Cosmos History

chapter 2. The Creation of New Scenes

1.start point?

2.the creation of space-time and gauge symmetry

origin of elements

chapter 3. Understandable and Subtle

1.origin of life

nerve system of c-elegans

chapter 1. From The Sun to The Cosmos

<The Detail of This Chapter.pdf>

gravitation theory

Prelusion: the scenes

1.The Sun

3.stars

4.galaxy

5.the large-scale structures of cosmos

6.CMB

0. The Physical View of The Cosmos

We always assume that the unknown objects obey the same physical rule which we took from known objects until it fail.

1. The Sun

[measurement]

To measure the property of distant object, we have to know the distance from it to our instruments at first.

<geometry>

parallax triangle geometry=>the distance between the sun and the earth: 1AU~1.5E11m~2E4*radius of the earth.

<light>

sphere geometry + measurement on the earth=>luminosity of the sun

<motion>

the movement of the earth=>mass of the sun

2. 20pc~100pc from the sun

<geometry>

parallax triangle geometry based on the anniversary movement of the earth->1pc=10^5AU

2681 stars<20pc, their average interval is 1pc.

Based on the measurement data of these 2681 stars, we can get elementary understanding about star's luminescence property. Very lucky, it is simple!

(1) blackbody radiation from photosphere of stars

Because that photosphere of stars is nearly thermal equilibration, so the stable stellar radiation is approximate blackbody radiation.

For blackbody radiation, the temperature of blackbody uniquely determine intensity distribution upon the frequencies of radiation.

(2) absorption line from stellar atmosphere

the temperature of stellar photosphere: obafgkm

Integrating radiation intensity distribution on frequencies, we get a function: F(L, T, R)=0, or L=constant*R^2*T^4. where L (luminosity); T(temperature); R(radius).

3. Stars

<main sequence stars>

the measurement of temperature + luminosity of stars=>

All the stars that we have measured their temperature and luminosity can be obviously sorted into some different classes: most of them belong to main sequence stars, which means that their

Hertzsprung-Russell relation: temperature ~ luminosity

<the structure theory of main sequence star>

10E2pc->10E5pc

<the evolution theory of main sequence star>

4. Galaxy

Cepheid variables

Mpc~10Mpc

SN Ia: 10Mpc~100Mpc

Hubble

5.the principle of universe

origin of elements

elements heavier than Fe:

Tc->Ru

in low-mass asymptotic giant branch (AGB) stars, (1.5~3M_sun) (Silicon carbide grains)

slow neutron capture (the s-process)

in massive stars (>=10M_sun)

under explosive conditions by rapid neutron capture (the r-process) or by proton capture/photodisintegration reactions (the p-process)