I am adding something in response to the latest answer. First of all, In Quran Sky is called a Canopy, you know why? Because like a roof or canopy, the upper sky/atmosphere protects us from harmful cosmic rays just as the roof protects from the heat. see this website:
Second point: the days mentioned in Quran are periods rather than days, see this site for details:
Third point: That it was not proven by science that the moon was split in two. Science cannot prove or disprove a historical event with limited amount of information. For example, if there was a magnitude 5 earthquake 8000 years back in Mexico city, can science prove that? no, Science has limitations because it's based on observations. Science cannot disprove a theory until it observes a contradiction to that theory. In here, we are talking about historical event in which the moon was split in two by a supernatural force. Then the moon may have been merged. Science cannot go back to past to observe this event. So how it can disprove the possible event that moon was split and merged back to normal again.
Fourth point: That, the moon will become dark, sun and moon will join together. How profound scientific indication this verse has! Do you know about the big crunch theory. See this website for details:
according to this theory the universe will stop expanding and gravity will cause the universe to collapse. Often physicists use a balloon to explain the expansion of universe. Have you seen a Balloon loose air? The big crunch will be like that. If you consider the spots on the balloon as galaxies, stars and planets, we can imagine that because of the collapse they will come close together again and it's completely normal for sun and moon to fall on one another and be joined together, in such a scenario the sun may loose light (black holes are stars that loose light is'nt it? so why can't sun loose it) and this will cause the moon to loose it's light too.
Fifth point: "to guard".i do not see anything wrong with this verse. Can you devise a mathematical theory that says, it is wrong. That's the limitation of Science. It's domain is only limited to observable things (or things the effect of which can be observed). One cannot devise a mathematical theory which can disprove this because, Angels and devils are not observable in the material world.
Stars do not have direction purposes???? see here how stars are used for direction/navigation:
Sixth point: Science does not believe in moon and sun's reckoning purpose. Reckoning means to estimate something. Don't we use sun and moon for estimating????? see this University of Washington pdf document about how to estimate size of earth by using distance from Sun and Moon.
May ALLAH forgive me for my mistakes.So far it does not contradict Islam. In fact, Quran encourages research and investigation, it has verses with profound scientific implications.
"Do not the Unbelievers see that the heavens and the earth were joined
together before we* set them apart? We made from water every living
thing. Will they not then believe? (The Noble Quran, 21:30)"
*(Islam is a strictly monotheistic religion, by 'we' ALLAH refers to himself but this is a kingly way of referring to oneself in Arabic language)
how can earth and heavens (planets, stars, galaxies) be joined together, it's only possible in an extremely dense state of universe, now it's been widely accepted for last couple of decades that the universe (and space-time) started with big bang. During this event, all the matter were packed in an extremely dense state. Since the big bang the universe has been expanding.
the second part of the verse gives another proven fact that, wherever there is water, there is life. I guess you know how desperately NASA scientists are looking for water in Mars.
Even the expansion of universe was mentioned in Quran:
"And the heaven We constructed with strength, and indeed, We are
Refer to these website for more on holy Quran, Astronomy and Science in general. There are many more websites, you just need to explore a bit.
It's not haram for a muslim to become a physicist or astronomer. Quran holds scholarly people in high regard. see the second website to read the verses about scholarly people.