One of the first things many of us did as a child when we heard the distant rumbling of an aeroplane over our heads was rush out to catch a glimpse of it. If you did the same, you may have noticed that it took ages for the plane to get out of eyesight, giving the impression that the plane was moving at a very low speed. But we all know how fast an aeroplane travels. So why does a plane seem to move so slow from afar, when in reality it is flying at a stupendous speed? If you have ever wondered the same, we have the answer for you.

This question was posted on the website Quora. One user stated: “There is a reference system that comes with everything that is flying quickly, so that we can compare how fast that thing is. However, there isn’t anything to contrast with the aircraft in the air to determine its speed, it gives the impression that it is flying slowly.”

The plane appears to be travelling quite slowly as it reaches its cruising altitude. This is due to the fact that there is frequently no independent reference point when the aircraft is in the sky, which allows us to compare and see how quickly it is moving. An aeroplane can be made to look faster by using reference points to gauge its speed. In the absence of any clouds or other barriers, the plane seems to fly flawlessly against the steady blue sky. Because of this, it may be exceedingly challenging to gauge an aircraft’s speed.

When the plane is taking off or is about to land, there are numerous objects on land like the airport infrastructure, buildings and many more against which the speed of the plane can be gauged and hence its real speed is clearly visible.

One user further explained this phenomenon and wrote, “This is called motion parallax. Things that are closer to us move past us faster than things that are far away. For reference, imagine travelling by train. If you pass through a line of houses which are near the railway tracks, they will pass through quickly. A line of houses far away wouldn’t pass through so quickly.”