ISLAND UNIVERSES

What if one walk to the end of the world?The Great Debate

905: Sufi (small cloud)

18th Charles Messier: Catalogs of nebulous objects

1758: Hershel: Andromeda is the nearest great nebulae.

1845 Lord Ross: Elliptical, spiral nebulae

1864: William HugginsSpectrum of Andromeda is similar to stars (continuous and superimposed by dark lines)

1885 SupernovaS-Andromeda

Type Ia

Type I Supernovae Binary system One is greater in mass AGB: Rapid mass loss -> angular

momentum …White dwarf attracts the mass of

the companion Mass loss -> Orbit period: hours!

Nova Roche Lobe Astronaut orbiting space shuttle Hill Sphere

The largest sphere, centered at the second body, within which the sum of the three fields is always directed towards the second body. A small third body can orbit the second within the Hill sphere.

Nova Accretion Fusion of H and He Nova is a variable star RS-Oph

WD reaches Chandrasekhar limit

The limit is never attained Increase of pressure -> T near core Convection for 1000 years Carbon fusion (unknown) Oxygen fusion

Type I Supernovae…

Fusion -> Raises T A MS star expands but WD has

degeneracy pressure The story of cold plasma, Pauli,

Heisenberg P = Kn5 / 3 instead of PV = NkT T has minor effect on pressure ->

Nothing to stop T raising Instability

Instability

Thermonuclear explosion 1046 j -> Unbind the star

Abs. Mag. = -19.3! Type I supernovae are found all

around the world, elliptical glx, GCs, etc. And S-And.

Standard Castle

SN Type Ia. It takes months for SN to dim

The Great Debate April 26 1920On The Scale of The Universe

Harlow Shapley Heber Curtis

The Great Debate Harlow Shapley Milky Way is the

entire universe Andromeda’s

observed rotating (speed of light)

Heber Curtis Andromeda has

more novae than observed in the entire sky

SN S-And Island Universes

Andromeda (M31) Galaxy

Milky Way

Celestial Coordinate Systems

Equatorial Coordinates

Shapley’s GCs Method

Galactic Coordinates