History of Universe (Baez timeline)

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Discussion Overview

The discussion revolves around a timeline of the history of the universe posted by Baez, which includes significant events from the Big Bang to the evolution of life on Earth, as well as projections into the future. Participants explore various aspects of the timeline, including cosmological eras and historical developments.

Discussion Character

  • Exploratory
  • Debate/contested
  • Historical

Main Points Raised

  • Some participants appreciate Baez's timeline for its comprehensive coverage of cosmological events and the evolution of life.
  • One participant notes the absence of the Hadron and lepton eras in Baez's timeline, suggesting these are significant omissions.
  • Another participant questions the accuracy of the timeline regarding the age of grasses, citing fossil records that indicate grasses are between 55 and 70 million years old.
  • Concerns are raised about the timeline's treatment of historical developments, particularly the omission of the Chinese printing press and its significance.
  • One participant expresses skepticism about the precision of various timelines, highlighting discrepancies in the timing of cosmological events such as the lepton and hadron eras.
  • Another participant reflects on the challenge of creating a similar timeline, indicating interest in the topic.

Areas of Agreement / Disagreement

Participants express a mix of appreciation and criticism regarding Baez's timeline. There is no consensus on the accuracy of specific details, particularly concerning cosmological events and historical milestones.

Contextual Notes

Discrepancies in timelines regarding the timing of cosmological events are noted, with references to different sources that provide varying information on the lepton and hadron eras. The discussion highlights the complexity of establishing a unified historical account in cosmology.

marcus
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Baez posted this timeline last week, its up to date
and it has big bang temperatures and cosmology stuff
as well as evolution of life on Earth stuff

and it also has projected history sever billion years into future
so it is a pretty good timeline, hope you check it out and
have some reactions

http://math.ucr.edu/home/baez/timeline.html
 
Astronomy news on Phys.org
Nice link. For another thumbnail try
http://www.stoertz.org/discourses/prehistoric.html
 
Last edited by a moderator:
marcus said:
Baez posted this timeline last week, its up to date
and it has big bang temperatures and cosmology stuff
as well as evolution of life on Earth stuff

and it also has projected history sever billion years into future
so it is a pretty good timeline, hope you check it out and
have some reactions

http://math.ucr.edu/home/baez/timeline.html


Very neat. I was fascinated by some of the life history. Who knew that grass was just a little older than apes? And birds go so far back?
 
I like Baez timeline, but he forgot to mention the Hadron era and the lepton era, both occurring before the starting of the radiation era
 
selfAdjoint said:
Very neat. I was fascinated by some of the life history. Who knew that grass was just a little older than apes?
Not so fast! According to http://, grasses are between 55 and 70 million years old, with clear 'grass pollen' in the fossil record from 60 million years ago. However, it does seem clear that dinosaurs didn't eat grass!

For those PF readers who don't already know, the 'grasses' include rice, wheat, and maize, and domesticated animals depend partly or wholly on grasses. Among the implications of increased levels of CO2 are the extent to which C3 plants will lose out to C4 ones (CAM plants aren't relevant here?); how many economically important grasses are C3 species?

It's also a little disappointing to see that Baez ignores the Chinese development of the printing press (at least 400 years before Gutenberg).
 
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The Chinese press was important to the Chinese, but the European press was one of the things that led to the European exploration/plundering/colonizing expeditions, which led to the modern world.
 
Please do not expect a mathematical physicist to get his details on human history 100% correct.
 
I was thinking of creating a similar timeline. Looks like he beat me to it.
 
I'm very confused because I have examined a large quantity of timelines, and they seem to disagree in the ciphers, so in these times of "precision cosmology", it seems like a bad disease that we are not able to agree in the instants that things occurred.
Example: according to www.fact-index.com/t/ti/timeline_of_the_big_bang.html[/url] the lepton era occurred from 1 s until 3 min. after Big Bang. But according to [PLAIN]www.physics.gmu.edu/classinfo/astr103/CourseNotes/Html/Lec09/Lec09_pt2_cosmologyModern.htm it happened from 10-4 to 1 sec. after Big Bang. Similar disagreements can be found for the hadron era in different timelines. Some timelines mention the quark era, but others no. Some mention the electroweak era, but others no. Chronos link mentions both the Planck era, and the quantum gravity era, but I don't know how to differentiate between these two. I'd like a common consensus, history interests me also, you can never say that the Russian revolution happened in 1941 for example! :mad:
 
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