Sujet : Re: Gravitational red-shifting in the biggest star. What are the real colors?
De : hertz778 (at) *nospam* gmail.com (rhertz)
Groupes : sci.physics.relativityDate : 28. Sep 2024, 03:34:50
Autres entêtes
Organisation : novaBBS
Message-ID : <d53d725fd59b543ff824b3be8893ec92@www.novabbs.com>
References : 1
User-Agent : Rocksolid Light
This link illustrates a bit:
https://en.wikipedia.org/wiki/Gravitational_redshiftUsing the most common formula from that link: "To first approximation,
gravitational redshift is proportional to the difference in
gravitational potential divided by the speed of light squared"
Δf/f = Δλ/λ = z = GM/c² (1/R - 1/r) = Φ(R)/c² - Φ(r)/c²
G = 6.6743E−11 m^3 kg^−1 s^−2
M = 5E+09 x 1.989E+30 Kg = 9.945E+39 Kg
R = 1,700 x 634,000 Km = 1,077,800,000,000 m
Φ(R)/c² = 6,842,736.59
In comparison, Φ(RSun)/c² = 0.000002327
At r = 10,000,000 R = 10,077,800,000,000,000,000 m
Φ(r)/c² = 0.684273659
Δf/f = Δλ/λ = z = 6,842,736
The z-value can be expressed succinctly in terms of the escape velocity
at R, since the gravitational potential is equal to half the square of
the escape velocity, thus:
z = 1/2 (v_escape/c)²
v_escape = 3699.4 c
But then, light can escape from UY Scuti.
Yet, it was discovered in 1860.
WHAT IS WRONG WITH MY CALCULATIONS, BASED ON THE WIKI LINK?