As a New Yorker, I would say trying to spot a Times Square star is little more than a silly task.
To see even the lightest of it, you should look among fluorescent lanterns, flashing signs, bag tickers, and other illuminated distractions. It’s best to take the train a hundred miles north of the state. Out there, observing the stars no longer requires any effort. An impressive canopy of sparkles hangs over you, like it or not.
But even from the deepest, darkest, most remote location, you’ll never see all the stars with the naked eye. Physically you cannot detect all galaxies, nebulae, exoplanets, quasars, you could continue, in your line of sight, even with your favorite optical telescope. There are billions and billions (billions) of cosmic phenomena out there. It’s just that our human eyes aren’t made to see the light they emanate. It’s called infrared light.
Therefore, many space treasures are invisible to us. Fortunately, though, that doesn’t mean they’re beyond us.
As Stephen Hawking once commented, humans are unique because we always find a way to transcend our mortal limits. We do it “with our minds and our machines.” And, of course, over the years, astronomers have developed fascinating alternative solutions for infrared, which have finally paved the way for NASA’s James Webb Space Telescope.
Fighting human restraint
Already, high-budget space telescopes like NASA’s Hubble and Spitzer are clearing up some cosmic infrared secrets. They contain instruments that seek elusive light and then translate this information into signals understandable by human learners. This, in turn, allows us to see many things in the universe that are normally hidden from our eyes.
The famous deep field image of Hubble seen through the infrared detection lens. These bright spots are not stars. Each is an entire galaxy.
NASA, ESA and R. Thompson (Arizona University)
However, if these massive telescopes are episodes one and two of the astronomy infrared detection series, the agency’s new powerful Webb space telescope, whose first full-length image set was released on July 12, it’s a whole new season.
Levels beyond the infrared capabilities of Hubble and Spitzer, the JWST is literally built for work.
Enlarge the image
This composite image compares infrared and visible views of the famous Orion Nebula and the surrounding cloud. The infrared image is from NASA’s Spitzer Space Telescope, and the visible image is from the National Observatory of Optical Astronomy, based in Tucson, Arizona.
NASA et al.
The pioneering telescope is a $ 10 billion gold-plated machine filled with infrared detectors, accented with high-tech lenses and programmed with ultra-powerful software. Its Holy Grail device is called the Near Infrared Camera, or Nircam, and will lead the charge by collecting a large amount of infrared signals from deep space for astronomers to see on the ground.
This is why the JWST is often said to have the promise of revealing an “unfiltered universe”.
Looking through the JWST lens instead of a standard optical telescope would be like looking at the stars from my hypothetical dark New York area instead of Times Square. There would be countless more flashes in both cases, even though you are seeing the same sky. It’s just that in our analogy with the dark shadow zone, we’re seeing additional stars because we’re not inhibited by light pollution. The JWST, on the other hand, is collecting infrared light from deep space and decoding it for us.
It will point to exactly the same universe that Hubble has been examining for decades and scientists have studied for years, but it will access luminescence that we cannot see, possibly revealing hidden phenomena transmitted into space such as violent black holes, exotic exoplanets, large spiral. galaxies and … maybe even signs of extraterrestrial life?
His first images have already left us with much more than just breath. In fact, NASA staff who were the first to look at the images of the JWST’s “first light” said they were moved to tears. “What I saw thrilled me, as a scientist, as an engineer, and as a human being,” said Pam Melroy, NASA’s deputy administrator.
These images from NASA’s Hubble Space Telescope compare two diverse views of the turbulent heart of a vast stellar nursery, known as the lagoon nebula. On the left, there is a standard optical version. On the right, infrared.
NASA, ESA and STScI
But before we get into the details of the JWST infrared mechanics, we need to talk about the electromagnetic spectrum. More specifically, a bit of an enigma that poses us humans.
Why can’t we see infrared light?
At some point in your life, you may have wondered what it would be like to see a new color. Something that can’t be described, the way “green” doesn’t really have a definition beyond “the hue of a caterpillar,” or, if you’re a fan of objectivity, “a wavelength of 550 nanometers “. After thinking about it for a while, I would bet that you have become accustomed to the disturbing reality that you will never know the answer.
