Under influence of gravity the Hydrogen molecules are attracted to each other. There is deuterium fusion???(How is deuterium formed in the first place???)

The atom with near light velocity in the dense nucleus is unthinkable. There has to be some other explanation for fusion trigger. The trigger must be lightning of very high voltage that must be producing very high temperatures and highly kinetic particles, which may be culminating in a fusion reaction.

Under influence of gravity the Hydrogen molecules are attracted to each other. There is deuterium fusion???(How is deuterium formed in the first place???)

 

In the sun, deuterium is formed in some reactions when protons collide, and one proton is converted to a neutron, a positron and a neutrino

 

http://hyperphysics.phy-astr.gsu.edu/hbase/Astro/procyc.html

 

The atom with near light velocity in the dense nucleus is unthinkable.

 

Are they near light speed? kT in the sun's core is around an MeV or two, as compared to the mass of almost a GeV. Non-relativistic regime, so the speed isn't all that close to c.

 

Regardless, whether you can conceive of it or not is not a criterion for it being true or a compelling reason to look for some other explanation.