“Relativistic mass goes to infinity when approaching the speed of light, does it mean that sufficiently fast massive object may turn to black hole?”
- this question is indeed very interesting, and now cannot be answered in general case. The problem is in that equivalence of inertial and gravitational masses is rigorously known now from experiments only at statics, while what happens when a mass moves in the 3D space is practically unknown.
The equivalence of the masses at statics is rigorously scientifically explained in the Shevchenko-Tokarevsky’s 2007 Planck scale initial models of fundamental Nature Gravity and Electric forces, see
- and in the model it is rigorously shown that at acceleration of a small body that has rest mass m0 at a free fall in Gravity field of extremely large mass M, including “black holes”, which fundamentally aren’t some perforated in the spacetime “holes”, up to practically speed of light, the inertial mass of small body remains be constant be equal to m0, while its current rest mass, m, constantly decreases, since the initial energy m0c2 is spending, seems first of all, on the acceleration.
However in this case now we cannot exclude the case, that the Gravity Force mediators, which fundamentally don’t contain energy at statics, can obtain energy at bodies motion, and so the initial energy can be contained not only in current mass m, but also outside the body.
Etc., again, now we cannot answer the question – what happens if some external force accelerates some body pumping in it additional to m0c2 energy; the answer will be got after really scientific theory of Gravity Force will be developed basing on the initial model above.
The "Relativistic mass" concept itself is wrong. It is possible to attain the speed of light and even beyond it, the latest research work claims. Read the following research work on RG for details;
Speed of sunlight (NOT artificial light or Einsteinian light) with massive different frequencies, and huge different wavelength with visible and invisible character cannot have constant speed.