mistermack wrote:When I was first chewing over this idea, it was the similarity between acceleration and gravity that was nagging at me.
Acceleration of what?
And gravity is a force, so it acts upon mass by accelerating it.
Why would they be so similar? When you open the throttle of a powerful bike, you immediately feel a new "gravity" pulling your body backwards. Yet there is one big problem staring at you, if you try to picture the two phenomena being the same. And that is the speed of light.
I have a force of about 80kg pushing at my feet 24/7. I'm obviously not going anywhere, so how can this be due to acceleration? Ok, so introduce the idea of space accelerating past me into the Earth. Now I could be accelerating, relative to space. BUT, if I keep accelerating at 9.81 m/s², I worked it out that I would hit the speed of light in less than a year. (353 days and 20 hrs to nearest hour, if you're interested.)
The speed of light in an accelerating frame of reference isn't the same as in an inertial frame.
So in less than a year, I would have broken the speed of light, relative to the space passing me by.
So how can you constantly accelerate, and yet not go any faster?
You're making the mistake of mixing up accelerating frames of reference with inertial frames of reference.