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Dr. Jay Maron

Timeline of the universe

                Millions of years ago

Big bang             13700
First planets formed 13000
Earth formed          4500
Photosynthesis        3000
Oxygen atmosphere      600
Multicellular life     600
Vertebrates            480
Tetrapod vertebrates   400
Mammals                170
Dinosaur extinction     66
Cats                    25
Cheetahs                 6
Tigers                   1.8
Humans                   1
Lions                     .9
Agriculture               .01
Civilization              .005
Calculus                  .0004
An alien planet could conceivably have formed as early as 1 billion years after the big bang, meaning that there are likely aliens with a head start on us by billions of years.

An alien civilization could easily build a rocket that travels at 1/10 the speed of light, which would take 1 million years to cross the galaxy. The aliens have plenty of time to get here.

Dinosaurs and birds


                                            ->  Reptiles  ->  Dinosaurs  ->  Birds
Vertebrates   ->   Tetrapod vertebrates  --
                                            ->  Mammals
A tetrapod is a vertebrate with four limbs. Reptiles, dinosaurs, birds and mammals all evolved from tetrapods, and the essential elements of the tetrapod design haven't changed since its emergence. Elements of the tetrapod design include:

A spine
A skull
A ribcage
Four limbs
One bone in the upper limb and two bones in the lower limb.

Humans have the most complex wrists and hands in the animal kingdom.

Bruce Lee: There is only one type of body, 2 arms, 2 legs, etc that make up the human body. Therefore, there can only be one style of fighting. If the other guy had 4 arms and 2 legs, there might have to be a different one. Forget the belief that one style is better than the other, the point of someone that does not just believe in tradition, but actually wants to know how to fight is to take what you need from every martial art and incorporate it into your own. Make it effective and very powerful, but don't worry if you are taking moves from many different arts, that is a good thing.

Not a tetrapod
Not a tetrapod

Oxygen cycle

Earth photosynthesis
Banded iron formation

Define one "Earth Atmosphere Oxygen Mass" (EAOM) as the mass of the oxygen in the Earth's atmosphere, equal to 1.4*10^18 kg.

Oxygen          Mass        Flux        Half life
Reservoir      (EAOM)    (EAOM/year)

Atmosphere        1        .000214      4500 years
Biosphere          .0114   .000214        50 years
Lithosphere     207        4.3*10^-7     400 million years

Land photosynthesis   = .000118 EAOM/year = 165*10^12 kg Oxygen / year
Ocean photosynthesis  = .000096 EAOM/year = 135*10^12 kg Oxygen / year
The time required by photosynthesis to generate one EAOM is 4700 years.

Early in the Earth's history, oxygen produced by photosynthesis was absorbed by iron dissolved in the oceans, creating "banded iron formations". Once photosynthesis overwhelmed the ocean's iron, an oxygen atmosphere became possible.


A desert planet like Tatooine would have a hard time generating an oxygen atmosphere.

Carbon cycle

This diagram of the fast carbon cycle shows the motion of carbon between land, atmosphere, and oceans, in billions of tons of carbon per year. Yellow numbers are natural fluxes, red are human contributions in billions of tons of carbon per year. White numbers indicate stored carbon.

Carbon content of the Earth, with the atmosphere normalized to 1

Atmosphere      1.00
Biomass          .62
Surface ocean   1.25
Deep ocean     46.2
Ocean sediment  7.5
Soil            2.88
Fossil carbon  12.5
Given the global rate of fossil fuel burning, it would take ~ 89 years to double the atmosphere's carbon.

Photosynthesis moves carbon from the atmosphere to plants, and the carbon returns to the atmosphere through plant respiration and through microbial decomposition of dead plants. Given the global rate of photosynthesis, it takes photosynthesis ~ 7 years to cycle through the atmosphere's carbon.

Ozone cycle

Ozone cycle
Radiation as a function of altitude
Ozone distribution

Ozone production from solar radiation          =  400 million tons / day
Ozone loss from combining with oxygen radicals =  400 million tons / day
Total atmospheric ozone                        = 3000 million tons
The Sun produces 12% of the ozone layer each day.

Water absorption spectrum

Before the Earth had oxygen and ozone, the continents were uninhabitable and the only place photosynthesis could take place was underwater. Water is more transparent to visible light than to ultraviolet light.

Nitrogen cycle

Cyanobacteria can fix 1.8 kg of nitrogen per hectare per day. Nitrogen can be fixed in the ocean at twice the rate than what is possible on land.

Global temperature

History of atmospheric carbon dioxide

Sea level

World totals
Atmosphere temperature rise=   .017 Kelvin/year      (.9 Kelvin since 1800)
Sea level rise             =  2.8   mm/year          (225 mm since 1800)
Atmosphere CO2 frac        =   .0035                 (.0027 in 1800)
Atmosphere carbon          =720     Gtons
Photosynthesis of carbon   =120     Gtons/year
Human carbon emissions     =  9     Gtons/year   = 1240   kg/person/year
Energy produced            =   .57  ZJoules/year =   78.6 GJoules/person/year
Electricity produced       =   .067 ZJoules/year =    9.2 GJoules/person/year
Food                       =   .027 ZJoules/year =    3.7 GJoules/person/year = 2500 Cal/person/day
Sunlight energy            =3850    ZJoules/year
Wind energy                =  2.25  ZJoules/year
Photosynthesis of biomass  =  3.00  ZJoules/year
Ocean heat gain            =  7.5   ZJoules/year
World power                = 18     TWatts       = 4500   Watts/person
Energy cost                = 16     T$/year      = 2210   $/person/year   (27.8 $/GJoule)
Population                 =  7.254 billion
Food                       =  1.58  Tkg/year     =  218   kg/person/year  (As carbs)
Earth land area            =148.9   Mkm2         =    2.0 Hectares/person
Rainfall over land         =107000  km3/year     =   14.8 tons/person/year
River flow                 = 37300  km3/year     = 5140   tons/person/year
Water total use            =  9700  km3/year     = 1390   tons/person/year
Water for agriculture      =  1526  km3/year     =  218   tons/person/year
Water for home use         =   776  km3/year     =  111   tons/person/year
Water desalinated          =    36  km3/year     =    5   tons/person/year

Greenhouse gases

       Contribution to    Half life in the atmosphere
     greenhouse warming
H2O    36-72%
CO2     9-26%             90 years
CH4     4-9%              12 years
Ozone   3-7%               1 week

The importance of oxygen

Oxygen clan
Sulfur clan

Oxygen clan vs. Sulfur clan
                       Chuck                    Sulfur-reducing bacteria
                       (Oxygen Clan)            (Sulfur Clan)

Mass                   100 kg                   single-cellular
Power source           Hydrocarbons + oxygen    Hydrocarbons + sulfur
ATP per glucose        30                       2
Resting power          100 Watts                tiny
Peak power             kilowatts                tiny
Peak power/weight      10 Watts/kg              tiny
Strength               Kilonewtons              tiny
Computation            10^14 synapses           -
Brain power            20 Watts                 -
Achilles heel          H2S                      Oxygen

Aerobic organisms have an energy advantage over anaerobic organisms.

