Massive improvements over the first chapter, annexes, preface and macros.
This commit is contained in:
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5
Makefile
5
Makefile
@ -31,6 +31,9 @@ VIEWER = zathura $(VIEWER_OPTS)
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SOELIM_OPTS =
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SOELIM = soelim $(SOELIM_OPTS)
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GRAP_OPTS =
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GRAP = grap $(GRAP_OPTS)
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PIC_OPTS =
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PIC = pic $(PIC_OPTS)
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@ -49,6 +52,6 @@ SHOPTS = --outlang-def=./.source-highlight_groff-output-definition
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export SHOPTS
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$(SRC).pdf:
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cat $(SRC).ms | $(SOELIM) | $(EQN) | $(GHIGHLIGHT) | $(PIC) | $(REFER) | $(PRECONV) | $(GROFF) > $@
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cat $(SRC).ms | $(SOELIM) | $(EQN) | $(GHIGHLIGHT) | $(GRAP) | $(PIC) | $(REFER) | $(PRECONV) | $(GROFF) > $@
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include Makefile.custom
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@ -5,7 +5,7 @@ upload:
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scp $(RAM)/$(SRC).pdf tacos:/var/www/htdocs/t.karchnu.fr/doc/
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run_universefromnothing:
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cat $(SRC).ms | $(SOELIM) | $(EQN) | $(GHIGHLIGHT) | $(PIC) | $(REFER) | $(PRECONV) | $(GROFF) > $(RAM)/$(SRC).pdf
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cat $(SRC).ms | $(SOELIM) | $(EQN) | $(GHIGHLIGHT) | $(GRAP) | $(PIC) | $(REFER) | $(PRECONV) | $(GROFF) > $(RAM)/$(SRC).pdf
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serve:
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find . -name "*.ms" | entr gmake -B run_$(DOC)
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68
macros.ms
68
macros.ms
@ -136,3 +136,71 @@ To be defined or to finish.
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..
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.\" MS Accents
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.\".AM
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.defcolor citation rgb 0.4 0.4 0.4
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.defcolor citationbar rgb 0.3 0.3 0.7
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.de CITATION1
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.KS \" start a keep
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.ft I \" citation in italics
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.mk C \" set a marker for line drawing
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.in +1 \" indent a bit
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.gcolor citation
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..
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.de CITATION2
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.mk D \" set second marker to come back here
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.ft \" back to previous font
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.in -1 \" remove indent
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.gcolor \" remove previous color
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.gcolor citationbar
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\r\L'|\\nCu' \" draw line (\r moves upward, \L draw the line, ...)
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.sp '|\\nDu' \" return to the second marker
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.gcolor \" remove previous color
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.sp -2 \" get two lines back
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.KE \" end of the keep
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..
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.de NAMECITATION
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.ps -2
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\(em\h'1'\\$*
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.ps
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..
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.defcolor explanation rgb 0.7 0.4 0.4
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.defcolor explanationbar rgb 0.8 0.3 0.3
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.de EXPLANATION1
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.KS \" start a keep
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.ft B \" citation in italics
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.mk C \" set a marker for line drawing
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.in +1 \" indent a bit
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.gcolor explanation
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..
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.de EXPLANATION2
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.mk D \" set second marker to come back here
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.ft \" back to previous font
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.in -1 \" remove indent
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.gcolor \" remove previous color
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.gcolor explanationbar
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\r\L'|\\nCu' \" draw line (\r moves upward, \L draw the line, ...)
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.sp '|\\nDu' \" return to the second marker
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.gcolor \" remove previous color
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.sp -2 \" get two lines back
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.KE \" end of the keep
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..
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.de METAINFO1
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.ft CW
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.ps 9
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.vs 10p
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..
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.de METAINFO2
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.vs
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.ps
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.ft
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..
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.de PRETTY_PERCENTAGE
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\v'-.7m\s[\\n(.s*6u/10u]+.7m'\\$1\v'-.7m\s0+.7m'\
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\(f/\s[\\n(.s*6u/10u]\\$2\s0
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..
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@ -2,7 +2,8 @@
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Annex: events
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.LP
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.BULLET
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.UL "16XX" ,
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.UL "1665" ,
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Isaac Newton
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.BULLET
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.UL "1784" ,
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first observation of Cepheid variable star.
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@ -42,7 +43,7 @@ Annex: vocabulary
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.LP
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.BULLET
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.UL "perihelion" :
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point of an orbit where the object (ex: a planet) is the closest from another object (ex: a star).
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point of an orbit where the object (e.g.: a planet) is the closest from another object (e.g.: a star).
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.BULLET
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.UL "aphelion" :
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opposite of perihelion, point of an orbit where the object is the farthest from another object.
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@ -58,15 +59,27 @@ of the orbital course (nodal precession), which can be caused by a third gravita
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.UL "nebulae" :
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.I "fuzzy thing"
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(or cloud) in latin.
