They might have gone a little too far with the masslessness angle.
AFAIK, it is widely accepted that (in my words) around 40% of the 'heft' you notice it takes to lift something is due to energy.
It works like this:
inside the protons and neutrons are particles called quarks. They are constrained to zip around in extremely tiny spaces at extremely high velocities. Those high velocities represent energy (makes sense) and energy equals mass through Einsteins equation, energy equals mass times the velocity of light, squared. (a tiny bit of mass equals an enormous amount of energy).
So, the energy of motion of the quarks is equal to an additional amount of mass. And since the velocities are very high, the equivalent mass amounts to about 40% of what we note to be the mass of those particles.
A similar effect has been noted in the solar system (!!!). Mercury has an elliptical orbit (as opposed to circular) as it moves around our sun. The point of closest approach to the sun very slowly moves around the sun (with respect to the distant stars) as a result of the gravity of the other planets and asteroids in the solar system.
A careful study of all these effects reveals a mystery. That point moves around the sun slightly faster than the sum of all the forces acting upon it. This was noted over 150 years ago. Einstein was aware of the mystery, and realized the gravitational field of the sun represents and enormous amount of energy. That energy is equivalent to an additional amount of mass over and above what is apparent to us. And when the math is done (leave that to Einstein and the folks that do that for a living) Mercury is behaving EXACTLY the way the calculations describe it.
The suns gravity also affects the positions we appear to note for the stars we see near the sun during a total solar eclipse, but that is for another thread . . . .
AFAIK, it is widely accepted that (in my words) around 40% of the 'heft' you notice it takes to lift something is due to energy.
It works like this:
inside the protons and neutrons are particles called quarks. They are constrained to zip around in extremely tiny spaces at extremely high velocities. Those high velocities represent energy (makes sense) and energy equals mass through Einsteins equation, energy equals mass times the velocity of light, squared. (a tiny bit of mass equals an enormous amount of energy).
So, the energy of motion of the quarks is equal to an additional amount of mass. And since the velocities are very high, the equivalent mass amounts to about 40% of what we note to be the mass of those particles.
A similar effect has been noted in the solar system (!!!). Mercury has an elliptical orbit (as opposed to circular) as it moves around our sun. The point of closest approach to the sun very slowly moves around the sun (with respect to the distant stars) as a result of the gravity of the other planets and asteroids in the solar system.
A careful study of all these effects reveals a mystery. That point moves around the sun slightly faster than the sum of all the forces acting upon it. This was noted over 150 years ago. Einstein was aware of the mystery, and realized the gravitational field of the sun represents and enormous amount of energy. That energy is equivalent to an additional amount of mass over and above what is apparent to us. And when the math is done (leave that to Einstein and the folks that do that for a living) Mercury is behaving EXACTLY the way the calculations describe it.
The suns gravity also affects the positions we appear to note for the stars we see near the sun during a total solar eclipse, but that is for another thread . . . .
