The red giant fairytale

de-1.09.2009 / en-5.05.2022

The ridiculous theory of the red giant

by Pierluigi Peruzzi

Important note:
My theory refers to the "normal yellow star" and NOT to the existing "red giants".

The yellow star as a future red giant
Or the reason why our sun will not explode

Today's theory about the sun inflating over time, turning red, then swallowing the earth, and finally becoming a white dwarf, and finally exploding, makes my diaphragm very uncomfortable.

In particular, that our sun, shortly before its death, still quickly snatches away the earth, seems to me extremely human. However in no way factual and not at all physical.

For this reason I have set up my own thesis or even theory about the red sun. Thereby I agree with the rest of mankind in one point: Sooner or later our sun will become a red star. Only the course of events will definitely be different.

We must not forget that the very first "red giant theory" dates back to the time when it was believed that electrons whir around atomic nuclei in a ridiculous roller coaster and when some books still said that electric energy was an "unknown fluid". But since one does not like to throw the old theories of venerable scientists over the heap, so one invents theory crutches.

Also we must not disregard that the theory on the "bloating" of the sun, is in direct connection with the mass loss. The mass loss is caused inside the sun by the fusion process.

1. My countertheory

1.1. The force of gravity

So that I can explain my theory better, we must deal first with the gravity on the surface of a celestial body. By this I do not mean the attraction of the celestial body, but only its surface gravity. In almost every red sun theory gravity and mass of the star are practically decisive.

General formula of gravity:  

Gravitational constant x mass
The earth as example = 9,8m/s2:

(6.673 x 10-11m3/kg s2) x (5,954 x 1024kg)
6,37 x 106m x 6,37 x 106m

1.2. Example of two different spherical celestial bodies

schwerkraft eines himmelskörpers nach spezifischem gewicht

To be able to explain everything better, I would like to show a blatant example of two fundamentally different celestial bodies. Whereby one celestial body is smaller and has a smaller mass than the other, but still has more gravity on its surface. This is decisive for my theory.

Calculation example of the 2 different spherical celestial bodies:

Celestial bodie A: Celestial bodie B:
Radius 1000 km Radius 400 km
Consists of pure water ice H2O Consists of pure lead Pb
Specific weight approx. 1.0 g/cm3 Specific weight approx. 11.34 g/cm3
Volume 4'188'790'204 km3 Volume 268'082'573 km3
Mass 4,18879 x 1021kg Mass 3,040 x 1021kg

Gravity on the surface of the large, heavy celestial body A:
=  - 0.28m/s2

Gravity on the surface of the small, lighter celestial body B:
=  - 1.27m/s2

(6.673 x 10-11m3/kg s2) x (4,18879 x 1021kg)

10 x 106m x 10 x 106m

(6.673 x 10-11m3/kg s2) x (3,040 x 1021kg)

4 x 105m x 4 x 105m

Important: In this example, the smaller and lighter celestial body has the greater gravity on the surface because its specific gravity is much higher!

  2. My real theory

  2.1. The phases of solar death or the life cycle of the yellow star.

Phase 1 Yesterday
Bright yellow-white star. Very hot. Increased fusion activity.

sonne phase 1Phase 1 of the sun

Phase 2 Today
Strong, small yellow sun with the right thermal radiation for the earth. Normal nuclear fusion. Hydrogen is burned to helium. So an increase of the specific gravity is going on.

sonne phase 2Phase 2 of the sun

Phase 3 Tomorrow
Due to its nuclear fusion, the sun continues to lose "light" mass. For the time being, there are no major deviations.

sonne phase 3Phase 3 of the sun

Phase 4 The day after tomorrow

The sun has burned almost all the "light" mass and begins to turn red. This results:

  • That the sun now consists of heavier material. I.e. their specific weight has increased, while the total mass of the sun has decreased!
  • The attraction of the sun, outside in the space, outside of the sun, decreases, due to the lighter mass of the sun.
    However, the gravitational attraction on the surface of the sun has increased! See my example above.
  • The planets slip a little bit to the outside, because the attraction outside of the sun has decreased.
  • The nuclear fusion activities have decreased and therefore the immense pressure inside decreases. I.e. the heavy mass contracts again. The sun shrinks. The radius becomes smaller. On the surface there are less and less hydrogen gases. Helium and other gases now predominate and the gravity on the surface of the sun increases further by these factors.
  • The "fewer" gases on the surface are now compressed again by 2 factors:
  • the increased gravity on the surface, and the "less" gases consist of heavier material, which again press on the solar atmosphere.
  • sonne phase 4Phase 4 of the sun

    I.e. that by the heavier specific weight, which the sun has acquired, the gravity on the surface is strengthened. Not to be confused with the effective attraction of the celestial body itself! This has decreased.

    Now our sun becomes a red dwarf!
    Without having previously inflated and swallowed any planets!


    The following factors speak against an " inflating " of the sun:

  • The pressure inside a star decreases successively. I.e. the star now shrinks and the specific weight increases. Consequently, the increasing surface gravity will compress the solar atmosphere. The star then decreases rapidly in diameter.
  • H becomes He. That means hydrogen is burned to helium. Helium has 4 times the atomic weight of hydrogen. Consequently the sun shrinks now again, because helium needs less space than hydrogen. And as a consequence the specific gravity increases rapidly. Again a factor which increases the surface gravity of the star.
  • The total temperature of the sun decreases. Consequently, all the material of the star must expand back. Every child knows that a temperature increase makes all elements expand and a temperature decrease makes all elements shrink. Also here a rapid increase of the specific weight. The consequence of this we have already mentioned.
  • The surface temperature of the sun decreases. From about 7,000C today to 5,000C. Maybe even less. Again, every child knows that gases show an increase in pressure when the temperature increases and a decrease in temperature results in a contraction of the gases due to a decrease in pressure. I.e. the solar atmosphere shrinks again by another factor. No flatulence.

  • Addendum from August 20, 2011

    Thanks to NASA's Space Hubble telescope, it has been found that over 50% of the stars in the Milky Way are small red dwarfs. Even our neighboring star Alpha Centauri hosts such a star.

    Since these small stars have less than half of our solar mass, they should be simply small yellow stars which are dying. Since they are smaller, the fusion process should soon be over. See my theory above.

    In addition, we must not forget the supernova of 1987 in the large Magelan cloud. There a blue giant chased it away. Consequently, one can forget all today's theories.

    And now allow me a last question:
    Why didn't JUPITER swallow IO when it was in the Red Sun phase?

    Last but not least:

    I claim that after the "red phase" the brown phase begins. After that the sun extinguishes without causing any supernova or "swallowing" planets. Justification: Because this is a logical conseguence and the supernova theory - which should be based on a white dwarf - is only a theory crutch.

    Important note:
    My theory refers to the "normal yellow star" and NOT to the existing "red giants".