When the James Webb Space Telescope launched at the end of last year, astronomers have given it an infinite number of missions. I say infinite because ultimate goal of this engineering marvel is not simply about answering all the questions we have about the universe. It’s to answer questions that no mortal human would have thought to ask.
But before we get to that mind-blowing end goal, our shiny new goal is strut mindfully through tasks we have given it, one of which is to pierce the veils of cosmic gas and dust and reveal the secret escapades of the stars within. What standard optical telescopes, like Hubble, can’t always see.
Here, on Tuesday, the JWST decoded a shimmering scene behind one of space’s dark curtains, a dusty canopy that shrouds a pair of merging galaxies some 270 million light-years from Earth.
What am I looking at?
We have two realms, called IC 1623 A and B, stuck on a collision course through space and time. They are located in the constellation Cetus and have long been of interest to scientists for several reasons.
Perhaps most strikingly, they could be forming a supermassive black hole – a gargantuan vacuum with enough gravitational pull to warp the fabric of our universe as we know it.
But this budding cavern of destruction should be adorned with a necklace of light.
The ultra-high intensity galaxy merger IC 1623 also spurred the creation of a nearby rapid star-forming region. This is called a starburst, and this one in particular, according to the European Space Agency, is creating new stars at a rate more than 20 times that of the Milky Way galaxy.
And this did the JWST catch.
Hubble has already given us a preliminary view of IC 1623 A and B, but astronomy’s new contract with space has pierced the duo’s cosmic veil, just as scientists had hoped all along. In doing so, he showed us the luminous core of this fusion and presented humanity with a complete and fascinating picture of IC 1623 rather than a hidden image with a central region left to our imaginations.
Why can JWST do what Hubble can’t?
Two words: infrared imaging.
All of the light emanating from deep space can be classified on a kind of diagram known as the electromagnetic spectrum. Different wavelengths of light, which also result in different colors in our eyes, are located on different parts. On one side you have redder wavelengths and on the other bluer ones.
But if you go beyond the red side of the electromagnetic spectrum, as some lights actually do, you come to infrared light.
Infrared light, unlike ordinary red light, is essentially invisible to the human eye. That means it’s also invisible to instruments that act like human eyes, albeit very powerful versions like the Hubble Space Telescope.
But infrared light is precisely the type of light emanating from stars in most clouds of thick cosmic dust, like the veil surrounding IC 1623. So to understand what’s going on inside, we need an infrared light-detecting telescope. And this is JWST.
By the way, starlight and other phenomena far, far away from Earth also come to our planet as infrared light. This is why the JWST is ready to bring us information on the far the universe as it was at the beginning of time, information invisible to us and to the Hubble Space Telescope. More on that here.
Returning to IC 1623, ESA explains that “Webb’s infrared sensitivity and impressive resolution at these wavelengths allow him to see past dust and resulted in the spectacular image above, a combination MIRI and NIRCam images”, in reference to two of JWST’s high-tech instruments.
Another easter egg in this image, as with all JWST photos, is the eight-pronged diffraction spikes you see in the very center. (It looks like six spikes, but there are two mini spikes running horizontally across the middle. They’re just hard to see). All JWST images have this signature, unlike Hubble’s four-fold version.
Typically, these spikes are very prominent when lots of light is present in an image, which is why the latest telescope image of two galactic nuclei has its bright central snowflake.
Hopefully the next time JWST sets its sights it will be on one of those sites with evidence of something we never thought to ask.
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