Aerobic respiration:     Glucose  +  Oxygen   -->   H2O  + 30 ATP of energy
Anaerobic respiration:   Glucose  +  Sulfur   -->   H2S  +  2 ATP of energy
Aerobic organisms also have a weight advantage over anaerobic organisms. Aerobic organisms can get oxygen from the air whereas anaerobic organisms have to carry their oxidizer.
For the reaction
Hydrocarbons  +  Oxygen  -->  H2O  +  CO2  +  energy
Mass of oxygen / Mass of hydrocarbons ~ 8
These two factors give aerobic organisms an overwhelming energy advantage over anaerobic ones, and this is the reason why nearly all multi-cellular organisms are aerobic.

Oxygen is usually toxic to anaerobic organisms.

Anaerobic organisms produce H2S and CS2, which is toxic to most aerobic organisms.

Before the Earth had an oxygen atmosphere, sulfur-reducing bacteria ruled the Earth. When oxygen appeared, aerobic organisms took over because of the energy advantage. Sulfur-reducing bacteria retreated underground where there is no oxygen. On occasion the sulfur bacteria make a comeback, such as during the runaway global warming event 251 million years ago. During this episode, the atmosphere became flooded with H2S, causing a mass extinction of aerobic species.

Peter Ward's book "The Medea Hypothesis" has a nice discussion of the rivalry between aerobic and anaerobic organisms, and of the interaction between the Earth's geology and biology.

In the film "Avatar", the atmosphere of Pandora is toxic to humans because of H2S.


Oxygen is more electronegative than sulfur, which is why reacting hydrocarbons with oxygen yields more energy than by reacting them with sulfur.

The only element that rivals oxygen's electronegativity is fluorine, but fluorine gas is highly reactive and HF is a strong acid.

Brain to body mass ratio

The human brain consumes 20 Watts.

Even though the brain is a power-hungry organ, organisms take the trouble to develop large brains.

                 Brain    Total    Brain/
                 mass     mass     body
                 (kg)     (kg)
Sperm whale         8
Orca whale          6
Elephant            5     2800      .0018
Blue whale          4
Bottlenose dolphin  1.7
Neanderthal         1.9
Human               1.6     64      .025
Gorilla              .6
Chimpanzee           .4
Orangutan            .4
Horse                .4    235     .0017
Pig                  .20
Dog                  .10    12     .0080
Cat                  .04     4     .0091
Squirrel             .009    1.4   .0067
Mouse                .001     .04  .025
Shrew                .0002    .002 .1
Bat                  .0001
Frog                               .0058
Small bird                         .071
Shark                              .0004
Ant                                .14
"The body cannot exist without the mind" - Morpheus


Antimatter       90 billion
Hydrogen bomb      25000000    theoretical maximum yield
Hydrogen bomb      21700000    highest achieved yield
Uranium            20000000    as nuclear fuel
Hydrogen                143
Natural gas              53.6
Gasoline                 47
Jet fuel                 43
Fat                      37
Coal                     24
Carbohydrates & sugar    17
Protein                  16.8
Wood                     16
Lithium-air battery       9
TNT                       4.6
Gunpowder                 3
Lithium battery           1.3
Lithium-ion battery        .72
Alkaline battery           .59
Compressed air             .5        300 atmospheres
Supercapacitor             .1
Capacitor                  .00036
The chemical energy source with the highest energy/mass is hydrogen+oxygen, but molecular hydrogen is difficult to harness. Hydrocarbons + oxygen is the next best choice. Carbon offers a convenient and lightweight way to carry hydrogen around.

Reacting hydrocarbons in an oxygen atmosphere yields the optimal power-to-weight ratio.

Given the enormous power required by brains, if intelligent life exists in the universe, it likely gets its energy from reacting hydrocarbons in an oxygen atmosphere. Most likely we would be able to eat their food.

        MJ/kg  Calories/gram
Sugar    16        5
Protein  17        5
Alcohol  25        7
Fat      38        9


Bruce Lee: When the opponent expands I contract, when he contracts I expand, and when there is an opportunity, I do not hit, it hits all by itself.

The diaphragm creates pressure in the abdomen, which expands the ribcage and creates negative pressure for inhalation. Any air-breathing alien has to find a way to generate negative pressure. The ribcage expansion also puts tension energy into the rib muscles, which can be released in a sudden pulse to launch motion of the limbs.

Breathing is coordinated with skeletal motion to minimize energy expenditure. Motion cycles between the following two columns.

Breathe in                Breathe out
Diaphram contracts        Diaphram expands
Ribcage expands           Ribcage contracts
Spine muscles contract    Spine muscles release
Arms rotate out           Arms rotate in
Elbows rotate out         Elbows rotate in
Thumbs rotate out         Thumbs rotate in
Head rises                Head descends
Lower back arches         Lower back sags
Legs rotate out           Legs rotate in
Gut squashed by diaphram  Gut expands
Daydream                  Focus
Rebalance                 Exertion
Arms out                  Arms in
High moment of inertia    Low moment of inertia
Discard angular momentum  Discard pressure
When you are in action, your breathing adjusts to support the timing of your skeletal motion, and if it has any spare time, it sucks in as much air as possible.

When you are relaxing, your breathing adjusts to minimize energy, coordinate cycles, and smooth transitions.


Tetrapod limbs have 2 long bones. A limb with only one long bone is obviously insufficient and 2 long bones are sufficient to support 3D motion of the hand. 3 long bones is probably unnecessary.

There is 1 bone in the upper limb and 2 bones in the lower limb, with a universal joint at the shoulder/hip, a locking joint at the knee/elbow, and a universal joint at the wrist/ankle. The shoulder/hip universal joints can be realistically supported because the torso has abundant muscle mass and torque. The locking joint is harder to support because the upper limb has less muscles and torque than the torso. This is why the lower limb has 2 bones, to help with torque and to stabilize the hand.

The hand is small enough that it can be supported by a univeral joint (the wrist).

The length of limbs is limited by the ability of the torso to deliver force and torque to the hands and feet.

Humans have the most complex wrists in the animal kingdom. Only humans can fully exploit the universal joint of the wrist.

Humans are one of the only animals capable of good balance while on one foot.

Ulna and tibia


In your forearm, the ulna is the large bone and the radius is the small bone. The forearm should ideally rotate around the large bone.

The ulna connects to your hand on the pinky side and the radius connects to the thumb side. Your hand should rotate about the pivot point where your ulna connects to your wrist.

In your lower leg the tibia is the large bone and the fibula is the small bone.

