Mars And Stars

Comparing Poul Anderson with SM Stirling led to discussing Stirling's Mars novel, In The Courts Of The Crimson Kings. This led to discussing other science fictional treatments of Mars which in turn led to discussing other planets, the Solar System, the galaxy, the universe and the end of the universe. The universe and its end led back to earlier comparisons of Anderson with James Blish who in fact described Anderson's Tau Zero as the ultimate hard sf novel.

Tau Zero is:

sf because it is about an interstellar spaceship;
hard sf because its plot is fully consistent with the relativity theory and cosmology that were accepted when it was written;
a novel because it is a long prose narrative;
ultimate because it shows human beings surviving and human society continuing against the background of the universe.

This recalls CS Lewis' characterization of John Milton's Paradise Lost as the ultimate epic (a long narrative heroic poem):

Homer's epics were Primary because they showed incidents during the heroic age;
Virgil's epic was Secondary because it recounted a historical turning point, the founding of Rome;
Milton's epic is ultimate because it recounts Biblical history from before the Creation until after Armageddon.

Finally, I am glad of the increase in scientific knowledge and prefer to live in Anderson's universe.