Allah is He, who created the sun, the moon, and the stars (all) governed by laws under His command.
There has been a gradual, but relentless, migration from a regional view of the application of the Islamic calendar to a global view. This comes as no surprise since it is impossible to coordinate activities among Muslims who are located all over the world without using a shared timekeeping system.
Today the dominant timekeeping system used worldwide is the solar calendar known as the Gregorian calendar. Most Muslims have adopted its use globally for conducting their "civil" affairs, and have adopted the Islamic calendar on a regional basis for conducting their "religious" affairs. But this is changing. The use of a solar calendar that pays tribute to false gods or some portion of Allah's creation has always been a contradiction among the only people on earth who profess not to associate partners with Allah in any way.
Now there are other forces at work. What frequently has been described as a call for uniting Muslims throughout the world to celebrate major events such as 'Eid-ul fitr and 'Eid-ul Adha on the same day, is becoming an insistence on applying globally a common Islamic calendar to end the confusion over what day is today for the different regions of the world. And what has been widespread divergent views on the use of the sighting of the crescent in one region to apply to a different region, is now giving way to the increasing convergent view that a sighting in one part of the world applies to the whole world.
Over the years, a number of dedicated Muslim brothers and sisters have engaged in a disciplined effort to understand better Allah's laws that govern the visibility of the new crescent moon. Among them is Khalid Shaukat (his website is Moonsighting.com) who has developed successfully the criteria for calculating accurately the visibility of the crescent. His work is based on decades of research and several thousand authentic observations collected over a period of 150 years in different locations in the world. Documented evidence shows that the visibility calculations agree with actual observations made every month for more than 16 years.
Recently, he has called for the adoption of a global lunar calendar that uses a simple method for determining the visibility of the new crescent. This method leads to results that are fully consistent with his criteria that have been proven to be accurate. It is the same method that is used to determine Islamic calendar dates for the Time & Strategy website. Here is how it works.