Young stars have temper tantrums, spinning faster than their older cousins, displaying rapid changes. Often these changes in brightness are caused by "cold spots" that cover huge areas on the stars' surfaces, causing them to dim. As the stars spin, they "twinkle" from an observer's point of view as the light and dark regions rotate into view. Other times, the brightness variability is caused by huge clouds of dust blanketing the stars, blocking starlight from view.
But Spitzer doesn't stop at studying stellar formation, it can also see clues of how planetary systems form.
Surrounding many of these young stars are disks of dust and gas that may eventually clump together, coalesce and form planets. Fortunately, Spitzer is very well suited to look out for these dusty disks.
As stars heat up surrounding dust, it glows with infrared light; wavelengths that the space telescope can easily spot.
So although Spitzer has depleted its coolant, it hasn't quit making ground-breaking discoveries. The telescope continues to reveal more science behind the development of stars, but it may also give us a clue as to how planetary systems, like our solar system, evolved.
Image (top): A cropped portion of the Orion Nebula's star-forming region. [See the full, high resolution image] (NASA/JPL/Caltech)
Source: NASA Spitzer mission website