That's about it. Even though the distance between the speed achieved and "c" (the speed of light in a vacuum) is small as a matter of percentage of "c," the distance is infinite in terms of mass or energy (energy = mass times a factor).
Once relativistic speeds (say, 90% of the speed of light) are achieved, large energy inputs result in large mass increases, but small speed increases.
99.9999991% of the speed of light is not 99.9999991% of the way to "infinite mass." 99.9999991% of the speed of light in a vacuum results in a mass multiplier of about 7,500.
MUCH APPRECIATE YOUR CLARIFICATIONS.
I forget how old I was . . . probably BA university 1965-1969. The prof asked something about this and I noted the bit about the earth would have to begin to rotate around the infinite mass or some such.
The prof was quite surprised at my answer and with a smile on his face, said that was right.
So, that’s the background of that curiosity of mine.
Has long been a bit of a curiosity and puzzle to me with regard to the collider in Europe.