Everyday quantum physics

Modern engineering more and more deals with photons one at a time. A photon is a packet, or quantum, of electromagnetic energy. As such it obeys quantum physics, which can seem rather strange compared to Newtonian physics. I'd like to examine the everyday effects of quantum physics as exemplified in a standard red light photon. The standard photon was chosen because it can be produced by a Helium-Neon laser, an easy to make tool which puts out only the standard photons, nothing else.
This standard red photon is exactly 632.99 nanometers long and has an energy of 1.959 electron-volts. This gets us immediately into quantum effects.

Size and energy work backwards here. A photon of twice the energy - 4 electron-volts - has half the wavelength, 315 nM. This is uv-b (ultraviolet-b) radiation, energetic enough to tan you, or do skin damage. Shorter wavelengths are x-rays, with energy to go clear through you. A photon of twice the wavelength of our standard red one is infrared, and has half the energy.

As a quantum, a photon is an all or nothing thing. The photon either interacts, delivering all of its energy, or it does not, and it keeps all of its energy. A photon 670nM long, with slightly less energy than our standard one, will interact with a chlorophyll-a molecule and deliver its energy to a single electron. The standard photon does NOT energize the electron with a little left over, it just bounces off the chlorophyll molecule and delivers no energy at all.

Atoms are much smaller than our standard photon. A hydrogen atom is about 0.1 nM in diameter. When an electron inside an atom jumps to emit the standard photon, what comes out is over 5000 times the size of the atom emitting it. This makes where and when it comes up extremely uncertain when compared to the atom itself. When a red light photon is absorbed by chlorophyll, all of its energy is suddenly crammed into a space less than 1/5000th its size. The photon has to hit just right to do this, resulting in uncertainty in when and whether it interacts. We can only deal with these uncertainties in the mathematics of probability, called statistical quantum mechanics. As discussed in an earlier post, nobody has a feel for statistics, so where and when photon-matter interactions occur can produce some big surprises.

In summary, a photon is a quantum of energy that has all-or-nothing interactions. While the smaller they are, the larger their energy, they are much larger than the matter they interact with, so their interactions are probabilistic.

Human dominance of biology

Many people suffer from the false image of a vast 'natural' world compared to a miniscule human influence. This is the reverse of the actual situation. The sun is the primary natural source of energy and variability, but it changes slowly. The overwhelming human influence on the planet is due to our success as a species and our ability to manipulate energy which have, in the last 200 years or so, yielded a large-animal population - us - at least 5 times larger than any previous species bigger than a cat has achieved. The only times the planet's biosphere has seen this rapid a change in the past have involved cataclysmic events like large meteor strikes.

Humans, at 6 plus billion and rising, are the commonest large animals on the planet. The next most commmon mammals are domestic livestock that total another 3 billion or so. Even pets, at 50 million dogs and 70 million cats in North America greatly outnumber the whitetail deer, the commonest large wild mammal at 15 million.
The total wild waterfowl population of North America is 70 million birds. North American poultry production is 14 million tons per year - over 100x as much. We, with our livestock, are overwhelmingly the large animal population of the world. We will thus overwhelm all other large animals in our influence on the world.

Since animals eat plants, it shouldn't be a surprise that the majority of land vegetation is planted and harvested by humans. Something that really brings this home, though, is the animation of primary production available at http://earthobservatory.nasa.gov/Newsroom/NPP/Images/npp_20012002_sm.mpg

Rainfall gets used for agriculture, manufacturing, and to wash down our habitation areas. All non-human usage combined about equals these totals. http://www.globalchange.umich.edu/globalchange2/current/lectures/freshwater_supply/freshwater.html

We are the dominant large animal life, the dominant plant life user, and the single largest users of fresh water. In addition we control energy out of proportion to other animal usage- several horsepower per person. Total CO2 output now providing this energy overwhelms natural sources,but to look at the energy itself take a look at the night sky view at
http://images.google.com/imgres?imgurl=http://www.phoenix5.org/gallery/earthlightsFull.jpg&imgrefurl=http://www.phoenix5.org/gallery/earthlights1500.html&h=296&w=591&sz=18&tbnid=VEumcq6aKN4J:&tbnh=66&tbnw=131&start=14&prev=/images%3Fq%3Dearth%2Bat%2Bnight%26hl%3Den%26lr%3D%26sa%3DG
and realize that this light is just wasteage from a small portion of our energy usage.

