Is it permissible to study and learn about astronomy? Can you rely on astronomical calculations to ascertain the beginning of Ramadan?

Islam does not oppose knowledge and learning nor does it stand in their way. On the contrary, Islam encourages studying, thinking about and contemplating in the universe, and deriving scientific theories that benefit humanity. The Quran says, “Say: Behold what is in the heavens and the earth! But revelations and warnings avail not folk who will not believe” (10:101); and it says, “Say (O Muhammad): Travel in the land and see how He originated creation, then God brings forth the later growth. Lo! God is Able to do all things” (29:20).

Astronomy is one of the fields whose study and knowledge are explicitly encouraged in the Quran in order to study cosmic phenomena to gain knowledge of their inner secrets. This is found in the following verse: “And We appoint the night and the day two portents. Then We make dark the portent of the night, and We make the portent of the day sight- giving, that ye may seek bounty from your Lord, and that you may know the computation of the years, and the reckoning; and everything have We expounded with a clear expounding” (Quran17:12). This is also found in the following, “And the sun runs [on course] towards its stopping place. That is the measuring of the Mighty, the Wise. And for the moon We have appointed mansions till she return like an old shrivelled palm-leaf. It is not for the sun to overtake the moon, nor doth the night outstrip the day. They float each in an orbit (Quran 36: 38-40).

Muslims encountered astronomy and gained proficiency in all of its equations and put it to work in the service of their religion. They calculated the time of dawn, sunrise, noon, afternoon, sunset, and nightfall so that the person who made the call to prayer would do so after consulting a sheet with the correct times written on it according to the astronomical calculations. Muslims stopped seeking guidance by placing a stick in the ground and measuring its shadow, although a person may still find themselves in need of this method if they do not have a watch or do not know the local times of prayer.

What is provided by Islamic Law is both easy and readily available to all people, because Islam is a universal religion. Ascertaining the times of prayer and fasting by way of astronomical calculations is not in opposition with the prophetic methodology. The strange thing is that we find no difference of opinion concerning prayer, while there is great difference of opinion concerning fasting, even though prayer is more important.

Concerning fasting in Ramadan, the origin of ascertaining the beginnings of all the Arab months including Ramadan is the visual sighting of the new moon. The Quran says, “And whosoever of you is present, let him fast the month” (2:185). And the Prophet said, “Begin your fast according to the sighting of it [i.e. the new moon] and end your fast according to the sighting of it.”

There is no doubt that the appearance of the new moon is an established physical phenomenon, and there is no argument concerning the possibility of perceiving it with the naked eye when the conditions for physically sighting it are met. This could be done in addition to the assured scientific means that are agreed upon and are now known to specialists. These means are known to both Muslims and non-Muslims as the new moon is a scientific reality according to the consensus of astronomers and there is no conjecture involved.

Al-Subki was asked about someone who sighted the new moon and was alone in his testimony in a case where calculations belied him. Al-Subki responded with a long answer, the relevant part of which is the following, “This is another manifestation: when the calculations state that it is not possible to sight the new moon and this conclusion is reached based on sound and certain premises because of the closeness of the moon to the sun, in this case you cannot allow for the physical sighting of the new moon since it is impossible.

If one or more people, whose information is open to being belied or incorrect, inform us of it [i.e. that they sighted the new moon], the position taken is to understand their information as a fabrication or a misapprehension. If two people were to testify to its sighting, their testimonies would not be accepted since the calculations are certain and the testimony and informing is uncertain, and what is uncertain does not disclaim what is certain let alone take precedence over it.

The condition of the declaration [i.e. of the sighting of the moon] is that what is being bore witness to is physically, intellectually, and legally possible. If the evidence of the calculations indicates the certain impossibility [of sighting the new moon] it is legally impossible to accept it due to the impossibility of that which is being sighted since the law does not advance impossibilities.”

For this reason our opinion is that it is better to act in accordance with astronomical calculations since they have been subsumed under empirical and certain knowledge which makes relying on them give one certainty, as has preceded. As for the sighting with the naked eye, it is uncertain due to the possibility of there being barriers that can come in the way of the sighting of the new moon which gives precedence to considering astronomical calculations where there is a discrepancy.

And God Almighty knows best.