Taking Flight

I have a recurring dream that comes in two varieties and they both involve me having the power of flight. I'm not concerned with the interpretation of these dreams, which is a bit woo-woo for me, but the physics, if physics can be said to apply in dreams.

In the first variety I am in the open and lean into the wind, which carries me aloft to a maximum of 40 or 50 feet but, strangely, I remain in the same geographical location, as if I'm flying like a kite, but without any physical tether to keep me in that place. It's almost as if I'm hovering; but it's the wind that keeps me aloft and not some mysterious power I may have.

In the second variety I actually overcome gravity and levitate through the exercise of intense willpower, which takes some considerable effort. This is the more intriguing dream, as I can't be making myself massless, as I am still subject to push and pull in the normal manner and my body retains inertia in the horizontal direction. It's a bit like Iron Man's suit, but with any mechanical contrivance being replaced by a mental force that negates and opposes the earth's gravity.

If I were massless in the 2nd dream variety, I would shoot off at the speed of light, as that's the attribute of massless particles and objects, not that I'm aware of any physical objects that are massless - only elemental particles, such as photons.

In my 20s or 30s I read a short story by Isaac Azimov where a scientist had invented a beam than made objects massless. He was ridiculed by a friend and the scientist decided to teach his 'friend' a lesson. He invited him to a demonstration at his home, the demonstration taking place after a meal with several other people and taking place on a billiard table. The scientist lined up a few billiard balls on the table, switched on the beam that created masslessness, which was shining down on to the table from above, and invited one of his guests to knock a selected ball into the path of the beam via a 3 ball shot - white on one colour, which then ricochets off another ball and sends the 3rd ball into the masslessness beam. 

The angles had been arranged in a precise manner such that the 3rd ball would pass into the beam on a trajectory that was directly in line with the friend who had ridiculed the scientist, who was stood at a certain position around the table. The shot was duly taken and the ball chosen to enter the beam did so, whereupon it immediately shot off at the speed of light - because that's what massless objects do - instantly leaving the scientist's friend dead, with a billiard ball shaped hole in his body.

The problem with this story is, if massless objects zoom off instantaneously at the speed of light, how would anyone know they became massless? All they'd see is the object instantaneously disappearing. Yes, should the object be able to retain its shape on its instant translation to luminal speed, there would be a tell tale hole somewhere as the object smashed through any containment, but the chances are that it would instantaneously shatter into elemental particles that would travel through anything without a trace.

When it comes to Superman and his ability to fly, I found this interesting explanation:

Negative mass would also explain Superman's power of flight – though not in the obvious way. Negative mass and positive mass are supposed to fall towards each other, so he feels gravity the same way everyone else does. However, he also feels air molecules all over his body. If he turned them to negative mass, they would push his body upwards. By contrast, if he turned the outer skin of his body to negative mass (or his aura), the air pressing back against it would cause it to push him forward. So Superman uses air pressure and negative mass to fly around planets with atmosphere. This shouldn't work in space, except for the fact that tiny particles are constantly popping in and out of existence throughout the vacuum. Superman could use these particles the same way he used air molecules. It's also possible that Superman exerts some kind of energy which encourages the production of these particles in space, helping him fly faster.

In one Superman film, Christopher Reeve flies around Earth at supra-luminal speed to reverse time, but that would only work (hypothetically) for him and not the Earth.