The tibia connects to your foot at the big toe side and the fibula connects at the little toe site.

Shoulders and hips

The lower limbs are connected directly to the spine so that the can deliver force from the ground to the spine. The upper limbs are not directly connected to the spine so that they can absorb shock and move with precision. If an organism has no collarbone then there is no skeletal connection between the limbs and spine at all. If an organism has a colarbone then the connection sequences is:

Spine  -  Ribs  -  Breatbone  -  Collarbone  -  Shoulder blade  -  Humerus
The function of the spine is to smooth out angular momentum generated by the limbs.


      Density  Pressure Escape Gravity   N2     O2    N2    CO2     Ar    H2   H3   CH4  Temp
      kg/m^3    (Bar)    km/s   m/s^2  kg/m^3  frac  frac   frac   frac  frac frac  frac (K)
Venus    67     92.1     10.36   8.87  2.34           .035  .965                          735
Titan     5.3    1.46     2.64   1.35  5.22           .984                          .014   94
Earth     1.2    1       11.2    9.78   .94    .209   .781  .00039 .0093                  287
Mars       .020   .0063    .64   5.03   3.8    .00054 .0013  .027  .953   .016                   210

        Gravity    H2      He    CH4  Escape
        m/s^2     frac    frac  frac  speed (km/s)
Sun    279.4      .735     .248       617.7
Jupiter 24.79     .90      .10  .003   59.5
Saturn  10.44     .96      .03  .004   35.5
Uranus   8.69     .83      .15  .023   21.3
Neptune 11.15     .80      .19  .015   23.5
Titan is the smallest object with an atmosphere and Mercury is the largest object without an atmosphere.


      Atmos                                                                Atmos    Max     Min
      Density  Pressure  Gravity   N2      O2     N2    CO2   Temp  Lapse  Height  height  Height
      kg/m^3    (Bar)     m/s^2  kg/m^3   frac   frac   frac   (K)  (K/km)  (km)    (km)
Mars     .020    .0063   3.71     .00054  .0013  .027  .953    210   4.5    15      22     -7.15
Titan   5.3     1.46     1.35    5.22            .984           94   1.3    14        .5   -2
Venus  67      92.1      8.87    2.34            .035  .965    735  10.5     7      11
Earth   1.28    1.0      9.78     .94     .209   .781  .00039  287   9.8     9       8.8   -0.8
Moon    0       0        1.62                                  220                   8     -6
Ceres   0       0         .27                                  168
"Atmospheric height" is the height at which the atmosphere density is exp(-1) times the density at sea level.

"Lapse" is the adiabatic lapse rate.

"Max height" is the maximum elevation.

"Min height" is the minimum elevation.

The atmosphere of Titan is non-toxic and there is enough atmospheric pressure that you don't need a pressure suit. You can roam around Titan with a ski suit and scuba gear. Gravity is so low that human-powered flight is easy.

Radioactive heating of the Earth


              Watts/kg     half life  mantle      Watts/kg
              of isotope   (years)    abundance   of mantle
uranium-238    9.46e-5       4.47e9    30.8 e-9   2.91 e-12
uranium-235   56.9 e-5        .70e9      .22e-9    .125e-12
thorium-232    2.64e-5      14.0 e9   124   e-9   3.27 e-12
potassium-40   2.92e-5       1.25e9    36.9 e-9   1.08 e-12
The Earth loses heat at a rate of .087 Watts/m^2, for a global heat los of 4.42e13 Watts.

80% of the Earth's heat is from radioactivity and 20% is from accretion.

The radioactive heating rate 3 billion years ago is twice that of today.

The Earth's core temperature is ~ 7000 K.

Io is heated by tidal forces from Jupiter.

Magnetic fields

Solar wind

          Dipole     Field at  Magnetopause  Axis     Rotation  Volcanic
          moment     equator   (planet       angle    (days)
         (Earth=1)   (Gauss)    radii)     (degrees)
Sun      5 million                                      25.0
Mercury       .0007   .003         1.5      14          58.6    No
Venus        <.0004  <.00003       -         -         243.0    Yes
Earth        1        .305        10        10.8         1.00   Yes
Mars         <.0002  <.0003        -         -           1.03   No
Jupiter  20000       4.28         80         9.6          .41
Saturn     600        .22         20        <1            .44
Uranus      50        .23         20        58.6          .72
Neptune     25        .14         25        47            .67
Io                                                              Yes
Europa        .0016   .0072        4.5

Habitable zone
The "Goldilocks Zone"

Expanded discussion of the habitable zone

Stability of the solar system

Expanded discussion of orbital stability

Planet migration

Io, Europa, Ganymede, Callisto
Jupiter and its moons
Io, Europa, Ganymede

Goldreich & Tremaine (1980): "We present an illustrative application of our results to the interaction between Jupiter and the plantary disk. The angular momentum transfer is shown to be so rapid that substantial changes in both the structure of the disk and the orbit of Jupiter must have taken place on a time scale of a few thousand years."

Extrasolar planetary systems

This is a plot of all known planetary systems with at least 3 planets.

Each row corresponds to a planetary system and the solar system is 2/3 of the way down.

Dot size          =  (Planet Mass)^(1/3)
Dot X coordinate  =  Log(distance from star)
Yellow dot        =  Planets orbit a star with high metallicity
Red dot           =  Plaents orbit a star with low metallicity
The magenta dot indicates the location of the Goldilocks zone. For a given star, Radius of Goldilocks zone ~ (1 AU) * (Star luminosity / Sun luminosity)^(-1/2)

Horizontal cyan lines indicate the range between the planet's perigee and apogee.

Horizontal green lines correspond to 6 times the planet's Hill radius, a measure of the planet's zone of gravitational dominance.

Vertical blue lines indicate the planet's orbital inclination.

Same as above except for:

Horizontal yellow line  =  Range from perigee to apogee
Horizontal red line     =  6 times the planet's Hill radius
The planets of the solar system are smaller and more widely spaced than what is typical for exoplanetary systems. In the Galactic Museum of Natural History, the solar system might be classified as a "Dwarf planetary system".

What could go wrong?

Meteor Crater, Arizona

Planet property   If too little                           If too much

Mass              Cannot capture atmosphere               Becomes gas giant
                  No volcanism
                  Cannot generate a magnetic field

Distance from     Too hot                                 Too cold for surface water
star              Inside the snow line

Atmospheric       Cosmic rays reach the surface           Blocks too much sunlight
thickness         Atmosphere loses heat at night          for photosynthesis

Water content     If you don't have oceans then you       No dry land
                  don't have enough photosynthesis
                  to generate an oxygen atmosphere

Planet spin       Does not generate a large-scale
                  magnetic field

Planet spin tilt                                          Extreme seasons

Star temperature  Not enough blue light for               Too much UV light

Star metallicity  Small planets                           Too many gas giants

Star mass         Planet is so close to the star that it
                  is tidally locked to the star

Moon mass         Planet tilt becomes unstable, causing
                  extreme seasons

A moon of a gas giant can potentially be protected from the solar wind by the gas giant's magnetic field. It can also potentially have volcanism from tidal heating by the gas giant.
Mass extinctions

The Earth has been beset by asteroids, supervolcanoes, global ice ages, runaway global warming, supernovae, gamma ray bursts, and the industrial age.

