Over half a year since its first science image was released, JWST’s data continues to educate us.
Behind galaxy cluster SMACS 0723 lies a series of brightened, magnified, gravitationally lensed galaxies.
One such galaxy — the Sparkler — appears three independent times.
Even the mid-infrared (MIRI) instrument captured it thrice.
The “sparkles” seen throughout it, though visually remarkable, are scientifically invaluable.
These “knots” of star-formation correspond to globular clusters: where 100,000+ stars form locally, all at once.
Only, when viewed in detail, these knots possess stellar populations already billions of years old.
This current star-formation episode appears to represent a second burst of stellar creation within them.
We’ve never seen globular clusters this distant before: at a redshift of 1.378, or ~9.2 billion years ago.
In fact, only one globular cluster is presently forming nearby: R136 within the Tarantula Nebula.
Many nearby globulars contain a longstanding mystery: two separately-aged populations of stars.
It’s mysterious because the initial burst of star-formation should expel all remaining star-forming gas.
But “the Sparkler” provides a way out: a second galaxy-wide wave of star-formation, repopulating already existing globular clusters.
With the power of gravitational lensing, numerous similarly longstanding puzzles could fall to JWST.
Mostly Mute Monday tells an astronomical story in images, visuals, and no more than 200 words. Talk less; smile more.