RAADSELS VAN DE STERRENKUNDE Ronald Westra Dep. Mathematics

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1 RAADSELS VAN DE STERRENKUNDE Ronald Westra Dep. Mathematics
Maastricht University February 2, 2006

2 Introduction to Astrophysics

3 lectures :

4 IInhoud 1. Geschiedenis en schalen 2. Zon en het Zonnestelsel
1. Geschiedenis en schalen 2. Zon en het Zonnestelsel 3. Evolutie van sterren 4. Melkwegstelsels 5. Grootschalige strukturen en dynamica 6. Kosmologie en Antigravity

5 IInhoud College 1: Schalen in ruimte en tijd
Schalen in ruimte en tijd Geschiedenis van de astronomie De natuur van het licht Optica en telescopen

6 Astronomic Scales in Space and Time
1. Astronomic Scales in Space and Time

7 Earth Sun Jupiter.

8

9 Galaxy M31, known as the Andromeda nebula

10 Collection of galaxies
Collection of galaxies. The three fuzzy galaxies left merging, The crisp galaxy in the center is on the background

11 Large-scale map of the observable universe showing the the largest structures visible in the universe. Each point in this diagram represents one single galaxy

12 The Universe at the young age of 300,000 years
The Universe at the young age of 300,000 years. The colors represent temperature fluctuations in the Cosmic Background Radiation Wilkinson Microwave Anisotropy Probe

13 Subtle variations in the CBR.

14 The Giant Impact Theory suggests that a Mars-sized object crashed into the early Earth. Most of the debris thrown into space fell back on Earth, but a fraction aggregated into the Moon. This theory is supported by the similar composition of rocks on the Earth and Moon.

15 Geschiedenis van de astronomie

16 History of astronomy Ancient history Hindu Astronomy
Mesopotamia / Sumer / Chaldea, Babylonia Mesoamerica China Ancient Greece Middle Ages

17 Nicolaus Copernicus ( ) The Copernican heliocentric system

18 The Ptolomaic heliocentric system

19 The Ptolomaic heliocentric system

20 Nicolaus Copernicus De revolutionibus orbium coelestium

21 Nicolaus Copernicus (1473-1543)

22 Galileo Galilei ( )

23 Johannes Kepler ( )

24 Tyho Brahe ( )

25 Johannes Kepler

26 Johannes Kepler

27 Kepler's elliptical orbit law:
Johannes Kepler Kepler's elliptical orbit law: The planets orbit the sun in elliptical orbits with the sun at one focus. 2. Kepler's equal-area law: The line connecting a planet to the sun sweeps out equal areas in equal amounts of time. 3. Kepler's law of periods: The time required for a planet to orbit the sun, called its period, is proportional to the long axis of the ellipse raised to the 3/2 power. The constant of proportionality is the same for all the planets.

28 Isaac Newton ( )

29 Voorbeeld: zwaartekracht
Observaties aan bv planeetbanen Experimenten met bv valbewegingen en slingers (Mathematische) Theorie

30 Newton zet de standaard
T * Absolute ruimte en tijd * afgeleide grootheden: snelheid, versnelling, impuls ·   * abstractie van een puntmassa * abstracte grootheden: kracht, energie ·             * abstracte grootheden: kracht hangt van positie af *

31 Newton zet de standaard
T * De natuurwet als principe: [1] de ratio van de verandering van de impuls van een puntmassa is gelijk aan de resulterende kracht die op de puntmassa werkt

32 Newton zet de standaard
T * De natuurwet als principe: [2] de zwaartekracht op een bepaalde plek h de ratio van de verandering van de impuls is gelijk aan de kracht van een massa van M kilo op een puntmassa op is omgekeerd evenredig met het kwadraat van de afstand r van zijn centrum

33 VVolgens Newton T tijd t plaats x impuls p kracht F

34 VVolgens Newton T

35 Optica en telescopen

36 Physics of Light

37 Physics of Light

38 Solar absorption spectrum

39 Optica en telescopen

40 Optica en telescopen (Newton’s oorspronkelijke telescoop)

41 Optica en telescopen

42 Optica en telescopen

43 Optica en telescopen

44 Optica en telescopen

45 Optica en telescopen Hubble Space Telescope

46 Optica en telescopen X-ray astronomy moon

47 Hubble Space Telescope

48 Hubble Space Telescope

49 Hubble Space Telescope

50

51 The End

52 Appendix van deel 1

53 2. Stellar Evolution

54 Some characteristics of the sun
radius (R) cm mass (M) g mean density () g/cm3 total energy output (L) Joule/sec age sec core temperature K surface temperature K distance to earth cm

55 Nuclear fusion in centre of sun

56 Spectral Types O – B – A – F – G – K – M – R – N – S

57 Absolute and Relative Luminosity

58 Original Hertzsprung-Russell Diagram ( HRD)

59 Binding energy per nucleon as function of mass number A.

60 Glowing gaseous streamers of an extinct titanic supernova explosion of a massive star in Cassiopeia A (Cas A)

61 Composite image of the Crab Nebula showing superimposed images of X-ray (blue) (by Chandra X-ray space telescope), and optical (red) (by the Hubble space telescope).

62 First published registration of a pulsar, Hewish et al., Nature 217, p. 710, 1968.

63 Path of the stellar evolution of a main sequence star of one solar mass in the Hertzsprung-Russell diagram log Teff in K log L/ L

64 sun L/ L surface temperature (K) The HRD for 10 stellar clusters. At right ordinate the age in billion years of the bifurcation point from the main sequence.

65 Abundances of chemical elements in the neighbourhood of our sun
Abundances of chemical elements in the neighbourhood of our sun. The marks are from the intensities from spectral absorption lines in the sun’s atmosphere, the lines from meteorite and terrestrial data.

66 An example of an unstable – but not-periodic – star is this massive ‘Wolf-Rayet star’ NGC2359, that irregularly ejects large parts of its own outer envelope in gargantuan explosions. The star itself is in the central bubble, the clouds are remnants of previous ejections.

67 main sequence Luminosity surface temperature
RR Lyrae Cepheids instability strip surface temperature Luminosity Variable stars in the HRD. Pulsating variable stars are found in the instability strip connecting the main sequence and the red-giant region. long period variables

68 Relation between luminosity and oscillation period for Cepheid type 1 variable stars.