Millions of
years ago

   66          Cretaceous–Paleogene extinction, caused by a 10 km asteroid.
               Dinosaurs become extinct.
  201          Triassic-Jurassic extinction.  Cause unknown.
  252          Permian-Triassic extinction.  Runaway global warming
  370          Late-Devonian extinction.  Cause unknown.
  445          Ordovician-Silurian extinction events.  Global glaciation.

Elements of single-cellular life

Life appeared on the Earth within a billion years of its formation.

Shortly after that, between 3500 and 3800 million years ago, the "Last Universal Common Ancestor" lived.

The LUCA had the following properties: Single-cellular with a bilipid cell wall. ATP to power enzymes. A DNA codon system with 4^3=64 options coding for 20 proteins. This code hasn't changed since.

Building blocks for life
        Abundance in  Mass frac in
        Crust (ppm)   Human body
Oxygen      460000     .65
Carbon        1000     .18
Hydrogen      1500     .10
Nitrogen        20     .03
Calcium      45000     .014
Phosphorus    1100     .011
Potassium    20000     .0025
Sulfur         400     .0025
Sodium       25000     .0015
Chlorine       200     .0015
Magnesium    25000     .0005
Iron         60000     .00006
Fluorine       500     .000037
Zinc            75     .000032
Silicon     275000     .00002
Trace elements        <.00001
Among the elements required for life, nitrogen is the scarcest. The nitrogen in the first 250 km of the Earth's crust has the same mass as the nitrogen in the atmosphere.
           Used by   Used by
           humans    bacteria
Hydrogen      *      *
Boron         *      *
Carbon        *      *
Nitrogen      *      *
Oxygen        *      *
Fluorine             *
Sodium        *      *
Magnesium     *      *
Silicon              *
Phosphorus    *      *
Sulfur        *      *
Chlorine      *      *
Potassium     *      *
Calcium       *      *
Vanadium             *
Manganese     *      *
Iron          *      *
Cobalt        *      *
Nickel               *
Copper        *      *
Zinc          *      *
Arsenic              *
Selenium      *      *
Bromine       *      *
Molybdenum           *
Tellurium            *
Iodine        *      *
Tungsten             *

Cell walls
Lipids and cell membranes

Cell walls are formed from a double layer of lipids. They are elastic and they self-assemble.

Each lipid has a polar and a non-polar end. The polar end faces the water and the non-polar end faces another lipid.

* Video of the self-assembly of a bilipid layer
* Video of an amoeba

If life were to exist in a non-polar solvent it would have to find another way to make cell walls.

ATP and ATP Synthase

Enzymes use ATP as an energy source to power chemical reactions. ATP and ATP synthase are common to all Earth life.

* Video of the ATP synthase enzyme in action

Amino acids

Amino acids have the above form, where R stands for an arbitrary molecule.

The 21 amino acids used by eucaryote life


Synthesis of two amino acids. Proteins are chains of animo acids with a backbone of the form:


DNA and the genetic code

DNA codes a sequence of amino acids. The 64-element codon system is universal to Earth life.

The codon ATG both codes for methionine and serves as an initiation site: the first ATG in an mRNA's coding region is where translation into protein begins.

21 amino acids are used by eucaryote. More than 500 amino acids are known.



An "Alkane" is a carbon chain with hydrocarbons attached. At standard temperature (300 K), alkanes are solid if they have more than 20 carbons. This is why lipids (long alkanes) are the optimal form of energy storage. Short alkanes are liquids or gases at STP and are hard to store.

In the following table, the first section shows properties of alkanes and the second section shows properties of other energy sources.

Alkane   Carbons  Energy of   Melt  Boil  Solid    Liquid    Gas       Phase at
type              combustion  (K)   (K)   density  density   density   300 K
                  (MJ/kg)                 (g/cm^3) (g/cm^3)  (g/cm^3)
Hydrogen     0     141.8      14.0   20.3           .07      .000090   Gas
Methane      1      55.5      90.7  111.7           .423     .00070    Gas
Ethane       2      51.9      90.4  184.6           .545     .0013     Gas
Propane      3      50.4      85.5  231.1           .60      .0020     Gas
Butane       4      49.5     136    274             .60      .0025     Gas
Pentane      5      48.6     143.5  309             .63                Liquid
Hexane       6      48.2     178    342             .65                Liquid
Heptane      7      48.0     182.6  371.5           .68                Liquid
Octane       8      47.8     216.3  398.7           .70                Liquid
Dodecain    12      46       263.5  489             .75                Liquid
Hexadecane  16      46       291    560             .77                Liquid
Icosane     20      46       310    616     .79                        Solid
Alkane-30   30      46       339    723     .81                        Solid
Alkane-40   40      46       355    798     .82                        Solid
Alkane-50   50      46       364    848     .82                        Solid
Alkane-60   60      46       373    898     .83                        Solid

Gasoline   ~ 8      47                               .76               Liquid     Mostly alkanes with ~ 8 carbons
Natural gas         54        91    112                                Gas        Mostly methane
Coal                32         -      -                                Solid      Mostly carbon
Wood                22         -      -                                Solid      Carbon, oxygen, hydrogen
Pure carbon  1      32.8       -      -                                Solid      Pure carbon, similar to coal
Methanol     1     175.6  337.8           .79                          Liquid
Ethanol      2     159    351.5           .79                          Liquid
Propanol     3     147    370                                          Liquid

An alkane with 7 or more carbons has a heat of combustion of 46 MJoules/kg.

A nitrogen molecule is more tightly bound than an oxygen molecule, making it impossible to extract energy from hydrocarbons with nitrogen. Few things burn in a nitrogen atmosphere, lithium and magnesium being examples.



A sugar generally has the formula CN H2N ON, where N = 2, 3, etc. The common sugars are hexoses with N=6.

         Number of   Number of
          carbons     sugars
Diose        2          1
Triose       3          2
Tetrose      4          3
Pentose      5          4
Hexose       6         12       At least 6 carbons are required to form a ring
Heptose      7       many       Rarely observed in nature
Octose       8       many       Unstable.  Not observered in nature.
"Number of sugars" refers to the number of different types of sugar molecules for each carbon number.

Each sugar molecule has two mirror-symmetric forms, the "D" and "L" form. Only the D forms are found in nature.

The following figures show all sugars up to 6 carbons. All can be metabolized by humans.