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Galaxies were named this way before we understood what we saw.
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.BULLET
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.UL "Cepheid variable star" :
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star whose brightness varies over some regular period.
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.UL "Cepheid variable" :
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star whose brightness varies over some regular period, indicating a change in diameter and temperature.
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.BULLET
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.UL "Doppler Effect" :
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a wave coming at you will be stretched if the source is moving away from you, or compressed if the source is coming toward you.
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.ENDBULLET
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.SH
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Annex: people involved (and mentionned in the book)
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Annex: people involved
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.LP
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.BULLET
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.UL "Johannes Kepler" :
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known for the first heliocentric model.
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.BULLET
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.UL "Isaac Newton" :
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.BULLET
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.UL "Christian Doppler" :
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australian physicist, known for the "Doppler Effect".
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.BULLET
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.UL "Albert Einstein" :
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.BULLET
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.UL "Georges Lemaître" :
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@ -88,4 +101,97 @@ Made the first observation of the expansion of the universe.
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.BULLET
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.UL "Harlow Shapley" :
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discovered the Sun wasn't at the center of the Milky Way, and that our galaxy was much larger than we previously thought.
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.BULLET
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.UL "Vesto Slipher" :
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astronomer, he measured the spectra of light coming from several galaxies.
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.ENDBULLET
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.SH
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Random explanations
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.PP
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Diffraction: behavior of waves when reaching an aperture.
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.PS
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reset
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rad_large_circle = 0.6 # Size of circles.
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rad_empty_space = 0.5 # Size of circles.
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rad_light_source = 0.3 # Size of circles.
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rad_aperture = 0.1 # Size of circles.
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fill_large_circle = 0.1 # Represents light intensity.
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fill_empty_space = 0.6 # Represents light intensity.
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fill_light_source = 0 # Represents light intensity.
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txt_x_shift = 0.05 # Shift from arrow start.
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txt_y_shift = 0.05 # Shift from arrow start.
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space_between_arrows_y = -0.25 # Allow space for text.
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CIRCULAR_DIFFRACTION_FIGURE: [
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circlerad = rad_large_circle
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circle fill fill_large_circle
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circlerad = rad_empty_space
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move to last circle + (-circlerad, 0)
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circle fill fill_empty_space
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circlerad = rad_light_source
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move to last circle + (-circlerad, 0)
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circle fill fill_light_source
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circlerad = rad_light_source
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move to last circle + (-circlerad, 0)
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LIGHT_SOURCE: circle fill fill_light_source
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circlerad = rad_aperture
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move to last circle + (-circlerad, 0)
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APERTURE: circle fill fill_light_source dashed
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# LEGEND.
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move; move
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arrow to APERTURE chop 0 chop rad_aperture
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move to last arrow.s + (txt_x_shift,txt_y_shift)
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"Aperture, where light can pass through" ljust
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move to last arrow.s + (0,space_between_arrows_y)
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arrow to LIGHT_SOURCE chop 0 chop rad_light_source
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move to last arrow.s + (txt_x_shift,txt_y_shift)
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"Main visible light source, very bright" ljust
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move to last arrow.s + (0,space_between_arrows_y)
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arrow to LIGHT_SOURCE chop 0 chop rad_empty_space
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move to last arrow.s + (txt_x_shift,txt_y_shift)
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"Empty space, very little light" ljust
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move to last arrow.s + (0,space_between_arrows_y)
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arrow to LIGHT_SOURCE chop 0 chop rad_large_circle
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move to last arrow.s + (txt_x_shift,txt_y_shift)
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"Halo, thin light" ljust
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]
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move to CIRCULAR_DIFFRACTION_FIGURE + (0, -1)
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"Circular diffraction"
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.PE
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.\" Exponential: oldvalue + growth factor -> newvalue
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.G1
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GROWTHFACTOR=0.07
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frame ht 2.5 wid 2.8
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define expo { $1+$1*GROWTHFACTOR }
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value = 1
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draw LINEAR solid
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for i from 1 to 100 by 1 do {
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next LINEAR at i, i
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times at i, value
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value = expo(value);
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}
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line from 0,650 to 3,650
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" linear curve" ljust at 1,650
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" exponential curve" ljust at 1,600
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times at 1,600
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label top "Exponential curves: growth over time (7%)" up .2
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.G2
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@ -1,32 +1,128 @@
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.NH
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a cosmic mystery story: beginnings
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.PP
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.ft CW
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.METAINFO1
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Contrary to the book, I'll describe things chronogically in the summary.
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.ft
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.METAINFO2
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1514: Nicolaus Copernicus suggests an heliocentric model.
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Between 1609 and 1619: Johannes Kepler publishes his
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.I "laws of planetary motions" ,
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which fixes a few problems with the view of Copernicus on the matter:
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.BULLET
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Planets move around the sun in ellipses.
