Cosmology* » Sun +
How the size of the Sun is defined?
We can see the Sun, because the energy from the Sun comes towards us.
But, the energy that comes from the Sun towards us is its own energy. It is the one and same energy which the Sun consist of.
Here with us it just is less thickly than what it was "inside" the Sun. I wrote inside with the apostrophes, because now we can ask how big the Sun seriously is?
When the Sun caught fire, the energy has already openned forth from that area.
At the time when the Sun started to radiate light, It filled the certain amount of the space.
Nowadays that energy of the Sun fills in the space much larger area and the Sun has changed for the less densed energy, in the space which does not expand or arch.
If Sun is 5 billion years old, then the diameter of the ball forming from the energy of the Sun is 10 billion light years.
Quite a big Sun.
Much larger than five billion years ago.
In other words the energy of Sun has simply expanded or exploded or openned for much less densed energy as it was before, in the space which does not expand or arch.
How about amortal which forms from the "atoms" of photon energy.
This mortal goes away from the Sun with the photons opening from the Sun.
Even thought mortal goes away from the Sun billoion years, it would not observe for having removed farther from the Sun.
Nor wouldnt it notice how its own energy had changed to less densely..
Actually the mortal could not ever even see the Sun as we see it now.
The mortal atoms are the photons removing from the Sun. They explode and release energy waves, which have the nature of electrons and photons.
The surface of the mortals planet has opened from Sun five billion years ago. To this surface it can dig holes or walk on it.
For the mortal the Planet and its surface seems to be as big as always. It can stay on the surface, because the surface of the planet removes with increasing speed away from the Sun.