2 carbons:


3 carbons:


4 carbons:


5 carbons:


6 carbons:



         Energy  Sweetness

Succrose   1.00    1.00      Benchmark
Glucose             .74
Maltose             .32
Galactose           .32
Lactose             .16
Fructose           1.73
Psichose            .70
Tagatose    .38     .92
Sorbose            1.0
Honey               .97

Complex sugars
Monosaccharde:   1 sugar molecule
Disaccharide:    2 monosaccharides
Polysaccharide:  More than 2 monosaccharides, such as starch and cellulose
Sucrose    =  Glucose     + Fructose
Maltose    =  Glucose     + Glucose
Lactose    =  Galactose   + Glucose
Lactulose  =  Galactoce   + Fructose
Trehalose  =  Glucose     + Glucose
Cellobiose =  Glucose     + Glucose
Chitobiose =  Glucosamine + Glucosamine
Starch and cellulose are long chains of glucose molecules.




Fatty acid with 16 carbons
Sugar (glucose)
Pyruvic acid

Fatty acids and sugars are metabolized in the following stages, with each stage yielding energy.

Fatty acid    ->     Acetyl      ->     CO2 and H2O

Sugar         ->     Pyruvate    ->     CO2 and H2O

Blood delivers fatty acids to cells.

The citric acid cycle (Krebs cycle) converts acetyl or pyrovate into H2O and CO2. Coenzyme-A carries the acetyl around.

Fat metabolism

A fat molecule is converted into a fatty acid by lipolysis, and then the fatty acid is converted into acetyl by beta oxydation, and then the acetyl is converted into H2O and CO2 by the citric acid cycle.

Beta oxidation cleaves 2 carbons from a fatty acid, which becomes acetyl. This process is repeated until te entire fatty acid has been converted into acetyls.

The steps of beta oxidation are:

Sugar metabolism (glycolysis)

Glycolysis converts a glucose molecule into 2 pyrovate molecules. A summary of the reaction showing only the starting and ending points is:

The full reaction is:

Citric acid cycle

Citric acid

The citric acid cycle (Krebs cycle) converts acetyl or pyrovate into H2O and CO2.

Fat metabolism oxidizes a carbon chain so that the chain can be split into acetyl. The strategy of the citric acid cycle is to further oxidize the acetyl (now a part of citrate) so that the remaining carbon bonds in the acetyl can be broken.


An alcohol is a carbon chain with one OH attached.


Methanol     1       Toxic
Ethanol      2       Inebriating
Propanol     3       3 times more inebriating than ethanol
Isopropanol  3       Toxic
Butanol      4       6 times more inebriating than ethanol

Fatty acids (carboxylic acids)

Formic acid
Acetic acid
Palmitic acid

Palmitic acid has 16 carbons and is the most common fatty acid found in food.

   2    Vinegar
   4    Found in butter
   8    Found in coconuts
  10    Found in coconuts
  12    Found in coconuts
  16    Most common fatty acid.  Found in palm oil
  18    Found in chocolate
  20    Found in peanut oil

Metabolism molecules

Guanosine triphosphate
Acetic acid
Citric acid
Vitamin C

Toxic molecules


CO                     Carbon monoxide
HCN             6.4    Hydrogen cyanide
CH2O                   Methanol
CH2O                   Formaldehyde
H2S                    Hydrogen sulfide
NO2                    Nitrite
Cl2                    Chlorine
Fl2                    Fluorine
Ethanol      7060
Salt         3000
Caffeine      192
Aspirin       200
NaNO2         180      Sodium nitrite
Cobalt         80
NaF            52
Capsaicin      47      Chili pepper
Mercury        41
Arsenic        13
Nicotine         .8
Almost anything with fluorine or bromine is toxic.

Weakly toxic:

C2H2          Acetylene.  Inebriating
C3H6          Propene.  Inebriating


Turmeric: curcumin
Cumin: cuminaldehyde
Chili: capsaicin
Mustard: allyl isotyiolcyanate

Bay: myrcene
Garlic and onion: allicin
Clove: eugenol

Raspberry ketone
Tangerine: tangeritin
Lemon: citral
Lemon peel: limonene

Chocolate: theobromine
Smoke: guaiacol
Cardamom: terpineol
Wintergreen: methyl salicylate

Hydrogen   White
Carbon     Black
Nitrogen   Blue
Oxygen     Red
Sulfur     Yellow
        Scoville scale (relative capsaicin content)

Ghost pepper    1000000
Trinidad        1000000      Trinidad moruga scorpion
Naga Morich     1000000
Habanero         250000
Cayenne           40000
Tabasco           40000
Jalapeno           6000
Pimento             400

Molecule        Relative hotness

Rresiniferatoxin   16000
Tinyatoxin          5300
Capsaicin             16         Chili pepper
Nonivamide             9.2       Chili pepper
Shogaol                 .16      Ginger
Piperine                .1       Black pepper
Gingerol                .06      Ginger
Capsiate                .016     Chili pepper
Caraway: carvone
Black tea: theaflavin
Cinnamon: cinnamaldehyde
Citrus: hesperidin
Fruit: quercetin

Mint: menthol
Juniper: pinene
Saffron: picrocrocin
Saffron: safranal
Wine: tannic acid

Black pepper: piperine
Oregano: carvacrol
Sesame: sesamol
Curry leaf: girinimbine
Aloe emodin
Whiskey lactone

Signalling molecules




Vitamin A (beta carotene)
Vitamin A (retinol)
Vitamin C (ascorbic acid
Vitamin D (cholecalciferol)

Organic chemistry

Propane with hydrogens included
Propane with hydrogen excluded

Molecules are often depicted with the hydrogens excluded.

Functional    Organic
group         molecule

C-H3          Alkane (lipid)
C-H2OH        Alcohol
C-OOH         Fatty acid (carboxylic acid)
C=O           Carbonyl group.  Aldehyde if at end, ketone if not at end
Humans can metabolize just about any chain hydrocarbon and any sugar.

Tyrosine, an amino acid with a phenol


Opsin         Wavelength  Humans   Notes
Parapinopsin UV   365              Catfish
Neuropsin         380              Bird vision.  Found in the brains of humans
OPN1SW            440     Blue     All mammals
Panopsin Blue     450              Fish vision.  Found in the brains of humans
Parapinopsin Blue 470              Catfish and lamphrey
SWS2              480              Extinct in mammals
Melanopsin        480              Found in the brains of humans
VA                500              Vertebrates except mammals.  Vertebrae ancient opsin.
RH1               500     White    Black/White
Panopsin Cyan     500              Fish vision.  Found in the brains of humans
Pareitopsin       522              Lizards
OPN1MW            534     Green    All mammals
OPN1LW            564     Red      Once possessed by mammals, then lost by most
RH2               600              Black/White.  Extinct in mammals
Retinal G                          Found in the brains of humans


Heme cofactor carrying an iron atom

Metals are held by a cofactor, which is held by a protein. Many cofactors are porphyrin rings conposed of 4 pyrroles. Examples of porphyrins:

Porphin (Iron)
Corrin (Cobalt)
Corphin (Nickel)
Chlorophyll building blocks (Magnesium)

Porphin resonance
Porphin is an aromatic molecule because it is flat and because it resonates between different electronic states.


