This 24 hour argument is out of context.
The discussion is not how Adam Harishon built his clock/sundial (if he divided the day into 24 parts or 12 parts or 2 parts), the discussion is if ששת ימי בראשית were 100 billion years (ר”ל) or six days.
Apologetics vs. Literal understanding of chumash, midrash, gemara, rashi, etc.
I still wonder: Do the apologists celebrate Shabbos with their families every 7 billion years?
I once met a staunch מאמין in science who didn’t keep Shabbos ר”ל. When I asked him why, he said that of course he keeps Shabbos! But according to the orthodox Jews he spoke to, the six days of creation cannot be taken literally, so they must have been billions of years.
“Don’t worry,” he said, “today is still Sunday for me. In 6 billion years I’ll start preparing for Shabbos!”
When I tried explaining him that Shabbos is definitely literal, he argued:
“Don’t lie to me! I know the 10 commandments: Work for six days and rest on the seventh, BECAUSE G-d created the world in six days and rested on the seventh. Whatever 7 days means in creation is what it means with regards to Shabbos!”
[מעשה שהי’ יכול להיות]
מנחם שמו