Reddit reviews Astronomy Today (8th Edition)

> what is a good source of reference to understand what we know today?

Not that The Origin of Species isn't insightful in any way by itself, but it isn't what you want here. If you actually want to be educated in these subjects you should do what other people do to get educated in these topics, namely read textbooks and/or watch lectures on the subjects.

If you want to learn about evolution, pick up some textbooks on evolutionary biology and/or human evolution. Here are two textbooks that I happen to know are very good:

• Understanding Humans: An Introduction to Physical Anthropology and Archaeology
  
  
• Evolutionary Analysis (5th Edition)
  
  Here's a textbook on astronomy that I know is good:
  
  
• Astronomy Today (8th Edition)
  
  You could probably find online versions of these textbooks and other textbooks like them and there are online lectures from actual universities out there on these topics too.
  
  > I really would like to have an educated response to the religious apologist argument about evolution and big bang only being "theory".
  
  If someone describes evolution and the big bang as "just a theory" it's because (among other reasons) they do not understand evolution and the big bang. If you want to have an "educated response" to them you will need to understand (and not just accept) evolution and the big bang yourself.
  
  If you just want to tell them why they're wrong then you can get away with having a very basic understanding of these topics, but by no means would this constitute an "educated response" to them. It would just be your way of "winning" the argument. An "educated response" would be one where you actually teach these people something that they had no idea they didn't know based on an understanding of where they've gone wrong.

I was always partial to Astronomy Today. You can find older editions for significantly cheaper, although you'll get outdated information about Pluto and exoplanet discoveries.

This one?
https://www.amazon.com/Astronomy-Today-8th-Eric-Chaisson/dp/0321901673

Here you go: http://www.amazon.com/Astronomy-Today-Edition-Eric-Chaisson/dp/0321901673