A brief summary of what we know about cosmology

Sean Carroll has compiled a nice list of 19 items of what we currently know and don’t know about the Big Bang, in the hope of dispelling some common misconceptions. I found items #12 and #16 helpful in clarifying my own thinking about how to express these ideas.

12. The early universe had a low entropy. It looks like a thermal gas, but that’s only high-entropy if we ignore gravity. A truly high-entropy Big Bang would have been extremely lumpy, not smooth.

16. Dark energy is not a new force; it’s a new substance. The force causing the universe to accelerate is gravity.


  1. polishsalami says

    I found the estimates of the size of the Universe proposed by inflation to be mind-boggling.

Leave a Reply

Your email address will not be published. Required fields are marked *