Every now and then some Muslim scholar will pop up claiming Islam accords with modern science (or at least modern astronomy, Darwin remains beyond the pale). Zakir Naik, a popular preacher, when asked why the Quran refers to Earth as being like a carpet, responds that carpets can be wrapped around a globe. Sure they can, but somehow I doubt Allah would say 'carpet' when He meant 'globe'. There's one verse in the Quran that says, 'He spread out the Earth', which some creative interpreters, Naik included, have suggested can also be translated as 'He made the earth egg-shaped'. I'm reminded of the old saw that every word in Arabic means itself, its opposite, and a camel.
But I'm not hugely concerned about the Earth of the Quran, whether carpet or egg shaped. One thing that does bother me, though, is the Islamic calendar. It's the most useless thing ever invented: no rational being, whether human or superhuman, setting out to create a logical register of days and months, would display as a finished product this calendar.
The background to the monstrous folly goes something like this: the Arabian calendar, which the early Muslims inherited, was strictly lunar, unlike the many Indian / Hindu calendars, which are lunisolar. A lunisolar calendar year approximates quite closely to an actual solar year, and needs an adjustment (or intercalation) only of a day every now and then to keep in tune with the earth's orbit, very much like the Leap Day (as in today, February 29) added every four years in the calendar we follow. A year in a purely lunar calendar like the Arabian one, on the other hand, is between 11 and 12 days short of a solar year. This means that, every so often, an entire month has to be added to keep the calendar honest. So that's what the Arabs would do, circa 600 AD. When Muhammad began receiving messages from Allah, he denoted four months as holy months, months during which no wars were supposed to be fought. Ramadan was one of them. Occasionally, though, the Arabian calendar would repeat the month of Ramadan to keep in step with the sun, leading to all sorts of problems from a ritual point of view. Imagine 60 days of fasting.
So the revelation came through that intercalation was forbidden. Allah had decreed twelve months, and humans had no business duplicating any of them. With intercalation out of bounds, the new Islamic calendar drifted entirely free of the sun, which was a problem because, in human affairs unconnected to religion, the sun is of crucial importance, while the moon means jack. The Arabian calendar as modified by Islam provided no indication whether it was a good time to plant crops, whether a given day could be expected to be hot or balmy or snowy, and whether the sun would set early or late. The calendar would only tell you whether it was a day of fasting or not; whether it was OK to march to battle or not; and other stuff related explicitly to the faith itself.
It's no wonder that few Muslim nations run their civic and financial affairs on the basis of the Islamic calendar. Saudi Arabia claims to work entirely by the lunar year, but I'm sure Saudi officials peek at a proper calendar before undertaking any journeys. After all, the fact that it's the middle of Shawwal or the beginning of Rajab tells them nothing about whether they should pack an overcoat for London.