What we do, as the overwhelming variable in present-day earth's environment, is the most influencial factor in the world we will live in. Since no projection of earth's human population shows it as dropping, our influence will continue to be overwhelming for the forseeable future. The world is not human habitation spotted through a wilderness. It is cities, suburbs, farms and ranches with occasional parklands.

Human influence on atmospheric CO2

This will be an evaluation of how much CO2 humans put into the atmosphere, showing how easily obtainable facts and a little math can dispel a lot of superstition. I strongly urge you to go through the calculations yourself.

How much CO2 is in the atmosphere?
as of the year 1800, about 280 ppm (parts per million), as of 2000, about 370 ppm http://earthguide.ucsd.edu/globalchange/keeling_curve/01.html
How much is that? Here we can take advantage of a couple of neat tricks. First, as we know from barometric pressure, the atmosphere over our heads weighs as much as a column of water 10 meters deep, so the atmosphere weighs the same as a layer of water 10 meters deep covering the earth. Second, the kilometer was originally defined as 1/10,000 of the distance from the equator to the pole, so figuring earth's area uses simple numbers that are easy to remember. Finally, a cubic meter of water weighs a metric tonne. Do the math and you find that the atmosphere weighs 5.03*10e15 tonnes. Times 370 parts per million means there were 1.87*10e12 tonnes of CO2 in the atmosphere as of the year 2000.
Since fossil fuels are mostly carbon, this amount is usually expressed by its carbon content. With carbon having an atomic weight of 12 and oxygen 16, the carbon content of CO2 is 12/44 of this total or 510 billion tonnes of carbon in the atmosphere as CO2.
how much are we putting in?
I always go to the CIA factbook first for geopolitical and economic data
http://odci.gov/cia/publications/factbook/index.html
gives oil and natural gas production , at 75 million barrels/day and 2.6 trillion cubic meters/year
http://www.eppo.go.th/ref/UNIT-OIL.html gives conversions, so oil is 3750 million tonnes/year, and natural gas is 2300 million tonnes/year. Natural gas (CH4) is 3/4 carbon, while oil is about 11/13, so the carbon content is 3190 and 1750 respectively for a total of 4940 million tons of carbon a year from oil and natural gas.
http://www.eia.doe.gov/emeu/aer/txt/ptb1114.html gives coal at 5227 million short tons/year or about 4700 tonnes. Using an average carbon content of 50% this is 2350 million tonnes
Total carbon usage, then, is just over 7.300 billion tonnes per year as of 2001.
According to these back-of-the-envelope calculations, we're putting out CO2 equal to about 1.4% of the atmospheric total every year, and this has increased the total in the atmosphere by a little over 1/3 since the industrial revolution.

Simple history of the universe

Everything, including the spaces between that we now see in a sphere 13.7 billion light-years across was contained in a pinpoint 13.7 billion years ago. As far as we can tell, it wasn't all there was, and the rest of what there was was similarly compressed. This superhot pinpoint expanded and cooled through exotic states until about 700,000 years after the big bang, where matter had condensed out and energy was low enough for atoms to form. At this point the universe became transparent with a temperature of 3000 kelvins. It was cool enough for matter and physics as we know it today to happen, with most of the energy in the universe transformed into atoms of hydrogen and helium. The leftover 3000k thermal radiation wavelength stretched along with the universe, and we see the leftover as the cosmic background radiation at about 3 kelvin today. In addition to this normal matter and energy, there seems to be dark mass, which interacts gravitationally equally to normal matter but which we haven't seen except for gravitational effects that indicate that it's about 90% of the known universe, and dark energy, that seems to be associated with how big space has gotten.
In normal and dark matter, gravity causes clumping, forming stars when the hydrogen eventually falls together tightly enough to light off a fusion reaction because of the gravitational packing and heating. This fusion reaction can produce all the light elements. If a big enough star is formed, a supernova can result in higher grade fusion that can almost instantaneously form all of the heavier elements.
Later stars in the aggregations called galaxies sweep up the remnants of earlier explosions and you get something like the solar system.
In solar systems, most of the matter clumps into the star, which lights off your fusion furnace. In our solar system this happened about 4.5 billion years ago. The rest of the matter condenses into planets and smaller pieces. These get cold enough for chemistry to happen. In at least one case, life has resulted.