Let us begin with one of my favorite :
1."The quran provides that the length of a normal gestation (pregnancy) is six months (Luqman 31:14; al-Baqarah 2:233; al-Ahqaf 46:15). Luqman 31:14 and al-Baqarah 2:233 provide a nursing period of 24 months. Al-Ahqaf 46:15 provides a total of 30 months for both gestation and nursing combined. This leaves only six months for the period of gestation. We know that this is not true. Normal gestation lasts nine months.
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2.the great whale carrying the earth on it's back , also the earth is flat
quran 68:1
and here I would like to reference islam wiki
while many islamic scholars deny this the 8 big books that explain the quran -the books of tafseer- mention it , which muslims return to to understand the quran like:
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Tafsir At-Tabari
At-Tabari mentions several interpretations. One of them is this:
هو الحوت الذي عليه الأرَضُون
It is a whale (الحوت), which on it the Earths.
At-Tabari tafsir on 68:1
In Islamic cosmology there are seven flat Earths, just like there are seven heavens:
Allah is He Who created seven heavens, and of the earth the like of them
They are placed on the whale like flapjacks on a plate, stacked one atop the other.
Tafsir Al-Qurtubi
Al-Qurtubi mentions several interpretations. One of them is that the Nun is the whale which is under the 7th (lowest) Earth:
نۤ> الحوت الذي تحت الأرض السابعة>
<Nun> - the whale (الحوت), which is under the Earth the seventh.
Tafsir Al-Qurtubi on 68:1 [9]
From his use of the word "tahat" or "under" it can be surmised that in Al-Qurtubi's cosmology the earth is seen as flat.
ِTafsir Al-Kabir (by Ar-Razi)
بالحوت الذي على ظهره الأرض وهو في بحر تحت الأرض السفلى
..with the whale (بالحوت) which over its back is the Earth and it is in the sea under the Earth (الأرض) the lowest.
Tafsir Al-Kabir on 68:1[10]
Al-Kabir here repeates the idea that there are multiple flat earths balanced on the back of the whale.
ِTafsir Fath Al-Qadir (by Shawkani)
This tafsir is from the 18th century and it mentions several interpretations. One of them is the idea that the world is carried on the back of a whale:
Hadith Al-Kafi (shia)
Hadith Al-Kafi, one of the most prestigious Shi'ite hadith, also confirms that a whale carries the earth upon its back:
H 14813 – From him, from Salih, from one of his companions, from Abdul Samad Bin Basheer, who has reported the following: Abu Abdullah (asws) has said that: ‘The whale which is carrying the earth secretly said to itself that it is carrying the earth by its own strength. So Allah (azwj) the High Sent to it a fish smaller than a palm’s length, and larger than a finger. So it entered in its gills and shocked it. It remained like that for forty days. Then Allah (azwj) Raised it and was Merciful to it, and Took it out. So whenever Allah (azwj) Intends the earth to be in a quake, He (azwj) Sends that (small) fish to that (big) fish. So when it sees it, it becomes restless, so the earth gets engulfed by the earthquake’.
Al-Kafi, vol. 8, part 6, [12]
Tafsir Al-Tusi (shia)
The first comprehensive Shia tafsir[13] says this about the Nun:
وقال ابن عباس - فى رواية عنه - إن النون الحوت الذى عليه الارضون
And said Ibn Abbas (ابن عباس) - in his narration - that Nun (النون) is a whale (الحوت) which on it are the Earths (الارضون).
Al-Tibbyan by Al-Tusi on 68:1 [14]
There is thus attestation of Nun the whale in both the Sunni and Shi'ite tradition.
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the rising and setting place of the sun
quran 18:86
the sun sets in muddy water spring
hadith :
a).Abu Dharr said: I was sitting behind the Apostle of Allah who was riding a donkey while the sun was setting. He asked: Do you know where this sets? I replied: Allah and his Apostle know best. He said: It sets in a spring of warm water. - Sunan Abu Dawud 3991
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b).The Prophet (ﷺ) asked me at sunset, "Do you know where the sun goes (at the time of sunset)?" I replied, "Allah and His Apostle know better." He said, "It goes (i.e. travels) till it prostrates Itself underneath the Throne and takes the permission to rise again, and it is permitted and then (a time will come when) it will be about to prostrate itself but its prostration will not be accepted, and it will ask permission to go on its course but it will not be permitted, but it will be ordered to return whence it has come and so it will rise in the west. And that is the interpretation of the Statement of Allah: "And the sun Runs its fixed course For a term (decreed). that is The Decree of (Allah) The Exalted in Might, The All- Knowing." (36.38) sahih bukhari
Quran 18:90:
Until, when he came to the rising-place of the sun, he found it rising on a people for whom We had not made against it any shield.
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and here's a few more scientific errors from the same website :
