The light they produce is too redshifted and blocked by too much intervening gas to be seen even by Hubble.
The most distant galaxy ever discovered is already late, dating back to 407 million years after the Big
But the very first stars should go back hundreds of million years further.
Sometime between the Cosmic Microwave Background, at 380,000 years, and that first galaxy, the first stars must have formed.
Owing to the second-most-distant galaxy ever found, MACS1149-JD1, we can understand when.
We see MACS1149-JD1 as it was 530 million years after the Big
Oxygen is only produced by previous generations of stars, indicating that this galaxy is already old.
MACS1149-JD1 was imaged with microwave (ALMA), infrared (Spitzer), and optical (Hubble) data combined.
The results indicate that stars existed nearly 300 million years before our observations.