2 ms·

> and not all extensions must be infinite any examples?

• raattgift 7y ago
  > any examples? Sean Carroll has an excellent "zoo" of ideas in a set of slides at https://www.slideshare.net/seanmcarroll/what-we-dont-know-about-the-beginning-of-the-universe https://www.slideshare.net/seanmcarroll/what-we-dont-know-ab... where he gives a reasonable overview of a number of ideas including those which have an earliest time (even if it is far earlier than the hot big bang), and those which do not. Indeed, a couple of the slides touch on Hawking's idea in the article at the top: discussing or debating that particular model (and "choosing sides") is not especially new. The references [in square brackets] on each of the slides are mostly easy enough to find via your favourite search engine.