Snow – especially the 22 inches of it that’s fallen in the past few days – has remade our world. Trees, roads, homes, even my dog are clad in fluffy white. While it makes for extra work to clear, most of us marvel at the sheer beauty of the transformation. Nature can change a landscape overnight. It can also remake a chaotic mess of hydrogen gas and dust into a brand new generation of stars.
The Orion Nebula, located just below Orion’s famous three belt stars, is a turbulent place. Just look at photographs, or if you’ve got a telescope, see for yourself. Swirls of glowing gas snake around fresh-faced stars while clumps of nebulosity look like clouds on the move.
Buried within the nebula’s foggy folds are hundreds of newborn stars, only a handful of which are old enough to have blown away their dusty birth cocoons and show as brilliant, blue-white beacons in a typical telescope.
Enter NASA’s Spitzer Space Telescope and the European Space Agency’s Herschel Mission. The two orbiting observatories gaze at the universe through infrared-sensitive eyes. Infrared light lies just beyond the red end of the rainbow spectrum. Though invisible to our eyes, we sense it as heat. Because infrared can penetrate dust and gas with relative ease, Spitzer and Herschel can see inside Orion’s clouds and spy stars in the earliest stages of firing up as feisty newborns.
Spitzer sees shorter wavelengths of infrared light (closer to the color red) and Herschel sees longer. By combining the two, scientists created this beautiful image of glowing cores of warm, contracting gases that in a several hundred thousand years will be hot enough to initiate nuclear fusion and blaze as true stars. This is how it all gets started. From dark clouds, light is born.
Not only do we see the earliest beginnings of stardom happening in Orion, but these hatchlings are changing right before our eyes, rapidly heating up and cooling down. Some of them vary in their brightness by up to 20 percent in a matter of weeks.
One possibility for the rapid changes might be that “lumpy filaments of gas funnel from the outer to the central regions of the star, temporarily warming the object as the clumps hit its inner disk. Or, it could be that material occasionally piles up at the inner edge of the disk and casts a shadow on the outer disk,” according to scientists involved in the study.
Humans of the distant future will have the privilege of looking Orion-ward to see a brilliant star cluster swathed in a few remaining tendrils of dust – a landscape as radically transformed as the one outside my window today.