What would happen if the earth was the size of the sun?


A couple of days ago, I sent the following question in the mail description of the channel:

According to modern astrophysical studies, any object with a mass of more than 8% of the mass of our Sun, under the action of its own gravity, will turn into a star.

The average density of the Earth is almost 4 times the density of the Sun, which means with the same dimensions of the planet will have 16 times a large mass, that is, guaranteed to become a star.

If we assume that the planet will consist only of heavy elements, and will not have a lot of hydrogen (although it does not happen in reality), then in the process of formation of the planet, it will turn into a molten ball.

In this ball, thermonuclear reactions will not go (as they will not be «fuel»), and the ball will cool very much (within billions of years).

Through some sufficiently large time, the surface of this ball solidhes and the temperature will become comparable to the earth. However, gravity on the surface of such a celestial body will be so strong that no complex organisms or man-made structures will simply be able to exist there.

The issue of the existence of bacteria and other protozoa in such conditions remains unexplored, but it is hypothetically possible, although it is doubtful.