In 2003, NASA's Spitzer Space Telescope launched into space to begin a mission to observe the heavens in infrared. That kind of light is emitted by warm objects, so its main imaging camera -- called IRAC, for Infrared Array Camera -- had to be cooled using liquid helium, or else the infrared light it gave off would interfere with its own observations!
This type of coolant leaks away slowly, and after about five and a half years -- a much longer period of time than originally hoped, which was a bonus -- the liquid helium was finally depleted. However, this didn't end the mission; instead it marked the beginning of the "warm phase". Observations could still be made, though only with some of the detectors that weren't so severely affected by the raised temperature.
That was in May 2009. Spitzer has now been running warm for 1000 days, and to celebrate that milestone the folks running the observatory released their favorite 10 Spitzer IRAC images. Over the years I've featured half these images on the blog (see the list below), but I have no idea how I missed this amazing shot:
Isn't that cool? Well, so to speak. Haha. Because of the warm mission, you see. Ha ha.
But what is it? Just off the top of the picture is a young star. It's a newborn, a mere baby, probably less than a million years old, and like human babies it tends to spew matter out of both ends. In this case, the star's rapid spin coupled with its intense magnetic field create two powerful jets of material that blast away from its poles at speeds of up to 100 kilometers per second! What you're seeing here is one of those jets as it plows through a cold cloud of gas and dust. The shape may be due to the material in the jet following the twisted magnetic field lines, or it may be formed as the shock waves emanating from the interaction become unstable, a bit like breaking waves from a ship ramming through the water at high speed. Either way, it looks for all the world -- the galaxy! -- like a rainbow tornado.
What you're actually seeing is warm molecular hydrogen -- two atoms bound together, called H2. The color represents temperature: near the tip of the jet is where it's warmest as it slams into the surrounding material, and it's cooler farther back. Remember, this is an infrared picture, so it's false color to help us see what's going on. The shape is funny: it's a bit of an optical illusion, and I have a hard time convincing my brain it's not narrowing due to perspective, like looking down a long cylinder. It actually is physically wider at the top and narrower at the bottom, where the tip of the jet is still pushing its way through interstellar material.
And this is just one of the ten images from Spitzer to celebrate its anniversary! The other nine are equally amazing. They have pictures and a brief description on their page, but I've written lengthier posts about half of them (in order in the picture above): The Milky Way mosaic, the Orion Nebula, the W5 nebula, the star-forming cloud DR22, and the Helix nebula (scroll down a bit on that page to see it). I've written about many, many other images from Spitzer over the years as well; search the blog for more! I have a few of my favorite recent ones listed in Related Posts below, too.
One thing that's true for every observation by Spitzer: they're all amazing. And recently, NASA gave the OK to run Spitzer for at least two more years, and so here's to seeing lots more science from this wonderful telescope!
Image credit: NASA / JPL-Caltech / J. Bally (University of Colorado); also E. Churchwell (Univ. of Wisconsin); Univ. of Toledo; CfA; J. Hora (CfA) & W. Latter (NASA/Herschel).