Eid On The Moon

Eid On The Moon
Clocks run a little faster on the Moon. Blame it on Einstein’s theory of General Relativity. The lower gravity of the Moon means that a clock on the surface of the Moon will gain 56 millionths of a second every day over clocks here on Earth. To you and I, this may not be a big deal. But for lunar missions and for future human settlements on the Moon, such a discrepancy, if not corrected, can create serious problems.

In fact, just this past November, major space agencies of the world agreed to create an internationally accepted common reference time for the Moon. Currently, missions keep independent on-board chronometers that sync with clocks on Earth. As the surface of the Moon and the lunar orbit gets more crowded, a common time will be needed. Hence there is a desire for a Moon Standard Time, akin to the standard time on Earth, the Universal Coordinated Time (UTC).

Back on Earth, we have a hard time agreeing about just seeing the Moon. The problem is usually more acute towards the end of Ramzan. To defend astronomers, of course, we can accurately determine and predict the position of the Moon with respect to the Sun and the Earth. In fact, astronomers have a scientific definition of a “new Moon,” but that is when the Moon is not visible from any part of the world. We can calculate that for hundreds of thousands of years in the future.

The visibility of a crescent that marks a new Islamic month however, is a tougher challenge. Amongst other things, it depends on the time past after the astronomical new Moon. The more time passes, the thicker the crescent, and therefore easier to see in the evening skies.

Moon-sighting is also a question of authority. This was stated clearly by the famed former chairman of the Ruet Hilal Committee, Mufti Muneeb back in 2002. In a television debate with the head of the Meteorological Department, Mufti Muneeb said that the end of Ramzan is a religious matter and it has nothing to do with science. More precisely, “it is not the job of the Meteorological Office to make an announcement as to when moon of an Islamic calendar would be visible.”



This month, for example, the astronomical new Moon was at 9:12 am Pakistan time on April 20th. By the time evening rolled around in Pakistan, the Moon was still too thin to be visible to the naked eye. However, you can see a beautiful crescent in the western skies on Friday, the evening of April 21st. Eid in Pakistan, therefore, is expected to be on Saturday, April 22nd. In the US, a very thin crescent was visible on Thursday evening, resulting in the Eid on Friday. This is a wonderful example of how different parts of the Earth see the Moon at different times and how that relates to differences in lunar-calendar based festivities.

I know that the issue of Moon-sighting generates a lot of emotions (as an astronomer, mine included!) Of course, we can use science. We can come up with a criterion based on the time or position of the Moon. Turkey, for example, uses calculations for their Eid holidays. I don’t think their faith is much impacted by that, even if they miss out on the intrigue and suspense of a late-night twist announcement. Plus, Pakistanis loved Ertugrul. Perhaps, using calculations for Eid may be an appropriate tribute to one of our closest geopolitical friends.

We have seen this happen with the resistance to using the printing press for the printing of the Quran, the radio for airing Quranic recitation, and the controversy over the use of loudspeakers in prayers.



Moon-sighting is also a question of authority. This was stated clearly by the famed former chairman of the Ruet Hilal Committee, Mufti Muneeb back in 2002. In a television debate with the head of the Meteorological Department, Mufti Muneeb said that the end of Ramzan is a religious matter and it has nothing to do with science. More precisely, “it is not the job of the Meteorological Office to make an announcement as to when moon of an Islamic calendar would be visible.”

Of course, over the past several years, we have seen rival Eid announcements in Pakistan, and governmental disagreements with the Ruet Hilal Committee. This year, the rhetoric has been less heated, and science seems to have been consulted alongside eye-witness testimony.

These types of tensions have come up in the past with the introduction of new technologies. For example, we have seen this happen with the resistance to using the printing press for the printing of the Quran, the radio for airing Quranic recitation, and the controversy over the use of loudspeakers in prayers (for a wonderful discussion of the latter, please see Troubling Technology: The Deobandi Debate on the Loudspeaker and Ritual Prayer by Ali Altaf Mian).

In fact, a better parallel is illustrated by Ahmad Dallal in his book, Islam, Science, and the Challenge of History. He starts the book with the debates over the use of mathematical astronomy and astrolabe in determining the direction of qibla in North Africa. Some argued for the preservation of tradition that provided a reasonable estimate for locations close to Mecca. But these approximations did not work for places farther away than Hijaz. Others argued for the use of astrolabe and mathematics to figure out the actual direction of qibla from their respective locations.

This debate continued for a few centuries and centered on “whether mathematical knowledge should take precedence over religious authority in a matter where, admittedly, the realms of science and religion overlapped.” The preponderance of qibla finding applications today suggests that, whatever the debate at the time, the use of scientific tools in the service of religion won out. In fact, it is often highlighted that Muslim scholars at the time made advances in mathematical astronomy partly to solve religious problems, such as the timings of daily prayers and finding the direction of qibla.

Leaving aside the struggles over authority, the record over time shows that Islam, like other religions, is quite flexible, and so are the believers. The issue of Moon sighting will get resolved in favor of a calculation based calendar in Pakistan as well. It may make take a year or ten. We just happen to be living at a time when the debate is playing out live.

One impetus perhaps may come from the Moon. In the coming decades, there will be human settlements on our natural satellite. Not only will the search for a crescent Moon from the lunar surface be futile, humans will have to adjust to very different daily rhythms. Since the Moon is tidally locked with Earth, it takes 29.5 Earth days for it to rotate from noon to noon. That is one long day! It is not just about religion; humans, who have evolved with the circadian rhythms of 24-hour cycles, will have to figure out how to live in such a different environment.

We still have some time to think about celebrating Eid on the Moon. In the mean time, here on Earth, Eid Mubarak!

Dr. Salman Hameed is the founder of Kainaat Studios that produces high-quality astronomy content in Urdu. He is also Professor of Integrated Science & Humanities at Hampshire College, USA, and an astronomer affiliated with the Five College Astronomy Department (FCAD) in Massachusetts, USA.