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.BULLET
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The Sun is not near the center but at a focal point of the elliptical orbit.
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.BULLET
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Neither the linear speed nor the angular speed of the planet in the orbit is constant, but the area speed (closely linked historically with the concept of angular momentum) is constant.
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.ENDBULLET
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1665: Isaac Newton uses a prism to see the sunlight disperse into the colors of a rainbow.
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He manages to obtain this result by only letting the light of the sun enter a room by a small hole in the window shutter.
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His conclusion: the white light contains all these colors.
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.EXPLANATION1
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Sunlight contains a spectrum of colors.
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.EXPLANATION2
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(around) 1815: another scientist
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.FOOTNOTE1
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His name is not given in the book.
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.FOOTNOTE2
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analyses the dispersed light: some colors aren't there.
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His conclusion: some materials in the outer atmosphere of the sun are absorbing the light of certain colors or wavelengths.
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Known materials are tested to see what are the colors they
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.I absorb ,
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which includes: hydrogen, oxygen, iron, sodium, and calcium.
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.EXPLANATION1
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Materials may
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"absorb"
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some part of the solar spectrum.
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Different materials, different parts of the spectrum.
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.EXPLANATION2
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1784: first observation of Cepheid variable star, which are stars whose brightness varies over some regular period.
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1908-1912: Henrietta Swan Leavitt discovers a relation between Cepheid variable stars' brightness and period of their variation.
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And this leads to knowing the distance between these stars: we now can make wild approximations on astonomic distances between us and these stars.
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1842: Christian Doppler discovers the Doppler Effect.
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.ft CW
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.ps 8
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.vs 9p
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If one could determine the distance to a single Cepheid of a known period, then measuring the brightness of other Cepheids of the same period would allow one to determine the distance to these other stars.
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.vs
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.ps
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.ft
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.EXPLANATION1
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Doppler Effect: a wave coming at you will be stretched if the source is moving away from you, or compressed if the source is coming toward you.
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.EXPLANATION2
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Determining the distance between us and stars always has been a challenge in astronomy.
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The observed brightness of stars goes down inversely with the square of the distance to the star.
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1868: another scientist
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.FOOTNOTE1
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Again, not named in the book.
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.FOOTNOTE2
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observes two missing lines in the yellow part of the solar spectrum.
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This doesn't correspond to the effect of materials we know on Earth.
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His conclusion: these
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.I absorbed
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colors must be the result of an element that doesn't come from Earth.
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This element is then named
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.I helium .
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A generation after we understood the sun has elements we don't have (as much) on Earth,
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.FOOTNOTE1
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Yeah, not even a date, again.
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.FOOTNOTE2
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.I helium
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is isolated on Earth.
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.EXPLANATION1
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The spectrum of radiation of stars provides their composition, temperature and evolution.
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.EXPLANATION2
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1908-1912: Henrietta Swan Leavitt discovers a relation between the brightness of Cepheid variable stars and their pulsation period.
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.EXPLANATION1
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The light spreads out uniformly over a sphere whose area increases as the square of the distance.
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Thus since the light is spread out over a bigger sphere, the intensity of the light observed at any point decreases inversely with the area of the sphere.
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.EXPLANATION2
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.NAMECITATION "TODO: find out who and when this was discovered"
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.EXPLANATION1
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Observing the pulsation period of a Cepheid indicates its true luminosity.
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Also, the observed brightness of stars goes down inversely with the square of the distance to the star.
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Therefore, comparing its known luminosity to its observed brightness gives us the actual distance to the star.
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.EXPLANATION2
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Knowing the distance between us and these stars leads to a new map of the world.
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Other galaxies will soon be discovered, as some stars are too far to be within our Milky Way.
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.\".CITATION1
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.\"If one could determine the distance to a single Cepheid of a known period, then measuring the brightness of other Cepheids of the same period would allow one to determine the distance to these other stars.
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.\".CITATION2
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.\".NAMECITATION "Lawrence Krauss"
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.
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Starting in 1912, Slipher observes the spectra of light coming from nearby stars and distant spiral nebulae
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.FOOTNOTE1
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.I Nebulae
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that we will soon find out they are actually entire galaxies.
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.FOOTNOTE2
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are almost the same.
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The difference is a shift of the same wavelength in the
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.I absorbed
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lines.
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1916, A. Einstein publishes his work on the
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.I "general theory of relativity" .
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This work is about gravity, space and time, and explains not only how objects move in the universe, but also how the universe itself might evolve.
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Amongst many uses of this theory, the orbit of Mercury can be predicted more accurately than before with Newton's theory of gravity.
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This fixes a small difference between observation and theoretical results.
|
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.FOOTNOTE1
|
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The planet doesn't come back to its initial position after an ellipse around the sun.
|
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There is a slight precession of the perihelion of Mercury: 43 arc seconds (only
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.PRETTY_PERCENTAGE 1 100
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of a degree) per century.
