
This image is only a glimpse of Webb’s massive
ability to capture precise atmospheric elements hundreds of light years away.
We’ve always wondered whether life exists beyond Earth. And Webb could be the tool to
help us answer this question and change the meaning of our existence forever.
The James Webb Space Telescope has only just begun its journey, and the road ahead is still long and
daunting. Analyzing the Universe’s origins, understanding the birth and death of stars,
discovering distant galaxies and finding exoplanets are only just the beginning.
The truth is, looking more than 13 billion years into the past is bound to raise more questions
than we could ever imagine, but it also has the potential to answer questions as well.
Some of which we’ve been asking since the days of Galileo, and even ones we never knew we had.
When Galileo raised his telescope to the sky and looked at the craters on the Moon,
he acted on an almost instinctual human curiosity that has been with us since the dawn of time.
More than 400 years later, this same curiosity is bringing us even closer to our cosmic background.
Earth is only a small stage in the cosmic arena, and with the beginning
of a new era of space discovery we now know that more than we ever did before.
There is no doubt that in the upcoming years, Webb will bring the Universe
even closer to us and help us know more about the reality of our cosmic existence.
So whenever you find yourself looking up at the night sky and its beautiful stars,
remember, “Somewhere, something incredible is waiting to be known.”
Carl Sagan.