When you look up at the night sky, you’re only seeing a tiny fraction of the estimated
septillion stars out there in the universe…and honestly it’s not your fault. Even astronomers
have a hard time. But now the James Webb Space Telescope may
just make things a lot easier and push the very limits of infrared light observation
to travel back over 13 billion years ago for a glimpse of our universe’s first light.
So first, what exactly is infrared light? Well, we can’t see it, but we can feel it
as heat. On the electromagnetic spectrum, Infrared
lies right outside of the visible light section, as longer, redder wavelengths. You’ve probably
seen infrared light used in remote controls and even temperature guns commonly found during
the COVID-19 pandemic. But for astronomy, infrared light seems to
excel in revealing the unseen. Since the beginning of the universe, physical
space has been in a constant state of expansion. Although stars and galaxies both keep their
size, the shape and space between them continues to expand.
And as light travels through the ever growing reaches of space, it is stretched to longer
and longer wavelengths. So some of these wavelengths we as humans can actually see,
as long as it falls along the visible light region, in what’s known as our “window
of visibility”. Any wavelength extended beyond or falling
short of that region is effectively invisible to us.
And because of the estimated age of the universe, most of the light from our oldest stars actually
lies beyond the visible region since it has been constantly expanding for billions of
years. This is known as Cosmological Redshift. Infrared technology allows us to look back
to these oldest stars, all thanks to the unique ability of longer wavelengths to pass through
dense clouds of cosmic dust. Shorter wavelengths are usually blocked by these clouds, hindering
astronomers' studies of the universe. And this new technology exposed infinite possibilities
of study. Even encouraging the launch of the first infrared observatory in 1983, the Infrared
Astronomical Satellite, which completed a full infrared survey of the sky. And by 1998
had helped usher in the identification of hundreds of thousands of new objects which
were previously unseen. This led to other infrared discoveries like the largest ring
around Saturn and identifying one of the furthest supermassive black holes ever discovered.
Now astronomers and engineers are pushing this science to the limit once again with
the highly anticipated Webb telescope. The observatory hosts four scientific instruments
and two detectors on board, allowing it to study near-infrared and mid-infrared wavelengths.
The Near-infrared camera hosts on-board coronagraphs
that can hone in on very faint objects even if they
are near extremely bright lights, similar to how you would hold your hand up in front
of the sun to see another object. Then there’s the Near-Infrared Spectrograph, which has
a unique technology to analyze the spectrum of an object using a micro-shutter array.
This contains 100 microshutter cells, measuring as wide as a human hair. This technology reveals
physical properties of a target including chemical composition, mass, and temperature.
Next up is the Mid-Infrared Instrument which will use its on board cameras and you guessed
it, mid-infrared light to provide amazing imagery, even more impressive than that of
the Hubble Space Telescope. And finally the Fine Guidance Sensor/Near InfraRed Imager
and Slitless Spectrograph will accurately find targets, investigate exoplanets, and
detect first light within star systems. Using these instruments, Webb’s goal is to observe
early light in the universe over 13 billion years ago, essentially peering back in time
to help piece together how the universe shifted from a state of helium and hydrogen to the
complex worlds we see today. And what’s really cool is that it’s a
huge international collaboration between NASA, European Space Agency and the Canadian Space
Agency. This next generation observatory is a nod
to our endless curiosity as human beings to know more about how it all began. So now the
fun part begins and I can’t wait to see how our hard work has paid off when we get
those first images back... So what are some of your biggest questions
about the Webb telescope? Let us know in the comments below and make sure to subscribe. Thanks for
watching Seeker and I’ll see you next time.