Heme A
Heme B
Heme C
Heme O
Hemo B


Oxygen bonds to the iron in a heme molecule and becomes superoxide.
Hemoglobin is a set of 4 helix proteins that carry 4 iron ligands, and each iron ligand carries 1 oxygen molecule.
Human hemoglobin is composed mostly of heme B.
The oxygen density of hemoglobin is 70 times the solubility of oxygen in water.

Hemoglobin fraction of red blood cells   =  .96      (dry weight)
Hemoglobin fraction of red blood cells   =  .35      (including water)
Oxygen capacity of hemoglobin            = 1.34 Liters of oxygen / kg hemoglobin
Iron ligands per hemoglobin              =    4
O2 molecules per ion ligand              =    1


Chlorophyll A

Chlorophyll A
Chlorophyll B
Chlorophyll D

Chlorophyll C1
Chlorophyll C2
Chlorophyll F

All chlorophyll uses magnesium.

A      Universal
B      Plants
C1     Algae
C2     Algae
D      Cyanobacteria
F      Cyanobacteria

Zinc fingers

Zinc stabilizes the proteins that manipulate DNA and RNA.

Carbonic anhydrase
Element   Humans  Cofactor  Function

Hydrogen    *
Helium                      No biological role
Lithium                     No biological role
Beryllium                   Toxic becauseit displaces magnesium in proteins
Boron       *               Plant cell walls.  Metabolism of calcium in plants & animals
Magnesium   *     Chlorin   Chlorophyll
Scandium                    No biological role
Titanium                    No biological role
Vanadium                    Found only in rare bacteria.
Chromium                    No biological role
Manganese   *               Superoxide dimutase.  Converts superoxide to oxygen
Iron        *     Porphin   Hemoglobin
Cobalt      *     Corrin    Cobalamin (Vitamin B12)
Nickel            Corphin   Coenzyme F430 (Creates methane. Found only in archaea)
Copper      *     Heme      Cytochrome C oxidase. Electron transport chain
                            Hemocyanin, an alternative to hemoglobin used by some animals
                            Hemoglobin carries 4 times as much oxygen as hemocyanin
                            Plastocyanin protein, used in photosynthesis
                            Sometimes used in superoxide dimutase
Zinc        *               Component of proteins that manipulate DNA and RNA (Zinc fingers)
                            Component of carbonic anhydrase, which interconverts CO2 and HCO3
                            Metallothionein proteins, which bind to metals such as
                            zinc, copper, selenium cadmium, mercury, silver, and arsenic
Molybdenum                  Nitrogen fixase. Convert N2 to NH3
Selenium    *               Component of the amino acide selenocysteine
Bromine     *               Limited role
Iodine      *               Component of thyroxine and triiodotyronine, which
                            regulate metabolic rate
Lead                        Toxic because it displaces calcium in bones


Superoxide dimutase
Superoxide dimutase, manganese in purple

Carbonic acid
Hydrogen peroxide

Superoxide dimutase converts superoxide to oxygen or hydrogen peroxide.

The peroxidase enzyme decomposes hydrogen peroxide to water. Peroxidase contains the selenocysteine amino acid, which contains selenium.

Nitrogen fixation

Nitrogen fixase uses an iron-molybdenum cofactor.



Selenium is a component of the amino acid selenocysteine.

Copper group without an oxygen
Copper group with an oxygen

The hemocyanin protein uses copper to carry oxygen. It has an oxygen density that is 1/4 of hemoglobin.

Plastocyanin is a copper-containing protein used in photosynthesis.




Carbonic acid

Nitric acid

Nitrous acid

Silicic acid

Phosphoric acid

Sulfuric acid

Potassium oxide
Selenium oxide


Iron(III) Oxide         Fe2O3        Ferric oxide.  Most common form
Iron(II) Oxide          FeO          Rare
Iron(II,III) Oxide      Fe3O4        Magnetite
Copper(I) Oxide         Cu2O         Cuprous oxide
Copper(II) Oxide        CuO          Cupric oxide
Copper(III) Oxide       Cu2O3


Lignin is the structural component of wood.

Badass organisms

Audax bacteria
Conan the Bacterium

Audax: Lives underground, eats rock, and gets its energy from molecules generated by radioactivity. It can colonize a planet from scratch.

Conan: Survives radioactivity, outer space, acid, and freezing. It has four independent sets of chromosomes with active repair mechanisms.

Tardigrade (water bear): Survives temperatures from absolute zero to 161 C. Survives outer space. Found everywhere on the Earth from Mount Everest to the bottom of the ocean.

Colossal Squid

The colossal squid is up to 14 meters long, has eyes up to 27 cm in diameter, and inhabits the ocean at depths of up to 2 km.

Mantis Shrimp

The eyes of a Mantis shrimp have 12 color channels, including UV, and they are sensitive to linear and circular polarization. Each eye is trinocular, giving it a total of 6 channels for depth perception.

The Mantis shrimp has two clubs for striking.

Impact speed = 23 m/s
Acceleration = 10400 g  (similar to a .22 calibre bullet)
Impact force = 1500 Newtons
The strike produces cavitation bubbles that add to the damage.


Top speed of 33 meters/second
Accelerates from 0 to 28 meters/second in 3 seconds

White-throated Needletail

Fastest bird. Top horizontal speed of 45 meters/second.

Andean Condor

Mass of up to 15 kg
Wingspan of up to 3.1 meters


Mass of 75 kg
Wingspan of 7 meters
Wing loading of 85 Newtons/meter^2
Wing area of 8.1 meters^2

Edward Lasker: While the Baroque rules of Chess could only have been created by humans, the rules of Go are so elegant, organic, and rigorously logical that if intelligent life forms exist elsewhere in the universe, they almost certainly play Go.


          Red = equal tuning           Orange = just tuning

Just tuning is based on integer ratios and equal tuning is based on logarithms, and there is no direct connection between them. Fortuitously, 12-tone equal tuning gives a set of notes that are nearly identical to those for just tuning. The correspondence is close, but not exact, and violinists use a compromise between just and equal tuning that is situation dependent.

The synthesis of just and equal tuning offers rich contrapuntal possibilities, as was explored during the Baroque age by composers such as Vivaldi, Bach, and Handel.

