Edit: My apologies! I did reply before reading the rest of the replies, so part of my comment on 39:6 is already made.
I saw an article by a Professor Armstrong who is supposed to work for Nasa
Can you link to this article please? Who is this Professor Armstrong?
At sura 36.6 the quran states that he sent down eight head of cattle in pairs.
Do you mean Surah 39:6?
He creted you from one soul, and he made its mate from it. And he sent down to you the livestock in eight pairs. he created you in your mother's belly, in creation after another creation, in triple darkness. This is Allah your lord, to him the kingdom, there is no god except him. So how then have you turned away?
Surah 36:6 mentions nothing of cows or pairs. However when I googled your exact sentence, I found it posted on many other places. Is this actually your post? (just curious).
So when the quran says that Iron was sent down by Allah, at sura 57.25 this is evidence the quran is from God.
Iron coming from "heaven" was known about to even the ancient Egyptians. They called it "metal from the heavens." How would it be evidence that the Quran is from god, if it simply repeats what was well-known long before Islam?
Furthermore, reading this ayah in context clearly shows it's talking about iron weapons so that "they [the people] may know who helps him [Muhammad in Jihad]"
We have already sent Our messengers with clear evidences and sent down with them the Scripture and the balance that the people may maintain [their affairs] in justice. And We sent down iron, wherein is great military might and benefits for the people, and so that Allah may make evident those who support Him and His messengers unseen. Indeed, Allah is Powerful and Exalted in Might.
So when the quran says Iron was sent down by Allah, it is mistaken.
I think you're reading it far too literally. Allah says in the Quran in other places that he sent food and garments and animals and the scriptures and the prophet. He didn't send them from outer space nor directly from heaven (as Muhammad was born, clothes are made etc..). You're forgetting the Quran is poetry and sometimes talks figuratively. So Allah is not literally saying he 'sent down from heaven' (janna) or from outer space (samaawat in the Quran) any of these things. Basically it's saying that Allah is responsible for the creation of all these things and you have them all because of him.
It's the same trap that Muslim's fall into because they're so desperate to ram their Quran into the scientific arena where it doesn't belong (and doesn't claim itself to belong).
There is also the matter of Allah sending down Manna and Quails, sura 2.57
Taken from the bible, yes.
More importantly the quran states Allah sent down a table of food.
Sura 5.112 to sura 5.115 tells of a story that God sent down a table of food for Jesus and the disciples. But this story appears nowhere in Christian doctrine, and it is assumed to be a miss interpretation by Muhammad, of the meaning of the last supper. As described in the bible at the Acts of the Apostles. Chapter 10.9 to 10.16
Well, no. Information was passed around orally in those days. The "news readers" of the day were the most entertaining poets and poetesses. They would travel around and give news and stories to the people with recitations. In that part of Arabia the Jews were literate, but the rest were generally not. This is why the Quran is a recitation and not much thought was given to having it written down (until later). The Quran also takes the Jews to task for charging people to recite to them from the Jewish texts.
So the Arabs at that time were familiar with Jewish texts and with folklore and mythology and other forms of information. Since he didn't have the actual books in front of him (and it is debated whether he could read or not), it appears from the contents of the Quran, that Muhammad mixed up a lot of information, so we find jewish folklore, wrong info about Christianity (derived from the beliefs of only certain sects of Christianity) and other non-canonical Christian writings were included in the Quran as if "that's what all Christian's/Jews believe" when it actually simply isn't so.
Some examples:
1. Sulameyn (Solomon) and the ants
2. Christians include Maryam (Mary the mother of Jesus) in the Trinity.
3. Cain learned how to dispose of Abel's body by observing a raven kill another then scratch a hole in the dirt to bury it.
and so on.