When I was studying astrophysics, I had to get my head around gravitation, Newton’s falling bodies, which all of us experiment with from an early age, and Einstein’s truly elegant theory of general relatively. My first flight was a discovery flight and my only instructions were to make the most of each sensation.
The aircraft accelerated sharply before the weightlessness phase, which made it even more amazing, as if my weight (which had more or less doubled in a few seconds) was evaporating rapidly from my legs towards my head. I expected to have a tingling sensation in my stomach or a rush of adrenalin, like on a rollercoaster, but I didn’t. That’s when I really felt what Einstein experimented with in his mind more than a century ago: gravity and acceleration are two sides of the same coin. In the aircraft cabin, I had no way of “feeling” that I was in free fall for more than 2,000 meters. All I could see were objects floating around, as if my instructor had pressed a magic button to remove the effects of gravity.