First stars now thought to be 400 MLY after BB?

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Discussion Overview

The discussion revolves around the timing and composition of the first stars, known as Population III stars, in relation to the Big Bang (BB). Participants explore the implications of recent findings suggesting these stars formed approximately 400 million light-years after the BB, as opposed to earlier estimates of 200 million light-years. The conversation includes questions about the elemental composition of these stars and the implications of light years as a measure of distance versus time.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • Some participants reference a website indicating that WMAP's results suggest the first stars appeared about 400 million light-years after the BB.
  • One participant asserts that the first stars were primarily composed of hydrogen and helium, with trace amounts of lithium and beryllium, and provides a mass ratio of hydrogen to helium as approximately 3:1.
  • Questions arise regarding whether the timeframe for the birth of the first stars is currently accepted to be between 200 and 400 million light-years post-BB.
  • Another participant confirms that current estimates lean towards the higher end of that range, around 400 million years, while clarifying that light years measure distance, not time.
  • There is a discussion about the implications of inflation on the meaning of light years, questioning whether light years can represent both distance and time during the early universe's expansion.
  • One participant explains that while the universe was much larger than 380,000 light years at that time due to inflation, the redshift still reflects the relative age of the universe when the observed photons were released.

Areas of Agreement / Disagreement

Participants generally agree on the elemental composition of the first stars and the timeframe for their formation, but there is some debate regarding the interpretation of light years as a measure of both distance and time, particularly in the context of cosmic inflation.

Contextual Notes

There are unresolved questions regarding the implications of inflation on the measurement of light years and the interpretation of cosmic distances during the early universe.

Chaos' lil bro Order
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excellent websitehttp://www.solstation.com/x-objects/first.htm

According to the site, WMAP's results show that the first stars (Population III) appeared about 400 million LightYears after the BB, instead of the 200 million LightYears previously thought.

I have a question about this...

Was the first star purely Hyrdrogen based? What is known about the composition of the first star(s)?
 
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Chaos' lil bro Order said:
Was the first star purely Hyrdrogen based? What is known about the composition of the first star(s)?

The first stars were composed of the elements generated in primordial nucleosynthesis -- that is, almost entirely hydrogen and helium. There were tiny abundances of lithium and beryllium as well. By mass, the ratio of hydrogen to helium was about 3:1.
 
Roger that ST, ty.

Do cosmologists think the first stars were born 200-400 million LYs post BB? Is that the currently accepted view?
 
Chaos' lil bro Order said:
Do cosmologists think the first stars were born 200-400 million LYs post BB? Is that the currently accepted view?

That's right, somewhere in that ballpark. Current estimates favor the high end of that range, ~400 million years. Note that light years is a measure of distance, not time.
 
SpaceTiger said:
That's right, somewhere in that ballpark. Current estimates favor the high end of that range, ~400 million years. Note that light years is a measure of distance, not time.


Can't LY be a measurement of both, or does this lose meaning during Inflation when space (may?) have expanded superluminally?
 
Correct. The universe was much larger [think VERY much larger] than 380,000 light years when it was 380,000 years old due to inflation and expansion. But the redshift does not lie. It still reflects the relative age of the universe at the time the photons we now observe were liberated.
 
Chaos' lil bro Order said:
Can't LY be a measurement of both, or does this lose meaning during Inflation when space (may?) have expanded superluminally?

A light year is the distance that light travels in a year. The analogous unit of time is just a "year".
 

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