                         Just and equal tuning

Note  Index  Interval      Equal  Just tuning  Major  Minor  Pythagorean
                           tuning              scale  scale  tuning
A       0   Unison         1.000  1.000 = 1/1    *      *      1/1
Bflat   1   Minor second   1.059                             256/243
B       2   Major second   1.122  1.125 = 9/8    *      *      9/8
C       3   Minor third    1.189  1.200 = 6/5           *     32/27
C#      4   Major third    1.260  1.250 = 5/4    *            81/64
D       5   Fourth         1.335  1.333 = 4/3    *      *      4/3
Eflat   6   Tritone        1.414                              729/512
E       7   Fifth          1.498  1.500 = 3/2    *      *      3/2
F       8   Minor sixth    1.587                        *    128/81
F#      9   Sixth          1.682  1.667 = 5/3    *            27/16
G      10   Minor seventh  1.782                        *     16/9
Aflat  11   Major seventh  1.888                 *           243/128
A      12   Octave         2.000  2.000 = 2/1    *      *      2/1
In equal tuning, the frequency ratio of an interval is


Equal tuning is based on equal frequency ratios. Just tuning adjusts the frequencies to correspond to the nearest convenient integer ratio. For example, in equal tuning, the frequency ratio of a fifth is 1.498. Just tuning changes it to 1.500 = 3/2.

The 12-tone scale is ubiquitous in Earth music and it arises from elegant mathematics. If alien life plays music, they likely use the 12-tone scale.

The major and minor scales select 8 notes from the 12 note scale, favoring notes that have nice integer ratios.

Expanded discussion of just and equal tuning

History of music and mathematics

In the 6th century BCE, Pythagoras developed a 12-tone scale based on the ratios 2/1 and 3/2. This tuning was widely used until the 16th century CE. Pythagoriean tuning gives good results for fourths and fifths but poor results for thirds.

1572  Bombelli publishes complex numbers

1523  Pietro Anon introduced "meantone tuning" to fix the thirds, using a
      frequency ratio of 5/4 for major thirds.  His treatise "Thoscanello de la
      musica" expanded the possibilities for chords and harmony.

1555  Andrea Amati develops the four-string violin.

1584  "Equal tuning" introduced. Equal tuning divides the octave logarithmically.
      The first known examples of equal tuning were:
      Vincenzo Galilei in 1584  (Father of Galileo Galilei)
      Zhu Zaiyu in 1584
      Simon Stevens in 1585

1585  Simon Stevin introduces decimal numbers (For example, writing 1/8 as 0.125).
      This greatly expanded the calculational power of numbers.

1586  Simon Stevin drops objects of varying mass from a church tower to demonstrate that
      they accelerate uniformly.

1604  Galileo publishes a mathematical description of acceleration.

1614  Logarithms invented by John Napier, making possible precise calculations
      of equal tuning ratios.  Stevin's calculations were mathematically sound but
      the frequencies couldn't be calculated with precision until logarithms were

1637  Cartesian geometry developed by Fermat and Descartes

1684  Leibniz publishes The Calculus

1687  Newton publishes the "Principia Mathematica"

1722  Bach publishes the "Well Tempered Clavier"
      Until ~ 1650, most keyboards used meantone tuning. This tuning gives good results if you
      confine yourself to a small number of keys and use few accidentals but it can't be made
      to work for all keys.
      J.S. Bach tuned his own harpsichords and clavichords and he customized the tuning to
      work in all 24 keys ("well temperament").  He demonstrated its effectiveness
      in "The Well Tempered Clavier".

1821  Cauchy publishes the "Cours d'Analyse", introducing rigor to mathematics.


Leopold Auer
Albert Einstein
Jascha Heifetz
Yehudi Menuhin

In the baroque age, violinists played with a pure, vibratoless tune, using bow speed rather than vibrato for expressivity. After the baroque age, an epidemic of vibrato emerged and is still with us, especially at Juilliard and Lincoln Center. Vibrato obstructs the resonances of just intonation.

"There are performers who tremble consistently on each note as if they had the permanent fever" - Leopold Mozart, 1756

The violinist and teacher Leopold Auer, in his book "Violin Playing as I Teach It" (1920), advised violinists to practise playing completely without vibrato, and to stop playing for a few minutes as soon as they noticed themselves playing with vibrato in order for them to gain complete control over their technique.

From the Wikipedia page on Yehudi Menuhin: After building early success, he experienced considerable physical and artistic difficulties caused by overwork during the war as well as unfocused and unstructured early training (reportedly he said "I watched myself on film and realized that for 30 years I'd been holding the bow wrong"). Careful practice and study combined with meditation and yoga helped him overcome many of these problems. When he finally resumed recording, he was known for practising by analyzing music phrases one note at a time.

Human skeleton

Atlas vertebra

Axis vertebra

Altazimuth telescope mount
Keck telescope altazimuth mount

The atlas vertebra functions like a telescope altazimuth mount


The Atlas-Skull joint controls pitch and the Axis-Atlas joint controls yaw.

Alexander Technique emphasizes gaining an awareness of these motions.

Neck ligaments
Neck muscles


Visual pathway
Motor cortex
Motor cortex

Visual information passes through the motor cortex before being combined at the rear of the brain. The brain and body are an image stabilization system for the eyes.

The muscles of the back are continuously connected between the shoulder blades and the hips, to coordinate motion of the limbs.


Bruce Lee: "Balance is the all-important factor in a fighter's attitude or stance. Without balance at all times, he can never be effective."

Jascha Heifetz masterclass In this clip, at time=5:45-6:15, Heifetz emphasizes the importance of balance and posture.

* Marie Daniels illustrates the importance of balance for playing the viola.

Balance flows from a stance with knees in and heels out.

* Gordon Liu demonstrates the wire style at time=4:37

Bruce Lee: "One should seek good balance in motion and not in stillness."

Bruce Lee: "Balance is the control of one's center of gravity plus the control and utilization of body slants and unstable equilibrium, hence gravity pull to facilitate movement. So, balance might mean being able to throw one's center of gravity beyond the base of support, chase it, and never let it get away."

* Jet Li and the Drunken Sword. Try this with a viola bow.

Bruce Lee: "The center of gravity kept under delicate and rapid motion are characteristic habbits of athletes in games that require sudden and frequent changes of direction." Bruce Lee: "The short step and the glide, as contrasted with the hop or cross step, are devices to keep the center of gravity. When it is necessary to move rapidly, a good man takes small enough steps so that his center of gravity is rarely out of control."

Bruce Lee: "In general for athletic contests, a preparatory stance a coiled, or semicrouched posture and a lowered, forward center of gravity. with the bending of the forward knee, the center of gravity moves forward a little. For general readiness, the lead heal usually remains just touching even after the knees bend. Slight ground contact of the heel aids in balance and decreases tension."


Bruce Lee: Experiments indicate that auditory cues, when occurring close to the athlete, are responded to more quickly than visual ones. Make use of auditory clues together with visual clues, if possible. Remember, however, the focus of attention on general movement produces faster action than focus on hearing or seeing the cue.