It is because colors are nothing more than the products of light that is reflected in some source.
The different colors are dictated by different wavelengths of light, which you can imagine as zigzag curves of various proportions. When we see a blue umbrella, for example, our eyes pick up narrower blue wavelengths emanating from the waterproof material. As we admire a blazing sunset, our eyes pick up a bunch of longer, more relaxed red and yellow wavelengths.
All of these wavelengths are well organized in what is known as the “electromagnetic spectrum.” But here’s the problem.
This infographic illustrates the spectrum of electromagnetic energy, highlighting specifically the parts detected by NASA’s Hubble, Spitzer and Webb space telescopes.
NASA and J. Olmsted [STScI]
Although there are an infinite amount of light wavelengths, humans can only “see” a small part of the spectrum: the region of visible light, which encapsulates the colors of the rainbow. Precisely because of this, we will never experience the pleasure of seeing a color other than the rainbow.
Our bodies will not allow this to happen, and we can do nothing to change it except build a superpower telescope, of course.
Spying on secret wavelengths
Because infrared light falls beyond the region of visible light, despite its name, it does not appear red. It doesn’t look like anything. In fact, it is best described as a heat signature: we can “feel” infrared wavelengths, which is why many thermal imaging equipment includes infrared detectors. Firefighters, for example, call in the infrared to find out where a fire may be burning in a building without having to enter.
But specifically for astronomy, the non-visibility of infrared wavelengths is a major problem.
The universe is expanding. Constantly. Which means that as you read this, stars, galaxies, and quasars, super luminescent objects that act like cosmic lanterns, travel farther and farther away from Earth. And as they do so, the wavelengths of the light they emit gradually extend from our perspective, like an elastic rubber stretching. They stretch, tilt, and stretch until they shift to the red end of the spectrum. They “move to the red.”
The center of our Milky Way is usually hidden from standard optical telescopes due to dust and gas clouds. But the infrared cameras of the Spitzer Space Telescope were able to penetrate much of the dust, revealing stars in the crowded galactic center. The upcoming James Webb Space Telescope can offer even more spectacular vision than this, causing fainter stars and sharper details.
NASA, JPL-Caltech, Susan Stolovy (SSC / Caltech) et al.
Take a star that was born near the beginning of time, for example. At some point, once the Earth existed, this star may have radiated wavelengths of blue light to our young planet. But as it moved away, along with the expansion of the universe, these wavelengths of blue light began to stretch from the Earth’s point of view, getting redder and redder … and more red … and redder.
“Shifting to red is the stretching of light toward longer wavelengths that occurs as light travels through the expanding universe and can be used to measure distance,” Paul said. Geithner, deputy director of the JWST project, in a statement.
In fact, he said the JWST’s Nircam, “will take a series of photographs using filters that collect different wavelengths and will use the brightness changes it detects between these images to estimate the redshifts of distant galaxies.”
Eventually, however, these wavelengths extend even beyond the spectrum of visible light. They step on infrared water and disappear from the sight of our naked eye. Think again about this example of an ancient star.
Now, billions of years later, these slowly reddening wavelengths have moved to the infrared region of the spectrum, from our perspective. The ancient star only sends us the kind of stellar light that our eyes cannot see.
You can see a picture of all of Webb’s main instruments in this collage. These are not the end results of the telescope’s full-color “first light”. They are just testing products.
NASA / STScI
Stars and galaxies, MIA
This means that all distant, super-rare, and probably information-rich distant stars and galaxies are invisible to us, along with everything that illuminates these stars and galaxies. We miss the pieces of the history of our universe: its opening chapters.
But thanks to its infrared hunting instruments, the JWST infrared detectors could show us those missing pieces. They were able to elucidate what the cosmos was like during its first moments after the Big Bang. They could also find distant exoplanets floating among their own ex-moons and look for distant artificial light that could indicate extraterrestrial life. They will offer us a landscape of the universe clear enough to remind us of our microscopic place in it.
A comparison of the visible and infrared views of the Hubble monkey …