What happens to a drone hovering high up in the air?

By MUNGAI KIHANYA

The Sunday Nation

Nairobi,

20 October 2024

Apollo Ong’ara writes: “The Earth rotates on its axis and the Sun is stationary, hence the day and night phenomena. If we place a stationary drone object 30,000 feet above Nairobi at sunrise 6am, will the people in Kinshasa get to see it at 6am their time? Or is there a force that ensures object X moves along with the Earth, such that we shall always see it in Nairobi?”

This is question is quite common but many people do not have the courage to ask it. I must commend Apollo for being courageous enough. The basic principle that is often missed is that, as the earth moves, it carries everything in its vicinity with it – including the all the air in the atmosphere. Heck! it even drags the moon along the journey round the sun.

To understand what goes on, we should first ask: what holds the drone above the ground? It is held up in the air by its spinning propeller blades. In other words, the drone is actually holding onto the air. But, since the air is moving with the earth, it follows that, the drone will also move with the earth. Consequently, the people in Kinshasa will not see it at all.

We may dig deeper and ask what Apollo means when he says that the drone “stationary”. What is the point of reference from which we say the drone is motionless? Is it the ground on which we are standing? If that is the case, then why would we expect it to drift westward to Kinshasa? Won’t it stay above Nairobi?

Perhaps Apollo is using the sun as the point of reference. In such a case, the drone would need to be propelled westward instead of vertically upward. The reason for this is that the earth is in motion around the sun. Thus, the people of Kinsasha would get to see it.

Unfortunately, however, any object that attempts to be stationary with respect to the sun will be pulled in by the sun’s gravity. Therefore, we must devise a way of countering this force – perhaps fit some rocket to push the drone away from the sun.

Finally, the point of reference may be at the centre of the Earth, again the drone would need to be propelled westward and the people of Kinsasha would get to see it. Fortunately, there is an atmosphere of air around the earth so the propellers of the drone will perform the job of countering earth’s gravity.