Walaikum Asalam Jessica,

Thank you for trusting me with your question about Surah Yasin. What translation do you have? I find the Sahih International is my favorite. Yusuf Ali is alright but has some weird translations. And Pickthall is kind of archaic and difficult to get through.

The translation of 36:40 in Sahih International states:

It is not allowable for the sun to reach the moon, nor does the night overtake the day, but each, in an orbit, is swimming.

Tafsir Ibn Kathir says:

(It is not allowable for the sun to reach the moon). Mujahid said, “Each of them has a limit which it does not transgress or fall short of. When the time of one comes, the other goes away, and when the time for one to prevail comes, the time of the other ceases.”

`Ikrimah said concerning the Ayah,

(It is not allowable for the sun to reach the moon) this means that each of them has its time when it prevails. So it is not appropriate for the sun to rise at night. (nor does the night overtake the day) means, after night has passed, it is not right for another night to come until it has been day. The authority of the sun is during the day and the authority of the moon is at night.

Ad-Dahhak said,

“The night does not depart from here until the day comes from here — and he pointed to the east.”

Mujahid said:

(nor does the night overtake the day) “They seek one another rapidly.” The meaning is that there is no gap between night and day; each of them follows the other with no interval, because they have been subjugated and are both constantly pursuing one another. (but each, in an orbit, is swimming) means, night and day, the sun and the moon, all of them are floating, i.e., revolving, in their orbits in the heaven. This was the view of Ibn `Abbas, `Ikrimah, Ad-Dahhak, Al-Hasan, Qatadah and `Ata’ Al-Khurasani. Ibn `Abbas, may Allah be pleased with him, and others among the Salaf said, “In an orbit like the arc of a spinning wheel.”

So basically what the verse and the exegesis (Tafseer) of the verse are saying is that night and day have their prescribed times and they are not allowed by Allah to overtake one another outside of their set times and they flow one after another.

All this, of course, is from man’s perspective here on earth. We know that we on earth orbit the sun and the moon orbits the earth and they obviously do not compete in their celestial context, but to us here on earth night and day, moon and sun flow one after another and do not come and go erratically.

This verse is not talking about or saying that we do not have eclipses. As we see the Prophet (peace be upon him) acknowledge these events and told the people not to be superstitious about them.

Narrated by Abu Masud:

Allah’s Apostle said, “The sun and the moon do not eclipse because of someone’s death or life but they are two signs amongst the signs of Allah, so pray whenever you see them.”

I hope this helps. All the Best. Salam.