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.FOOTNOTE2
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1916, general theory of relativity: a decade-long struggle to create a new theory of gravity by Albert Einstein.
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This work is also about space and time, and explains not only how objects move in the universe, but also how the universe itself might evolve.
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However, the theories of Newton and Einstein are both, at some point, inconsistent with the observations.
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Gravitation is thought to be an attractive force: objects should then always collapse into each other.
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Also, the scientific community still thinks the universe as static, eternal and composed of a single galaxy (our Milky Way) surrounded by a vast, dark, infinite empty space.
|
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And without accurate knowledge of the distances with observed stars, nor better images, this idea seems consistent with the observations.
|
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1923-1924, with the period-luminosity relation and the measurement of Cepheid variable stars, Hubble determines that the distance with some Cepheids was too great to be inside our Milky Way.
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The universe contains
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@ -42,32 +138,31 @@ we currently know as Andromeda).
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1925: Mount Wilson 100-inch Hooker telescope.
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A. Einstein publishes his work on the
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.I "general theory of relativity"
|
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in 1916 but this doesn't match with observation and what we
|
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.I thought
|
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the universe was at the time.
|
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The scientific community still imagined the universe to be static, eternal and composed of a single galaxy (our Milky Way) surrounded by a vast, dark, infinite empty space.
|
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This idea was consistent with the observations.
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On the contrary, the theories of Newton and Einstein were both inconsistent with the observations since gravitation was thought to be an attractive force: objects should then always collapse into each other.
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1927: Georges Lemaître is the first person to suggest the universe was expanding.
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This is his conclusion after solving the Einstein's equations for general relativity.
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.EQ
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delim $$
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.EN
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However, his theory is able to predict the orbit of Mercury slightly better than before with Newton's theory of gravity.
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The new theory fixes a small difference between observation and theoretical results.
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.FOOTNOTE1
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The planet doesn't come back to its initial position after an ellipse around the sun.
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There is a slight precession of the perihelion of Mercury: 43 arc seconds (only $1 over 100$ of a degree) per century.
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.FOOTNOTE2
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.EQ
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delim off
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.EN
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The first person to suggest the universe was expanding was Georges Lemaître in 1927, while solving the Einstein's equations for general relativity (which leads to this conclusion).
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Then in 1930 he proposed that the universe began in a very small point called
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1930: Georges Lemaître proposes that the universe began in a very small point, which he called
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.I "Primeval Atom" .
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This wasn't accepted by the scientific community right away: actual observations were provided by Edwin Hubble.
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This isn't accepted by the scientific community right away: actual observations were provided by Edwin Hubble beforehand.
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Current state of knowledge: expansion of the universe started 13.72 billion years ago.
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Our galaxy is one of the about 400 billion other galaxies in the observable universe.
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.SH 2
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Random facts: current state of knowledge
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.LP
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The expansion of the universe started 13.72 billion years ago.
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Our galaxy is one of the about 100 to 400 billion other galaxies in the observable universe.
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Over 200 million stars already exploded within our galaxy, providing us the material resources necessary for life on Earth.
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Big Bang created light elements in massive quantities, such as hydrogen.
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However, heavier elements require the stars to be created (by their massive gravity), and their explosion to be dispersed accross the galaxy.
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.EXPLANATION1
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Life on Earth is, literally, made of stars.
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.EXPLANATION2
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|
||||
A supernovae (the explosion of a star) occurs once every hundred years or so per galaxy.
|
||||
The last one in our galaxy was in 1604.
|
||||
|
||||
Rare events, such as supernovae, happen constantly at the scale of the universe.
|
||||
Therefore, each night with a good enough telescope, you can expect to see a supernovae.
|
||||
|
||||
@ -15,6 +15,9 @@ Philippe Pittoli
|
||||
This book summaries what we know about the universe, how it began and how we managed to learn this.
|
||||
|
||||
This document is a summary of the book, ordered by chapters.
|
||||
Since not everything is explained in
|
||||
.I trivial
|
||||
terms in the book, I'll try my best to provide explanations for a few concepts along the way.
|
||||
.SHINE "You're welcome."
|
||||
|
||||
Check out for newer versions on my website:
|
||||
|
||||
@ -7,7 +7,7 @@ Religion argues for an infinite regression that could only be solved by some mag
|
||||
.I infinite
|
||||
and
|
||||
.I eternal
|
||||
so our universe don't have to.
|
||||
so our universe doesn't have to.
|
||||
Theologians and religious people are a bit mocked for their many, many dishonest arguments to keep their beliefs.
|
||||
For example, the
|
||||
.I "Intelligent Design"
|
||||
|
||||
Loading…
Reference in New Issue
Block a user