Microwave Eyes

On the Cosmos

When we look at the universe with our Mark I eyeballs through optical instruments, we’re detecting only a portion of the total radiation that is emitted from objects and events in space.  That is, we’re only seeing part of the light that bounces around the cosmos. The rest of it is slithering by us and we aren’t even aware of it.  In a multi-wavelength universe, it’s the equivalent of having blinders on — only the blinders are filtering out (or actually not letting us “see” those other wavelengths).

That multiwavelength “blindness” is curable however.  We simply use additional means to detect the many other wavelength regimes.  The Planck satellite is our microwave “eye” on the sky these days. This mission, launched and operated by the European Space Agency, is peering into places our eyes can never see. And, it’s seeing some amazing spaces.

sy ESA.

The Planck mission's view of the Orion Nebula in microwave emissions. The first image covers much of the constellation of Orion. The nebula is the bright spot to the lower centre. The bright spot to the right of centre is around the Horsehead Nebula, so called because at high magnifications a pillar of dust resembles a horse’s head. The giant red arc of Barnard’s Loop is thought to be the blast wave from a star that blew up inside the region about two million years ago. The bubble it created is now about 300 light-years across. Courte

Planck’s operators turned its gaze toward the Orion Nebula, a star-forming region about 1,500 light-years away. It’s well-studied in many wavelengths and astronomers have found stars in all stages of formation within the molecular créche.

Star formation is one of those processes that we can’t see much of in the optical. Oh, we can see the newborn stars after they’ve eaten away their birth cocoons, and often enough we can see those glowing clouds of gas and dust. But, we can’t see into the birthplaces to observe the whole process from start to finish. For that, we need to use infrared-sensitive detectors — or,  as ESA is doing — we use Planck’s microwave-sensitive instruments. It can see right past the clouds of gas and dust that would otherwise hide everything from our view.

Planck’s images of Orion show emission given off as high-speed electrons interact with the magnetic fields that thread our galaxy. They also show the emission from gas that has been heated by hot young stars in the nebula. And, Planck can also detect microwave signatures of  the cold dust clouds that are about to complete their collapse and begin the process of hatching new stars.

Keep an eye out for more great results from Planck! Its mission is to map the whole sky in microwave emissions and search out the signals from the earliest events of the universe. As it looks out across the light-years, it will bring us penetrating views of our own galaxy’s many shrouded regions.  I can’t wait to see what else it shows us!