Monday, July 25, 2022

The Dark Ages in the early universe

 


 

 

 

 

 

 

 

 

 

 

 

 

It is fascinating to find that your picture of the universe is quite incomplete. On July 7, 2022 my brother-in-law Tony Stark spoke to the Cape Cod Astronomical Society about Astronomy’s Final Frontier: The Dark Ages at High Redshift. He invited my wife and I to sit in at the Dennis-Yarmouth Regional High School. Tony is a Senior Astronomer at the Harvard-Smithsonian Center for Astrophysics. Their web page about the Early Universe says:

 

“Until roughly 380,000 years after the Big Bang, the entire universe was a thick opaque cloud of plasma of electrons and nuclei. As the universe expanded, it cooled off enough to let the plasma become atoms, and the cosmos became transparent. We observe the light from this time as the cosmic microwave background (CMB).

…. When the CMB formed, the ordinary matter in the universe transitioned from a hot opaque plasma to incandescent hydrogen and helium gas. Astronomers call this the ‘dark age’ of the universe, since no stars had formed yet.

Researchers are using the best observatories in the world both to study the dark age and to find evidence for the first stars in the universe. As the first stars and black holes formed, they turned much of the hydrogen gas in the universe into plasma again, a process astronomers call “reionization”. The environment producing the earliest stars was radically different than star-forming regions today. The raw ingredients were almost exclusively hydrogen and helium, since stars themselves produce heavier elements through nuclear fusion.”

Tony’s LinkedIn page mentions that there is an Antarctic ridge named after him.

 

The NASA image of the CMB time line came from Wikimedia Commons.

 


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