Time in milliseconds:

.000003  Time for light to cross a 10 meter orchestra
    .2   Electric synapse. These synapses are 2-way and they do not amplify signals
   2     Chemical synapse. These synapses are 1-way and they can amplify signals
   1     Time for a neural signal to travel 10 cm, the size of a brain
  10     Time for a neural signal to travel from your fingers to your brain
   3     Time for sound to travel 1 meter, the distance to an adjacent musician
   7     Period of a 130 Hertz wave. This is the frequency of the viola C string
  30     Time for sound to travel across a 10 meter orchestra.
  62     Time between notes in "Flight of the Bumblebee"
For an orchestra to have good timing it must use visual cues. Sound isn't fast enough. This is especially true at the rear of the viola section amidst the cacophony of winds and brass.

History of Kung Fu

 -776       First Olympic games
 -648       The sport of "Pankration" is introduced in the Olympic Games. Similar to MMA.
 -536 -520  Milo of Croton dominates Olympic wrestling
 -450       Gautama Buddha develops the art of meditation
  464       Batuo, a monk from India, founds the Shaolin Temple
  500       Bodhidharma, a Buddhist monk, teaches at the Shaolin temple
 1600       Emergence of sumo in Japan
~1700       Shaolin temple destroyed by the Chinese Emperor.
            The monks who escaped spread Shaolin kung fu throughout China. These monks were:
            Ji Sin  - Developed Tiger Crane style
            Ng Mui  - Developed Wing Chun
            Bak Mei - Known as "Pai Mei" in kung fu films. Appears in "Kill Bill"
~1700       Fong Sai Yuk. Portrayed by Jet Li in the "Fong Sai Yuk" film series.
 1847 1924  Wong Fei Hung. Master of Hung Gar style. Portrayed by Jet Li in
            the "Once Upon a Time in China" film series.
 1860 1938  Jigoro Kano. Developed Judo and taught it to Mitsuyo Maeda and Moshe Feldenkrais
 1868 1910  Huo Yuanjia. Portrayed by Jet Li in the film "Fearless"
 1869 1955  F.M. Alexander. Developed "Alexander Technique"
 1893 1972  Yip Man. Practitioner of Wing Chun. Teacher of Bruce Lee
 1904 1984  Moshe Feldenkrais. Developed "Feldenkrais Technique"
 1917       Mitsuyo Maeda teaches Judo to the Gracie family.
            Helio Gracie subsequently develops Brasilian Jiu Jitsu
 1933       Jigoro Kano trains Feldenkrais in Judo
 1940 1973  Bruce Lee
 1940       Chuck Norris
 1951       Masahiko Kimura vs. Helio Gracie
 1952       Sammo Hung
 1954       Jackie Chan
 1955       Gordon Liu
 1963       Jet Li
 1963       Michelle Yeoh
 1963       Donnie Yen
 1970       Shaw Brothers Studios begins mass-producing kung fu films
 1993       Age of Mixed Martial Arts begins when Royce Gracie wins a tournament
              consisting of fighers with diverse styles.
 2000       Kazushi Sakuraba vs. Royce Gracie
 2009-      Ben Askren dominates MMA with wrestling
 2012       Miesha Tate vs. Ronda Rousey
 2013       Ben Askren signs with One FC.  UFC declines in significance

Interviewer:  Other than wrestling what would you say the best base to be a
              successful MMA fighter would be?
Ben Askren:   Wrestling

Aliens from film

Pierson's Puppeteer from the Niven universe

How long would it take an alien spacecraft to reach the Earth?

Hydrogen+oxygen rocket
VASIMR ion drive
Nuclear thermal rocket
Orion fusion rocket

Rocket propulsion system             Exhaust speed
Hydrogen+oxygen rocket                     4.4
Chang-Diaz ion drive                      50          VASIMR design
Nuclear thermal rocket, H2 exhaust         9
Orion fusion rocket                    10000
Antimatter rocket                      1/2 C
All of these rockets are possible with current technology except for the antimatter rocket.

Distance to Alpha Centauri, the nearest star    4.3  light years
Milky Way diameter                              0.1  million light years
Distance to Andromeda                           2.5  million light years
Distance to the Virgo Supercluster             54    million light years
Light travel time during age of universe    13750    million light years

Age of the universe  ~  13.75 billion years
Age of the Earth     ~   4.54 billion years
An alien civilization in the Virgo Supercluster with a 1 billion year head start on us has plenty of time to get here.

The Doomsday Destroyer from Star Trek

Valence sites
   1           2        3          4           3          2          1          0
                                                                  Hydrogen    Helium
Lithium    Beryllium  Boron      Carbon     Nitrogen    Oxygen    Fluorine    Neon
Sodium     Magnesium  Aluminum   Silicon    Phosphorus  Sulfur    Chlorine    Argon
To be a part of a chain, an atom needs at least 2 valence sites and it needs to be able to form strong bonds.

Bond strengths in eV
       Single  Double  Triple   Quadruple
B  B    3.04
B  C    3.69
B  O    5.56
C  C    3.65   6.45    8.68   6.32
C  N    3.19   6.38    9.19
C  O    3.73   7.7    11.11
C  Si   3.30
C  P    2.74
C  S    2.82   5.94
N  N    1.76   4.33    9.79
N  O    2.08   6.29
N  Si   3.70
N  P
N  S
O  O    1.50   5.15
O  Si   4.69
O  P    3.47   5.64
O  S           5.41
Si Si   2.30
Si S    3.04
Si P
P  P    2.08
P  S           3.47
S  S    2.34   4.41
H  H    4.52
H  C    4.25
H  N    4.05
H  O    3.79
H  F    5.89
H  Si   3.30
H  P    3.34
H  S    3.76
H  Cl   4.48

96.47 kJoules/mol = 1 eV

Predictions about the aliens

Oxygen atmosphere
Fats and sugars for fuel
We'll be able to eat each other's food
As large as or larger than us
Flight is likely
Come from a small planet
Star is less hot than the sun
The planet is volcanic
The planet has a magnetic field
The planet has high metallicity


If a planet is close enough to a star it becomes tidally locked to the star. Mercury is just barely close enough for this and it orbits such that

3 * Orbit period = 2 * Spin period

If it were any closer it would be forced into a lock such that

Orbit period = Spin period

All of the solar system's moons are locked to their planets in this way. None of the planets are locked to their moons except Pluto.

For a low-mass star, the habitable zone is closer to the star than it is for the sun. If the star is sufficiently small, a planet in the habitable zone will be close enough to be locked to the star and will experience extreme weather.

Let L = Luminosity of a star / Luminosity of the sun (Watts). If a star is such that the habitable zone is at Mercury's orbit, what is L? What stellar mass corresponds to this luminosity?

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