Discussion Overview
The discussion revolves around the highest redshift (Z number) that a galaxy can have, exploring the epoch at which galaxy formation becomes impossible. Participants consider theoretical limits, the timeline of atomic and star formation, and the implications of redshift measurements.
Discussion Character
- Exploratory
- Technical explanation
- Debate/contested
Main Points Raised
- Some participants suggest that galaxies are being discovered at increasingly higher redshifts, prompting questions about the epoch at which galaxy formation ceases to be possible.
- One participant references a Wikipedia article that discusses the highest redshifts and lists distant astronomical objects, indicating that there is existing literature on the topic.
- Another participant posits that atoms formed around Z=20, implying that galaxies would form sometime after that, although this claim is questioned regarding the timing of star formation.
- A later reply clarifies that atoms formed before Z=1089, which corresponds to the redshift of the Cosmic Microwave Background (CMB), and suggests that the first stars, rather than atoms, would have initiated reionization.
- One participant states that the current limit on redshift is believed to be between Z=22 and Z=23, theorizing that star formation could not have begun before this period, while also suggesting the possibility of supermassive black hole seeds forming earlier.
Areas of Agreement / Disagreement
Participants express varying views on the timeline of atomic and star formation, with some uncertainty regarding the exact redshift values and the implications for galaxy formation. No consensus is reached on the highest redshift at which galaxies can exist.
Contextual Notes
Limitations include the dependence on definitions of redshift and the unresolved nature of the timeline for star and galaxy formation. The discussion reflects ongoing debates in astrophysics regarding early universe conditions.
Who May Find This Useful
Readers interested in cosmology, astrophysics, and the formation of galaxies in the early universe may find this discussion relevant.